Rats are considered the principal maintenance hosts of Leptospira. The objectives of this study were isolation and identification of Leptospira serovars circulating among urban rat populations in Kuala Lumpur. Three hundred urban rats (73% Rattus rattus and 27% R. norvegicus) from three different sites were trapped. Twenty cultures were positive for Leptospira using dark-field microscopy. R. rattus was the dominant carrier (70%). Polymerase chain reaction (PCR) confirmed that all isolates were pathogenic Leptospira species. Two Leptospira serogroups, Javanica and Bataviae, were identified using microscopic agglutination test (MAT). Pulsed-field gel electrophoresis (PFGE) identified two serovars in the urban rat populations: L. borgpetersenii serovar Javanica (85%) and L. interrogans serovar Bataviae (15%). We conclude that these two serovars are the major serovars circulating among the urban rat populations in Kuala Lumpur. Despite the low infection rate reported, the high pathogenicity of these serovars raises concern of public health risks caused by rodent transmission of leptospirosis.
In 2007, the first free mass distribution of insecticide-treated bed nets (ITNs) occurred in southern Zambia. To determine the effect of ITNs on heterogeneity in biting rates, human DNA from Anopheles arabiensis blood meals was genotyped to determine the number of hosts that had contributed to the blood meals. The multiple feeding rate decreased from 18.9% pre-ITN to 9.1% post-ITN, suggesting that mosquito biting had focused onto a smaller fraction of the population. Pre-ITN, 20% of persons in a household provided 40% of blood meals, which increased to 59% post-ITN. To measure heterogeneity over a larger scale, mosquitoes were collected in 90 households in two village areas. Of these households, 25% contributed 78.1% of An. arabiensis, and households with high frequencies of An. arabiensis were significantly spatially clustered. The results indicate that substantial heterogeneity in malaria risk exists at local and household levels, and household-level heterogeneity may be influenced by interventions, such as ITNs.
High levels of genetic diversity in Plasmodium falciparum populations are an obstacle to malaria control. Here, we investigate the relationship between local variation in malaria epidemiology and parasite genetic diversity in Papua New Guinea (PNG). Cross-sectional malaria surveys were performed in 14 villages spanning four distinct malaria-endemic areas on the north coast, including one area that was sampled during the dry season. High-resolution msp2 genotyping of 2,147 blood samples identified 761 P. falciparum infections containing a total of 1,392 clones whose genotypes were used to measure genetic diversity. Considerable variability in infection prevalence and mean multiplicity of infection was observed at all of the study sites, with the area sampled during the dry season showing particularly striking local variability. Genetic diversity was strongly associated with multiplicity of infection but not with infection prevalence. In highly endemic areas, differences in infection prevalence may not translate into a decrease in parasite population diversity.
The St. Elizabeth strain of Plasmodium vivax originated in the South Carolina State Hospital instead of the St. Elizabeth Hospital in Washington, DC.
To investigate echinococcosis in co-endemic regions, three polymerase chain reaction (PCR) assays based on the amplification of a fragment within the NADH dehydrogenase subunit 1 (ND1) mitochondrial gene were optimized for the detection of Echinococcus shiquicus, Echinococcus granulosus G1, and Echinococcus multilocularis DNA derived from parasite tissue or canid fecal samples. Specificity using parasite tissue-derived DNA was found to be 100% except for E. shiquicus primers that faintly detected E. equinus DNA. Sensitivity of the three assays for DNA detection was between 2 and 10 pg. Ethanol precipitation of negative PCR fecal samples was used to eliminate false negatives and served to increase sensitivity as exemplified by an increase in detection from 0% to 89% of E. shiquicus coproDNA using necropsy-positive fox samples.
Severe malaria is characterized by a massive release of proinflammatory cytokines in the context of sequestration of parasitized and normal red cells (RBCs). High-mobility group box 1 (HMGB1) is a DNA- and heparin-binding protein that also acts as a cytokine when released from cells in the extracellular milieu after a proinflammatory stimulus. In this study, we have measured the circulating levels of HMGB1 in 76 children with severe or uncomplicated malaria. Sera from both severe (P = 0.0022) and uncomplicated (P = 0.0049) patients had significantly higher circulating HMGB1 levels compared with healthy controls. Elevated HMGB1 in patients with ongoing Plasmodium falciparum infections might prolong inflammation and the febrile state of malaria and could offer a potential target for therapeutic intervention.
Artemisinin-based combination therapies (ACTs) and trimethoprim-sulfamethoxazole (TS) prophylaxis are important tools for malaria control, but there are concerns about their effect on gametocytes, the stage of the parasite responsible for transmission. We conducted a longitudinal clinical trial in a cohort of HIV-infected and uninfected children living in an area of high malaria transmission intensity in Uganda. Study participants were randomized to artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DP) for all treatments of uncomplicated malaria (N = 4,380) as well as TS prophylaxis for different durations. The risks of gametocytemia detected by microscopy in the 28 days after antimalarial therapy were compared using multivariate analyses. The risk of gametocyte detection was significantly higher in patients treated with DP compared with AL (adjusted relative risk = 1.85, P < 0.001) and among children prescribed TS prophylaxis (adjusted relative risk = 1.76, P < 0.001). The risk of gametocytemia and its potential for increasing transmission should be considered when evaluating different ACTs and TS prophylaxis for malaria control.
In a recent randomized controlled trial, the use of protease inhibitor (PI)-based antiretroviral therapy (ART) was associated with a significantly lower incidence of malaria compared with non-nucleoside reverse transcriptase inhibitor-based ART in a cohort of human immunodeficiency virus-infected Ugandan children living in an area of high malaria transmission intensity. In this report, we compared the prevalence of asymptomatic parasitemia and gametocytemia using data from the same cohort. The prevalence of asymptomatic parasitemia did not differ between the two ART treatment arms. The PI-based arm was associated with a lower risk of gametocytemia at the time of diagnosis of malaria (6.6% versus 14.5%, P = 0.03) and during the 28 days after malaria diagnosis (3.4% versus 6.5%, P = 0.04). Thus, in addition to decreasing the incidence of malaria, the use of PI-based ART may lower transmission, as a result of a decrease in gametocytemia, in areas of high malaria transmission intensity.
Transmission by the oral route of Coxiella burnetii is controversial. Our objective was to evaluate dairy products in the transmission of Q fever. Pasteurized, unpasteurized, and thermized dairy products were tested for C. burnetii by using a quantitative polymerase chain reaction specific for IS1111 and IS30A spacers, culturing in human embryonic lung fibroblasts cells, and inoculation into BALB/c mice. We tested 201 products and C. burnetii was identified in 64%. Cow milk origin products were more frequently positive than goat or ewe products (P = 0.006 and P = 0.0001, respectively), and industrial food was more frequently positive than artisanal food (P < 0.0001). Food made from unpasteurized milk contained higher bacteria concentrations than food made from pasteurized milk (P = 0.02). All cultures were negative and mice did not show signs of illness. Farm animals are highly infected in France but consumption of cheese and yogurt does not seem to pose a public health risk for transmission of Q fever.
This work is a molecular epidemiologic study to detect the incidence of Coxiella burnetii in rodents on Heixiazi Island at the Sino-Russian border of Heilongjiang Province. Liver tissues were extracted and processed to test the incidence of C. burnetii infection using polymerase chain reaction analysis. In total, 18% (66 of 370) of rodents tested positive for infection. The results of logistic regression analysis indicated that infection with C. burnetii was associated significantly with weight and month of capture, and infection was found in all rodent species that were observed; there was no significant difference of sex on the infection of C. burnetii. Though phylogenetic analysis disclosed heterogeneity in the nucleotide sequences isolated from the island rodents, the majority of observed strains were among the most common strains found worldwide. This is the first report on the incidence of C. burnetii in rodents on Heixiazi Island at the Sino-Russian border.
Conventional understanding suggests that simultaneous infection with more than one species of Leishmania is unlikely. In Peru, co-infections are clinically relevant because causative species dictates prognosis, treatment response, and follow-up. We describe a case of Leishmania (Viannia) braziliensis and L. (V.) lainsoni co-infection in a Peruvian patient with cutaneous leishmaniasis.
India is one of three countries that account for an estimated 300,000 of 500,000 cases of visceral leishmaniasis (VL) occurring annually. Bihar State is the most affected area of India, with more than 90% of the cases. Surveys were conducted in two villages within the Saran district of Bihar, India, from 2009 to July of 2011 to assess risk factors associated with VL. Forty-five cases were identified, and individuals were given an oral survey. The results indicated that men contracted the disease more than women (58%), and cases over the age of 21 years accounted for 42% of the total VL cases. April to June showed the highest number of new cases. Of 135 households surveyed for sleeping conditions, 95% reported sleeping outside, and 98% slept in beds. Proximity to VL cases was the greatest risk factor (cluster 1 relative risk = 11.89 and cluster 2 relative risk = 138.34). The VL case clustering observed in this study can be incorporated in disease prevention strategies to more efficiently and effectively target VL control efforts.
Tuberculosis (TB) is a major public health problem in Ethiopia and the Amhara region. Assessment of knowledge, attitude, and health-seeking practice in this region is essential to plan, implement, and evaluate advocacy, communication, and social mobilization work. This may improve the case detection rate. The aim of this study was to assess the knowledge, attitude, and practice of patients toward TB in the Eastern Amhara region of Ethiopia. A cross-sectional survey was conducted among suspected and confirmed TB patients who were 18 years of age and older. For this purpose, 422 participants were enrolled. A structured and pre-validated questionnaire was used to collect data. In addition χ2 and multivariate logistic regression analysis was used to see an association with different variables. The mean and median knowledge score of respondents about pulmonary TB was 6.81 and 7, respectively. The majority of respondents had several misconceptions in all aspects of the most infectious form of TB. About half of the respondents did not know the current free cost of TB diagnosis and treatment. The 69.9% of respondents claimed that cost is the main reason for not getting care. The majority of respondents had several misconceptions about TB. The TB control program needs to consider advocacy, communication, and social mobilization for addressing the gap in the study sites.
A total of 1,220 subjects from Equatorial Guinea living in Spain (median age = 41 years; 453 male and 767 female) was examined for antibodies to human immunodeficiency virus (HIV) and Hepatitis B (HBV), C (HCV), and D (HDV) viruses. Extracted RNA and DNA from the positive samples were used to quantify viral load. The prevalence of HIV antibodies, HCV RNA, and HBV surface antigen (HBsAg) was 10.8% (N = 132), 11.6% (N = 141), and 7.9% (N = 96), respectively. The most prevalent HIV variant was CRF02_AG (38.5%; N = 40). HCV genotype 4 (60%; N = 36) and HBV genotype A3 (32%; N = 8) were the hepatitis variants most frequently found. Superinfection with HDV was seen in 20.9% (N = 24) of HBsAg carriers. A control group of 276 immigrants from other sub-Saharan countries showed similar rates of HIV and HBsAg, although no HCV cases were found. Immigrants constitute a major source of HIV and hepatitis viruses in Spain; therefore, it is important that control measures are intensified.
A 38-year-old man, returned from Ivory Coast 2 months ago and presented with a 3-month history of pruritus exclusively on the scrotum. Itching was continuous during the day and no pruritus was described in his wife and son. Clinical examination of the genitals revealed several nodules on the scrotum, a chancrous lesion was seen on the penis, and multiple excoriations were noted. Dermoscopy exam with a dermatoscope of the whole body was performed and no papules, nodules, or burrow were found. Microscopic examination of several superficial skin samples obtained by scraping in the peri-genital area revealed one adult of Sarcoptes scabiei. The patient and his relatives were successfully treated with Ivermectin 200 μg/kg with a second dose 2 weeks later. Very rare cases are described on localized scabies (scalp, feet) and they mainly occurred in an immunocompromised patient unlike this patient who does not have any immunosuppression.
Malaria infections in pregnancy are associated with adverse outcomes for both mother and child. There are few data on hyper-reactive malarial splenomegaly, an aberrant immunological response to chronic or recurrent malaria in pregnancy. This retrospective assessment reviewed the impact of mefloquine treatment on pregnant women with suspected hyper-reactive malarial splenomegaly in an area of low malaria transmission in the 1990s, showing significant reductions in spleen size and anemia and anti-malarial antibody titers without any notable negative effect on treated women or their newborns.
Anopheles darlingi Root is the most important malaria vector in the Amazonia region of South America. However, continuous propagation of An. darlingi in the laboratory has been elusive, limiting entomological, genetic/genomic, and vector–pathogen interaction studies of this mosquito species. Here, we report the establishment of an An. darlingi colony derived from wild-caught mosquitoes obtained in the northeastern Peruvian Amazon region of Iquitos in the Loreto Department. We show that the numbers of eggs, larvae, pupae, and adults continue to rise at least to the F6 generation. Comparison of feeding Plasmodium vivax ex vivo of F4 and F5 to F1 generation mosquitoes showed the comparable presence of oocysts and sporozoites, with numbers that corresponded to blood-stage asexual parasitemia and gametocytemia, confirming P. vivax vectorial capacity in the colonized mosquitoes. These results provide new avenues for research on An. darlingi biology and study of An. darlingi–Plasmodium interactions.
This study evaluates the efficiency of rural health centers in Rwanda in delivering the three key human immunodeficiency virus/acquired immunodeficiency syndrome services: antiretroviral treatment, prevention of mother-to-child transmission, and voluntary counseling and testing using data envelopment analysis, and assesses the impact of community-based health insurance (CBHI) and performance-based financing on improving the delivery of the three services. Results show that health centers average efficiency of 78%, and despite the observed variation, the performance increased by 15.6% from 2006 through 2007. When the services are examined separately, each 1% growth of CBHI use was associated with 3.7% more prevention of mother-to-child transmission and 2.5% more voluntary counseling and testing services. Although more health centers would have been needed to evaluate performance-based financing, we found that high use of CBHI in Rwanda was an important contributor to improving human immunodeficiency virus/acquired immunodeficiency syndrome services in rural health centers in Rwanda.
Immunization remains the most cost effective method for the control of infectious diseases. Therefore, there is a global effort to deploy new vaccines for disease control and eradication. These new vaccines must be tested in the settings in which they will be used. This necessity has required the conduct of many vaccine trials in Africa, where several infectious diseases with significant public health impact are prevalent. However, these areas have peculiarities and are just beginning to gain expertise in the conduct of such trials. The vaccine developers and sponsors of these trials may also not be conversant with some issues unique to the trial site. The understanding gap from both partners can result in challenges if not addressed during the planning phase of the trial. This review seeks to highlight the issues surrounding the conduct of clinical trials in resource-constrained settings and suggests some ways of circumventing them.
Since the first case of strongyloidiasis reported in China in 1973, there have been 330 confirmed cases as of 2011. The present study conducted a meta-analysis on 106 cases for which detailed information on clinical symptoms, diagnosis, and outcome was available. Most (63%) cases were from the past decade. Immunocompromised patients and those given cortical hormones accounted for 68% of the cases, and case-fatality rate was 38%. General clinical symptoms included abdominal pain (53%), diarrhea (46%), fever (40%), and vomiting (39%). The parasite positivity rate in feces, sputum, and urine by microscopic diagnosis was 75%, 24%, and 8%, respectively, and gastrointestinal endoscopy or other biopsy detection rates were 17%. A lack of specific clinical manifestations makes early diagnosis and correct treatment difficult. Strongyloidiasis is an emerging disease in China, and public and clinical awareness needs to be raised to improve prevention and control.
We measured prevalence of Schistosoma haematobium, Wuchereria bancrofti, Plasmodium falciparum, hookworm, and other geohelminths among school-aged children in four endemic villages in Kwale County, Kenya and explored the relationship between multiparasite burden, undernutrition, and anemia. In 2009–2010 surveys, cross-sectional data were obtained for 2,030 children 5–18 years old. Infections were most prevalent for S. haematobium (25–62%), hookworm (11–28%), and falciparum malaria (8–24%). Over one-half of children were anemic, with high rates of acute and chronic malnutrition. Associations with infection status showed significant age and sex differences. For boys, young age, low socioeconomic standing (SES), S. haematobium, and/or malaria infections were associated with greater odds of anemia, wasting, and/or stunting; for girls, heavy S. haematobium infection and age were the significant cofactors for anemia, whereas low SES and older age were linked to stunting. The broad overlap of infection-related causes for anemia and malnutrition and the high frequency of polyparasitic infections suggest that there will be significant advantages to integrated parasite control in this area.
Preventive chemotherapy with praziquantel is recommended in adults by the World Health Organization when prevalence of schistosomiasis in school-aged children (SAC) is ≥ 50%. This study ascertained the value of this threshold in predicting prevalence and intensity of Schistosoma hematobium (SH) infection in adults in central Nigeria. We evaluated urogenital schistosomiasis prevalence in 1,164 adults: 659 adults in 12 communities where mean hematuria among SAC in 2008 was 26.6% and 505 adults in 7 communities where the mean hematuria among SAC in 2008 was 70.4%. No statistically significant differences were found between the two groups of adults in prevalence of hematuria, prevalence of SH eggs, or intensity of infections. We conclude that, in this setting, the SAC threshold is not useful for treatment decisions in adults. Given the increased risk of subtle morbidity or urogenital schistosomiasis as a risk factor for human immunodeficiency virus (HIV), more liberal treatment of adults with praziquantel is warranted.