Kissing bugs (Triatoma species) are bloodsucking insects that are found primarily throughout the Americas. They are best known as vectors of Chagas disease. Very little is known about how these insects interact with humans here in the United States, especially Arizona.
Eleven species of Triatominae are native to North America and Hawaii. Their northern limit of distribution in the United States is likely determined by intolerance to cold temperatures. Natural infections of T. cruzi have been found in nine of these species collected from 10 states. Seven species of Triatominae are found in Arizona, with the most common species being Triatoma rubida (common in foothill regions of Phoenix and Tucson),Triatoma protracta, andTriatoma recurva.
Biology and Natural History of Kissing Bugs
Kissing bugs have a gradual development with five immature instars. These bugs feed on the blood of vertebrates, starting with the first instars, which take a blood meal within 2-3 days after hatching from the egg. Once reaching the adult stage these bus can be rather large, ranging in length from about 12 to 36mm. Kissing bugs seek refuge in rodent burrows, cavities, caves, and other locations with moderate temperatures, feeding throughout their lives in these locations. Females over their lifespan can lay up to several hundred eggs depending upon conditions. Active dispersal is achieved by flight in adults, usually around dusk and early evening. Immature kissing bugs cannoy fly but crawl when stimulated to find a food source.
Habitat and Host Association
Kissing bugs inhabit a variety of ecological environments, including human domestic environments. Within these environments their feeding patterns can vary. Kissing bugs will acquire a blood meal from a variety vertebrate hosts, which inlcude most commonly burrowing anmials such as the "pack rat". However, they are also opportunistic and have demonstrated some interesting behaviors here in Arizona, such as feeding on humans. When analyzing the contents of a blood meal source, kissing bugs have had human blood present in 30-40% of specimens. Other animals, including domestic pets (dogs, cats, birds), livestock (horses, goats, and sheep), and wild animals (horses, pigs, coyotes, racoons, frogs, snakes) have been isolated on blood meal analysis.
The tritomines living in Arizona are all non-domestic species that often feed on packrats (Neotoma species), yet they readily feed on a variety of vertebrate hosts they encounter, including humans. The Arizona-Sonora Desert Museum in Tucson, Arizona, is a regional educational living zoo that inadvertently supports large populations of Triatoma rubida and Triatoma protracta. These bugs plague many museum animals. One report from a local veterinarian showed that some animals were fed upon to the point of chronic blood loss, and possibly causing death, including a rare protected mountain rattlesnake (James L. Jarchow, DVM, personal communication). When and how some species of triaromines became specialists on humans is a mystery.
In the southwest, including Arizona, kissing bugs are the most active during the dispersal period. This time typically begins during the month of May and will last until late July. This is when humans are most likely to come into contact with kissing bugs. During this time period we find adult kissing bugs traveling, sometimes miles, in search of a mate and blood meal, as well as place for the female to her lay her eggs. Adults kissing bugs can fly! You can find them when conditions are calm. They usually avoid flying if the wind is greater then 5mph and/or when it is raining.
Kissing bug bites are the most common cause anaphylaxis due to an insect bite in the United states. Anaphylaxis is a medical emergency that results from the release of chemical signals in response to proteins in the bug's saliva. Victims usually are awakened at night with shortness of breath, low blood pressure, dizziness, skin rash, and generalized itching. Patient's who experience these symptoms after a kissing bug bite should call emergency medical services (911) so that they can be evaluated in the emergency room. Epinephrine injections and other interventions can reverse the low blood pressure, swollen airways and rashes that often accompany anaphylaxis. Patients may expeience anaphylaxis or anaphylactoid reactions each time they are bitten. Furthermore, each species of kissing bug produces its own unique salivary proteins, thus a peson can have anaphylaxis to one or more different species. Unfortuantely, one adult woman from Hawaii died from anaphylaxis as reported in 2015. The bite of kissing bug itself is painless, however swelling and inflammation at the site of the bite may last for weeks.
Protecting Your Home
Seal cracks and crevices so bugs cannot enter your home
Install screens on windows and doors
Change outside lights to yellow bulbs
Keep your yard clear of clutter
Prevent pack-rats from nesting
Use insecticide around the home
Sleep under a mosquito net at night