Observations on the Rôle of Cockroaches in Disease

As the cause of rlisease and as possible carriers of pathogenic organisms cockroaches have received less attention than other domestic pests, and less than might have been expected considering their wide distribution, their abundance, especially in tropical countries, their hlthy habits and the opportunities they have of contaminating food, and the almost universal loathing with which they are regarded.It is generally admitted that they are eminently htted to be disseminators of infections, and from time to time they have come under suspicion as such, but hitherto no definite charge appears to have been brought home against them.There is, however, some experimental evidence that certain pathogenic organisms may be transported by them or may pass through their intestines.Morrell (1911), for example, as the result of his experiments, concluded that the insects are able by contamination with their faeces to bring about the souring of milk, to infect food and milk •with intestinal bacilli, to transmit the tubercle bacillus, to disseminate pathogenic staphylococci, and to tram•mit from place to place destructive moulds.Longfellow ( 191 3) showed that they may carry on their legs Bacillus coli communis, B. proteus vulgaris, Staphylococetts aureur, S. citreus, and a bacillus of the subtilis type, and found the same organisms in their faeces.He, therefore, considered that, as possible carriers of infection, it is almost as important to prevent the multiplication of cockroaches as of house-flies.This view, however, may be somewhat exaggerated, since Herms (1915) has pointed out that the feet of cockroaches are less well provided with spines and hairs than those of the house-fly, and are, therefore, less well adapted to the collection of ftlth.Barber (1912), working in Manila, has shown that cockroaches may be infected with plague bacilli, and more