Pathological, epidemiological features, and statistical study of histopathological changes in chicken transmissible viral proventriculitis

Transmissible viral proventriculitis (TVP) is a chicken disease whose etiology is not fully understood. This study aims to describe histopathological, macroscopic, and epidemiological data associated with possible new etiological agents. The samples comprised 62 broiler farms, 4 laying hen flocks, and 3 broiler breeders. The disease was identified by proventriculus thickening, confirmed through histopathological examination as the most reliable diagnostic method for TVP. Prevalence, clinical signs, gross lesions, epidemiological features, and statistical analysis were calculated. Microscopic findings confirmed the disease, which was classified into three distinct statuses: TVP characterized by the presence of both lymphocytic infiltration and necrosis; lymphocytic proventriculitis (LP) identified by lymphocytic infiltration alone, without the presence of necrosis (WP) denoting cases devoid of both lymphocytic infiltration and necrosis in the proventriculus. These statuses occurred at 23.6 %, 52.8 %, and 23.6 % rates, respectively. The disease prevalence was 20.9 % in flocks aged 15 to 40 days, with a mortality rate from 0.1 % to 0.5 % upon discovery. TVP and LP are marked by intense lymphocytic proliferation and necrosis, hinting at the involvement of infectious agents. Conversely, the absence of these characteristics in WP points to non-infectious etiologies for proventriculitis. The distinct proventricular wall hypertrophy observed in TVP and LP, as opposed to WP, reinforces the interpretation that, only for the conditions of this study, infectious agents amplify existing conditions rather than serve as primary catalysts for the disease.