NATURAL AND EXPERIMENTAL INFECTION OF BEDBUGS WITH WUCHERERIA BANCROFTI IN BRITISH GUIANA.

Abstract

Summary In Georgetown, British Guiana, 100 Cimex hemipterus (older nymphs and adults) were collected from a bed used by two persons who were positive and two persons who were negative for microfilariae of Wuchereria bancrofti. Eighty-three of the bedbugs contained at least one living or dead parasite. Early first-stage larvae were found in the abdomen, thorax, legs, and antennae. Eight bugs had a total of 9 sausage forms, of which 2 were dead and 3 apparently moribund. Also found were 2 sluggish second-stage larvae, and 3 infective larvae of which 2 were non-motile. Rupture of the stomach from overengorgement and consequent release of the parasites into the hemocoele was observed in 12 bugs. The development of W. bancrofti was studied in five lots of bedbugs fed on a human carrier having 165 to 200 microfilariae per 20 cmm of blood at the time of feeding. Little development occurred in 100 first- and second-instar nymphs, which sucked up relatively few parasites. Four lots of 50 older bedbugs were given, respectively, 0, 1, 2, and 3 non-infective blood meals at 4-day intervals after the infective meal. It was found that as the number of additional feedings increased, the parasites survived longer and developed further. No infective larvae had developed by the 20th day. Because the mortality of larvae was high in both natural and experimental infections, and only a few developed to more advanced stages, it is concluded that C. hemipterus is not a suitable host for W. bancrofti.