[Rodents and the plague in Iran and Brazil. New data]

Rats of the Meriones species (gerbil rodents), involved in the epidemiology of plague in Iran, have an abdominal cutaneous gland which leaves secretions on the floor of the galleries in which they live. Its odorous marking is specific to the species having dug the burrow and is repulsive for all other species. This fact must be accounted for: locally, the eradication of the most sensitive species would probably help in limiting or perhaps even doing away altogether with the plague focus. In north-eastern Brazil, the statistical interpretation of field data revealed the fundamental role of the Rattus rattus, thereby justifying the continued and intensified fight against this domestic rodent.