Public health importance of rodents in South America.

Indigenous South American rodents are abundant, varied, and adaptable, and occupy most of the available natural habitats. Knowledge of their taxonomy and biology is generally superficial. Near human habitations the introduced Rattus and Mus are common and their contacts with man are often close. Cities in South America are expanding to keep pace with increases in the human population and hitherto virgin land is being settled or cleared for food production. Thus domestic rodents are brought into contact with indigenous species and the inevitable exchange of parasites may then produce unpredictable threats to human health. The role of both wild and domestic rodents in the transmission of certain infectious diseases, such as plague, sylvatic Venezuelan encephalitis, South American haemorrhagic fevers, murine typhus, and cutaneous leishmaniasis, is well established. The involvement of rodents in some other diseases, such as leptospirosis, American trypanosomiasis, South American hydatid disease, and vesicular stomatitis, is less well understood. In certain other infections, including bartonellosis and the South American spotted fevers, a wild rodent reservoir is inferred but not yet identified.