Formalin-fixed and paraffin-embedded tissues of chickens are useful for retrospective studies on pathology of H5N1 Highly Pathogenic Avian Influenza Virus (HPAI) outbreaks in Nigeria

In a retrospective study, histopathology and immunohistochemistry (IHC) were performed on formalin-fixed paraffin embedded (FFPE) archival tissues from chickens obtained during outbreaks of highly pathogenic avian influenza (HPAI) H5N1 that occurred in Nigeria in 2006 and 2007. Ten samples as representative of 10 outbreaks were selected, and following the detection of HPAI viral antigen in different chicken tissues using IHC, RNA was extracted from each sample and molecular analysis was performed using real-time reverse transcription-polymerase chain reaction (rRT-PCR) targeting matrix protein. Seven rRT-PCR positive samples were then subjected to conventional and rRT-PCR assays for the amplification of hemagglutinin (HA) gene. Four of them were further characterized by sequence analysis of a short HA2-part of the H5 gene. Along the 154 nucleotides sequenced, differences at 4 positions were detected in one sample. One of these mutations led to an amino acid exchange at position 544 (Ala>Thr) whereas the others were silent. The study suggests the potential application for retrospective IHC and PCR analysis of FFPE tissues from chickens involved in the AI outbreaks for pathologic studies and providing short fragment sequences which may help in the characterization of viral strains and tracing the outbreaks. This is important as archived poultry tissues can be re-examined for possibility of earlier introduction of the virus.Keywords: Avian influenza; FFPE; H5N1; Nigeria; Immunohistochemistry; real-time RT-PC

Dog anti-rabies vaccination coverage in Jos South LGA of Plateau State, Nigeria CI Odita1, IS Tekki2*, DG Moses3, JI Barde3, KO Egwu3,

Domestic dog (Canis familiaris), a well-known companion of man, is the main reservoir host of rabies virus and source of infection to humans in 95% cases in Africa. Vaccination of dogs against rabies is the most effective way of controlling the disease. WHO recommends that annual vaccination coverage of dog populations should be 70% and above for effective control of rabies. However, vaccination coverage of dogs is very low in most African countries, including Nigeria, where the global burden of the disease is highest next to Asia. The aim of this study was to determine and compare rabies vaccination coverage of dog population in Jos South Local Government area (LGA), Plateau State, Nigeria, using two survey approaches. Data on vaccination profile of rabid suspected dogs in Jos South LGA, were retrieved from records of cases presented to the National Veterinary Research Institute (NVRI), Vom, Nigeria, for confirmatory diagnosis from 2011 to 2016. Field data on demography and vaccination profile of owned domestic dogs were also obtained by face to face interview with dog owners in the LGA using structured questionnaire. Vaccination coverage of 4.9% and 19.7% were obtained for record and field surveys respectively, for sample estimates. Although average vaccination coverage was estimated as 12.4%, the true population vaccination coverage could be between 12% and 18%, (95% CI). The P-value (0.000) for association between survey approach and true vaccination coverage of dog populations in Jos South LGA was significant. Consequently, evaluation of regular vaccination by active survey is key to achieving WHO recommended vaccination coverage. Nigeria can only align with the world rabies elimination target of 2030 set by the WHO, OIE and FAO by active disease surveillance and enforcement of responsible dog ownership.Keywords: Domestic dog, Jos South LGA, Rabies, Surveillance, Vaccinatio

Epidemiology and clinicopathological manifestation of resurgent highly Pathogenic Avian Influenza (H5N1) virus in Nigeria, 2015

In January, 2015 the National Veterinary Research Institute, Vom, Nigeria received some chicken carcasses from the Kano state Ministry of Agriculture. The carcasses were from a backyard-commercial poultry farm and a live bird market (LBM) in Kauna and Sabon gari, Kano state, northwestern Nigeria respectively. The farm kept  different types of chickens of various ages and stages and was experiencing high mortality of 350 birds daily with eventual 100% mortality observed in the older birds (54weeks). In a concurrent incidence, reports were received of unusual high mortality of birds brought from the northern part of the country at two LBMs in  Onipanu and Mushin, Lagos state, southwestern Nigeria. A total of 8 chicken  carcasses from the Kano suspicion were subjected to postmortem examination and testing. One broiler-chicken (4weeks old), 4 layer-chicken (22 weeks old) and 3 indigenous bred-chickens (from LBM) showed severe pathological lesions  consistent with highly pathogenic avian influenza (HPAI). Moribund birds from the Lagos suspicion had cyanotic comb and wattles, torticollis and paralysis of the limbs. Parenchymatous organs, nasal and trachea swabs were collected from the dead and moribund birds respectively. The specimens were analyzed by RT-PCR and virus isolation in embryonating chicken eggs. All samples were found to be positive for HPAI (H5N1) subtype. This marks the re-introduction of HPAI (H5N1) subtype into Nigeria for a second time in the space of 9-years. So far, over 542 cases (January to December, 2015) have been confirmed positive for HPAI (H5N1) in 20 states of the country. Possible circumstances surrounding the resurgent and spread are discussed herein.Key words: Epidemiology, Resurgent HPAI H5N1, Pathology, Nigeria