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The etiology of transmissible viral proventriculitis (TVP) of broiler chickens has been discussed since its initial recognition 40 years ago. Regardless of its low direct impact on mortality rate, it leads to high economic losses in the broiler industry through reduction of food conversion, weakening of birds, and their increased susceptibility to pathogens. The aim of the present study was to examine the potential presence of TVP on the broiler chicken farms in Bosnia and Herzegovina, to characterize microscopic lesions, and to investigate the viruses implicated in etiology of TVP by PCR-based methods. In total, 143 diseased broiler chickens from 16 farms in Bosnia and Herzegovina were euthanized and subjected to necropsy and subsequent histopathology of proventriculi. A representative number of proventriculi samples (n = 50) that exhibited histopathologic changes were processed for molecular detection of chicken proventricular necrosis virus (CPNV), girovirus (GyV3), chicken anemia virus (CAV), and infectious bursal disease virus (IBDV) by PCR-based methods. In addition, samples of bursa of Fabricius (n = 39) and spleen (n = 50) were tested for IBDV. Histopathology revealed changes consistent with TVP in 39.8% (57/143) and LP (lymphocytic proventriculitis) in 2.1% (3/143) of samples. All 50 proventricular samples showed positivity to CPNV with Ct values ranging between 18 and 26. GyV3 was detected in eight samples (16%), with Ct values ranging from 11.1 to 27.5. The presence of CAV was more prominent (38%), with 19 positive broiler chickens (Ct ranging from 9.6 to 35.6). Pooled samples of spleen, bursa, and proventriculi from three farms were positive for IBDV. The obtained results represent the first documented data on TVP and the first record of CPNV and GyV3 presence in broiler farms from Bosnia and Herzegovina. Full article

Transmissible viral proventriculitis (TVP) and chicken proventricular necrosis virus (CPNV) affect the broiler industry globally and are emerging diseases of economic importance. Here, we present the findings of TVP from processed broiler carcasses in Argentina following marked condemnation at the processing plant. We studied a total of 122 abnormally presenting proventriculi at processing from 42-to-50-day-old, male Cobb500^™ broiler chicken carcasses from 11 farms belonging to the same company in 13 episodes of proventriculi–gizzards condemnation between December 2021 and April 2022. The proventriculi were enlarged and pale with a widened gastric isthmus. A histopathologic lesion score system was developed based on the presence of a combination of key microscopic findings, the distribution, and the severity of the lesions. Scoring of the affected proventriculi revealed 65% (79/122) with a score of 4, 23% (28/122) with a score of 3, and 12% (15/122) with a score of 2. Focal to multifocal immunoreactivity against the VP2-CPNV antigen within the necrotic glandular epithelial cells was noted in the affected proventriculi using immunohistochemistry. We found 84.4% (103/122) of the studied proventriculi with TVP lesions grossly and microscopically scored were positive for CPNV by RT-PCR. The sequencing results of the PCR product showed a high nucleotide sequence similarity (88.97%) to previously published VP1-CPNV sequences. We confirmed CPNV infection in most of the TVP affected proventriculi in all condemnation episodes at a broiler chicken processing plant in Argentina during the studied period. This study documents TVP associated with CPNV detection at processing plants in Argentina for the first time. Full article

Transmissible viral proventriculitis (TVP) of chickens is manifested in decreased body weight gains, poor feed conversion and weight diversity. Although TVP etiology has not been defined, a Birnaviridae family member, named chicken proventricular necrosis virus (CPNV) is considered as a potential factor of a disease. This study was undertaken in order to reproduce TVP and to evaluate its etiology. Broiler chickens of the TVP-infected group were inoculated with TVP positive proventriculi homogenate on the 24th day of life. Samples were collected, on infection day and 14 days post-infection (dpi). The 14 dpi anatomo- and histopathological evaluation, revealed that we have succeeded to reproduce TVP. TVP-infected birds gained 30.38% less body weight. In the TVP-infected group a seroconversion against picornaviruses, fowl adenoviruses (FAdV) and infectious bursal disease viruses (IBDV) was recorded with an ELISA test. Using RT-PCR and PCR, CPNV was detected in proventriculi and FAdV in spleens and livers of infected birds, 14 dpi. Our study supports that CPNV is involved in the development of TVP. We did not record the presence of IBDV in TVP or control birds, despite our recording of a seroconversion against IBDV in TVP infected birds. CPNV and IBDV belong to the same family, which allows us to assume serological cross-reactivity between them. The role of FAdV needs further evaluation. Full article