Chagas' disease

Chagas' disease



Chagas' disease

Introduction

Chagas' disease is a parasitic infection endemic in many rural areas of Latin America. Between 16 - 18 million persons are infected in the countrysides of all Latin American countries, including Mexico, and migration of rural populations to the cities is bringing the disease to urban areas, the result of blood transfusions and organ transplants. Chagas' disease is a threat to international travelers as well. (Franco-Paredes C; Von, A; Hidron, A; Rodríguez-Morales, AJ; Tellez, I; Barragán, M; Jones, D; Náquira, CG et al. 2007)

Cause

Chagas' disease is an infection caused by a protozoal parasite transmitted by contact with the feces of the vinchuca (also known as cone nose, assassin bug, kissing bug, or reduviid bug), which transmits the parasite through its bite. The vinchuca is about 2 centimeters long, with an oval-shaped, brownish-colored body and a long, narrow cone-shaped head. It breeds and lives in palm trees. The insect is transported to dwellings in palm fronds to be used as roofing, and hides among the palm fronds and in the cracks of the mud or adobe walls of the thatched houses. The vinchuca depends on blood for survival. It comes out to feed at night, attracted to the exposed parts of the body, especially the face. During its feeding, it contaminates the wound with its feces, introducing the parasite which causes the disease. (Franco-Paredes C; Von, A; Hidron, A; Rodríguez-Morales, AJ; Tellez, I; Barragán, M; Jones, D; Náquira, CG et al. 2007)

Explanation

Signs and symptoms

Following a bite, usually on the skin of the eyelid or on the conjunctiva, a hard, violet-hued swelling called a "chagoma" appears after one week. Eventually the parasites reach the heart, liver, brain, or spleen, causing an acute form of the disease in about two percent of patients, especially small children, resulting in fever, a generalized rash, anorexia, diarrhea, vomiting, swollen lymph nodes, and an enlarged liver. Meningoencephalitis can occur and may cause death in children. (Franco-Paredes C; Von, A; Hidron, A; Rodríguez-Morales, AJ; Tellez, I; Barragán, M; Jones, D; Náquira, CG et al. 2007)

In adults, an acute infection of the heart is the main result, damaging the heart muscle. Most of the victims of Chagas' disease survive the acute heart infection, the symptoms subside within four to eight weeks, and the person continues to live an apparently healthy life. The disease however progresses and goes on unrecognized, remaining undiagnosed until a routine blood test may disclose it. The disease finally surfaces after 10 to 20 years in the form of chronic heart disease, as the infected heart muscle fibers are slowly replaced by scar tissue, thinning the walls of the heart, severely affecting heart function, and ultimately resulting in death. The nervous system may also be affected causing convulsions, paralysis, and brain damage.

Treatment

If Chagas' disease is recognized in its early stages, drug treatment may clear the patient of parasites. However, in chronic cases, once the disease has damaged the heart, brain, and other organs, only the symptoms of the disease can be ...