Infection of kissing bugs with Trypanosoma cruzi, Tucson, Arizona, USA

Abstract

Triatomine insects (Hemiptera: Reduviidae), commonly known as kissing bugs, are a potential health problem in the southwestern United States as possible vectors of Trypanosoma cruzi, the causative agent of Chagas disease. Although this disease has been traditionally restricted to Latin America, a small number of vector-transmitted autochthonous US cases have been reported. Because triatomine bugs and infected mammalian reservoirs are plentiful in southern Arizona, we collected triatomines inside or around human houses in Tucson and analyzed the insects using molecular techniques to determine whether they were infected with T. cruzi. We found that 41.5% of collected bugs (n = 164) were infected with T. cruzi, and that 63% of the collection sites (n = 22) yielded >or=1 infected specimens. Although many factors may contribute to the lack of reported cases in Arizona, these results indicate that the risk for infection in this region may be higher than previously thought.

Figure 1

Adult female kissing bug of the species Triatoma rubida, the most abundant triatomine species in southern Arizona. Scale bar = 1 cm. 
Photo credit line: Photograph by C. Hedgcock.

Figure 2

Temporal pattern of adult Triatoma rubida insects collected in metropolitan Tucson, Arizona, USA, May–August, 2006. A) Average minimum daily temperature recorded in 2006 during the period shown (data obtained from www.wrh.noaa.gov/twc/climate/reports.php). B) Percentages of all adults (n = 134), males (n = 52), and females (n = 82) collected during the period, in 5-day intervals (e.g., the percentage of insects collected during May 15–19 is represented on May 17). Information about sex or collection date was not available for 16 adults, so they were not included in this plot.