Abstract
A colony of Onychomys torridus was evaluated for the prevalence of infectious, parasitic and congenital diseases. Multiple limb defects including brachydactyly, syndactyly, and hemimelia were observed in offspring from the colony. The colony was parasitized by Ornithonyssus bacoti (tropical rat mites) on 2 occasions. No infectious diseases were detected. Normal haematologic values were determined in healthy adult animals.