Kissing Bug – Disease Vector
Conenose Bugs Transmit a Dangerous Parasite – Trypanosoma cruzi
The kissing bug, an insect of many names, lives close to people in Central and South America and sucks their blood, transmitting Chagas disease in the process.
What is a kissing bug?
Kissing bugs, classified among the reduviid bugs, are also known as triatomid bugs, conenose bugs, barbiero, and assassin bugs (although the name “assassin bug” more specifically refers to reduviids that do not bite humans). Whatever you choose to call it, however, this bug is a serious pest in Central and South America.
Kissing bugs and parasites
The kissing bug is so called because of its habit of biting humans on the lips, usually while the victim is sleeping. When the bug bites, it also defecates on the skin – it is the bug’s feces, rather than its saliva, that contain the parasite Trypanosoma cruzi, the agent of Chagas disease or American sleeping sickness. Like many insect bites, the bite of the triatomid bug itches, and the victim soon scratches, rubbing bug feces and parasites into the wound.
Where the bugs live
Conenose bugs live in or near dwellings, particularly in thatched roofs, dirt floors, and walls with many cracks and crevices. They may also be found in considerable numbers in wood piles and tiled roofs, and increase in number with higher densities of people. In addition to biting humans, triatomid bugs also feed on animals and transmit Trypanosoma cruzi to them as well. Thus, animals such as cats, dogs, and rats are important reservoirs of the infection in areas where Chagas disease occurs.
Triatomid bugs occur in North America as well as Central and South America, and research has shown that they carry T. cruzi in all areas where they are found; however, the incidence of transmission to humans in North America is low. This may be because of better housing, relatively low levels of contact between humans and animal reservoirs, and the habits of the bugs themselves (some species do not defecate while biting, while others are simply not as efficient at transmitting the parasite).
Xenodiagnosis
Kissing bugs are sometimes used as diagnostic tools for the same disease that they transmit: because T. cruzi parasites may be almost impossible to detect in the blood of an infected person due to low numbers, the technique of xenodiagnosis is sometimes used. In xenodiagnosis, lab reared triatomid bugs that are free of the parasite are deliberately allowed to feed on a patient who is thought to be infected. After a suitable time lapse, the feces of the bugs are checked for parasites: the presence of parasites in the bugs confirms infection in the patient.
Read about Chagas disease and how it threatens the blood supply:
A Parasite in the Blood Supply
Related content:
Sources:
Garcia, Lynn S. and David A. Bruckner. Diagnostic Medical Parasitology 3rd ed. Washington: ASM Press, 1997.
Schmidt, Gerald D. and Larry S. Roberts. Foundations of Parasitology 6th Ed. Boston: McGraw Hill, 2000.
