First report on the prevalence and histopathological characterization of Histomonas meleagridis in backyard chickens from Batna Province, Eastern Algeria.

BACKGROUND

Histomonas meleagridis is a protozoan parasite responsible for histomoniasis, a severe disease in turkeys that causes characteristic cecal and hepatic lesions and potentially high mortality. Chickens are generally less affected but are recognized as important reservoirs and asymptomatic carriers. Despite its global distribution, the epidemiological situation of histomoniasis in Algerian backyard poultry remains poorly documented. This is of particular concern because backyard flocks, including turkeys, are often located near commercial poultry farms, and no effective treatment is currently available.

AIM: This study aimed to investigate the prevalence and histopathological characterization of H. meleagridis in backyard chicken farms in the Batna region (Eastern Algeria).

METHODS

A total of 43 backyard chickens (Gallus gallus domesticus, Linnaeus, 1758), including 17 males and 26 females, were examined from September 2024 to May 2025. The backyard farms (n = 20) within the study region were randomly selected. Chickens presenting clinical signs suggestive of histomoniasis were submitted for diagnostic investigation and screened for H. meleagridis infection using macroscopic and microscopic methods. Positive and negative H. meleagridis samples were subsequently evaluated using a lesion scoring system to assess the severity of cecal and hepatic lesions.

RESULTS

A total of 21 chickens (48.83%) from 12 farms showed macroscopic lesions typical of histomoniasis, whereas 18 chickens (41.86%) from 13 farms tested positive through histological analysis. Among the 43 chickens examined, 19 were infected with Heterakis gallinarum, corresponding to a prevalence of 44.18%. Co-infection with both parasites was detected in 7 birds (16.27%). Infected chickens exhibited significantly more severe lesions in the liver and ceca than uninfected birds (p < 0.05). No significant difference was found between lesions in H. meleagridis-infected birds and those co-infected with H. gallinarum.

CONCLUSION

To the best of our knowledge, this is the first report on the prevalence and histopathological characterization of H. meleagridis in backyard chicken farms in Batna province, Eastern Algeria. Our findings suggest that H. meleagridis is the primary cause of cecal lesions, whereas H. gallinarum does not significantly aggravate the lesions. Given the proximity of these farms to commercial poultry operations, especially turkey farms, the study highlights the pathogenic importance of H. meleagridis, which could pose a serious threat to the commercial poultry industry, particularly due to the limited availability of effective treatments.