A Survey of Helminth Infections in the Black Rat from Stara Zagora District, Bulgaria

A field study was conducted to disclose the prevalence of different helminth parasites in the black rat, Rattus rattus , in some regions of Stara Zagora district, Bulgaria. Out of 67 examined rats, 53 (79.1%) were found to be positive. Helminths of three classes were detected such as Cestoda: Hymenolepis diminuta (47.8%), Hymenolepis nana (43.3%), Taenia taeniaeformis larvae (7.5%), Taenia polyacantha larvae (1.5%); Secernentea: Syphacia obvelata (4.5%), Aspiculuris tetraptera (3.0%) and Adenophorea: Capillaria hepatica (9.0%), Trichuris muris (3.0%). Of all the investigated rats, 27 (40.3%) were infected by one helminth species and 26 (38.8%) by more than one. Hymenolepis diminuta was a predominant species in cases of single infections (23.9%). The most frequent co-infections were observed by H. nana and H. diminuta (16.4%).