Development and Evaluation of Wild-Derived Rats as Potential Experimental Models for Research

Abstract

Wild rodents have been used as animal models in experimental studies of cellular aging, cerebral malaria, schistosomiasis, and leishmaniasis. Since they are the reservoirs of these diseases, recent studies have shown that research involving wild rodents is more efficient in giving a mirror image of the disease progression outside the laboratory setting. The study design was an analytic experimental study where observations were made between two groups of animals i.e. the wild-derived and lab-bred rats. The outcome of the intervention was obtained by comparing the two groups. This study sought to determine the usability of wild-derived rats as potential experimental animal models for biomedical research. Wild rats were randomly captured in areas with high transmission of Schistosoma mansoni and Leishmania donovani in Kisumu and Kitui counties, in Kenya and maintained in the animal house at Kenya Medical Research Institute (KEMRI) in Nairobi. Breeding was carried out, and the subsequent generations were used to assess schistosomiasis and leishmaniasis disease progression between the wild-derived, and laboratory-bred rats. We further monitored behavior patterns and food consumption rate for 3 months in a total of 6 experimental trials. The results on feed consumption capacity indicated that consumption was significantly higher in laboratory-bred groups (p=0.001) compared to wild-derived rats. Overall, laboratory-bred rats were significantly heavier than wild rats. In the use of rats to assess schistosomiasis and leishmaniasis disease progression, the wild-derived rats were more susceptible to leishmaniasis and may be considered for S. mansoni compared to wild (worms recovered p=0.031). In conclusion, the study indicated that wild rats are potential reservoir hosts for both schistosomiasis and leishmaniasis and have the potential to maintain cycles of infection until after successful chemotherapeutic intervention. Therefore, wild rats may provide natural means for parasites like S. mansoni and L. donovani to re-infect humans in endemic areas.