Rabies Virus Neutralizing Antibodies in Unvaccinated Rabies Occupational Risk Groups in Niger State, Nigeria.

Aims: To determine the presence of rabies virus neutralizing antibodies (rVNA) as well the potency of the rVNA in rabies occupational risk humans in Niger State of Nigeria. Study Design: Cross-sectional study. Place and Duration: Research was conducted at the Department of Veterinary Public Health, Ahmadu Bello University, Zaria, Nigeria and Rabies Unit, Centers for Disease Control and Prevention, CDC, Atlanta, USA, between May, 2012 and March, 2013 Materials and Methods: A total of 185 human volunteers were recruited from rabies risk occupational groups who filled a structured questionnaire on their previous bite history and vaccination status, between May and July, 2012. A 2 ml each of blood from volunteers was collected and centrifuged at 3000 rpm for 10 minutes and sera separated into pre-labeled vacutainers. Standard Rapid fluorescent focus inhibition test (RFFIT) was used to detect the presence of rVNA in the sera. Further end point titration of the rVNA positive human sera was conducted to determine the potency. Results: The results indicated that, detectable titre of rVNA was recorded in 16.4% (23 of 140) viable human sera screened. Although from the questionnaire survey, 21.7% (5 out of the 23 positives) responded to have been vaccinated over ten years prior. At least 3 of the respondents (1 dog butcher and 2 dog meat consumers) who responded not previously vaccinated had some neutralizing antibody titre range of 0.65 – 0.7 IU/ml which is above the minimum protective titre (0.5IU/ml) recommended by WHO. Similarly, 3 respondents (2 veterinarians and 1 animal health personnel) who responded to have been previously vaccinated (> 10 years earlier) yet had a high titre range of 0.5 – 5.4IU/ml. The highest specific rate for rVNA of 25% each was seen amongst the dog butchers and pet owners followed by hunters (20%) and dog meat consumers (14.8%). Up to 125 (67.6%) of the volunteers do consume dog meat with only 12 (9.6%) of them being dog butchers who source dogs for slaughter from households within and outside their territories. Conclusion: Although the WHO minimum protective titre of rVNA is 0.5 IU/ml, the presence of relatively high titres amongst these risk groups in this report is an indication of a serious public health threat. This study recommends the vaccination of rabies high risk groups and further screening of rabies occupational risk and non risk groups in the study area and Nigeria at large.

Investigation of Outbreaks of Infectious Bursa Disease in Zaria, Nigeria.

Aim: To investigate outbreak of IBD in Zaria, Nigeria. Study Design: Prospective study. Place and Duration of Study: Sample: Poultry Unit of the Ahmadu Bello University Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Ahmadu Bello University, Zaria between March 2009 to July 2009. Methodology: Poultry cases reported to the clinics were investigated. Date, age, address, flock size, morbidity rate, mortality rate, breed, species, type of birds, vaccination history were noted; post mortem and agar gel precipitation test were done on 10 flocks, the incidence rate, morbidity rate, mortality rate and organ (bursa, spleen and thymus) to body weight ratio of the 10 flocks were calculated. Results: Chicks in all the flocks revealed the clinicopathologic manisfestation of IBD which include depressions, somnolence, anorexia, ruffled feathers, trembling, postration followed by death. In all the flocks, the BF were either turgid, swollen and or haemorrhagic, severe haemorrhages on the thigh and pectoral muscles, haemorrhages at the junction of proventriculus and gizzard or oesophagus, congested or pale carcasses, swollen kidneys with prominent tubules and enlarged pale or congested liver were also observed during postmortem examination. All the bursal homogenates from the 10 flocks gave precipitation line in the AGPT. An incidence of 12.1% was recorded. Average morbidity (40.5%) and mortality (40.7%) rates were recorded in ten outbreaks of IBD. Improved breeds of chickens were more likely to suffer from IBD with broilers 3.87 times at risk. Birds, 3-6 weeks-old were at a risk of being infected with IBDV. Chickens vaccinated once against IBD were 4.8 times more likely to suffer from IBD. Conclusion: IBD is a disease of improved breeds of poultry with clinical disease seen only in chickens. The disease mostly affects chickens of 3 to 6 weeks of age. Birds vaccinated twice are less susceptible to the disease.