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author:("Kabir, unaids")
1.  Evaluating a surveillance system: live-bird market surveillance for highly pathogenic avian influenza, a case study 
The Pan African Medical Journal  2014;18(Suppl 1):11.
Highly pathogenic avian influenza H5N1 was first reported in poultry in Nigeria in February 2006. The only human case that occurred was linked to contact with poultry in a live bird market (LBM). LBM surveillance was instituted to assess the degree of threat of human exposure to H5N1. The key indicator was detection of H5N1 in LBMs. We evaluated the surveillance system to assess its operations and attributes.
We used the US Centers for Disease Control and Prevention (CDC) updated guidelines for evaluating public health surveillance systems. We reviewed and analyzed passive surveillance data for HPAI (January 2006-March 2009) from the Avian Influenza National Reference Laboratory, and live bird market surveillance data from the Food and Agriculture Organization of the United Nations, Nigeria. We interviewed key stakeholders and reviewed reports of live bird market surveillance to obtain additional information on the operations of the system. We assessed the key system attributes.
A total of 299 cases occurred in 25 (72%) states and the Federal Capital Territory (FCT). The system detected HPAI H5N1 virus in 7 (9.5%) LBMs; 2 (29%) of which were from 2 (18.2%) states with no previous case. A total of 17,852 (91.5%) of samples arrived at the laboratory within 24 hours but laboratory analysis took over 7 days. The sensitivity and positive predictive value (PPV) were 15.4% and 66.7% respectively.
The system is useful, flexible, complex and not timely, but appears to be meeting its objectives. The isolation of HPAI H5N1 virus in some of these markets is an indication that the markets are possible reservoirs of the virus in Nigeria. We recommend that the Federal Government of Nigeria should dedicate more funds for surveillance for HPAI as this will aid early warning and reduce the risk of a pandemic.
PMCID: PMC4199346  PMID: 25328630
Live bird market; highly pathogenic avian influenza; surveillance; Nigeria
2.  Prevalence of bovine genital campylobacteriosis and trichomonosis of bulls in northern Nigeria 
A survey was conducted to determine the prevalence of campylobacteriosis and trichomonosis, and their concurrence with brucellosis, in cattle in three states of northern Nigeria.
A total of 602 preputial samples was collected from bulls in 250 herds and tested using culture and identification. Various indigenous and exotic breeds were studied and four major management systems were encountered. Age of the cattle was estimated using dentition, farm records or cornual rings.
The estimated true animal-level prevalence of Campylobacter fetus infection was 16.4% (95% CI: 13.0-20.7), of which 18.5% was C. f. fetus and 81.5% was C. f. venerealis. Of the latter, 92% were C. f. venerealis biovar intermedius strains. Animal-level prevalences in Adamawa, Kano and Kaduna states were 31.8%, 11.6% and 8.3% respectively, and were highest in bulls >7 years old (33.4%) and in the Gudali breed (28.8%). Of the 250 herds, 78 (25.5%, 95% CI: 19.4-32.7) had at least one infected bull, and herd prevalence was highest in the pastoral management system (43.5%). After adjustment for confounding using multivariable analysis, the odds of C. fetus infection were highest in Adamawa state (P < 0.01), in the pastoral management system (P < 0.01), and in bulls >7 years old (P = 0.01), and tended to be higher in Bos taurus breeds (P = 0.06). There was a strong positive association between the presence of campylobacteriosis and brucellosis (P < 0.01), both within bulls (OR = 8.3) and within herds (OR = 16.0). Trichomonosis was not detected in any herds.
Bovine genital campylobacteriosis is prevalent particularly in the pastoral management system in northern Nigeria, with C. f. venerealis biovar intermedius as the major aetiology. There was a strong positive correlation between the occurrence of campylobacteriosis and brucellosis. No evidence of trichomonosis was found in herds in this study.
PMCID: PMC3751741  PMID: 23927676
Bovine; Brucellosis; Campylobacteriosis; Nigeria; Preputial samples; Trichomonosis
3.  A large seroprevalence survey of brucellosis in cattle herds under diverse production systems in northern Nigeria 
This study was carried out to investigate the status of brucellosis in cattle under various management systems in Adamawa, Kaduna and Kano states, northern Nigeria. Using multi-stage sampling, serum samples of 4,745 cattle from 271 herds were tested using the Rose-Bengal plate-agglutination test (RBPT) and positives were confirmed using a competitive enzyme-linked immunosorbent assay (c-ELISA).
Prevalence estimates were calculated by adjusting for sampling weights and where possible for test sensitivity and specificity. Thirty-seven percent of all animals were RBPT positive, and after confirmation with c-ELISA the overall animal-level prevalence, adjusted for sampling weights, was 26.3% (95% CI, 22.1%-31.0%). Of the herds sampled, 210 (77.5%; 95% CI, 68.6%-84.5%) had at least one animal positive to both tests; this did not differ significantly between states (P = 0.538). Mean within-herd seroprevalence in positive herds was 30.2% (95% CI, 25.3%-35.1%) and ranged from 3.1% to 85.7%. Overall animal-level seroprevalences of 29.2% (95% CI, 22.5%-36.9%) n = 1,827, 23.3% (95% CI, 18.9%-28.3%) n = 1,870 and 26.7% (95% CI, 18.8%-36.7%) n = 1,048 were observed in Adamawa, Kaduna and Kano states, respectively (P = 0.496). A significantly higher seroprevalence was found in males (38.2%; 95% CI, 31.7%-45.2%) than in females (24.7%; 95% CI, 20.4%-29.5%) (P < 0.001) and in non-pregnant females (27.8%; 95% CI, 22.9%-33.5%) than in pregnant females (17.2%; 95% CI, 13.6%-21.5%) (P < 0.001). Seroprevalence increased with increasing age (P < 0.001), from 13.5% (95% CI, 8.9%-19.9%) in cattle <4 years to 35.0% (95% CI, 28.5%-42.3%) in cattle >7 years. Seroprevalence also varied between management systems (P < 0.001): pastoral systems 45.1% (95% CI, 38.6%-51.9%), zero-grazing systems 23.8% (95% CI, 6.8%-59.2%), agro-pastoral systems 22.0% (95% CI, 17.3%-27.8%), and commercial farms 15.9% (95% CI, 9.5%-25.5%). Seroprevalence did not differ significantly between breeds or lactation status.
This is the first large study to assess the prevalence of bovine brucellosis over a wide geographic area of northern Nigeria, in a variety of management systems and using accurate tests. The seroprevalence of brucellosis was high, and higher than results of previous studies in northern Nigeria. The pastoral management systems of the traditional Fulanis may be encouraging the dissemination of the disease. Public enlightenment of the farmers about the disease, vaccination and appropriate national control measures are recommended.
PMCID: PMC3482151  PMID: 22920578
Brucellosis; c-ELISA; Management systems; Northern Nigeria; RBPT; Seroprevalence

Results 1-3 (3)