C HAGAS DI SE ASE Chagas, also known as American trypanosomiasis, is a dangerous disease caused by the parasite Trypanosoma cruzi. This protozoan is typically transmitted to animals (including humans) by insect vectors found only in rural areas of the Americas, from the southern U.S. states to Argentina’s northern provinces. The typical vector is a triatomine bug, often referred to as a kissing bug, but its common name varies from country to country. Triatomines are gregarious; they typically come out at night but take refuge during the day Avoiding
in dark, cool crevices between rocks and in tree bark and cracks on mud
Mosquito Bites
houses. In some areas, however, their behavior is changing, and they are
• Stay in screened areas when indoors, especially from dusk to dawn.
out during daylight hours as well. These blood-sucking insects are guided
• Sleep under mosquito netting.
Chagas can also be transmitted via blood transfusions (including organ
• When outdoors, wear clothing that covers most of your body, including the feet and ankles.
congenitally (from mother to fetus) or by lactation (from mother to nursing
• Use the insect repellent DEET (N,N-diethylmeta-toluamide) on yourself and the insecticide permethrin on your clothing and mosquito nets.
to their prey by odor, heat and carbon dioxide emissions. Recent studies suggest that bedbugs may also be a vector for the Chagas parasite.
transplants), through foods contaminated with an infected bug’s feces, baby). The parasite’s usual reservoirs are opossums, raccoons, armadillos and small rodents, but domestic animals such as cats and dogs can also harbor the parasite. The kissing bug defecates as it bites to suck blood. The subsequent scratching at the bite site allows the parasite to enter the host through the tiny bite wound. The bite site usually does not show any significant inflammatory process and is not painful. The acute phase of the infection, which lasts for a few weeks to a few months, may pass unnoticed because symptoms are typically nonexistent or mild, vague and unspecific. The chronic phase develops over several years. Between 60 percent and 80 percent of individuals with chronic Chagas never develop any other symptoms (known as indeterminate Chagas). remaining 20 percent to 40 percent may develop cardiac or digestive complications that can be life-threatening.
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