XXXV. On the spread of epidemic plague through districts with scattered villages: with a statistical analysis.

Extract

It is well established that plague, once it has gained a foothold in a place, tends to recur every year at the same season and that the plague season varies in different places. It has been demonstrated that in Bombay City the periods between the epidemics are bridged over by cases of acute plague amongst the rats accompanied by a few cases in man. Knowing, then, the factors which determine the rise and fall of the epizootic amongst the rats, once the infection is present, we have a fairly complete conception of the seasonal prevalence of human plague in a city such as Bombay. In the case, however, of a large province, such as the Punjab, with scattered villages, the question of the annual recrudescence in the several villages is not so simply answered. For, it will be remembered that in the two Punjab villages of Dhand and Kasel, which were under close observation by the Commission for a whole year, no acute plague was found amongst either man or rats in the long interval between the epidemics. While this is so, a certain number of rats were caught alive, which, although apparently in good health, harboured living and virulent plague bacilli in chronic abscesses (see above, p. 335).