RESUMO
Globally, vaccines are used to prevent and control the menace of infectious diseases in livestock with some reported to be inadvertently contaminated with extraneous agents (EAs). With the aim of screening and characterizing for some selected EAs, 44 live viral poultry vaccines were randomly selected based on availability. The vaccines comprised 14 manufacturers in 10 different countries including Nigeria were screened by Polymerase Chain Reaction. In 9% (4/44) of the vaccines, contamination with only avian leukosis virus (ALV) subgroup J (ALV-J) was recorded. Other exogenous ALV subgroups, chicken infectious anemia and infectious laryngotracheitis viruses were absent. The EAs was found in infectious bursal disease (nâ¯=â¯1), Fowlpox (nâ¯=â¯2) and Mareks disease (nâ¯=â¯1) vaccines. Phylogenetic analysis of the ALV-J env gene showed clustering with contemporary group I and II. The result underscores the importance of screening vaccines to avoid the introduction and spread of EAs that could pose a threat to poultry production.
Assuntos
Vírus da Leucose Aviária/imunologia , Leucose Aviária/imunologia , Contaminação de Medicamentos , Doenças das Aves Domésticas/imunologia , Vacinas Virais/imunologia , Animais , Leucose Aviária/virologia , Vírus da Leucose Aviária/classificação , Vírus da Leucose Aviária/genética , Produtos do Gene env/classificação , Produtos do Gene env/genética , Produtos do Gene env/imunologia , Nigéria , Filogenia , Reação em Cadeia da Polimerase/métodos , Aves Domésticas , Doenças das Aves Domésticas/virologia , Vacinas Atenuadas/imunologiaRESUMO
Genetic analysis of the complete haemagglutinin (HA) gene of fourteen Nigerian avian influenza isolates showed multiple basic amino acids at the cleavage site (321PQRERRRK del R*GLF333), characteristic of highly pathogenic avian influenza (HPAI). Substitution of Gln to Lys at position 322 (H5-specific numbering) was identified in one isolate. In some isolates, amino acid substitutions were observed across the HA gene, however the receptor binding, antigenic and glycosylation sites were conserved in all. Phylogenetic analysis revealed two clusters of the HPAI H5N1 clade 2.3.2.1c. Cluster I has close genetic relatedness (97.8-99.8%) with viruses circulating in some West Africa countries. Cluster II shared close identity (98.9-100.0%) with isolates from Europe, Côte d'Ivoire and Niger and viruses from this cluster were detected in five of the eleven states investigated in Nigeria. In view of the continuous HPAI outbreaks being recorded in Nigerian poultry and the zoonotic potential of the virus, extensive and continued characterization of HPAI isolates is advocated.
