Pathological and Epidemiological Assessment of Trematode Burden in Ruminants From Central Ethiopia

Trematode infections in ruminants cause major economic losses through reduced productivity and liver condemnation, with their epidemiology closely linked to snail habitats, rainfall patterns, and poor grazing management. A cross-sectional study was conducted from November 2022 to March 2023 to characterize pathological changes caused by trematode infections and identify associated risk factors in ruminants slaughtered at three selected abattoirs in central Ethiopia.

A total of 256 ruminants, 137 bovine, 64 ovine and 55 caprine were included in the study. The sample size was determined based on the number of animals slaughtered per week and the frequency of slaughtering. Haematological analysis, coproscopic examination, and both ante-mortem and post-mortem inspections were performed to detect trematode infections.

The overall prevalence trematode was 49.22%, with the prevalence of 32.42% and 16.80% for fasciolosis and paramphistomosis, respectively. There was no statistically significant association between fasciolosis and animal species, but a significant association was found between paramphistomosis and fasciolosis. Fasciolosis prevalence was highest in caprine (41.82%), followed by ovine (31.25%) and bovine (29.50%). For both fasciolosis and paramphistomosis, prevalence was higher in animals with poor body condition (47.62% and 28.57%, respectively), moderate in those with medium body condition (32.81% and 28.97%), and lowest in animals with good body condition (28.97% and 15.89%). Based on geographic origin, the highest prevalence of fasciolosis was recorded in animals from Jimma (52.63%), while paramphistomosis was most common in animals from Dukem (22.50%). Histopathological findings in Fasciola-infected animals revealed haemorrhages, hepatocytic wall dilatation, necrosis, hypertrophy, and portal fibrosis. In Paramphistomum-infected animals, muscular degeneration and loss of villi and microvilli were observed. Haematological analysis showed reduced red and white blood cell counts and elevated liver enzyme levels.

The study revealed a high prevalence of fasciolosis and paramphistomosis in the study areas. Further research is recommended to explore the epidemiology of trematode infections, identify intermediate snail hosts, and develop effective strategic control measures.