Abstract

This paper documents the richness of parasites inhabiting Rattus tanezumi and Rattus norvegicus. Rattus spp. revealed six ectoparasites, namely: Chirodiscoides, Radfordia ensifera, Laelaps nutalli, Ornithonyssus bacoti, Xenopsylla cheopis and Polyplax spinulosa (louse). While infestation with L. nutalli was heavy or intense in 15 (100%) and 13 (86.7%) R. norvegicus and R. tanezumi, respectively, only R. tanezumi harbored Chirodiscoides and P. spinulosa at 80.0%. While all 30 rats examined showed 100% parasitism with ecto- and endoparasites, Nippostrongylus, Capillaria hepatica, Taenia taeniaformis, Raillietina and Hymenolepis, Babesia infection was noted only in eight rats (26.6%), with seven cases recorded in males. While both species of rats examined revealed vulnerability or susceptibility to different kinds of parasites, R. norvegicus seems to have bigger body capacity to house and nurture more diverse parasite species. Most dominant endoparasites were Nippostrongylus in 12 (80.0%) R. norvegicus and 15 (100.0%) R. tanezumi, and C. hepatica in 13 (86.6%) R. norvegicus and 10 (66.6%) R. tanezumi. Interestingly, Taenia taeniaformis and Raillietina were detected only in R. norvegicus at 80.0% and 20.0% infection rates, respectively. In view of the argument expressed (Zain et al. 2012) of a clear accumulation of helminth diversity and species richness or burden with increasing age of rat species, a follow up assessment is highly recommended to include those aspects not covered in this paper.

Key words: Rattus norvegicus, Rattus tanezumi, Philippines, parasites