tetano
Editor, Senior Moderator
Vet Res Commun
. 2026 Oct 29;51(1):25.
doi: 10.1007/s11259-026-11587-5.
Mohammad Enamul Hoque Kayesh 1 , Md Kamruzzaman Akimul 2 , Mosharaf Hosen 3 , A K M M Anower 2 , Md Rezaul Karim 4
Affiliations Expand
Avian influenza virus (AIV) remains a major threat to poultry production in Bangladesh, where both highly pathogenic (HPAIV) and low-pathogenic (LPAIV) subtypes circulate. Although HPAIV is typically associated with high mortality, H9N2 LPAIV often causes mild clinical disease but has been associated with reduced egg production and economic losses in commercial poultry. This study describes the concurrent detection of H9N2 and Salmonella spp. in a 33-week-old Hy-Line Brown commercial layer flock in Moulvibazar, Bangladesh, in which a marked decline in laying performance was observed. A total of 50 birds were sampled for virological and bacteriological investigations. Oropharyngeal swabs were tested by real-time reverse transcription PCR (rRT-PCR) targeting the influenza A virus matrix (M) gene, followed by H9- and N2-specific assays. Cloacal swabs were cultured using selective enrichment and plating methods, and presumptive Salmonella spp. isolates were confirmed by PCR targeting the invA gene. Among the sampled birds, concurrent H9N2 and Salmonella spp. were detected in 11/50, while no birds were positive for H9N2 alone; Salmonella spp. alone was detected in 3/50 birds. The investigated flock exhibited markedly reduced egg production, remaining at 0% through 25 weeks of age and reaching a maximum of only 71.72% at 46 weeks, compared with the breed-standard value of 88%, while cumulative mortality reached 23.4% by 46 weeks, substantially exceeding the breed standard. These findings document the concurrent detection of H9N2 and Salmonella spp. and poor laying performance in the investigated flock. Given the single-flock design, absence of an H9N2-only comparison group and a contemporaneous healthy control flock, and incomplete assessment of other infectious and farm-level factors, the findings do not establish a causal relationship or determine whether Salmonella spp. contributed to the observed production losses. Further controlled and longitudinal studies involving multiple flocks and appropriate comparison groups are warranted to clarify the respective contributions of H9N2 and bacterial coinfections to production losses in commercial layer flocks.
Keywords: Salmonella spp.; Bangladesh; Concurrent detection; Egg production; H9N2 avian influenza virus; Layer chickens.
. 2026 Oct 29;51(1):25.
doi: 10.1007/s11259-026-11587-5.
Concurrent detection of low-pathogenic H9N2 avian influenza virus and Salmonella spp. in a poorly performing commercial layer flock in Bangladesh
Mohammad Enamul Hoque Kayesh 1 , Md Kamruzzaman Akimul 2 , Mosharaf Hosen 3 , A K M M Anower 2 , Md Rezaul Karim 4
Affiliations Expand
- PMID: 42955447
- DOI: 10.1007/s11259-026-11587-5
Abstract
Avian influenza virus (AIV) remains a major threat to poultry production in Bangladesh, where both highly pathogenic (HPAIV) and low-pathogenic (LPAIV) subtypes circulate. Although HPAIV is typically associated with high mortality, H9N2 LPAIV often causes mild clinical disease but has been associated with reduced egg production and economic losses in commercial poultry. This study describes the concurrent detection of H9N2 and Salmonella spp. in a 33-week-old Hy-Line Brown commercial layer flock in Moulvibazar, Bangladesh, in which a marked decline in laying performance was observed. A total of 50 birds were sampled for virological and bacteriological investigations. Oropharyngeal swabs were tested by real-time reverse transcription PCR (rRT-PCR) targeting the influenza A virus matrix (M) gene, followed by H9- and N2-specific assays. Cloacal swabs were cultured using selective enrichment and plating methods, and presumptive Salmonella spp. isolates were confirmed by PCR targeting the invA gene. Among the sampled birds, concurrent H9N2 and Salmonella spp. were detected in 11/50, while no birds were positive for H9N2 alone; Salmonella spp. alone was detected in 3/50 birds. The investigated flock exhibited markedly reduced egg production, remaining at 0% through 25 weeks of age and reaching a maximum of only 71.72% at 46 weeks, compared with the breed-standard value of 88%, while cumulative mortality reached 23.4% by 46 weeks, substantially exceeding the breed standard. These findings document the concurrent detection of H9N2 and Salmonella spp. and poor laying performance in the investigated flock. Given the single-flock design, absence of an H9N2-only comparison group and a contemporaneous healthy control flock, and incomplete assessment of other infectious and farm-level factors, the findings do not establish a causal relationship or determine whether Salmonella spp. contributed to the observed production losses. Further controlled and longitudinal studies involving multiple flocks and appropriate comparison groups are warranted to clarify the respective contributions of H9N2 and bacterial coinfections to production losses in commercial layer flocks.
Keywords: Salmonella spp.; Bangladesh; Concurrent detection; Egg production; H9N2 avian influenza virus; Layer chickens.