Free-roaming Kissing Bugs, Vectors of Chagas Disease, Feed Often on Humans in the Southwest

Abstract

BACKGROUND Kissing bugs, vectors of Trypanosoma cruzi, the parasite that causes Chagas disease, are common in the desert Southwest. After a dispersal flight in summer, adult kissing bugs occasionally gain access to houses where they remain feeding on humans and pets. How often wild, free-roaming kissing bugs feed on humans outside their homes has not been studied. This is important because contact of kissing bugs with humans is one means of gauging the risk for acquisition of Chagas disease. METHODS We captured kissing bugs in a zoological park near Tucson, Arizona, where many potential vertebrate hosts are on display, as well as being visited by more than 300,000 humans annually. Cloacal contents of the bugs were investigated for sources of blood meals and infection with T. cruzi. RESULTS Eight of 134 captured bugs were randomly selected and investigated. All 8 (100%) had human blood in their cloacae, and 7 of 8 (88%) had fed on various vertebrates on display or feral in the park. Three bugs (38%) were infected with T. cruzi. Three specimens of the largest species of kissing bug in the United States (Triatoma recurva) were captured in a cave and walking on a road; 2 of 3 (67%) had fed on humans. No T. recurva harbored T. cruzi. CONCLUSIONS This study establishes that free-roaming kissing bugs, given the opportunity, frequently feed on humans outside the confines of their homes in the desert Southwest and that some harbored T. cruzi. This could represent a hitherto unrecognized potential for transmission of Chagas disease in the United States.

Triatoma sanguisugaBlood Meals and Potential for Chagas Disease, Louisiana, USA

“…Results of our study, as well as those of Stevens et al ( 10 ) and Kjos et al ( 14 ), reject the assertion that kissing bugs in North America prefer blood from wild animals, which has been one explanation for the low prevalence of Chagas disease in the United States. Our study provides evidence of frequent vector/human/ T. cruzi contact in Louisiana and reveals the potential for transmission in the United States.…”

Evidence of Likely Autochthonous Transmission of Chagas Disease in Arizona

“…2 Kissing bug domiciliation or infestation of human dwellings has been described in this region of southern Arizona. 5,6 Furthermore, T. rubida in Tucson often harbor T. cruzi: 128 T. rubida captured in a zoological park had a rate of carriage of T. cruzi of 25%. 7 An earlier study by Reisenman et al 8 demonstrated a rate of carriage of T. cruzi by T. rubida to be 41% (N = 158 bugs).…”

Towards a phylogenetic approach to the composition of species complexes in the North and Central American Triatoma, vectors of Chagas disease

“…With regards to epidemiological importance, Triatoma gerstaeckeri , Triatoma sanguisuga , and Triatoma lecticularia have been implicated as the vectors of autochthonous transmission in the United States [23–27]; and all three species are found in close association with homes in rural areas of Texas and Louisiana [28–31]. Human blood meals are common in Triatoma rubida from Arizona and California [22,32]. Many species within the Lecticularia complex show morphological variation across their broad geographic range including T. rubida and T. sanguisuga .…”