Assassin bug. Macrophotograph of an assassin or kissing bug (Rhodnius prolixus) feeding on a human. This is a reduviid bug which lives in South and Central America. It feeds on human blood and is the vector of the protozoan parasite Trypanosoma cruzi, which causes Chagas disease. The protozoa are present in the faeces of the bug and are transmitted to humans when they enter wounds on the skin made by the feeding bug. They may also enter via the nose and mouth. T. cruzi migrates to the heart muscles and central nervous system, causing serious inflammation and lesions which may prove fatal if left untreated.
Chagas disease facts
Chagas disease is an infection caused by a protozoan parasite (Trypanosoma cruzi) that can result in acute inflammatory skin changes (chagomas) and may eventually cause infection and inflammation of many other body tissues, especially those of the heart and intestinal tract.
Chagas disease was first described in 1909 in Brazil.
Chagas disease is caused by a protozoan parasite named Trypanosoma cruzi that is transmitted to humans from the feces of triatomine bugs (kissing bugs).
The parasites usually enter the mammalian (human) host through the bug bite, or breaks in the skin or conjunctiva, replicate in mammalian cells, and may eventually reach other organs through the blood.
Chagas disease may proceed through three phases in an individual: acute, intermediate or indeterminate, and chronic.
Chagas disease symptoms vary widely from no symptoms to severe in the chronic phase.
Acute-phase symptoms of Chagas disease may be swelling and/or redness at the skin infection site (termed chagoma), rash, swollen lymph nodes, fever, head and body aches, fatigue, nausea, vomiting and/or diarrhea, liver and/or spleen enlargement, and the Romaña sign.
Chronic-phase symptoms and signs of Chagas disease may be irregular heartbeats, palpitations, fainting (syncope), cardiomyopathy, congestive heart failure, short of breath (dyspnea), emphysema, stroke, sudden death, chronic abdominal pain, chronic constipation, dilated colon, and difficulty swallowing.
Patient history, physical exam, direct microscopic visualization of the parasites, and detection of antibodies against the parasites are methods used to diagnose Chagas disease.
Treatment with antiparasitic drugs benznidazole (Rochagan, Ragonil) and nifurtimox (Lampit) kill or inhibit T. cruzi parasites.
Chronic-phase patients are usually treated using treatments directed at the specific symptoms or organ damage.
There is no vaccine against Chagas disease parasites for humans, but many experts suggest that elimination of primitive housing and education may prevent most cases of Chagas disease.
What is Chagas disease?
Chagas disease (also termed American trypanosomiasis) is an infection caused by a protozoan parasite (Trypanosoma cruzi) that can result in acute inflammatory skin changes (chagomas) and eventually may cause infection and inflammation of many other body tissues, especially those of the heart and intestinal tract. The disease may have three phases in an individual: acute, with mild or no symptoms that may last weeks to about two months; intermediate or indeterminate phase that has few if any symptoms and may last 10-20 years or longer; and chronic phase that appears after about 20 years, with the more severe symptoms appearing from gradual chronic organ damage (especially to the heart and intestine, although other organs may be affected) with symptoms that usually remain for life. People with Chagas disease seen in the U.S. usually have acquired it while living in a country where the disease is endemic (Mexico, Central and South America). The CDC estimates about 8-11 million people are infected in countries where the disease is endemic.