The control of infectious bronchitis (IB) is essential in intensive broiler production and is pursued through strict biosecurity and mass vaccination. Despite effective and routinely adopted, hatchery spray vaccination has been hypothesized to affect chicks’ body temperature and wellbeing. Recently, gel administration has been proposed as an alternative and proved feasible in experimental settings. In this study, IBV spray and gel vaccination methods were compared in field conditions. One hundred birds from the same hatch were enrolled in the study and vaccinated, half by spray and half by gel, with 793B and Mass vaccines. After vaccination, rectal temperature was measured and vaccine intake assessed. The two groups were housed for 35 days in separate pens and swabs and blood samples were collected at multiple time points for genotype-specific molecular analyses and serology, respectively. The temperature was significantly lower in spray-vaccinated chicks 10 min and an hour after administration. A similar trend in 793B titres was observed in both groups, while the Mass vaccine was detected later but persisted longer in gel-vaccinated chicks. No differences were observed in mean antibody titres. Compared to spray, gel administration appears equally effective and less impactful on body temperature, thus supporting its application for IBV vaccination.

Our study reports the first molecular detection of the protozoan pathogen Histomonas meleagridis, the causative agent of histomonosis, in the poultry red mite Dermanyssus gallinae. Mite samples were collected from a commercial poultry farm and a backyard flock in Hungary and analyzed using PCR assays that targeted the COX1 gene in mites and 18S rRNA gene in H. meleagridis. Phylogenetic analysis confirmed the identity of D. gallinae and revealed distinct genetic lineages between farm and backyard isolates. H. meleagridis DNA was detected in 10 of 17 mite samples, representing multiple variants within Genotype 1. No histomonosis was detected in the examined poultry, although one hen harbored Simplicimonas sp. The findings suggest that D. gallinae could serve as a carrier for H. meleagridis, potentially facilitating the persistence and transmission of the pathogen. This novel host–pathogen association highlights the need for further research into the epidemiological role of poultry ectoparasites in the spread of histomonosis.

Transmissible viral proventriculitis (TVP) is an emerging disease in chickens, linked to chicken proventricular necrosis virus (CPNV), a recently identified birnavirus. Here, we describe the first molecular-confirmed case of TVP in Bangladesh, affecting both a white layer flock and a coloured meat-type parent stock (PS). Affected birds exhibited growth retardation, diarrhoea, and increased mortality, alongside hallmark gross changes of proventricular enlargement and wall thickening. From the meat-type PS, proventricular samples were collected for histopathology and molecular diagnostics. Histological analysis revealed severe glandular epithelial damage, necrosis, mononuclear infiltration, epithelial hyperplasia, and metaplasia. Using RT-PCR on nucleic acid extracted from FTA card samples, we detected CPNV, in addition to infectious bronchitis virus (IBV), infectious bursal disease virus (IBDV), and avian reovirus (ARV). The amplified CPNV VP1 fragment was sequenced, and phylogenetic analysis placed the Bangladeshi strain within clades of previously reported CPNV isolates. This study represents the first report of CPNV and TVP in Bangladesh, highlighting the need for active surveillance in commercial and breeder poultry flocks to understand the virus’s epidemiology and support the development of control strategies.

Transmissible viral proventriculitis (TVP) is an emerging disease in chickens, linked to chicken proventricular necrosis virus (CPNV), a recently identified birnavirus. Here, we provide the first molecular confirmation of TVP in Bangladesh from a coloured meat-type parent stock (PS) flock, while documenting a contemporaneous white layer flock with consistent clinical signs and characteristic gross lesions. Affected birds exhibited growth retardation, diarrhoea, and increased mortality, alongside hallmark gross changes in proventricular enlargement and wall thickening. From the meat-type PS, proventricular samples were collected for histopathology and molecular diagnostics. Histological analysis revealed severe glandular epithelial damage, necrosis, mononuclear infiltration, epithelial hyperplasia, and metaplasia. Using RT-PCR on nucleic acid extracted from FTA card samples, CPNV was detected. In addition, infectious bronchitis virus (IBV), infectious bursal disease virus (IBDV), and avian reovirus (ARV) nucleic acids were also identified. The amplified CPNV VP1 fragment was sequenced, and phylogenetic analysis placed the Bangladeshi strain within clades of previously reported CPNV isolates. This study represents the first molecularly confirmed report of CPNV associated with TVP in Bangladesh, highlighting the need for active surveillance in commercial and breeder poultry flocks to understand the virus’s epidemiology and support the development of control strategies.

This study reports an outbreak of hepatitis-splenomegaly syndrome (HSS) in a color broiler parent stock flock in Bangladesh, marking the first known instance of HSS associated with avian hepatitis E virus (aHEV) genotype 7 outside Europe and only the second report of HSS in South Asia. The affected flock exhibited severe clinical signs, including a high cumulative mortality, reaching 31.6% in hens, and an abrupt decrease in egg production, dropping by over 20 percent. Histopathological analysis of liver and spleen samples revealed multifocal areas of necrosis, hemorrhages, and bacterial colonies. RT-PCR confirmed the presence of aHEV and immunohistochemistry showed signals within hepatic sinusoids and peri-ellipsoidal zones in the spleen. Complete genome sequencing of RNA from liver and bile samples on the Illumina platform established a pathogenic link to aHEV genotype 7. Despite aHEV’s known association with HSS, inconsistencies in disease manifestation suggest additional cofactors influencing pathogenesis, with secondary bacterial infections potentially contributing to clinical severity in this outbreak. Overall, this case expands the geographic distribution of aHEV genotype 7 and highlights the need for further epidemiological studies to investigate genotype–pathogenicity associations, especially in regions with limited prior data on HSS.