Abstract

Plague which is a flea borne zoonotic disease of mammals caused by the bacterium Yersinia pestis has occurred in Eastern and Southern parts of Zambia as epizootics. This study was conducted to determine factors associated with these outbreaks. The study was done in Namwala district of Zambia and a cross-sectional study design was used. The two stage cluster sampling technique was used. The first stage involved conveniently identifying the 8 villages where human cases of plague had been reported. The second stage was random selection of households within the villages. These were sampled without prior knowledge of whether the household had a case of human plague or not. The sampling unit was the households. A total of 45 households were sampled. Twenty six (42%) of the households reported to have had a human case. The mean age of these cases was 10.86 ± 6.74 years while 74% of these were males. The households who reported cases and those who did not report cases were not different in bush activities they were involved in, type of housing they lived in and in terms of floors of their respective houses. The households reporting cases as compared to those who did not report cases were more likely to have rodents with plague found in their surrounding (94.7% vs 73.1%), have dirty surroundings (84.2% vs 50%), have a radius of ≤ 20 meters as nearest human dwelling (94.7% vs 53.8%) and have unplastered walls of their houses (84.2% vs 38.5%) (P < 0.05). The entry of infected rodents with fleas to the human habitat and the contact of fleas with humans contribute to the outbreak of plague under conditions which favour survivor of fleas like unplastered houses, dirty surroundings and the existence of infected rodents within a household surrounding of 20 m or less. Employing measures which minimizes the contact between fleas and humans can reduce outbreaks.

Key words: Endemicity, Yersinia pestis, Namwala District, Zambia.