Toxoplasma gondii infection in Philippines Rattus spp. confirmed through bioassay in Mus musculus

• Main Authors: Cabanacan-Salibay, Cristina, Claveria, Florencia Garcia
• Format: Text
• Language: English
• Published: Faculty of Veterinary Medicine University of Zagreb 2006
• Subjects: Toxoplasma gondii; Rattus spp.; Philippines; serology; experimental mice; Rattus rattus
• Online Access: http://hrcak.srce.hr/5144; http://hrcak.srce.hr/file/8251

The absence of any published work on T. gondii infection in rats in the Philippines has compelled us to embark on this present study. Toxoplasma gondii infection was serologically ascertained in 55.5% of Rattus norvegicus and Rattus rattus mindanensis caught in agricultural (AGR), commercial (COM) and residential (RES) sites at Dasmariñas, Cavite. Infection accounted for 60.0% in R. norvegicus and 50.0% in R. rattus mindanensis, with anti-T. gondii antibodies (Abs) titre ranging from 1:64 to 1:2048. Chronic infection (≥1:256 anti- T. gondii Abs) was detected in 53 (61.0%) rats. There was an insignificant association between parasite infectivity, rat species and collection sites. In mice, seropositivity was 65.0% (93/144), and tissue cysts were detected only among those exposed to brain tissue of RES caught R. rattus mindanensis. Although mouse infection was clearly inoculum dose related, the consistent higher infectivity of T. gondii parasite from AGR and COM relative to RES caught Rattus spp. and other biological parameters, such as clinical manifestations, parasite encystations and mortality, suggest intraspecific strain differences in T. gondii infecting the Rattus spp. populations. We are currently assessing the severity of histopathology in seropositive mice exposed to brain tissue of chronically infected R. norvegicus and R. rattus mindanensis across the three collection sites, and we hope to provide additional information that would help clarify present findings and observations. The present study represents the first confirmed report of T. gondii infection of rats in the country.