Study on the Prevalence, Intensity, Seasonal Dynamics of Abomasal Helminths in Sheep from Different Climatic Zones of Iran

Gastrointestinal nematodes of small ruminants are one of the major causes of productivity loss.This study was carried out to determine the correlation between the prevalence, seasonal incidence and geographical distribution January 12, 2011of abomasal worm infection of native sheep in 3 different climatic zones of Iran, suitable for animal husbandry. From March 2008 to February 2009 the contents of abomasums of 341 sheep from Mazanderan province (Zone I), 318 from Isfahan province (zone II) and 390 from Khuzestan province (Zone III) were washed separately in a 100 mesh sieve. The worms present in each abomasum were collected separately, counted and preserved in 70% alcohol containing 5% glycerin for identification to the species. The overall percentage of infection was 30.98% and Haemonchus contortus, Teladorsagia circumcincta, Marshallagia marshalli, Ostertagia occidentalis, Ostertagia trifurcata and Parabronema skrjabini were 6 species identified in all 3 studied areas. The overall prevalence rate and intensity of worm’s burden as representative of Iran, as well as in each of 3 different climatic zones were low, although Teladorsagia circumcincta was the most prevalent and frequent worm species found. Using Chi-Square and ANOVA, no significant relationship was found between prevalence, season, age and sex in 3 regions, although the intensity of worm burden in zone I was significantly higher than the other two zones (P= 0.011).