Kissing Bugs Harboring Trypanosoma cruzi, Frequently Bite Residents of the US Southwest and Cause Severe Allergic Reactions, But Not Chagas Disease.

BACKGROUND: Kissing bugs are common household pests in the Desert Southwest of the United States. These hematophagous bugs enter homes and suck blood from resident humans and pets. They are vectors of Trypanosoma cruzi, an enzootic parasite in small mammals and the cause of Chagas disease in humans. Autochthonous cases of Chagas disease are rare in the US despite the presence of the vector and parasite. Environmental and biological factors accounting for this phenomenon need studying.

METHODS: Homeowners in Bisbee and Tucson, Arizona captured kissing bugs inside homes during 2017-18. Bugs were tested for presence of T. cruzi by PCR. Residents bitten by kissing bugs were tested for Chagas disease by serology. We evaluated invaded homes in the two cities.

RESULTS: Three species of kissing bugs (n=521) were collected in or near homes. Triatoma rubida was the most common triatomine in Tucson; T. recurva in Bisbee. T. protracta was uncommon. Seventeen percent of bugs captured in Bisbee and 51.1% in Tucson harbored T. cruzi. Bite victims (n=105) recalled more than 2200 bites. Reactions to bites were common including 32 episodes of anaphylaxis in 11 people (10.5%). Tests for Chagas disease (116) were negative. Median age of houses was 91years in Bisbee, 7years in Tucson. Bisbee houses had pier and beam foundations. Tucson houses were built on concrete slabs.

CONCLUSIONS: Kissing bugs harboring T. cruzi readily entered new and old homes. Bites of humans caused severe, life-threatening reactions. There was no serological evidence of Chagas disease among those bitten.