Wild aquatic birds are natural reservoirs of influenza A viruses and H3 subtype is one of the most prevalent subtypes in waterfowl. Two H3N8 viruses of low pathogenic avian influenza (LPAI) were isolated via egg inoculation technique from the fecal swab specimens from imported barnacle goose and paradise shelduck in Veterinary Research Institute Ipoh, Malaysia. The full length of eight gene segments of the two viruses were amplified and sequenced with specific primers. The sequences were molecularly characterized, and the sequence identity were assessed with other published sequences. The two viruses are identical and they possess the same amino acid sequences for all the eight gene segments. The viruses were highly similar to the H3 virus from Netherlands and N8 virus from Belgium respectively. Phylogenetic analysis revealed that all the eight gene segments were grouped in the Eurasian lineage, and genetic reassortment may occur between the internal genes of the H3 viruses and other AI subtypes. Though four amino acid substitutions were identified in the hemagglutinin gene, the viruses retained most of the avian-type receptor binding preference. Few amino acid substitutions were observed in all internal genes. Most of the neuraminidase inhibitors and adamantine resistance related mutation were not seen in the viruses. The replicative capacity, cross species transmissibility, and potential zoonotic risk of the viruses are worth further investigation. As H3 virus poses potential threats to both human and animals, and with the increase in the international trade of birds; strict quarantine practice at the entry point and good laboratory diagnostic capabilities is crucial to prevent the introduction of new AI virus into our country.
Low pathogenic avian influenza (LPAI) subtype H9N2 is a causative agent that has raised increasing concern about its impact on poultry and potential public health threats. Even though H9N2 is endemic in Peninsular Malaysia, it was first reported in Sabah in August 2022, after an outbreak associated with high mortality in broiler chickens. In the present study, based on the hemagglutinin (HA) gene, we report the genetic variations and phylogenetic analysis of a H9N2 virus isolated from broiler chickens in Sabah. The sequence analysis of the HA gene revealed a 98% similarity to the H9N2 virus recently isolated from China in 2018. The amino acids in the HA cleavage site displayed a characteristic LPAI motif (PARSSR/ GLF). Notably, at position 226, the isolate had amino acid Leucine (L) demonstrating its ability to bind to the receptor of mammals, resulting in the potential risk of transmission to humans. In addition, the H9N2 isolate harboured seven potential N-glycosylation sites. The phylogenetic analysis revealed that the isolate belonged to clade h9.4.2.5 in the Y280 lineage, similar to previously reported in Malaysia. However, we observed that the isolate in this study falls in a different cluster compared with previous Malaysian isolates, suggesting different source of H9N2 introduction into the country. This prompts us to propose continuous and thorough surveillance of poultry across the country and the necessity of implementing farm biosecurity to minimize economic losses and potential threats to public health.