Chagas disease -- a serious infection that may lead to heart disease and even death -- doesn't get much attention in the United States. Most people have never even heard of it. But in Latin America, this infectious illness is both a major threat and a high priority for health officials. According to the WHO, approximately 6 to 7 million people are currently infected. The disease isn't common in the Caribbean, such as Cuba or Puerto Rico, but is widespread in poor areas of Mexico, Central America, and South America.
Chagas disease has gotten more attention in the United States since 2006, when the American Red Cross began a clinical trial screening blood samples for the parasite that causes it. The agency found that one in 4,655 donations tested positive for the tropical infection. As a result, the American Red Cross screens all blood donations for the parasite.
What is Chagas disease?
Chagas disease -- if chronic -- is an incurable and occasionally fatal infection that can damage the digestive system, heart and nervous system. The infection may lurk in the body for years, damaging organs over the course of 10 to 40 years and often ending in heart failure. According to a study published in Circulation, the journal of the American Heart Association, heart problems from Chagas disease account for over 20,000 deaths a year. Chagas is caused by a protozoan parasite, Trypanosoma cruzi, that infects the blood.
Most victims catch the parasite in the same way: As they sleep at night, a large black-and-red insect known as a "kissing bug" crawls on their faces, bites their skin, and sucks their blood. Many of these insects, more formally called triatomine bugs, are infected with T. cruzi. As the bug dines on blood, it defecates. If a person rubs the bug droppings into the eyes, nose, bite wound, or another open sore, the parasite can find a new home.
The disease is not passed easily from person to person, but it is also possible to catch Chagas disease from uncooked foods that have been contaminated by insect droppings. Mothers can pass on the infection to their babies during pregnancy. In rare cases, people have become infected through blood infusions and organ transplants.
Who is at risk for Chagas disease?
Chagas disease is common in places where kissing bugs thrive, mostly mud and thatch dwellings in poor areas of Latin America. During the day, the bugs like to hide in deep, dark crevices close to a source of food. Walls and roofs made of thatch, straw, mud, or adobe often have all sorts of nooks and crannies that provide a perfect habitat.
Although it is extremely rare to contract the disease in the United States, it can occur. An American Red Cross study of blood donors found a handful of cases of the infection that had apparently been acquired in this country. Several species of "cone-nose" bugs found in 27 states (and as far north as northern California) carry the parasite that causes Chagas disease, and most of the infected donors mentioned that they spent time camping or hunting outdoors.
What are the symptoms of Chagas disease?
Symptoms of Chagas disease vary from person to person. Some people don't have any signs of illness, while others can become deathly sick. In the first few weeks or months, symptoms -- if there are any -- may be mild and easy to ignore. Patients have reported fevers, fatigue, rash, headaches, body aches, diarrhea, vomiting, and a loss of appetite. Swollen glands and heart pain are also possibilities. If a doctor examines you, he or she may find mild enlargement of your liver or spleen, and a swelling (called a chagoma) where the parasite entered your body. Some patients develop a swollen eyelid on the side of the face where the infection occurred.
In people with reasonably strong immune systems, these symptoms eventually fade. But that doesn't necessarily mean the trouble is over: In about 30 percent of cases, people develop a chronic form of the disease. In these cases, the parasites continue to invade the body's organs, eventually causing heart trouble (such as heart failure, an enlarged heart, or an irregular heartbeat) or digestive problems (including an enlarged colon, which is a dangerous and uncomfortable complication.)
What is the treatment for Chagas disease?
Most people don't have to be hospitalized during treatment. Taken in the early stages, antiparasitic medications -- namely nifurtimox and benznidazole -- can help keep the disease under control, but nothing can cure Chagas disease completely. In the U.S., these drugs are only available from the Centers for Disease Control and Prevention. Your doctor can contact the CDC to discuss whether and how you should be treated if you have Chagas disease.
How can Chagas disease be prevented?
Large-scale efforts to curb Chagas disease include upgrades to housing, careful use of pesticides, and thorough screening of the donated blood supply. If you're traveling to Latin America, the chances of contracting Chagas disease are remote if you stay in hotels or well-developed areas. If you do plan to spend time in the countryside and sleep in homes made of straw, thatch, or mud, consider wearing insect repellent and sleeping under bed netting treated with a long-lasting insecticide. In older or modest hotels, it's also a good idea to check for the bug under the mattress and spray a pyrethrin-based insecticide behind pictures and in drawers.
Although Chagas disease usually doesn't spread through food, it's always a good idea to be careful with food and drinks when traveling in areas with poor sanitation. Sticking with bottled or boiled water and steaming hot foods makes sense even if there isn't a kissing bug within miles.
Centers for Disease Control and Prevention. Parasites - American Trypanosomiasis (also known as Chagas Disease).
World Health Organization. Chagas disease Fact Sheet.
Rassi A, et al. Predictors of mortality in chronic chagas disease. Circulation.
Gelb M, and Hol G.J. Drugs to combat tropical protozoan parasites. Science. 297 (5580): 343-344.
Centers for Disease Control and Prevention. Blood Donor Screening for Chagas Disease -- United States.
Public Health Agency of Canada. American Trypanosomiasis or Chagas Disease.
National Public Radio. Interview with Dr. Susan Stramer, American Red Cross. Latin American disease may have spread to US. Weekend All Things Considered
World Health Organization. Triatomine bugs: Vectors of Chagas disease. http://www.who.int/water_sanitation_health/resources/vector210to222.pdf.
The Travel Clinic. Chagas Disease.
Bern C., et al. Evaluation and Treatment of Chagas Disease in the United StatesJ AMA.(18):2171-2181.