Browsing by Author "Teifke, Jens"
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Item Epidemiology, pathology and immunohistochemical detection of Nigerian Highly Pathogenic Avian Influenza (HPAI) H5N1 virus infection in chickens(Nigeria Veterinary Medical Association, 2007) Akanbi, Olatunde; Teifke, Jens; Ekong, Pius; Ighodalo, E T; Oyetunde, I L; Ogunsan, E A; Makinde, A ANigeria experienced an outbreak of Highly Pathogenic Avian Influenza (HPAI) H5N1 virus in both commercial and local poultry populations during January, 2006 as an extension of the global outbreaks. Up till August 2007, a total of 25 States of the 36 States of the Federation and the Federal Capital Territory (Abuja) have been affected by these outbreaks that occurred in about 200 premises, causing the death of millions of chickens. In younger birds and local chickens HPAI viruses caused rapid widespread mortality with minimal clinical evidence of disease while manifestation of clinical disease tended to be more overt with older flocks. Birds with HPAI typically presented with nonspecific signs of severe progressive depression, anorexia, decreased activity, huddling, and ruffled feathers. Somnolence, prostration, conjunctival pallor, catarrhal rhinitis, swollen and cyanotic combs and wattles sometimes congested and haemorrhagic, greenish-yellow diarrhoea, during high morbidity with mortalities up to 100% were observed in affected commercial and local flocks. Following confirmatory diagnosis by virus isolation, investigation of the organ predilections of the virus in formalin-fixed, paraffin-embedded (FFPE) tissues using histopathology and immunohistochemistry were carried out. Histologic lesions were observed in multiple organs and were characterized by hemorrhage, necrosis, mild inflammatory exudate, or a combination of these. In particular, the lung, heart, brain, spleen, pancreas, kidneys, combs and wattles were the most consistently affected tissues, which corroborated with the high predilection of viral antigen detected by immunohistochemistry in these organs. The advantage of immunohistochemistry over other diagnostic methods in HPAI diagnosis is invaluable in retrospective studies of FFPE tissues. In the near future, work up of cases which had similar lesions which may have been misdiagnosed or ignored due to the non incidence of HPAI in Nigeria prior to that period would be conducted.Item 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(Nigerian Veterinary Journal, 2017) Akanbi, Olatunde; Fereidouni, Sesan; Taiwo, Victor; Starick, Elke; Okewole, Philip; Binder, Alfred; Heenemann, Kristin; Teifke, JensIn 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.