Chagas disease (American trypanosomiasis)

Chagas disease (American trypanosomiasis) afflicts central and southern America, with cases reported as far north as Texas, Oklahoma, and California. It is the 4th leading cause of death in Latin America, with 43,000 deaths per year worldwide. Chagas disease threatens 100 million people in twenty-one countries. An infected woman can pass Chagas disease to her baby during pregnancy, at delivery, or while breastfeeding.

The Chagas disease is caused by infection of the parasite Trypanosoma cruzi. The parasite is related to the African trypanosome that causes sleeping sickness. Since T. Cruzi's discovery by Dr. Carlos Chagas in 1909, very few people outside of Latin America even know about it. Most of worldwide efforts to control infectious diseases have been focused on HIV/AIDS, tuberculosis, and malaria to the neglection of Chagas disease.

Chagas is a vector-borne disease, so the parasite must hitch a ride with an insect to get from one host to another. The 3 most important carriers of the disease are the insects: Triatoma infestans, Rhodnius prolixus, and Triatoma dimidiata. These insects have domesticated themselves to live with humans, biting them and thus transmitting the T. cruzi parasite. Their adaptation to the human habitat which offers abundant food (eg, blood of humans, domestic animals, associated rodents) and hiding places in cracks and crevices in walls made of dried mud, adobe, and thatched roofs, define their role as a vector to spread Chagas disease.

The insects transmit the parasite through its feces which it leaves near the site of a bite. These insects are also known as the Kissing Bugs because they characteristically bite the eyelids, lips, ear or nose of victims. A person bitten by their eye will usually see it swell; known as Romaña's Sign.

The vector insects thrive where there is poverty or overcrowding. It is commonly found living in the walls and fortifications of the houses. Migrating peasants often don't have the time or money to invest in a stable home. They construct temporary homes made of refuse as they move to earn a living. These shacks easily become infested with the insect. When peasant families settle in an area to build a house, they often cut down brush from the area. This forces Rhodnius out of nests where they feed upon birds and rodents. Overpopulation has depleted the buffer zone between humans and wildlife, causing more of the insect vectors to adapt to life in cities and houses.

The U.S has 16 species of triatoma (kissing bugs) in the US, some as far north as Kentucky. Infected immigrants may provide a meal for the insects, causing a Chagas outbreak in the U.S. Patients with heart ailments but no known risk factors for having it, may actually be infected with Chagas.

Chagas has also been spread to regions ourside its native habitat due to Latin American countries being major exporters of blood and organs. Some measures are being taken to curb the infection of Latin America's blood supply, but still tens of thousands of infections take place due to contaminated blood and organ transplants. Travelers to infected regions can should stay at well-constructed hotels and houses, eat well-prepared food, and wear insect repellent.

Chagas disease often present itself in 3 stages. After the initial infection, the person has Acute symptoms, with possible swelling of eyes, fever, fatigue, swollen lymph glands, rash, loss of appetitie , diarhhea. Small children may suffer chronic swelling of the brain. Usually these symptoms last 4-8 weeks and then disapear, with or without treatment. The intermidiate stage is usually symptom free.Ten to twenty years after being infected, people may develop the most serious symptoms of Chagas disease. Cardiac problems, including an enlarged heart, altered heart rate or rhythm, heart failure, or cardiac arrest are symptoms of the chronic stages of the disease. Chagas disease can also lead to enlargement of parts of the digestive tract, which result in severe constipation or problems with swallowing. The majority of infected people do not show symptoms until the chronic stage. Medication is most effective when administered during the acute stage of infection.

Rapid diagnostic tests are needed to help identify those who may have the disease. The drugs usually used to combat T. cruzi are extremely toxic and dangerous to use. There are no absolute cures. Raising the education of people in areas affected by Chagas is important. In some afflicted areas, the people believe that the insect is a omen of fertility, and no connection is made between the bite of the insect and the sick members of the household.