The Significance of a High Incidence of Xenopsylla Braziliensis Baker

Sir,?In the course of a rat-flea survey of a few towns in the Travancore State, I happened to note an unusually high incidence of Xenopsylla braziliensis Baker, particularly in one locality, viz, Athirampuzha, a typical rural inland conservancy town, situated at an elevation of about 100 feet above sea-level, enjoying a fairly warm climate. The area surveyed comprises chiefly the market, grain-stores and a few thatched houses. Six hundred and foriy-three rats were trapped and 1,444 fleas were caught off them. Twenty per cent of the fleas were indentified to be Xenopsylla braziliensis as against only i per cent of Xenopsylla c'heopis, from the same collection. For the sake of comparison and contrast, an area about half a mile from Athirampuzha and included within the same conservancy limits, consisting mainly of residential premises ?uly, was also marked out and a survey almost in continuation of the above one showed cent per cent of Xenopsylla astia. It was therefore surmised that Xenopsylla braziliensis is not indigenous, that it thrives close association with grain, and that its importation the result of commercial intercourse. From the available literature at my disposal, it would appear that its distribution is very limited in Southern india, e.xcept in the Mysore plateau, where _ probably conditions are very suitable for its multiplication. I should therefore like to invite the opinion of your readers as t? the special significance, if any, of such a high mcidence of Xenopsylla braziliensis.