the short version



Hiking and camping in rural Latin America can lead to exposure to the biting insect which carries this serious disease. The only preventives are education and information. There are no preventive medications or vaccines. Treatment exists, although it is often not completely satisfactory.



the long version



Valle de los Naranjos, Venezuela. It is late afternoon and the sun is sinking behind the mountains, bringing the first shadows of the evening. Down in the valley a campesino is tilling the soil; the quiet of the approaching night is broken only by a crop duster which periodically flies overhead and disappears further down the valley. Bertoldo, the pilot, is on his final run of the day when suddenly the engine dies, sending the plane onto the plowed field an emergency landing. The campesino drags him, stunned but unhurt, from the plane and offers his home for the night, a poorly constructed dwelling common in rural areas of Latin America known as el rancho (the hut) with walls of adobe, a dirt floor and a roof of palm fronds. On his ride back to Valencia the next day, Bertoldo reflects on his good fortune that he had only a few insect bites to show for his adventure. Bertoldo’s luck was short-lived. Two weeks after the night spent in the campesino’s hut, he came down with a fever and the right side of his face became red and puffy. He grew progressively weaker and a few weeks later he was in heart failure. As the result of the bite of an insect known as the vinchuca, Bertoldo had become infected by a parasite, Trypansoma cruzi, the cause of Chaga’s Disease. Three months later Bertoldo was dead.



THE VINCHUCA






The carrier of the Chagas’ Disease parasite is an inch long insect which depends on the blood of mammals to survive. The insect has a limited flight range; although it is furnished with two pairs of wings, these are used mainly as a parachute. “Vinchuca”, derived from the Quechua word huinchucaum, means “one who lets himself fall down”. The vinchuca is nocturnal, hiding during the day in crevices of walls of peasant huts and among palm fronds of the roof, coming out at night to feed. It is attracted to exposed parts of the body and has a preference for the face. In Europe and North America it is called the kissing or assassin bug. When the vinchuca finds the exposed face of a human victim, it releases from its proboscis a stylet with fine teeth which perforates the skin. A second hollow stylet taps a blood vessel. The feeding process lasts at least twenty minutes during which the vinchuca ingests several times its own weight in blood. Feeding is painless and the subject rarely wakens. During the feeding defecation occurs, contaminating the bite wound with feces containing parasites. Following feeding, the irritation of the bite causes the sleeping victim to rub the site, facilitating the introduction of the organism into the blood. The parasites are also capable of penetrating the thin layer of cells covering the lining of the mouth, nostrils and eye if carried there by contaminated fingers.



THE DISEASE



After one or two weeks the bite area, usually the face, becomes swollen and inflamed. This swelling, called a “chagoma” after Dr. Carlos Chagas who first described it, represents a reaction to the parasite, some of which reach the bloodstream and invade internal organs. Fever, vomiting, shortness of breath, convulsions and rigidity of the neck are symptoms of the acute generalized form of the illness which may result in rapidly progressive heart disease. Usually, however, the skin inflammation subsides and the victim continues to live an apparently healthy life. Unrecognized infection (but with a positive blood test indicating latent disease) may continue and progress slowly for years, surfacing after ten or twenty years as chronic heart disease. During this time, irreversible heart failure may appear, often with death occurring within a year.



SOCIAL IMPLICATIONS



Chagas’ Disease is a serious health problem in rural Latin America affecting mostly poor rural families. Since the 1960s, migration of rural populations has brought the infection to the periphery of large cities; in some countries the disease has reached the interior of urban areas. Besides spreading the infection to towns, this migration poses an additional risk through blood transfusions. Poor people are eager to sell their blood; infected blood donors sometimes slip through screening procedures. A recent survey in Sao Paulo shows that an average of fifteen percent of blood donors carry the infection, ten percent in Buenos Aires.



IMPACT OF CHAGAS’ DISEASE ON THE INTERNATIONAL TRAVELER



Because of the nature of their travel, hikers and campers are particularly vulnerable to Chagas’ Disease; it is essential that they know something of the disease and how to avoid it. Business travelers spending the night in the periphery or suburbs of cities ought at a minimum to check for insects in bedrooms. Chagas’ Disease is insidious-a traveler passing through Latin America could become infected and may remain apparently healthy until the first signs of chronic heart disease appear years later. Cases of Chagas’ Disease are often not recognized by doctors outside of Latin America since the symptoms of the late form are the same as other forms of chronic heart disease.



TO PREVENT CHAGAS’ DISEASE DURING YOUR TRAVELS



When traveling in areas with Chagas’ Disease, do not sleep in native huts, since parasite-carrying vinchucas hide in palm-frond roofs and the cracks of walls.
When checking into modest or older hotels, search for hidden insects under the mattress, behind pictures, in drawers or in dark corners of the room.
Before bed, apply insect repellent (available in sprays, lotions and towelettes) to exposed areas of skin. Any commercial preparation containing DEET (N.N-diethyl-meta-toluamide) is suitable.
Use a pyrethrin-containing insecticide (spray or coils) to kill insects which may be present in your sleeping quarters. Spray under your bed, inside closets, drawers and behind pictures.
Use a permethrin (Permanone) preparation on bednetting and bed clothing if at risk for bites from this crawling insect.
Protect your hands with a piece of cloth, paper, plastic or gloves if it is necessary to handle an insect.
Consider using bed nets to prevent contact with insects. Put a cloth over the bed net to prevent infected feces falling on you from the ceiling.
When camping, choose a campsite away from palm trees and stone piles where insects often hide.
If you require medical or surgical treatment involving blood transfusions, avoid private hospitals (clinicas) where blood donors may not have been adequately screened; there is apparently no risk of becoming infected by a blood transfusion at a university or municipal hospital in a major city.
Adapted from material distributed by the International Association for Medical Assistance to Travelers