Association between Heterakis dispar infections and concurrent diseases in reproductive geese: A retrospective...

Heterakis infection, caused by small nematodes that inhabit the caeca, is one of the most frequently reported parasitic infections in poultry. Despite its prevalence, the impact of Heterakis spp. on avian health remains inconsistently described. This study retrospectively analysed the association between Heterakis dispar infection and other diseases in farmed geese. Among 194 necropsied reproductive geese from 2015 to 2023, 143 were found to be infected with Heterakis dispar, whereas 51 were not. In geese with caecal nematodes, bacterial infection was the dominant cause of death (89.5 %). Peritonitis caused by Escherichia coli was identified as the cause of death in 58.7 % of Heterakis-infected geese and 41.2 % of non-infected geese, with a positive association. Conversely, a negative association was observed between Heterakis dispar infection and two other bacterial diseases: pasteurellosis accounted for 29.4 % of deaths in the nematode-negative group and 15.4 % in the nematode-positive group, whereas erysipelas accounted for 21.6 % and 8.4 %, respectively. No association was observed between Heterakis dispar infection and other conditions such as tetratrichomoniasis, necrotic enteritis, arthritis, or neoplasms. Presumably the larval stage of the Heterakis life cycle, which involves penetration of the caecal wall, may facilitate secondary infections by bacteria naturally residing in the caecum, particularly E. coli. These findings highlight a possible role of Heterakis dispar in predisposing geese to specific bacterial infections through damage to the mucosa of the caecum.