Survey of Babesia sp. and tapeworm infection in house rats (Rattus norvegicus) collected from Quiapo, Manila

Thirty-five house rats (Rattus norvegicus) from Quiapo, Manila were examined for the presence of Babesia sp. and tapeworm parasites. Giemsa-stained thin blood smears showed a 34.3 prevalence for Babesia sp. infection with percent parasitemia ranging between 0.30 to 1.15. These rats were collected from April 1995 to January 1996. The eight male (50) and four female (21) rats found positive for Babesia sp. infection were collected during the months of November 1995 to January 1996. Infection was noted highest in rats with body weights ranging between 171 to 220 grams. The data seem to suggest that male rats are more susceptible to infection. The parasites observed inside erythrocytes were of diploid and triploid form. Of the 35 rats examined, 32 (91.4) were found positive for tapeworms belonging to Hymenolepis spp. Fourteen (87.5) male and 18 (94.7) female rats had the infection. The morphology of the tapeworm scolex points to Hymenolepis nana as one definitive etiologic agent. The presence, however, of Hymenolepis diminuta which is reported as the more common tapeworm species in rats cannot be discounted. This is due to the non-recovery of the scolices needed for identification of Hymenolepis diminuta