- Dorsal view of Triatoma infestans, a vector for American trypanosomiasis - Reprinted with permission from Centers for Disease Control and the World Health Organization
Chagas disease is an insect-borne infectious disease which spreads via the triatomine bug. This vector is a reduviid bug. The responsible microorganism is the protozoan parasite Trypanosoma cruzi. Another name for the disease is American trypanosomiasis because transmission usually takes place in Latin American countries where it is endemic. Some cases have also occurred recently in the United States, Canada, Europe, and several Western Pacific countries (World Health Organization, 2010).
This disease is distinct from African trypanosomiasis which occurs in Africa and through a different microorganism. Moreover, the clinical courses of the two diseases are not the same.
Most Transmission in Latin America
Dr. Carlos Chagas, a Brazilian physician, discovered American trypanosomiasis in 1909. It especially occurs in rural and poor areas of Latin America. There may be 8 to 11 million people in Mexico, Central America, and South America with Chagas disease. Although people with this condition may reside in other parts of the world, transmission mainly takes place in Latin American countries.
After acquisition of Chagas disease, residents of Latin America may relocate to regions of the world where the insect vector is not present, and this accounts for disease occurrence in those other parts of the globe. There are some cases of transmission in the southern half of the United States as the triatomine bug is present there too, but these cases are not common.
Insect Vector Bites at Night
The triatomine bug is a blood-sucking insect which bites humans at night in their sleep. They become active at night and pursue areas of skin exposure such as the face. Since they bite humans on the face, some have called them kissing bugs. Other names for it include assassin bug and cone-nosed bug. After the insect bites the person, they defecate on the wound they left from the bite.
The individual awakens later and rubs or scratches the bite area or the eyes, mouth, or any other open wound. This rubs the feces from the insect into the wound or mucous membranes and thus enables the parasites to enter the human body since the feces contain the microbe.
Triatomine bugs acquire the parasite from humans or animals which already have the infection. It is a zoonotic disease; several thousand years ago this condition occurred only in wild animals.
Sources
- Centers for Disease Control. (2010). Parasites—American trypanosomiasis (also known as Chagas disease). Retrieved January 27, 2012.
- World Health Organization. (2010). Chagas disease (American trypanosomiasis). Retrieved January 27, 2012.
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact their physician for advice.
Michael Koger - Dr. Koger obtained his medical education at Meharry Medical College and specialized in Internal Medicine.
