Eight species in two genera of Triatominae have been tested as vectors of plague. The plague bacilli were found to remain infective in Triatoma protracta (Uhler) for 3 days at 30°C., but were negative on the fifth day when the bugs were injected as an aqueous suspension into guinea pigs and mice.
Four adult Triatoma phyllosoma pallidipennis (Stål) in 2 different groups transmitted plague by interrupted feeding; i.e., first feeding on an infected mouse and then feeding on a healthy mouse. These transmissions were probably due to contaminated mouth parts. Thirteen similar feedings were negative using 5 other species of Triatoma.
Triatoma protracta and Mestor megistus (Burmeister) infected with Trypanosoma cruzi Chagas and Pasteurella pestis (Lehman and Neumann) were fed to mice; 4 positive plague infections resulted one of which was pneumonic; 3 mice were negative. Thirteen other tests with plague-infected Triatominae fed to mice failed to transmit P. pestis through the gastrointestinal tract, but produced 3 pneumonic cases.
Triatoma platensis Neiva was the only species to yield plague positive feces out of 17 specimens tested.