Prevalence and Diversity of Gastrointestinal Nematodes in Small Ruminants in Iran: a Systematic Review and Meta-analysis

Purpose

Gastrointestinal nematodiasis is a significant challenge in small ruminant breeding. The present systematic review and meta-analysis shed light on the frequency and distribution of the infection in a nationwide perspective.

Methods

The review used 34 animal level datasets retrieved from 26 published articles and the pooled estimates were calculated using a random-effects model analysis.

Results

Altogether, 9690 small ruminants were examined post-mortem or by coproscopy, among which 4193 animals were infected with GINs, showing a weighted prevalence of 55% (95% CI 44–66%). Reports were documented in 12 provinces with the highest frequency in Eastern Azerbaijan (77%), Kermanshah (76.04%), and Guilan (71.62%). Moreover, the highest prevalences were estimated among goats [61% (95% CI 48–74%)] and in coproscopy [67% (95% CI 57–78%)]. The reported GINs represented 15 genera, including Haemonchus contortus, Marshallagia marshalli, Trichuris spp., Trichostrongylus spp., Ostertaginae species, Gongylonema pulchrum, Nematodirus spp., Parabronema skrjabini, Skrjabinema ovis, Chabertia ovina, Cooperia punctata, Camelostrongylus mentulatus, Bunostomum trigonocephalum, and Oesophagostomum venulosum. The most isolated nematode species in sheep and goats belonged to H. contortus [7.44% (95% CI 6.78–8.13%] and Trichuris spp. [18.42% (95% CI 16.54–20.41%)].

Conclusion

A considerable parasitic prevalence was calculated in small ruminants in Iran, demanding strategic interventions for better control the GIN infections and decrease the worms burden and their consequences in sheep and goat population in Iran.