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1.  National survey of notifications of tuberculosis in England and Wales in 1988. Medical Research Council Cardiothoracic Epidemiology Group. 
Thorax  1992;47(10):770-775.
BACKGROUND: A survey was undertaken to determine the distribution of tuberculosis in England and Wales and, by comparison with the findings of similar surveys in 1978-9 and 1983, to study trends in the incidence of the disease by ethnic group over the decade. METHODS: The survey included all cases of tuberculosis in England and Wales newly notified to the medical officers for environmental health during the six months from 2 January to 1 July 1988. Notification rates were calculated from population estimates from the 1988 Labour Force Survey. RESULTS: Clinical details were obtained from the clinician for 2149 (99.4%) of the 2163 newly notified and previously untreated patients. Over 90% were either white (53%) or of Indian, Pakistani, or Bangladeshi ethnic origin (39%). The notification rate in the white population was 4.7/100,000/year, a decline of 7.2% per year since 1978. The rate was 134.6/100,000/year in the population of Indian ethnic origin, and 100.5/100,000/year in that of Pakistani or Bangladeshi ethnic origin, a decline of 6% a year since 1978 for the two groups combined (standardised for age, country of birth, and length of time in the UK). In all ethnic groups rates of disease were much higher in the elderly than in the young. Bacteriological results were available in 1161 (80%) of the 1443 pulmonary cases. In 939 (81%) Mycobacterium tuberculosis was cultured; 614 cases (53%) also had positive smears, of which 424 (69%) were from white patients. CONCLUSIONS: Notification rates for tuberculosis in England and Wales declined over the decade, but major differences remained between ethnic groups.
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PMCID: PMC464035  PMID: 1481174
2.  Tuberculosis in England and Wales in 1993: results of a national survey. Public Health Laboratory Service/British Thoracic Society/Department of Health Collaborative Group 
Thorax  1997;52(12):1060-1067.
BACKGROUND: A national survey of tuberculosis notifications in England and Wales was carried out in 1993 to determine the notification rate of tuberculosis and the trends in the occurrence of disease by ethnic group in comparison with the findings of similar surveys in 1978/79, 1983, and 1988. The prevalence of HIV infection in adults notified with tuberculosis in the survey period was also estimated. METHODS: Clinical, bacteriological, and sociodemographic information was obtained on all newly notified cases of tuberculosis in England and Wales during the six months from 2 January to 2 July 1993. The prevalence of HIV infection in 16-54 year old patients with tuberculosis notified throughout 1993 was assessed using "unlinked anonymous" testing supplemented by matching of the register of patients with tuberculosis with that of patients with AIDS reported to the PHLS AIDS centre. Annual notification rates were calculated using population estimates from the 1993 Labour Force Survey. RESULTS: A total of 2706 newly notified patients was eligible for inclusion in the survey of whom 2458 were previously untreated the comparable figures for 1988 were 2408 and 2163. The number of patients of white ethnic origin decreased from 1142 (53%) in 1988 to 1088 (44%) in 1993 whereas those of patients of Indian, Pakistani, or Bangladeshi (Indian subcontinent (ISC)) ethnic origin increased from 843 (39%) in 1988 to 1014 (41%) and those of "other" (non-white, non-ISC) ethnic origins increased from 178 (8%) to 356 (14%). The largest increase was seen in the black African ethnic group from 37 in 1988 to 171 in 1993. Forty nine per cent of patients had been born abroad and the highest rates were seen in those who had recently arrived in this country. The overall annual notification rate for previously untreated tuberculosis in England and Wales increased between 1988 and 1993 from 8.4 to 9.2 per 100,000 population. The rate declined in the white, Indian, and black Caribbean ethnic groups and increased in all other groups. In the white group the rate of decline has slowed since the last survey: in several age groups the rates were higher in 1993 than 1988 but the numbers in these groups were small. Thirty six (4.1%) of the 882 previously untreated respiratory cases were resistant to isoniazid and three (0.3%) to isoniazid and rifampicin. Sixty two (2.3%) adults aged 16-54 years were estimated to be HIV-infected. Evidence of under-reporting of HIV positive tuberculosis patients was found. CONCLUSIONS: The number of cases and annual notification rate for previously untreated tuberculosis increased between 1988 and 1993. Although the decline in rates in the white population has continued, the rate of decline has slowed. The high rates in the ISC ethnic group population have continued to decline since 1988 whereas rates in the black African group have increased. An increased proportion of cases were found among people born abroad, particularly those recently arrived in this country. In previously untreated cases the level of drug resistance remains low and multi-drug resistance is rare. A small proportion of adults with tuberculosis were infected with HIV but there may be selective undernotification of tuberculosis in these patients. 



PMCID: PMC1758462  PMID: 9516900
3.  Changes in tuberculosis notification rates in the white ethnic group in England and Wales between 1953 and 1983. 
Since the early 1960s notification rates for tuberculosis in England and Wales for the whole population have been influenced by high rates in certain ethnic groups. Using data based on country of birth from the British (Thoracic and) Tuberculosis Association surveys of 1965 and 1971, and based on ethnic origin from the Medical Research Council surveys in 1978/79 and 1983, rates for the white ethnic group have been estimated at those four times, and compared with the published rates for the whole population in 1953, when only a very small proportion was of non-white ethnic origin. Between 1953 and 1983 the notification rate for the white ethnic group fell from 122.2 to 11.3 per 100,000 for males, an annual decline of 7.7%, the corresponding rates for females being 90.1 and 5.8, an annual decline of 8.8%. The greatest annual declines occurred between 1953 and 1965, 9.4% for males and 11.2% for females. The annual declines in the most recent period, 1978/79 to 1983, were 6.9% for males and 7.3% for females. In both sexes the decline was greatest in the 15-24 year age group and least in the oldest age group, and this has led to a change in the age pattern of annual notification rates. The highest rates in both sexes occurred in young adults in 1953 but in the oldest age groups in 1983. There is however no evidence of any cohort experiencing an increase in notification rate with increasing age.
PMCID: PMC1052767  PMID: 3256580
4.  Tuberculosis in children: a national survey of notifications in England and Wales in 1983. Medical Research Council Tuberculosis and Chest Diseases Unit. 
Archives of Disease in Childhood  1988;63(3):266-276.
A survey of all notifications of tuberculosis in children (aged less than 15 years) in England and Wales in 1983 showed a decline of 35% in the estimated annual number of previously untreated children notified since the previous survey in 1978-9. Of the 452 children in the 1983 survey, 217 (48%) were of white, 79 (17%) of Indian, and 104 (23%) of Pakistani or Bangladeshi ethnic origin. The decline in the number of Indian children notified (46%) was much greater than that for Pakistani and Bangladeshi children (16%). In both surveys the estimated annual notification rate was much higher for the Indian and the Pakistani and Bangladeshi ethnic groups (32 and 52/100,000, respectively in 1983) than for the white group (2.4/100,000 in 1983). The mean annual decline in rate between the two surveys was 14% for the Indian, 10% for the Pakistani and Bangladeshi, and 7% for the white children. In both surveys the rates for the children of Indian subcontinent (Indian, Pakistani, and Bangladeshi) ethnic origin born in the United Kingdom were considerably lower than for those born abroad. Of the 452 children in the 1983 survey, 342 (76%) had respiratory disease (including 26 (6%) with a non-respiratory lesion as well). Less than half (134, 45%) had a pulmonary lesion at independent assessment of chest radiographs, a further 115 (38%) had only enlarged intrathoracic nodes. Only 60 (19%) of the children with respiratory disease only had a positive culture from a respiratory specimen, but the culture positivity rate in those tested was 45%. Almost two thirds of the children with non-respiratory disease had lesions of the extrathoracic nodes, nearly all cervical. There were 20 children with tuberculosis meningitis in the 12 months, including 12 (6%) of the 217 white and six (3%) of the 183 children of Indian subcontinent ethnic origin.
PMCID: PMC1778764  PMID: 3258498
5.  Tuberculosis among Health-Care Workers in Low- and Middle-Income Countries: A Systematic Review 
PLoS Medicine  2006;3(12):e494.
Background
The risk of transmission of Mycobacterium tuberculosis from patients to health-care workers (HCWs) is a neglected problem in many low- and middle-income countries (LMICs). Most health-care facilities in these countries lack resources to prevent nosocomial transmission of tuberculosis (TB).
Methods and Findings
We conducted a systematic review to summarize the evidence on the incidence and prevalence of latent TB infection (LTBI) and disease among HCWs in LMICs, and to evaluate the impact of various preventive strategies that have been attempted. To identify relevant studies, we searched electronic databases and journals, and contacted experts in the field. We identified 42 articles, consisting of 51 studies, and extracted data on incidence, prevalence, and risk factors for LTBI and disease among HCWs. The prevalence of LTBI among HCWs was, on average, 54% (range 33% to 79%). Estimates of the annual risk of LTBI ranged from 0.5% to 14.3%, and the annual incidence of TB disease in HCWs ranged from 69 to 5,780 per 100,000. The attributable risk for TB disease in HCWs, compared to the risk in the general population, ranged from 25 to 5,361 per 100,000 per year. A higher risk of acquiring TB disease was associated with certain work locations (inpatient TB facility, laboratory, internal medicine, and emergency facilities) and occupational categories (radiology technicians, patient attendants, nurses, ward attendants, paramedics, and clinical officers).
Conclusions
In summary, our review demonstrates that TB is a significant occupational problem among HCWs in LMICs. Available evidence reinforces the need to design and implement simple, effective, and affordable TB infection-control programs in health-care facilities in these countries.
A systematic review demonstrates that tuberculosis is an important occupational problem among health care workers in low and middle-income countries.
Editors' Summary
Background.
One third of the world's population is infected with Mycobacterium tuberculosis, the bacterium that causes tuberculosis (TB). In many people, the bug causes no health problems—it remains latent. But about 10% of infected people develop active, potentially fatal TB, often in their lungs. People with active pulmonary TB readily spread the infection to other people, including health-care workers (HCWs), in small airborne droplets produced when they cough or sneeze. In high-income countries such as the US, guidelines are in place to minimize the transmission of TB in health-care facilities. Administrative controls (for example, standard treatment plans for people with suspected or confirmed TB) aim to reduce the exposure of HCWs to people with TB. Environmental controls (for example, the use of special isolation rooms) aim to prevent the spread and to reduce the concentration of infectious droplets in the air. Finally, respiratory-protection controls (for example, personal respirators for nursing staff) aim to reduce the risk of infection when exposure to M. tuberculosis is unavoidably high. Together, these three layers of control have reduced the incidence of TB in HCWs (the number who catch TB annually) in high-income countries.
Why Was This Study Done?
But what about low- and middle-income countries (LMICs) where more than 90% of the world's cases of TB occur? Here, there is little money available to implement even low-cost strategies to reduce TB transmission in health-care facilities—so how important an occupational disease is TB in HCWs in these countries? In this study, the researchers have systematically reviewed published papers to find out the incidence and prevalence (how many people in a population have a specific disease) of active TB and latent TB infections (LTBIs) in HCWs in LMICs. They have also investigated whether any of the preventative strategies used in high-income countries have been shown to reduce the TB burden in HCWs in poorer countries.
What Did the Researchers Do and Find?
To identify studies on TB transmission to HCWs in LMICs, the researchers searched electronic databases and journals, and also contacted experts on TB transmission. They then extracted and analyzed the relevant data on TB incidence, prevalence, risk factors, and control measures. Averaged-out over the 51 identified studies, 54% of HCWs had LTBI. In most of the studies, increasing age and duration of employment in health-care facilities, indicating a longer cumulative exposure to infection, was associated with a higher prevalence of LTBI. The same trend was seen in a subgroup of medical and nursing students. After accounting for the incidence of TB in the relevant general population, the excess incidence of TB in the different studies that was attributable to being a HCW ranged from 25 to 5,361 cases per 100, 000 people per year. In addition, a higher risk of acquiring TB was associated with working in specific locations (for example, inpatient TB facilities or diagnostic laboratories) and with specific occupations, including nurses and radiology attendants; most of the health-care facilities examined in the published studies had no specific TB infection-control programs in place.
What Do These Findings Mean?
As with all systematic reviews, the accuracy of these findings may be limited by some aspects of the original studies, such as how the incidence of LTBI was measured. In addition, the possibility that the researchers missed some relevant published studies, or that only studies where there was a high incidence of TB in HCWs were published, may also affect the findings of this study. Nevertheless, they suggest that TB is an important occupational disease in HCWs in LMICs and that the HCWs most at risk of TB are those exposed to the most patients with TB. Reduction of that risk should be a high priority because occupational TB leads to the loss of essential, skilled HCWs. Unfortunately, there are few data available to indicate how this should be done. Thus, the researchers conclude, well-designed field studies are urgently needed to evaluate whether the TB-control measures that have reduced TB transmission to HCWs in high-income countries will work and be affordable in LMICs.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030494.
• US National Institute of Allergy and Infectious Diseases patient fact sheet on tuberculosis
• US Centers for Disease Control and Prevention information for patients and professionals on tuberculosis
• MedlinePlus encyclopedia entry on tuberculosis
• NHS Direct Online, from the UK National Health Service, patient information on tuberculosis
• US National Institute for Occupational Health and Safety, information about tuberculosis for health-care workers
• American Lung Association information on tuberculosis and health-care workers
doi:10.1371/journal.pmed.0030494
PMCID: PMC1716189  PMID: 17194191
6.  National survey of notifications of tuberculosis in England and Wales in 1983. Medical Research Council Tuberculosis and Chest Diseases Unit. 
In a survey of all notifications of tuberculosis in England and Wales for the first six months of 1983 56% of the 3002 newly notified patients who had not been treated before were of white and 37% were of Indian subcontinent (Indian, Pakistani, or Bangladeshi) ethnic origin, findings similar to those of a survey in 1978-9. In the four and a quarter years between the surveys the number of patients notified had declined by 26%, the decline being 28% among those of white and 23% among those of Indian subcontinent ethnic origin. The white patients were on average older than the patients of Indian subcontinent ethnic origin, and a higher proportion of them had respiratory disease (82% compared with 66%). The pulmonary lesions were on average larger and more often bacteriologically positive in the white patients. There were considerable differences between the ethnic groups in the estimated yearly rates of notifications per 100 000 population in England in 1983. The highest rates occurred in the Indian (178) and the Pakistani and Bangladeshi (169) populations and were roughly 25 times the rate in the white population (6 X 9). In the Indian subcontinent ethnic groups the highest rates occurred among those who had arrived in the United Kingdom within the previous five years.
PMCID: PMC1417529  PMID: 3928070
7.  National survey of tuberculosis notifications in England and Wales 1978--9. Report from the Medical Research Council Tuberculosis and Chest Diseases Unit. 
British Medical Journal  1980;281(6245):895-898.
A survey of all tuberculosis notifications in England and Wales for a six-month period showed that 70% of 3732 newly notified, previously untreated patients had respiratory disease only, 23% had non-respiratory disease only, and 7% had both. Fifty-seven per cent of patients were of white and 35% were of Indian subcontinent (Indian, Pakistani, or Bangladeshi) ethnic origin, the latter group contributing over half the cases of non-respiratory disease. The estimated overall annual notification rate per 100 000 population for 1978--9 was 16.4 for England and 13.5 for Wales. The rates differed considerably between the different ethnic groups in England, the highest rates occurring in the Indian and in the Pakistani and Bangladeshi groups and the lowest in the white group; the differences in the non-respiratory rates were the more striking. Nearly a quarter of patients with respiratory disease had large pulmonary lesions, the proportion being higher for the white group than for the Indian subcontinent group. Over half the patients had positive cultures for tubercle bacilli and over a third had positive smears; both proportions were higher for the white group. This survey has identified many of the problems which tuberculosis presents in England and Wales today. These include the substantial number of patients with sputum-positive disease, the considerable variation in the rates in the different ethnic groups, and the not uncommon occurrence of childhood tuberculosis.
PMCID: PMC1714197  PMID: 7427500
8.  Epidemiology of Tuberculosis in a High HIV Prevalence Population Provided with Enhanced Diagnosis of Symptomatic Disease  
PLoS Medicine  2007;4(1):e22.
Background
Directly observed treatment short course (DOTS), the global control strategy aimed at controlling tuberculosis (TB) transmission through prompt diagnosis of symptomatic smear-positive disease, has failed to prevent rising tuberculosis incidence rates in Africa brought about by the HIV epidemic. However, rising incidence does not necessarily imply failure to control tuberculosis transmission, which is primarily driven by prevalent infectious disease. We investigated the epidemiology of prevalent and incident TB in a high HIV prevalence population provided with enhanced primary health care.
Methods and Findings
Twenty-two businesses in Harare, Zimbabwe, were provided with free smear- and culture-based investigation of TB symptoms through occupational clinics. Anonymised HIV tests were requested from all employees. After 2 y of follow-up for incident TB, a culture-based survey for undiagnosed prevalent TB was conducted. A total of 6,440 of 7,478 eligible employees participated. HIV prevalence was 19%. For HIV-positive and -negative participants, the incidence of culture-positive tuberculosis was 25.3 and 1.3 per 1,000 person-years, respectively (adjusted incidence rate ratio = 18.8; 95% confidence interval [CI] = 10.3 to 34.5: population attributable fraction = 78%), and point prevalence after 2 y was 5.7 and 2.6 per 1,000 population (adjusted odds ratio = 1.7; 95% CI = 0.5 to 6.8: population attributable fraction = 14%). Most patients with prevalent culture-positive TB had subclinical disease when first detected.
Conclusions
Strategies based on prompt investigation of TB symptoms, such as DOTS, may be an effective way of controlling prevalent TB in high HIV prevalence populations. This may translate into effective control of TB transmission despite high TB incidence rates and a period of subclinical infectiousness in some patients.
When occupational clinics provide free smear and culture-based investigation of tuberculosis symptoms, it can lead to prompt investigation and may aid TB control in high HIV-prevalence populations.
Editors' Summary
Background.
Around eight million people develop tuberculosis (TB) disease every year and of these nearly two million die. However, many more people are infected than have symptoms; perhaps one-third of the world's population is currently infected with TB. Most people infected with TB have what is termed “latent infection,” or in other words they are infected with the bacterium but do not experience any symptoms of disease. Individuals infected with TB who also have a weakened immune system, for example through HIV/AIDS, are much more likely to develop TB disease. In some regions HIV is very common—for example, approximately 11% of sub-Saharan African adults are HIV positive—and because of this cases of TB disease have risen substantially as HIV spreads. The Word Health Organization has a recommended international strategy for control of TB called “DOTS” (Directly Observed Therapy, Shortcourse). Among the five main elements of DOTS are mechanisms for promptly diagnosing and treating people who have TB disease. It is hoped that this strategy will help to reduce the number of new cases of TB diagnosed each year, because individuals promptly diagnosed and treated will then be less likely to transmit the disease to others.
Why Was This Study Done?
In this study the investigators wanted to find out if intensive DOTS, combined with giving people better access to test facilities to diagnose TB disease, could be effective in reducing the spread of TB from one person to another in Africa. It is not clear whether DOTS alone can control the spread of TB in populations with high numbers of HIV-positive people already infected with TB and so at high risk of going on to develop TB disease. Specifically, they wanted to collect data on the number of new TB cases being diagnosed per year and how that related to the proportion of the overall population that had infectious undiagnosed TB at any given point in time. They also wanted to find out whether providing good access to services for diagnosis and treatment of TB would affect either the number of new TB cases or the proportion of a given population that had infectious undiagnosed TB.
What Did the Researchers Do and Find?
This research study was carried out as part of a trial in which two different strategies for providing testing and counseling for HIV in the workplace were being compared. The trial took place within 22 companies in Harare, Zimbabwe, where HIV is very common in the adult population. Along with HIV testing and counseling, the trial provided for close follow-up and testing of anyone presenting with TB-like symptoms, with the aim of detecting as many cases in the population as possible. At the end of the two-year period, all workers were checked for undiagnosed TB disease, and cultures were carried out to find out how many of these people had infectious TB (but who might not necessarily have had symptoms). 6,440 workers were recruited into the study, of whom 19% were HIV positive. During the period of follow-up, 106 cases of TB were seen, and HIV-positive workers were far more likely than HIV-negative workers to experience TB disease. At the end of the study, 4,668 workers were checked for the presence of undiagnosed TB and 27 individuals were found to be affected, but not all of these people experienced any symptoms of disease.
What Do These Findings Mean?
At the end of this study, the proportion of workers found to have undiagnosed TB was fairly low—lower than the level found in other studies carried out in other parts of the world with a high burden of TB disease but low burden of HIV. The researchers therefore concluded that the systems set up within the trial (for close follow-up and testing for TB disease) were an effective way of controlling the overall proportion with infectious TB, even though HIV infection rates were also high. This is likely to mean that the spread of TB infection to others—a prerequisite for achieving TB disease control—was also well controlled. However, more intensive efforts to reduce the risk of TB disease in HIV-positive Africans already infected with TB are also needed, although this study did not aim to find out about the impact of such strategies.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040022.
Information from the World Health Organization on DOTS, the internationally recommended TB control strategy; a factsheet on TB is also available
The STOP TB Partnership is an international initiative involving several agencies seeking to combat the rise of tuberculosis
The US National Institute of Allergy and Infectious Diseases also publishes a factsheet for patients
US Centers for Disease Control, information for patients and professionals about TB
doi:10.1371/journal.pmed.0040022
PMCID: PMC1761052  PMID: 17199408
9.  Changes in annual tuberculosis notification rates between 1978/79 and 1983 for the population of Indian subcontinent ethnic origin resident in England. 
In two national surveys of tuberculosis notifications in England conducted in 1978/79 and 1983 the estimated annual notification rates for the Indian subcontinent (Indian, Pakistani, and Bangladeshi) ethnic groups were considerably higher than the rate for the white ethnic group. The mean annual decline in rates between the surveys appeared to be greater for the Indian and the Pakistani and Bangladeshi ethnic groups, 15% and 16% respectively, than for the white ethnic group (7%). Data from two small sample population surveys, the National Dwelling and Housing Survey in 1978 and the Labour Force Survey in 1983, were used to calculate the rates. However, comparison of the estimates for the population of Indian subcontinent ethnic origin in England from these surveys revealed discrepancies between them. Additional information from the Labour Force Survey on the year of first entry to the United Kingdom (UK) permitted the calculation of new estimates for the 1978 population, and based on these estimates the annual notification rates for 1978/79 were 287 per 100,000 for the Indian and 286 per 100,000 for the Pakistani and Bangladeshi ethnic groups. The rates for 1983 were 178 and 169 respectively, and the mean annual decline between the surveys was 11% for the Indian and 12% for the Pakistani and Bangladeshi ethnic groups. There were important changes in the characteristics of the population of Indian subcontinent ethnic origin in England between 1978 and 1983, and therefore the rates for both surveys have been standardised by the method of direct standardisation to a common reference population. Standardizing for year of entry to the UK, place of birth (UK or abroad), age, and sex reduced the mean annual decline in the notification rate to 4% for the Indian and 9% for the Pakistani and Bangladeshi ethnic groups. The much greater reduction in the rate of decline in the Indian ethnic group is due to the substantial decline between the surveys in the proportion of recent immigrants, the group with the highest annual notification rate, in that population. Future trends will continue to be influenced by immigration patterns, but it will also be important to monitor the rates among the increasing proportion of the population born in the UK or resident in England for more than five years.
PMCID: PMC1052560  PMID: 3655629
10.  Tuberculosis at the end of the 20th century in England and Wales: results of a national survey in 1998 
Thorax  2001;56(3):173-179.
BACKGROUND—A national survey of tuberculosis was conducted in England and Wales in 1998 to obtain detailed information on the occurrence of the disease and recent trends. This survey also piloted the methodology for enhanced tuberculosis surveillance in England and Wales and investigated the prevalence of HIV infection in adults with tuberculosis.
METHODS—Clinical and demographic data for all cases diagnosed during 1998 were obtained, together with microbiological data where available. Annual incidence rates in the population were estimated by age, sex, ethnic group, and geographical region using denominators from the 1998 Labour Force Survey. Incidence rates in different subgroups of the population were compared with the rates observed in previous surveys. The tuberculosis survey database for 1998was matched against the Communicable Disease Surveillance Centre HIV/AIDS database to estimate the prevalence of HIV co-infection in adult patients with tuberculosis.
RESULTS—A total of 5658 patients with tuberculosis were included in the survey in England and Wales (94% of all formally notified cases during the same period), giving an annual rate of 10.93per 100 000 population (95% CI 10.87 to 10.99). This represented an increase of 11% in the number of cases since the survey in 1993 and 21% since 1988. In many regions case numbers have remained little changed since 1988, but in London an increase of 71% was observed. The number of children with tuberculosis has decreased by 10% since 1993. Annual rates of tuberculosis per 100 000 population have continued to decline among the white population (4.38) and those from the Indian subcontinent, although the rate for the latter has remained high at 121 per 100 000. Annual rates per 100 000 have increased in all other ethnic groups, especially among those of black African (210) and Chinese (77.3) origin. Over 50% of all patients were born outside the UK. Recent entrants to the UK had higher rates of the disease than those who had been in the country for more than 5 years or who had been born in the UK. An estimated 3.3% of all adults with tuberculosis were co-infected with HIV.
CONCLUSIONS—The epidemiology of tuberculosis continues to change in England and Wales and the annual number of cases is rising. More than one third of cases now occur in young adults and rates are particularly high in those recently arrived from high prevalence areas of the world. The geographical distribution is uneven with urban centres having the highest rates. The increase in the number of cases in London is particularly large. Tuberculosis in patients co-infected with HIV makes a small but important contribution to the overall increase, particularly in London. To be most effective and to make the most efficient use of resources, tuberculosis prevention and control measures must be based on accurate and timely information on the occurrence of disease. A new system of continuous enhanced tuberculosis surveillance was introduced in 1999, based on the methodology developed in this national survey.


doi:10.1136/thorax.56.3.173
PMCID: PMC1758771  PMID: 11182007
11.  Scottish national survey of tuberculosis notifications 1993 with special reference to the prevalence of HIV seropositivity. 
Thorax  1996;51(1):78-81.
BACKGROUND: The study sought to determine the contribution of HIV seropositivity to the arrest of decline in tuberculosis notifications in Scotland. METHODS: Survey forms relating to each tuberculosis notification in 1993 were completed by the notifying consultant. Voluntary anonymous HIV testing of tuberculosis cases aged under 65 was requested. Age, sex, ethnic status, country of birth, employment status, occupation, previous tuberculosis, contact status, risk factors for HIV infection, HIV serostatus of cases aged under 65, site, radiological extent, and bacteriological status of tuberculous disease were determined. RESULTS: Five hundred and seventy four cases of tuberculosis were originally notified, of which 77 (14%) subsequently proved to be non-tuberculous and were therefore denotified. Of the 497 cases 423 (85%) were white and 58 (12%) were from the Indian subcontinent. Eighty five per cent of patients from the Indian subcontinent were aged < 55 years whereas 64% of white patients were aged > 55 years. Pulmonary disease was found in 74%, non-pulmonary in 22%, and combined disease in 4% of patients. Of 242 HIV tests performed, three were positive and five other HIV positive patients were known, giving an HIV positivity rate of 1.6% of all tuberculosis notifications in 1993. Annual notification rates for Scotland were 9.7 per 10(5) before and 8.7 per 10(5) after exclusion of previously treated cases; rates were 8.4 per 10(5) for the white population and 179 per 10(5) for those from the Indian subcontinent. CONCLUSIONS: The study documents the distribution of tuberculous disease in Scotland by age, sex, site, and ethnic group for the first time. Notification practices, with respect to denotification, need to be improved. Infection with HIV is presently uncommon in cases of tuberculosis in Scotland but continued vigilance is essential.
PMCID: PMC472805  PMID: 8658375
12.  Tuberculosis Recurrence and Mortality after Successful Treatment: Impact of Drug Resistance 
PLoS Medicine  2006;3(10):e384.
Background
The DOTS (directly observed treatment short-course) strategy for tuberculosis (TB) control is recommended by the World Health Organization globally. However, there are few studies of long-term TB treatment outcomes from DOTS programs in high-burden settings and particularly settings of high drug resistance. A DOTS program was implemented progressively in Karakalpakstan, Uzbekistan starting in 1998. The total case notification rate in 2003 was 462/100,000, and a drug resistance survey found multidrug-resistant (MDR) Mycobacterium tuberculosis strains among 13% of new and 40% of previously treated patients. A retrospective, observational study was conducted to assess the capacity of standardized short-course chemotherapy to effectively cure patients with TB in this setting.
Methods and Findings
Using routine data sources, 213 patients who were sputum smear-positive for TB, included in the drug resistance survey and diagnosed consecutively in 2001–2002 from four districts, were followed up to a median of 22 months from diagnosis, to determine mortality and subsequent TB rediagnosis. Valid follow-up data were obtained for 197 (92%) of these patients. Mortality was high, with an average of 15% (95% confidence interval, 11% to 19%) dying per year after diagnosis (6% of 73 pansusceptible cases and 43% of 55 MDR TB cases also died per year). While 73 (74%) of the 99 new cases were “successfully” treated, 25 (34%) of these patients were subsequently rediagnosed with recurrent TB (13 were smear-positive on rediagnosis). Recurrence ranged from ten (23%) of 43 new, pansusceptible cases to six (60%) of ten previously treated MDR TB cases. MDR M. tuberculosis infection and previous TB treatment predicted unsuccessful DOTS treatment, while initial drug resistance contributed substantially to both mortality and disease recurrence after successful DOTS treatment.
Conclusions
These results suggest that specific treatment of drug-resistant TB is needed in similar settings of high drug resistance. High disease recurrence after successful treatment, even for drug-susceptible cases, suggests that at least in this setting, end-of-treatment outcomes may not reflect the longer-term status of patients, with consequent negative impacts for patients and for TB control.
A retrospective, observational study was conducted to assess the effectiveness of a "DOTS" tuberculosis control program in Uzbekistan. High rates of disease recurrence were found among patients whose treatment had been initially successful.
Editors' Summary
Background.
Throughout history, tuberculosis (TB) has been a leading infectious cause of death—it kills about 2 million people every year. Until the 1940s, there was no effective treatment for TB, a chronic bacterial infection, usually of the lungs. Then, antibiotics active against the bacteria that cause TB—Mycobacterium tuberculosis—were introduced, and its incidence (the annual number of new cases) declined rapidly, particularly in developed countries. However, in the 1980s, there was a resurgence of TB, much of it driven by the HIV/AIDS epidemic—people with damaged immune systems are very susceptible to TB—and the emergence of drug-resistant M. tuberculosis. In 1995, the World Health Organization instigated what it called “DOTS,” an international strategy for global TB control. Central to DOTS is directly observed standardized short-course drug treatment. To prevent relapse and the emergence of drug-resistant bacteria, TB patients have to take antibiotics regularly for six months, even if they feel better sooner. The DOTS approach ensures that they do this by having trained observers watch them swallow their medications.
Why Was This Study Done?
DOTS aims to detect 70% of new cases of sputum smear-positive TB (sputum is mucus coughed up from the lungs) and to treat 85% of these patients successfully. Both a cure—a negative smear at the end of treatment—and completion of treatment are recorded as “treatment successes.” There is no requirement in DOTS to check for TB recurrence, and few studies have investigated the long-term outcomes of treatment, particularly in areas with a high TB burden or where there is a problem with multidrug-resistant TB. Such data are needed to indicate whether DOTS can deliver global TB control. In this study, the researchers asked how often TB recurred in patients treated in a DOTS program in Karakalpakstan, Uzbekistan, an area with one of the highest incidences of multidrug-resistant TB.
What Did the Researchers Do and Find?
The researchers identified about 200 sputum smear-positive TB patients who were treated consecutively in the Karakalpakstan DOTS program in 2001–2002. For most of the patients, follow-up data were available for an average of 22 months, a legacy of the pre-DOTS TB treatment system in Uzbekistan. The researchers found that, although three-quarters of new cases were “successfully” treated (i.e., close to the DOTS goal), a third of these “successes” were later re-diagnosed with TB. Recurrence of TB was particularly common among patients whose initial disease was multidrug resistant. Previous TB treatment was also associated with an increased risk of disease recurrence. Overall, nearly a quarter of the study patients died from TB during the follow-up period. Again, patients initially infected with multidrug-resistant TB fared particularly badly. Finally, only 65% of successfully treated patients were still alive and had not been re-diagnosed with TB 18 months after completion of their treatment.
What Do These Findings Mean?
These high rates of disease recurrence and mortality suggest that DOTS might not be sufficient to control TB in areas like Karakalpakstan where the disease burden is high and multidrug-resistant infections are common. These poor long-term outcomes, note the researchers, are not hinted at by the end-of-treatment outcomes reported by the DOTS program. Limitations in the present study mean, however, that further studies are needed before these findings can be extrapolated to other settings. For example, the study used historical data so the researchers could not determine whether inadequate adherence to the DOTS program had contributed to the poor long-term outcome or whether disease recurrence was due to a relapse of the initial infection (which might indicate poor treatment adherence) or a new infection. Nevertheless, the current results warn against relying on end-of-treatment outcomes to judge the potential effectiveness of DOTS in controlling TB, and suggest that the expansion of DOTS-Plus, a supplement to DOTS for use where multidrug resistant TB is common, should be made a priority.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030384.
US National Institute of Allergy and Infectious Diseases, patient fact sheet on tuberculosis
US Centers for Disease Control and Prevention, information for patients and professionals on tuberculosis
MedlinePlusencyclopedia entry on tuberculosis
NHS Direct Online, patient information on tuberculosis from the UK National Health Service
World Health Organization information on the global elimination of tuberculosis, including details of DOTS and DOTS-Plus
Medécin sans Frontières; information on TB and other health issues in Karakalpakstan
doi:10.1371/journal.pmed.0030384
PMCID: PMC1584414  PMID: 17020405
13.  From DOTS to the Stop TB Strategy: DOTS coverage and trend of tuberculosis notification in Ebonyi, southeastern Nigeria, 1998-2009 
Background
Nigeria ranks fourth among the 22 high tuberculosis (TB) burden countries. The estimated incidence of all TB cases in 2009 was 311/100,000 population. Since the implementation of DOTS in Ebonyi state, southeast Nigeria, the epidemiology of TB in the region has not been documented. Therefore, the objective of this study was to assess the type and case notification dynamics of TB following DOTS expansion and to examine age- and sex-specific trends in TB notification rate.
Methods
A retrospective trend analysis of case notification data from the Ebonyi State Ministry of Health records from 1998 to 2009 was conducted. Patients were diagnosed according to the National TB and Leprosy Control Programme guidelines. Denominators for TB notifications were derived from population census data.
Results
Of the 24, 475 cases notified between 1998 and 2009, 66% were smear-positive, 31% smear-negative and 3% had extra-pulmonary tuberculosis. Overall, the proportion of new smear-positive cases notified decreased continuously from 67% to 48% in 2009 while that of smear-negative cases increased from 29% to 40% in 2009. In 2005, 13 (100%) of the local government areas were covered by DOTS. Despite initial increase in case notification with DOTS expansion, the case notification rate had a mean annual decline of 3.1% for all TB cases (falling from 123/100 000 to 77/100 000), and of 5% for smear-positive patients (falling from 80/100 000 to 32/100 000). Smear-positive notification rate in children <14 years was consistently low while 25-34-year-old persons were affected most. However, smear-positive rates among persons aged =65 years did not change. Overall, annual new smear-positive notification rates were persistently lower in females than males.
Conclusion
TB notification rate shows a decreasing trend in our region with a pool of infectious cases in young-persons. Additional targeted, type and age-/sex- specific interventions for TB control are needed.
PMCID: PMC3215534  PMID: 22145056
Tuberculosis; Epidemiology; control; DOTS; case finding; Nigeria
14.  Increasing incidence of tuberculosis in England and Wales: a study of the likely causes. 
BMJ : British Medical Journal  1995;310(6985):967-969.
OBJECTIVE--To examine factors responsible for the recent increase in tuberculosis in England and Wales. DESIGN--Study of the incidence of tuberculosis (a) in the 403 local authority districts in England and Wales, ranked according to Jarman score, and (b) in one deprived inner city district, according to ethnic origin and other factors. SETTING--(a) England and Wales 1980-92, and (b) the London borough of Hackney 1986-93. MAIN OUTCOME MEASURE--Age and sex adjusted rate of tuberculosis. RESULTS--In England and Wales notifications of tuberculosis increased by 12% between 1988 and 1992. The increase was 35% in the poorest 10th of the population and 13% in the next two; and in the remaining 70% there was no increase. In Hackney the increase affected traditionally high risk and low risk ethnic groups to a similar extent. In the "low risk" white and West Indian communities the incidence increased by 58% from 1986-8 (78 cases) to 1991-3 (123), whereas in residents of Indian subcontinent origin the increase was 41% (from 51 cases to 72). Tuberculosis in recently arrived immigrants--refugees (11% of the Hackney population) and Africans (6%)--accounted for less than half of the overall increase, and the proportion of such residents was much higher than in most socioeconomically deprived districts. The local increase was not due to an increase in the proportion of cases notified, to HIV infection, nor to an increase in homeless people. CONCLUSIONS--The national rise in tuberculosis affects only the poorest areas. Within one such area all residents (white and established ethnic minorities) were affected to a similar extent. The evidence indicates a major role for socioeconomic factors in the increase in tuberculosis and only a minor role for recent immigration from endemic areas.
PMCID: PMC2549357  PMID: 7728031
15.  Increased risk of tuberculosis in health care workers: a retrospective survey at a teaching hospital in Istanbul, Turkey 
Background
Tuberculosis (TB) is an established occupational disease affecting health care workers (HCWs). Determining the risk of TB among HCWs is important to enable authorites to take preventative measures in health care facilities and protect HCWs. This study was designed to assess the incidence of TB in a teaching hospital in Istanbul, Turkey. This study is retrospective study of health records of HCWs in our hospital from 1991 to 2000.
Results
The mean workforce of the hospital was 3359 + 33.2 between 1991 and 2000. There were 31 cases (15 male) meeting the diagnostic criteria for TB, comprising eight doctors, one nurse and 22 other health professionals. Mean incidence of TB was 96 per 100,000 for all HCWs (relative risk: 2.71), 79 per 100,000 for doctors (relative risk: 2.2), 14 per 100,000 for nurses and 121 per 100,000 (relative risk: 3.4) for other professionals. The mean incidence of TB in Turkey between 1991 and 2000 was 35.4 per 100,000. Incidence of TB was similar in the Departments of Chest Diseases and Clinical Medicine but there were no TB cases in the Basic Science and Managerial Departments.
Conclusion
HCWs in Turkey who work in clinics have an increased risk for TB. Post-graduate education and prevention programs reduce the risk of TB. Control programs to prevent nosocomial transmission of TB should be established in hospitals to reduce risk for HCWs.
doi:10.1186/1471-2334-2-14
PMCID: PMC122064  PMID: 12144709
16.  Tuberculosis in children: a national survey of notifications in England and Wales in 1988. Medical Research Council Cardiothoracic Epidemiology Group. 
Archives of Disease in Childhood  1994;70(6):497-500.
A survey of all notified cases of tuberculosis in England and Wales in children (less than 15 years old) in 1988 was undertaken to study changes in the frequency and distribution of disease in the population since similar surveys in 1978-9 and 1983. There were 294 children with newly notified previously untreated tuberculosis, an annual rate of 3.1/100,000. Children of Indian, Pakistani, and Bangladeshi (Indian subcontinent) ethnic origin formed the largest group (134 (46%)), but only 29 (22%) of these children were born outside the UK. The rate for children of Indian subcontinent ethnic origin born abroad (53/100,000) was twice that for those born in the UK (26/100,000), but the latter was 17 times higher than the rate for white children (1.5/100,000). These ratios have changed little since the first survey in 1978-9 and highlight the need for improvement in the prevention and control of tuberculosis in children known to be at increased risk.
PMCID: PMC1029868  PMID: 8048819
17.  An evaluation of completeness of tuberculosis notification in the United Kingdom 
BMC Public Health  2003;3:31.
Background
There has been a resurgence of tuberculosis worldwide, mainly in developing countries but also affecting the United Kingdom (UK), and other Western countries. The control of tuberculosis is dependent on early identification of cases and timely notification to public health departments to ensure appropriate treatment of cases and screening of contacts. Tuberculosis is compulsorily notifiable in the UK, and the doctor making or suspecting the diagnosis is legally responsible for notification. There is evidence of under-reporting of tuberculosis. This has implications for the control of tuberculosis as a disproportionate number of people who become infected are the most vulnerable in society, and are less likely to be identified and notified to the public health system. These include the poor, the homeless, refugees and ethnic minorities.
Method
This study was a critical literature review on completeness of tuberculosis notification within the UK National Health Service (NHS) context. The review also identified data sources associated with reporting completeness and assessed whether studies corrected for undercount using capture-recapture (CR) methodology. Studies were included if they assessed completeness of tuberculosis notification quantitatively. The outcome measure used was notification completeness expressed between 0% and 100% of a defined denominator, or in numbers not notified where the denominator was unknown.
Results
Seven studies that met the inclusion and exclusion criteria were identified through electronic and manual search of published and unpublished literature. One study used CR methodology. Analysis of the seven studies showed that undernotification varied from 7% to 27% in studies that had a denominator; and 38%–49% extra cases were identified in studies which examined specific data sources like pathology reports or prescriptions for anti-tuberculosis drugs. Cases notified were more likely to have positive microbiology than cases not notified which were more likely to have positive histopathology or be surgical in-patients. Collation of prescription data of two or more anti-tuberculosis drugs increases case ascertainment of tuberculosis.
Conclusion
The reporting of tuberculosis is incomplete in the UK, although notification is a statutory requirement. Undernotification leads to an underestimation of the disease burden and hinders implementation of appropriate prevention and control strategies. The notification system needs to be strengthened to include education and training of all sub-specialities involved in diagnosis and treatment of tuberculosis.
doi:10.1186/1471-2458-3-31
PMCID: PMC240107  PMID: 14527348
tuberculosis; notification; completion; evaluation; capture-recapture
18.  Long-Term Exposure to Silica Dust and Risk of Total and Cause-Specific Mortality in Chinese Workers: A Cohort Study 
PLoS Medicine  2012;9(4):e1001206.
A retro-prospective cohort study by Weihong Chen and colleagues provides new estimates for the risk of total and cause-specific mortality due to long-term silica dust exposure among Chinese workers.
Background
Human exposure to silica dust is very common in both working and living environments. However, the potential long-term health effects have not been well established across different exposure situations.
Methods and Findings
We studied 74,040 workers who worked at 29 metal mines and pottery factories in China for 1 y or more between January 1, 1960, and December 31, 1974, with follow-up until December 31, 2003 (median follow-up of 33 y). We estimated the cumulative silica dust exposure (CDE) for each worker by linking work history to a job–exposure matrix. We calculated standardized mortality ratios for underlying causes of death based on Chinese national mortality rates. Hazard ratios (HRs) for selected causes of death associated with CDE were estimated using the Cox proportional hazards model. The population attributable risks were estimated based on the prevalence of workers with silica dust exposure and HRs. The number of deaths attributable to silica dust exposure among Chinese workers was then calculated using the population attributable risk and the national mortality rate. We observed 19,516 deaths during 2,306,428 person-years of follow-up. Mortality from all causes was higher among workers exposed to silica dust than among non-exposed workers (993 versus 551 per 100,000 person-years). We observed significant positive exposure–response relationships between CDE (measured in milligrams/cubic meter–years, i.e., the sum of silica dust concentrations multiplied by the years of silica exposure) and mortality from all causes (HR 1.026, 95% confidence interval 1.023–1.029), respiratory diseases (1.069, 1.064–1.074), respiratory tuberculosis (1.065, 1.059–1.071), and cardiovascular disease (1.031, 1.025–1.036). Significantly elevated standardized mortality ratios were observed for all causes (1.06, 95% confidence interval 1.01–1.11), ischemic heart disease (1.65, 1.35–1.99), and pneumoconiosis (11.01, 7.67–14.95) among workers exposed to respirable silica concentrations equal to or lower than 0.1 mg/m3. After adjustment for potential confounders, including smoking, silica dust exposure accounted for 15.2% of all deaths in this study. We estimated that 4.2% of deaths (231,104 cases) among Chinese workers were attributable to silica dust exposure. The limitations of this study included a lack of data on dietary patterns and leisure time physical activity, possible underestimation of silica dust exposure for individuals who worked at the mines/factories before 1950, and a small number of deaths (4.3%) where the cause of death was based on oral reports from relatives.
Conclusions
Long-term silica dust exposure was associated with substantially increased mortality among Chinese workers. The increased risk was observed not only for deaths due to respiratory diseases and lung cancer, but also for deaths due to cardiovascular disease.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Walk along most sandy beaches and you will be walking on millions of grains of crystalline silica, one of the commonest minerals on earth and a major ingredient in glass and in ceramic glazes. Silica is also used in the manufacture of building materials, in foundry castings, and for sandblasting, and respirable (breathable) crystalline silica particles are produced during quarrying and mining. Unfortunately, silica dust is not innocuous. Several serious diseases are associated with exposure to this dust, including silicosis (a chronic lung disease characterized by scarring and destruction of lung tissue), lung cancer, and pulmonary tuberculosis (a serious lung infection). Moreover, exposure to silica dust increases the risk of death (mortality). Worryingly, recent reports indicate that in the US and Europe, about 1.7 and 3.0 million people, respectively, are occupationally exposed to silica dust, figures that are dwarfed by the more than 23 million workers who are exposed in China. Occupational silica exposure, therefore, represents an important global public health concern.
Why Was This Study Done?
Although the lung-related adverse health effects of exposure to silica dust have been extensively studied, silica-related health effects may not be limited to these diseases. For example, could silica dust particles increase the risk of cardiovascular disease (diseases that affect the heart and circulation)? Other environmental particulates, such as the products of internal combustion engines, are associated with an increased risk of cardiovascular disease, but no one knows if the same is true for silica dust particles. Moreover, although it is clear that high levels of exposure to silica dust are dangerous, little is known about the adverse health effects of lower exposure levels. In this cohort study, the researchers examined the effect of long-term exposure to silica dust on the risk of all cause and cause-specific mortality in a large group (cohort) of Chinese workers.
What Did the Researchers Do and Find?
The researchers estimated the cumulative silica dust exposure for 74,040 workers at 29 metal mines and pottery factories from 1960 to 2003 from individual work histories and more than four million measurements of workplace dust concentrations, and collected health and mortality data for all the workers. Death from all causes was higher among workers exposed to silica dust than among non-exposed workers (993 versus 551 deaths per 100,000 person-years), and there was a positive exposure–response relationship between silica dust exposure and death from all causes, respiratory diseases, respiratory tuberculosis, and cardiovascular disease. For example, the hazard ratio for all cause death was 1.026 for every increase in cumulative silica dust exposure of 1 mg/m3-year; a hazard ratio is the incidence of an event in an exposed group divided by its incidence in an unexposed group. Notably, there was significantly increased mortality from all causes, ischemic heart disease, and silicosis among workers exposed to respirable silica concentrations at or below 0.1 mg/m3, the workplace exposure limit for silica dust set by the US Occupational Safety and Health Administration. For example, the standardized mortality ratio (SMR) for silicosis among people exposed to low levels of silica dust was 11.01; an SMR is the ratio of observed deaths in a cohort to expected deaths calculated from recorded deaths in the general population. Finally, the researchers used their data to estimate that, in 2008, 4.2% of deaths among industrial workers in China (231,104 deaths) were attributable to silica dust exposure.
What Do These Findings Mean?
These findings indicate that long-term silica dust exposure is associated with substantially increased mortality among Chinese workers. They confirm that there is an exposure–response relationship between silica dust exposure and a heightened risk of death from respiratory diseases and lung cancer. That is, the risk of death from these diseases increases as exposure to silica dust increases. In addition, they show a significant relationship between silica dust exposure and death from cardiovascular diseases. Importantly, these findings suggest that even levels of silica dust that are considered safe increase the risk of death. The accuracy of these findings may be affected by the accuracy of the silica dust exposure estimates and/or by confounding (other factors shared by the people exposed to silica such as diet may have affected their risk of death). Nevertheless, these findings highlight the need to tighten regulations on workplace dust control in China and elsewhere.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001206.
The American Lung Association provides information on silicosis
The US Centers for Disease Control and Prevention provides information on silica in the workplace, including links to relevant US National Institute for Occupational Health and Safety publications, and information on silicosis and other pneumoconioses
The US Occupational Safety and Health Administration also has detailed information on occupational exposure to crystalline silica
What does silicosis mean to you is a video provided by the US Mine Safety and Health Administration that includes personal experiences of silicosis; Dont let silica dust you is a video produced by the Association of Occupational and Environmental Clinics that identifies ways to reduce silica dust exposure in the workplace
The MedlinePlus encyclopedia has a page on silicosis (in English and Spanish)
The International Labour Organization provides information on health surveillance for those exposed to respirable crystalline silica
The World Health Organization has published a report about the health effects of crystalline silica and quartz
doi:10.1371/journal.pmed.1001206
PMCID: PMC3328438  PMID: 22529751
19.  Notification of tuberculosis: how many cases are never reported? 
Thorax  1992;47(12):1015-1018.
BACKGROUND: Notification of tuberculosis is essential for local contact tracing and for assessing the national incidence of tuberculosis. The accuracy of notification figures is uncertain. This study examined the notification rates of all patients diagnosed as having tuberculosis at two hospitals in the East End of London over five years. METHODS: In a retrospective survey of all patients aged 16 years or more presenting with tuberculosis to the London Chest Hospital or the Royal London Hospital from 1 January 1985 to 31 December 1989, cases of tuberculosis were identified from microbiology and histology records, statutory notifications, necropsy reports, coroners' records, hospital activity data, and death certificates. Clinical data were obtained from case notes and notification was determined from the local authority notification lists. RESULTS: Six hundred and nine adult patients with tuberculosis were identified. Notes were available for 580 cases (95%), of which 426 (73%) had been notified. The proportion of cases notified varied according to the specialty of the clinician in charge of the patient at diagnosis. Patients with a past history of tuberculosis and those who died within one year were less likely to have had their tuberculosis notified. Age, race, and lack of microbial or histological confirmation of diagnosis did not influence the proportion of cases notified. One hundred and eighty five patients had smear positive sputum, but 25 of these cases (14%) were not notified. Eighty five patients who had presented with pulmonary tuberculosis did not have their disease notified; 20 (24%) had smear positive sputum. CONCLUSIONS: Many cases of tuberculosis are not notified (27%). Fourteen per cent of all sputum smear positive cases of tuberculosis were not notified, and these patients are a considerable public health risk. The true incidence of tuberculosis in the area studied is at least one third higher than current notification figures suggest.
PMCID: PMC1021092  PMID: 1494763
20.  Incidence of and Risk Factors Associated with Pulmonary and Extra-Pulmonary Tuberculosis in Saudi Arabia (2010–2011) 
PLoS ONE  2014;9(5):e95654.
Setting
National Tuberculosis Program, Department of Public Health, Ministry of Health, Kingdom of Saudi Arabia (KSA).
Objective
To summarize data on the incidence of tuberculosis and associated risk factors for cases reported during 2010–2011.
Design
Retrospective analysis of routinely collected data through an established national disease notification system of the Ministry of Health in KSA.
Results
The estimated incidence of all forms of tuberculosis fell from 15.8/100000 (95% CI: 15.3/100,000–16.3/100,000) in 2010 to 13.8/100,000 (95% CI: 13.4/100,000–14.2/100,000) in 2011. Saudis experienced a decrease from 11.8/100,000 (95% CI: 11.3/100,000 to 12.3/100,000) in 2010 to 9.9/100,000 (95% CI: 9.5/100,000–10.4/100,000) in 2011 while the incidence in non-Saudis declined from 24.7/100,000 (95% CI: 23.6/100,000 to 25.7/100,000) in 2010 to 22.5/100,000 (95% CI: 21.5/100,000 to 23.4/100,000) in 2011. The proportion of Extra Pulmonary TB (EPTB) which increased minimally from 30% in 2010 to 32% in 2011 was higher than global figures and strongly associated with age, sex, nationality and occupation.
Conclusion
The current estimated incidence of about 14/100,000 in 2011 is less than half its estimated value of 44/100000 in 1990. Without prejudice to any under-reporting, the KSA appeared to be on the course for TB elimination by 2050 having reached the first milestone set by WHO. The proportion of EPTB remains higher than global figure and age, sex, nationality and occupation were significant independent predictors of EPTB.
doi:10.1371/journal.pone.0095654
PMCID: PMC4019475  PMID: 24824783
21.  Comparison of two active case-finding strategies for community-based diagnosis of symptomatic smear-positive tuberculosis and control of infectious tuberculosis in Harare, Zimbabwe (DETECTB): a cluster-randomised trial 
Lancet  2010;376(9748):1244-1253.
Summary
Background
Control of tuberculosis in settings with high HIV prevalence is a pressing public health priority. We tested two active case-finding strategies to target long periods of infectiousness before diagnosis, which is typical of HIV-negative tuberculosis and is a key driver of transmission.
Methods
Clusters of neighbourhoods in the high-density residential suburbs of Harare, Zimbabwe, were randomised to receive six rounds of active case finding at 6-monthly intervals by either mobile van or door-to-door visits. Randomisation was done by selection of discs of two colours from an opaque bag, with one disc to represent every cluster, and one colour allocated to each intervention group before selection began. In both groups, adult (≥16 years) residents volunteering chronic cough (≥2 weeks) had two sputum specimens collected for fluorescence microscopy. Community health workers and cluster residents were not masked to intervention allocation, but investigators and laboratory staff were masked to allocation until final analysis. The primary outcome was the cumulative yield of smear-positive tuberculosis per 1000 adult residents, compared between intervention groups; analysis was by intention to treat. The secondary outcome was change in prevalence of culture-positive tuberculosis from before intervention to before round six of intervention in 12% of randomly selected households from the two intervention groups combined; analysis was based on participants who provided sputum in the two prevalence surveys. This trial is registered, number ISRCTN84352452.
Findings
46 study clusters were identified and randomly allocated equally between intervention groups, with 55 741 adults in the mobile van group and 54 691 in the door-to-door group at baseline. HIV prevalence was 21% (1916/9060) and in the 6 months before intervention the smear-positive case notification rate was 2·8 per 1000 adults per year. The trial was completed as planned with no adverse events. The mobile van detected 255 smear-positive patients from 5466 participants submitting sputum compared with 137 of 4711 participants identified through door-to-door visits (adjusted risk ratio 1·48, 95% CI 1·11–1·96, p=0·0087). The overall prevalence of culture-positive tuberculosis declined from 6·5 per 1000 adults (95% CI 5·1–8·3) to 3·7 per 1000 adults (2·6–5·0; adjusted risk ratio 0·59, 95% CI 0·40–0·89, p=0·0112).
Interpretation
Wide implementation of active case finding, particularly with a mobile van approach, could have rapid effects on tuberculosis transmission and disease.
Funding
Wellcome Trust.
doi:10.1016/S0140-6736(10)61425-0
PMCID: PMC2956882  PMID: 20923715
22.  Non-compliance with health surveillance is a matter of Biosafety: a survey of latent tuberculosis infection in a highly endemic setting 
BMJ Open  2011;1(1):e000079.
Objective
This study aimed at identifying demographic, socio-economic and tuberculosis (TB) exposure factors associated with non-compliance with the tuberculin skin test, the management and prevention of non-compliance to the test. It was carried out in the context of a survey of latent TB infection among undergraduate students taking healthcare courses in two universities in Salvador, Brazil, a city highly endemic for TB.
Methods
This is a cross-sectional study of 1164 volunteers carried out between October 2004 and June 2008. Bivariate analysis followed by logistic regression was used to measure the association between non-compliance and potential risk factors through non-biased estimates of the adjusted OR for confounding variables. A parallel evaluation of occupational risk perception and of knowledge of Biosafety measures was also conducted.
Results
The non-compliance rate was above 40% even among individuals potentially at higher risk of disease, which included those who had not been vaccinated (OR 3.33; 95% CI 1.50 to 7.93; p=0.0018), those reporting having had contact with TB patients among close relatives or household contacts (p=0.3673), or those whose tuberculin skin test status was shown within the survey to have recently converted (17.3% of those completing the study). In spite of the observed homogeneity in the degree of Biosafety knowledge, and the awareness campaigns developed within the study focussing on TB prevention, the analysis has shown that different groups have different behaviours in relation to the test. Family income was found to have opposite effects in groups studying different courses as well as attending public versus private universities.
Conclusions
Although the data presented may not be directly generalisable to other situations and cultural settings, this study highlights the need to evaluate factors associated with non-compliance with routine testing, as they may affect the efficacy of Biosafety programs.
Article summary
Article focus
The reasons behind non-compliance with health monitoring are rarely investigated, even though high rates of non-compliance have been observed in several studies among groups ranging from the general population to students and healthcare professionals.
Non-compliance with the tuberculin skin test (TST) may affect the efficacy of tuberculosis control programs.
Key messages
Having information on the targeted disease, as well as being at risk of this disease, was found to be insufficient to ensure compliance with routine testing.
Non-compliance with the TST was associated with socio-economic status, gender and career choice, which suggests that cultural and psychological reasons for non-compliance are shared within such groups.
Investigation of the reasons associated with non-compliance among different groups would be a first step to improve the efficacy of Biosafety programs.
Strengths and limitations of this study
This study was conducted only among healthcare students and within the context of a survey for latent TB infection. The risk factors found here to be associated with non-compliance may not be directly generalisable to other situations and cultural settings. This study is limited by the fact that all the information collected was self-reported, except for the frequency of non-compliance and the TST induration measurements. Unlike in other TST surveys, non-compliance due to logistics problems was addressed and minimised.
doi:10.1136/bmjopen-2011-000079
PMCID: PMC3191424  PMID: 22021753
Health monitoring; latent tuberculosis; occupational risk; Biosafety; immunology; tuberculosis; epidemiology; health and safety
23.  Latent tuberculosis infection and associated risk factors among undergraduate healthcare students in Italy: a cross-sectional study 
BMC Infectious Diseases  2013;13:443.
Background
The screening of both healthcare workers and students attending teaching hospitals for latent tuberculosis infection (LTBI) is recommended in hospitals of many countries with a low-incidence of TB, including Italy, as a fundamental tool of tuberculosis (TB) control programs. The aim of the study was to estimate the prevalence of LTBI and evaluate the main risk-factors associated with this condition in a cohort of healthcare Italian students.
Methods
In a cross-sectional study, performed between January and May 2012, 881 undergraduate students attending the Medical, Nursing, Pediatric Nursing and Midwifery Schools of the University of Genoa, trained at the IRCCS San Martino-IST Teaching Hospital of Genoa, were actively called to undergo the Tuberculin Skin Test (TST). All the TST positive cases were also tested with an Interferon-Gamma Release Assay (IGRA) to confirm the diagnosis of LTBI. A standardized questionnaire was collected for risk-assessment analysis.
Results
Seven hundred and thirty-three (83.2%) subjects underwent TST testing. The prevalence of TST positives was 1.4%, and in 4 (0.5%) out of 10 TST positive cases LTBI diagnosis was confirmed by IGRA. No difference in the prevalence of subjects who tested positive to TST emerged between pre-clinical (n = 138) and clinical (n = 595) students. No statistically significant association between TST positivity and age, gender, and BCG vaccination was observed. The main independent variable associated with TST positivity was to be born in a country with a high TB incidence (i.e., ≥20 cases per 100,000 population) (adjusted OR 102.80, 95% CI 18.09-584.04, p < 0.001).
Conclusions
The prevalence of LTBI among healthcare students resulted very low. The only significant association between TST positivity and potential risk factors was to be born in high TB incidence areas. In countries with a low incidence of TB, the screening programs of healthcare students before clinical training can be useful for the early identification and treatment of the sporadic cases of LTBI.
doi:10.1186/1471-2334-13-443
PMCID: PMC3848912  PMID: 24059355
Tuberculosis; Latent tuberculosis infection; Tuberculin skin test; Interferon-gamma release assay; Healthcare students; Risk-factors
24.  Geographical distribution of tuberculosis notifications in national surveys of England and Wales in 1988 and 1993: report of the Public Health Laboratory Service/British Thoracic Society/Department of Health Collaborative Group 
Thorax  1998;53(3):176-181.
BACKGROUND—The geographical distribution of tuberculosis in England and Wales and changes since 1983 were examined using data from the 1988 and 1993 national surveys of tuberculosis notifications.
METHODS—Notification rates for England and Wales in 1988 and 1993 were calculated for geographical areas using Office for National Statistics (ONS) mid year population estimates. Those for the standard regions and the Greater London boroughs were calculated for the main ethnic groups. Those for the counties and local authorities were calculated for all ethnic groups combined. These were compared using data from the 1983 national survey as a baseline.
RESULTS—Wide regional variations in notification rates persist with Greater London having the highest rates. Rates in the ethnic group from the Indian subcontinent (ISC) were high in all regions, whilst those of the white ethnic group varied fourfold. Twenty seven of the 33 London boroughs showed increased rates in 1993 compared with 1988. In general, those local authority areas with high rates had high proportions of notifications in individuals of ISC ethnic origin, emphasising the continuing important contribution of ethnic minority groups to local tuberculosis rates. The number of local authority areas with notification rates four times the national average increased, but the number of areas with low or zero rates increased even more.
CONCLUSIONS—The distribution of tuberculosis in England and Wales continues to vary markedly by geographical area. The distribution is becoming increasingly polarised with a growth in the number of areas with very high rates of notifications and a greater increase in the number of areas with very few notifications. Patients from ethnic minorities continued to contribute a substantial and increasing proportion of all reported tuberculosis cases in most regions in 1988 and 1993. These findings have important implications for the provision of tuberculosis services in England and Wales.


PMCID: PMC1745172  PMID: 9659351
25.  Tuberculosis in Healthcare Workers and Infection Control Measures at Primary Healthcare Facilities in South Africa 
PLoS ONE  2013;8(10):e76272.
Background
Challenges exist regarding TB infection control and TB in hospital-based healthcare workers in South Africa. However, few studies report on TB in non-hospital based healthcare workers such as primary or community healthcare workers. Our objectives were to investigate the implementation of TB infection control measures at primary healthcare facilities, the smear positive TB incidence rate amongst primary healthcare workers and the association between TB infection control measures and all types of TB in healthcare workers.
Methods
One hundred and thirty three primary healthcare facilities were visited in five provinces of South Africa in 2009. At each facility, a TB infection control audit and facility questionnaire were completed. The number of healthcare workers who had had TB during the past three years was obtained.
Results
The standardised incidence ratio of smear positive TB in primary healthcare workers indicated an incidence rate of more than double that of the general population. In a univariable logistic regression, the infection control audit score was significantly associated with reported cases of TB in healthcare workers (OR=1.04, 95%CI 1.01-1.08, p=0.02) as was the number of staff (OR=3.78, 95%CI 1.77-8.08). In the multivariable analysis, the number of staff remained significantly associated with TB in healthcare workers (OR=3.33, 95%CI 1.37-8.08).
Conclusion
The high rate of TB in healthcare workers suggests a substantial nosocomial transmission risk, but the infection control audit tool which was used did not perform adequately as a measure of this risk. Infection control measures should be monitored by validated tools developed and tested locally. Different strategies, such as routine surveillance systems, could be used to evaluate the burden of TB in healthcare workers in order to calculate TB incidence, monitor trends and implement interventions to decrease occupational TB.
doi:10.1371/journal.pone.0076272
PMCID: PMC3788748  PMID: 24098461

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