Chagas disease, or American trypanosomiasis, is a condition that causes gradual organ damage. Without treatment, it can be fatal.
The disease develops due to the parasite Trypanosoma cruzi. Blood-sucking bugs known as triatomine bugs spread this parasite. These bugs are native to Latin America, where Chagas disease is most prevalent.
This article explains where the T. cruzi parasite is most common and how it can spread. It also outlines the symptoms of Chagas disease and the treatment options available.
The T. cruzi parasite that causes Chagas disease is native to the following areas:
- Central America
- South America
Chagas disease is a tropical disease that was once confined to Latin America. Countries within this region continue to experience the highest rates of this condition.
However, according to the World Health Organization (WHO), scientists are increasingly detecting Chagas disease in the following parts of the world:
- the southern United States
- many European countries
- some African countries
- some Eastern Mediterranean countries
- some Western Pacific countries
Experts believe that the spread of Chagas disease is due to the increased movement of people between countries.
Chagas disease primarily spreads through contact with the urine or feces of an infected triatomine bug.
However, it may also spread through other modes of transmission. The sections below will discuss these modes of transmission in more detail.
Triatomine bugs are large insects that feed on the blood of humans and other mammals. A triatomine bug may bite a human or animal that has T. cruzi. The bug will then become infected with the parasite.
A triatomine bug that has T. cruzi can pass the parasite onto any person it subsequently bites.
The parasite usually transmits in the feces and urine of the triatomine bug. The bugs tend to defecate or urinate close to areas where they feed. If a person touches the bite, they may accidentally rub the urine or feces into the bite, thereby exposing themselves to the parasite.
A person can also develop Chagas disease after consuming food that is contaminated with triatomine bug feces.
Other modes of transmission
The WHO advise that the transmission of the T. cruzi parasite can also occur via the following means:
- receiving a blood transfusion from a donor who has the parasite
- receiving an organ from a donor who has the parasite
- having exposure to T. cruzi in a laboratory setting
It is also possible for a pregnant woman to pass T. cruzi onto their child during pregnancy or childbirth.
Chagas disease has two phases: acute and chronic. Each phase is associated with different symptoms.
Symptoms of acute Chagas disease
The acute stage of Chagas disease lasts for around 2 months. During this time, there are a high number of parasites circulating in the blood.
According to the Centers for Disease Control and Prevention (CDC), some people do not experience any symptoms during the acute phase of Chagas disease. If symptoms do occur, they usually appear a week or so after receiving a bite from a triatomine bug.
The symptoms are typically mild and unspecific and may include:
Symptoms of chronic Chagas disease
The chronic phase of Chagas disease can occur 10–30 years after the initial infection. During this phase, the parasite gets into the heart or intestinal muscles. This can cause severe and even life threatening symptoms.
Some symptoms that a person may experience during the chronic phase include:
To treat Chagas disease, a doctor may prescribe one of two drugs: benznidazole or nifurtimox.
Both medications are almost 100% effective at curing the disease, but only if a person takes them soon after they get the T. cruzi parasite.
The effectiveness of these drugs declines the longer a person has the parasite infection before receiving treatment.
A person cannot catch Chagas disease in the same way they can catch a cold or flu. However, it is still not clear if the family members of a person who has Chagas disease should also receive treatment for the condition.
The CDC recommend that if the person with Chagas disease contracted T. cruzi while traveling with family, those family members should undergo testing for the parasite.
It is possible for pregnant women to pass T. cruzi onto their children during pregnancy or childbirth. These children should undergo testing to see if they have contracted the parasite.
A person should see a doctor if they have traveled to an area where Chagas disease is present and have experienced any of the following:
- a bite from a triatomine bug
- a bite from an unidentified insect
- any of the symptoms of Chagas disease
Prompt treatment with benznidazole or nifurtimox can often completely cure Chagas disease.
However, many people who have Chagas disease will not experience any symptoms until they enter the chronic stage of the condition. The longer it goes undetected, the higher the risk of complications.
People who have Chagas disease have around a 30% chance of developing complications. These complications may include:
- enlarged esophagus
- enlarged colon
- enlarged heart
- infection of the heart muscle, or myocarditis
- heart arrhythmias
- infection of the brain, or meningoencephalitis
To diagnose Chagas disease, a doctor will begin by asking about a person’s symptoms and medical history. They may also ask questions about recent travel, such as:
- where the person has traveled
- what the person did during their travels
- what type of accommodation the person stayed in
If the doctor suspects Chagas disease, they may order blood tests to check for parasite-specific antibodies within the person’s blood. These are antibodies that the immune system produces in an attempt to fight off a parasite infection.
Triatomine bugs live in forest ecosystems and inside homes that have plenty of cracks and crevices where they can hide. As a result, Chagas disease mostly affects less developed countries that have high levels of substandard housing.
According to the CDC, triatomine bugs may also dwell in the following places:
- beneath porches
- under cement
- between rocky structures
- in wood and brush piles, or beneath bark
- in outdoor dog houses or kennels
- in chicken coops or houses
- in rodent nests or animal burrows
The WHO recommend that people take the following actions to prevent the spread of T. cruzi:
- spraying insecticides inside the home and surrounding areas
- making improvements to houses to ensure that there is nowhere for triatomine bugs to hide
- cleaning the home to prevent triatomine bug infestations
- using bed nets to prevent contact with triatomine bugs during the night, which is when they typically come out to feed
- following good hygiene practices when preparing, storing, and eating food
- diagnosing and treating the condition in children whose biological mothers had Chagas disease and did not receive treatment before pregnancy
- screening blood donors to ensure that they do not have T. cruzi
- testing donor organs and tissues to ensure that they do not have T. cruzi
Chagas disease is a rare condition that causes gradual organ damage. It is due to the parasite T. cruzi. Most people contract T. cruzi after coming into contact with the urine or feces of a triatomine bug that has the parasite.
Certain drugs can usually cure Chagas disease, but only if a person receives the treatment in the earliest stages of the disease. However, some people do not experience any symptoms of Chagas disease until they enter the chronic stage of the condition.
People should see a doctor if they have recently traveled to a country where Chagas disease is present and have subsequently developed symptoms of the condition.
People should also see a doctor if they received a bite from a triatomine bug or an unidentified bug while visiting these countries.