Chagas: one bite now, causes heart failure 20 years later

Reduvid bug

One night you are sleeping peacefully, when suddenly a small bug drops down from the rafters above and decides to feed on your face.  After sucking your blood to its heart’s content, the bug proceeds to defecate in the same space it had just enjoyed a meal.  You awake the next morning with a swollen bite and scratch away to relieve the itch.  In a few days you develop flu like symptoms – headache, diarrhea, fever, the works.  A few weeks later, you have conquered the sickness.  Years pass and the incident seems nothing more than the distant haze of a memory.  Then one day, 20 years into the future, your heart stops working and you die.  An autopsy reveals a megacolon (enlarged colon) and a megaesophagus (enlarged esophagus).

This story is repeated 20,000 times every year throughout the Americas.  Chagas: a parasitic infection passed through the fecal matter of reduvid bugs, is the disease behind the mystery.  Health services estimate eight to 11 million people carry the disease in the western hemisphere.  Though early treatment of the disease can prevent its delayed chronic symptoms, the majority of carriers do not know they have been infected.

T. cruzi

Chagas is caused by Trypanosoma cruzi, a unicellular flagellar protozoa, resembling a microscopic flat worm.  Once inside the blood, the parasite replicates itself by asexual binary fission and begins a long process of colonization throughout the tissues of the colon, nerves, esophagus, and heart.

Besides transmission via the reduvid bug, commonly referred to as the “kissing bug” for its habit of sucking faces, Chagas can also be spread through blood transfusions, organ transplantations, breast milk, and across the placenta.   Fourteen thousand infants are born with congenital Chagas every year and 13 percent of all still births in Brazil can be attributed to the disease.

The disease was first discovered in 1909, by Brazilian immunologist Carlos Chagas.  Though a major Chagas outbreak hit the country in the 1920s, it did not become an internationally accepted public health concern until the 1960s. Before discovery and treatment, the parasite went completely unchecked.  In fact, some evidence suggests that Charles Darwin had contracted Chagas during a stopover in Chile.  He described feeling ill for six months in the port of Valparaiso, but quickly recovered afterward to resume his travels.  A year after returning to England he developed mysterious symptoms, which debilitated him for the rest of his life.

The bug that causes the disease has a variety of different names, including vinchuca in Argentina, Bolivia, and Paraguay, bareiro or “barber” in Brazil, pito in Colombia, chinche in Central America, and chipo in Venezuela.  It is mostly found in rural areas, hiding in thatched roofs and other organic house materials.  Modern efforts to reduce the 40,000 cases occurring every year focus on spraying insecticide, raising awareness of bites, and encouraging testing and treatment.

On the bright side, once the initial acute symptoms of the disease have been identified, treatment is 60-90 percent effective in preventing the development of the chronic symptoms, down the road.  So if you fall asleep under a roof made of straw and palm fronds, check your face in the morning, do not scratch, and wash bug droppings from the bite.  Everything will be alright in a Chagas free future.

Chagas bite causes initial swelling of eye


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