Conenose Bugs

Michael Merchant, Ph.D., Extension Urban Entomologist

Conenose, or kissing bugs (Triatoma sp.), are blood-feeding insects that are an occasional problem in Texas homes. Although conenose bugs bite humans and regularly transmit disease in parts of Latin America, for most U.S. victims the worst consequence is redness and itching at the site of the bite.

Identification: Conenose bugs are recognized by their elongated or "cone-shaped" head, prominent antennae, pear-shaped body, and spindly, stick-like legs. The body is black or dark brown with 12 orange spots ringing the outer edge of the abdomen. Adult conenose bugs are 1-3 cm in length. Long, beak-like mouthparts arise from the front of the head and are held under, and against, the center of the body when not in use.

Biology: Conenose bugs feed exclusively on the blood of vertebrate animals. Although generally rare, they are most common around animal nests or pet resting areas, emerging at night to search for a blood meal. Their bites are gentle and painless, and usually occur while the victim is asleep. They are generally unable to bite through clothing; and, on humans, blood meals are sometimes taken from the tender areas of the face (hence the name "kissing bug"). Other sites of attack (in order of decreasing frequency) include the hands, arms, feet, head, and trunk. Victims are frequently unaware of the bites until the following morning when unexplained reddened areas may be present on the skin of the arm or face.

Adult conenose bugs can fly and may enter buildings through open windows or by crawling through unsealed cracks or openings in buildings. During the day and between feedings, conenose bugs hide in any available crack or crevice.

Importance: Conenose bugs can be carriers of the protozoans that cause Chagas' disease, a serious disease of humans that occurs most commonly from Mexico to South America. Only five cases of Chagas' disease have been recorded in Texas since the first indigneous case was recorded in 1955. Transmission of the disease in the U.S., though possible, is very rare.

Natural reservoirs of the causative agent of Chagas' disease, Trypanosoma cruzi, are maintained in nature among small vertebrate animals, notably armadillos, opossums, rodents, bats, cats, and dogs. Conenose bugs commonly feed on several different hosts during their development. Nymphs feed on an infected host and become infected themselves. The parasite can then be transmitted during subsequent blood meals to an uninfested host. While feeding, the insect frequently defecates on the skin of its victim and the parasite is transferred from the feces to the eye or mucous membranes around the mouth or nose by contact with fingers or other body parts. Transfer of the parasite may also be hastened by scratching the site of the bite. Chagas' disease is difficult to diagnose, but is sometimes indicated in its initial stage by a swelling on one side of the face, known as the sign of Romana.

The most common reaction to bites by conenose bugs is reddening, swelling and itching around the site of the bite. Perhaps 5% of victims exhibit more serious allergic reactions with symptoms ranging from intense itching to rashes, swelling, and various other symptoms.

Control: Sightings of a single conenose bug may not mean that the structure is infested. Occasionally conenose bugs may be attracted to nighttime lights and fly, or otherwise gain entry, into buildings. Repeated sightings of conenose bugs, however, are a good indication that these insects have become established nearby.

Conenose bug infestations are generally more common in poorly constructed homes. Good sanitation and tight building construction tends to limit conenose bug infestations. Destroy trash piles, bird and animal nests and burrows; and control and exclude rodents and birds from the house. Seal exterior cracks and openings into infested buildings, make sure that chimney flues are closed tightly, and inspect and seal any openings from crawl spaces into house subflooring. Check pets for signs of feeding and examine pet houses.

Homeowners may treat the insides of home and pet houses with a pesticide labeled for indoor use, such as chlorpyrifos or diazinon; however, control of conenose bugs is usually best attempted by trained and licensed pesticide applicators. The most effective controls include wettable powder or microencapsulated formulations of pyrethroid insecticides such as cypermethrin, lambda-cyhalothrin, deltamethrin, or cyfluthrin--products only available to professional pest control companies. Pest control professionals should also be consulted when rodents or pest birds are present and prove difficult to control.

Additional References:

Ebling, Walter. 1975. Urban Entomology. University of California, Davis.

Goddard, Jerome. 1993. Physician 's Guide to Arthropods of Medical Importance. CRC Press, Boca Raton, FL.

Lent, H. and P. Wygodzinsky. 1979. Bull. American Museum of Natural History. 163 (Art. 3), 123.