Long-lasting Parasitism of Strongyloides venezuelensis in Mongolian Gerbils (Meriones unguiculatus)

Mongolian gerbils (Meriones unguiculatus) were infected with 100, 1,000 and 10,000 Strongyloides venezuelensis infective larvae (L3) to determine the duration of fecal egg output. Eggs per gram of feces (EPG) were counted chronologically, and adult worms in the small intestine were recovered on 100 days after infection. Changes of EPG in Mongolian gerbils infected with 10,000 L3 also were observed for 450 days. EPG was stable for each dose after the peak value noted 9 or 10 days after the infection. The EPG and number of worms recovered were dependent on the dose. The high EPG value continued for 450 days. These results demonstrate that Mongolian gerbils allowed a long-lasting parasitism of S. venezuelensis. Strongyloides venezuelensis-Mongolian gerbil systems may be useful for parasitological study of S. venezuelensis.