The global spread of HPAI (H5N1) between 2005 and 2006 was blamed on movement of migratory wild birds and trade in live poultry across continents from infected regions. A survey was carried out to detect the presence of avian influenza (AI) antibodies in wild birds and AI viruses in poultry and wild birds from Kogi state, Nigeria. Haemagglutination inhibition (HI) test and enzyme link immunosorbent assay (ELISA) were used to detect AI antibodies in some species of apparently healthy wild birds during the survey. Using HI test, the wild birds were negative for AI (H5) antibodies but ELISA detected AI (NP) antibodies in Black Stork (Ciconia nigra) with an overall seroprevalence of 4.5% and mean titre of 24.50±2.400 EU. Cloacal swabs from the same species of wild birds that were tested for antibodies and 710 oropharyngeal swabs from poultry were tested for AI viruses using RT-PCR with primers targeting the AI matrix proteins but were negative for AI viruses. The detection of AI (NP) antibodies in wild birds but failure to detect the viruses showed that the exposure might not be recent. We recommend that poultry should be prevented from contact with wild water birds and a broad based surveillance for AI viruses in poultry and wild birds should be carried out in Kogi state, Nigeria.

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An outbreak of highly pathogenic avian influenza (HPAI) subtype H5N8 in two multiage chicken flocks in Jos, Plateau State, Nigeria, is described. Diagnosis was made using tissue samples from the affected farms that were submitted to the Regional Lab for Animal Influenza and other Transboundary Animal Diseases, National Veterinary Research Institute, Vom. Pullets with broilers of 9 and 4 weeks of age respectively, from farm A (fA) and broilers, 4 weeks of age from farm B (fB) were submitted from flocks experiencing a drastic increase in mortality. The February 2019 outbreak resulted in10-60 % and 60 % mortality on fA and fB respectively. Clinical signs included anorexia, depression, hock sitting and sudden onset of increasing mortality. Gross lesions included edema of the head with cyanosis of comb and wattle; swollen abdomen due to ascites; generalized congestion of visceral organs with frank blood in the abdomen; congested mesenteric vessels with haemorrhages in the mucosa of small and large intestines; congested and frothy lungs with severe hemorrhagic tracheitis among others. In view of the clinical and gross pathology, HPAI was considered as the tentative diagnosis. Diagnosis of HPAI subtype H5N8 was confirmed by reverse transcriptase polymerase chain reaction and viral isolation in embryonated chicken eggs. The current outbreak has shown the presence of HPAI H5N8 in the country different from the H5N1 subtype that was introduced since 2006 in Nigeria. The co-circulation of these two subtypes if the current wave of infection is left unchecked will have adverse effects on poultry production, international trade and human health. Hence, the need for the re-evaluation and strengthening of the Government control policy to save the poultry industry from perennial economic loses.

The control of highly pathogenic avian influenza (HPAI) in Nigeria from inception is predicated on effective biosecurity by stamping out policy but outbreaks of the disease continued to re-occur with altered clinico-pathologic manifestations. This study undertook the qualitative assessment of the clinico-pathological features of HPAI H5N1 during the 2021/2022 outbreaks in commercial poultry and peri-domestic birds in northern Nigeria. A total of 22 commercial poultry farms with 53,932 laying chickens and 3 households with 120 backyard broiler chickens, 18 indigenous chickens, 10 peafowls and 9 geese were investigated for HPAI. The clinico-pathologic manifestations observed in commercial poultry were subtle compared to previous presentations of the disease except in the peafowls, geese, broilers and indigenous chickens. The interspecies mortality rates significantly varied from 1.6% to 19.6% for laying chickens and 33.3% to 100% for broilers, indigenous chickens, geese and peafowls. Based on the history of sudden and high mortality, clinical signs and post mortem lesions observed, three diseases; HPAI, very virulent Newcastle disease and fowl cholera were drawn out as differential diagnoses. However, a tentative diagnosis of HPAI was made and samples were sent to the National Veterinary Research Institute, Vom, Plateau State, Nigeria for confirmatory diagnosis. Results of the laboratory tests conducted on the samples using one step flu A screening and duplex real time RT-PCR,