Diseases of Human Plague in 1974 - 2003 in Kazakhstan

Plague is a natural focal zoonotic infection. The natural carriers of the plague bacteria are various animals (mostly rodents). A human becomes infected either by bite of an infected flea, or by direct contact with a sick animal (most often during cutting). From 1974 to 2003 on the territory of Kazakhstan 33 cases of people infected with plague (including 2 cases of bacteria carrier) were registered in 25 natural epidemic foci. Over the past 30 years bubonic, bubonic-septic, skin-septic, tonsillar-bubonic and tonsillar forms of the plague have been reported. The age range of people infected with plague ranged from 3 to 65 years. Among infected with plague the largest number were workers involved in various agricultural work and schoolchildren. By a sign of gender, the majority of cases are men. Sources of the disease were different: wild rodent fleas, camels, two cases of disease associated with cutting of plague-infected hare, one person became infected while cutting saiga carcass, one case of the disease was recorded as a result of a child bite by a wild rodent, an aerosol infection was registered in 9% of cases. During the years of observation the largest number of patients was recorded in July and in August. Modeling data on human plague disease using the K-function showed that there are clusters of outbreaks of human plague. Such clustering of outbreaks is observed at a distance of 1000 m, and from the distance between outbreaks of 4000 m there is a dispersed spatial arrangement of outbreaks. The proximity analysis showed that in outbreaks of plague from 1974 to 2003 there is a clustering of diseases of people with plague with a 99% confidence interval at a z-score value: - 2.03 and p values <0.01.