[Monitoring the natural foci of tularemia on Wrangel Island].

Long-term annual monitoring of the natural foci of tularemia was first made on Wrangel Island. The objects of the investigation were pellets of birds-myophages, blood samples from rodents, and excrements from carnivorous mammals. A total of 2626 biological samples were examined in the period 2002 to 2011. A serological test was ascertained to be the most effective method for the detection of tularemia epizooties; polymerase chain reaction should be used as an additional technique to examine blood samples, as well as rodent tubular bone debris taken from the pellets. Tularemia epizooties were registered in the populations of two species of lemmings every year, except in 2003. An intensive diffuse tularemia epizooty was first detected in this area, which emerged in 2019, peaked by spring 2011, and covered most of the island. The antigen of tularemia pathogen was identified in 43.46% of the samples under examination,which is a high quantitative indicator of the intensity of an epizootic process. The fact that positive samples are annually found in the same areas of the island suggests that the causative agent is steadily and long preserved in the parasitic system. The availability of stable and active natural tularemia foci on Wrangel Island calls for preventive measures, particularly vaccination of risk groups coming to the island to conduct researches.