Serologic Survey of Plague in Animals, Western Iran

To the Editor: Plague has been one of the most devastating infectious diseases in human history. The etiologic agent, Yersinia pestis, primarily affects rodents and is usually transmitted to humans through infec-tive flea bites. Endemic plague foci result from circulation of the plague bacillus in its rodent reservoir, the source of human plague cases (1). Carnivores such as dogs and foxes, which prey on rodents and eat their fresh carcasses, are valuable sentinel animals for plague serosurveillance in disease-endemic foci, although their infections are usually asymp-tomatic (2,3). Plague epidemics have caused loss of human life in various parts of Iran. During 1947–1966 in western Iran, 9 human epidemics occurred and caused 156 deaths. The last case of human plague was reported in 1966 (4). Field investigations identified 4 Meriones rodent species as Y pestis reservoirs; 2 were resistant (M. per-sicus and M. libycus), and the other 2 (M. tristrami and M. vinogradovi) were susceptible to death from infection (4,5). The epidemiologic investigations demonstrated a 3–4 year plague epizootic cycle in Iran (5).