Studies on Pathological Changes in the Gastrointestinal Tract Due to Helminth Infection in Backyard Chickens.

Backyard poultry farming is an important aspect for enhancing Pakistan's rural economy, yet helminth infections remain a major issue for flock health and productivity. This study was conducted to assess the prevalence of gastrointestinal helminth parasites and to record the associated gross and histopathological lesions in backyard chickens from 12 villages in and around Tandojam City, Sindh, Pakistan, between August and December 2022. A total of 76 adult chickens of both sexes were selected through systematic random sampling. Each chicken underwent a complete necropsy, and the gastrointestinal tract was carefully examined for helminth infestation. Tissue samples were collected and processed for histopathological evaluation using hematoxylin and eosin (H&E) staining. Out of 76 chickens examined, 68 (89.47%) were infected with parasites. Four species of cestode were isolated: Cotugnia digonopora (C. digonopora) (32.89%), Choanotaenia infundibulum (C. infundibulum) (27.63%), Raillietina cesticillus (R. cesticillus) (14.47%), and Amoebotaenia sphenoides (A. sphenoides) (3.94%). In addition, two nematodes were identified: Heterakis gallinarum (H. gallinarum) (43.42%) and Ascaridia galli (A. galli) (35.53%). Mixed infections involving both H. gallinarum and A. galli occurred in 12 birds (15.79%). Gross pathological changes included intestinal obstruction with bloody exudates, ballooning and enlargement of the ceca, petechial hemorrhages in the duodenum, and mild hepatic inflammation. Histopathologically, all infected chickens showed inflammatory cell infiltration, mucosal erosion, villous degeneration, and hemorrhagic enteritis. Notably, scolices of R. cesticillus and A. sphenoides were embedded within the intestinal epithelium. The detection of A. sphenoides in backyard chickens represents the first confirmed record of this species in Sindh Province, Pakistan. These findings highlight the high burdens of helminth infections in rural poultry and underscore the urgent need for routine anthelmintic treatment and strengthened biosecurity measures in backyard poultry across Sindh.