Chagas Disease (American Trypanosomiasis)
What Is Chagas Disease (American Trypanosomiasis)
Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening parasitic disease that affects roughly 10 million people worldwide with more than 25 million people at risk. The disease mainly occurs in rural Mexico and throughout Central and South America.
The parasite that causes Chagas disease is called _Trypanosoma cruzi_ and is transmitted to humans through the bite of an infected triatomine insect, also known as the “kissing bug”.
The triatomine insect lives in unkempt housing (cracks in the walls or ceiling), as well as in various areas outdoors, such as rock, wood, or brush piles, beneath bark or porches, animal burrows, chicken coops or dog houses. The insect seeks refuge during the day and emerges to feed at night.
The _T. cruzi_ parasite is a different species from the parasites that cause the related African forms of the disease, African trypanosomiasis.
How Do You Get Chagas Disease (American Trypanosomiasis)?
Chagas disease is acquired after the infected triatomine insect bites and the feces are inadvertently transferred into the skin, the lining of the eye, nose, or mouth when the bite is scratched or rubbed. The disease is also transmitted through blood transfusions and organ transplants, as well as from mother to infant. There have been some rare situations in which the parasite has been transmitted through contaminated food or food products.
Susceptibility and Resistance
Everyone is susceptible to Chagas disease, but the acute phase is generally more severe in younger people and children. People with compromised immune systems, including those with AIDS, are at greater risk for more serious infection.
What Are The Symptoms?
There are two phases of Chagas disease. The first acute phase lasts 2-3 months, and the second chronic phase can last for years. Many infected individuals do not develop symptoms but stay infected for the rest of their lives.
In the acute phase, symptoms are usually mild or completely absent but can include fever, swollen lymph nodes, and enlargement of the spleen and liver. A skin lesion known as a chagoma usually develops at the site of infection and lasts for up to 8 weeks. A characteristic sign of Chagas disease, known as Roma’s sign, is the purplish swelling of the eyelids occurring in less than 50 percent of all cases of Chagas disease.
In 20 to 30 percent of infections, the disease progresses to include irreversible chronic symptoms, such as cardiac damage, enlargement of the oesophagus or colon, and neurological damage. In later years, chronic Chagas disease can cause sudden death or heart failure due to progressive heart damage.
Preventative Measures
There is no vaccine to protect against Chagas disease. The risk to travellers of acquiring Chagas disease is generally low. This risk is increased if travellers camp, stay in poorly constructed housing, obtain unscreened blood transfusions, or ingest contaminated food or drink in countries where Chagas disease occurs. Travellers who cannot avoid camping, sleeping outdoors, or staying in poor quality housing should sleep under insecticide-impregnated bed nets and tuck in the edges to protect against the triatomine insect bite.
Treatment
If Chagas disease is suspected, a tropical medicine or infectious disease specialist should be consulted for diagnosis and treatment. Anti-parasitic drugs, specifically benznidazole or nifurtimox, are recommended to treat acute infection. These medications should be given early in the infection as their efficacy diminishes the longer a person has been infected. They are available from major hospitals in countries with Chagas disease.
Medications
Where Does It Commonly Occur?
The disease mainly occurs in rural Mexico and rural areas of Central and South America.
