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.
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.
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.
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.
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 managed. At present,
no drugs are available to prevent the infection, and there are
Hikers and campers are particularly vulnerable to Chagas'
disease, as are people working in rural areas. Even those travelers
spending the night in the suburbs or peripheries of cities ought
at minimum to check for insects in bedrooms. International travelers
passing through endemic areas may become infected, but may remain
apparently healthy until the first signs of infection appear years
later as chronic heart disease.
1) When traveling in endemic areas, do not sleep in natives'
hut, since parasite-carrying vinchucas shelter in the palm-frond
roofs and in the cracks of walls.
2) When checking into modest or older hotels, search for hidden
insects under the mattress, behind pictures, in drawers, or dark
corners of the room. Carry repellents and insecticides with you.
3) Before bed apply insect repellent to exposed parts of your
body (available in sprays, lotions and towelettes), which may
help to keep the insects away. Any commercial preparation containing
DEET (N, N-diethyl-meta toluamide) is suitable.
4) Use pyrethrin insecticides to kill insects which may be present
in your sleeping quarters. Spray the walls around your bed, especially
where there are cracks. Spray under your bed, inside closets,
drawers and behind pictures.
5) Protect your hands with a cloth, paper, plastic or gloves if
it is necessary to handle the insects.
6) Use bednets to prevent contact with insects. Put a cloth over
the bednet to prevent infected feces falling on you from the ceiling.
7) When choosing a campsite, stay away from palm trees, and do
not set your tent close to stone or wood piles, where insects
may be hiding.
8) If you require medical or surgical treatment involving blood
transfusions, avoid private hospitals where blood donors may not
have been adequately screened; there is no risk of becoming infected
this way at a university or civic hospitals in a major cities.
In Argentina, Brazil, Honduras, Uruguay and Venezuela blood bank
screening of blood is compulsory by law.