Ectoparasites of Commensal Rodents from Backyard Farmlands in Baguio City, Philippines

Abstract

Ectoparasites associated with rodents generally transmit vector-borne diseases to humans. This study aimed to determine the assemblage
of ectoparasites and the conditions of ectoparasite infestation at both the levels of population and species of rodent hosts
collected from private backyard farmlands in Baguio City, Northern Luzon, Philippines. Forty rodents were captured and identified as
Rattus tanezumi, Rattus exulans, Suncus murinus, and Mus musculus. A total of 35 rodents were found to harbor 1,658 ectoparasites
represented by eleven species. These species generally grouped as mites (Laelaps nuttalli, Laelaps echidninus, Ornithonyssus bacoti
and three other Laelaps species), lice (Polyplax serrata, Polyplax spinulosa and Hoplopleura pacifica), ticks (Ixodes granulatus), and
fleas (Xenopsylla cheopis). L. nuttalli, which had never been found to be associated with any vector-borne disease in humans, had
the highest prevalence. The most notable rodent ectoparasites (X. cheopis, O. bacoti and H. pacifica, P. spinulosa and P. serrata)
responsible for diseases such as bubonic plague, dermatitis, and murine typhus had relatively low prevalence, and therefore had low
probability of disease transmission. The condition of ectoparasite infestation varied among the rodent species, in which infestation was
found to be more common in the Rattus species. Results suggest that in Baguio City, the present condition of ectoparasite infestation
does not pose a risk of vector-borne disease transmission to people living near the farmlands.