The triatomine bug is known as the “kissing bug.” Despite this endearing term, triatomine bugs are actually blood sucking insects that can carry a parasite known as Trypanosoma cruzi. If the parasite is transmitted to people or animals, it can cause Chagas disease, an infectious condition that leads to fever, swelling, rash, fatigue, and potentially fatal heart problems.

Chagas disease is named after Carlos Chagas, who discovered the disease in Brazil in 1909. It is considered endemic in areas with low-standard housing and poor sanitation, where the triatomine bug prospers. Areas of Mexico, Central America, and South America are at especially high-risk, with anywhere from 8 to 11 million people infected in those regions. It can be deadly, with an estimated 10,000 fatalities reported in 2008.

How is Chagas Disease Contracted?

The primary mode of transmission for Chagas disease is the triatomine bug. Known as the “kissing bug” because of its tendency to bite the face, when a triatomine bug bites an infected person or animal and ingests their blood, it becomes infected. The bug then continues to feed and carries the parasite to other hosts, but the bite itself does not transfer the T. cruzi parasite. When triatomine bites, it defecates onto a person’s skin. The feces carry the T. cruzi parasite, which can then enter the body through the bite, the eyes, or mouth. This is common if a bite occurs at night and a person accidentally rubs the bite area in their sleep. After entering the bloodstream, the T. cruzi parasites multiply and spread.

The virus can also spread in ways other than bug bites including if a person eats raw food that has been contaminated by an infected bug. Also, it is possible to contract Chagas through a blood transfusion or organ transplant if the donor is infected. It is possible for pregnant women to transfer the parasite to their child during birth. Chagas disease cannot be transmitted person-to-person through casual contact.

Symptoms

There are two main phases to Chagas disease, each presenting a different set of symptoms.

Acute Phase

The initial phase of Chagas disease is known as the acute phase. It is possible to not experience any symptoms during this phase, which can last anywhere from a few weeks to a few months. Generally, the symptoms that show up can be confused with the flu: fever, fatigue and aching, headaches, loss of appetite, and diarrhea. The one trademark symptom of Chagas disease is known as Romaña's sign, identified by swollen eyelids near the site of a bite. This symptom occurs in fewer than half of the people bitten. Death is rare in acute phase, occurring in less than five percent of children who contract the illness.

The acute symptoms are mild and will subside on their own after a few weeks. This does not mean the infection is cured. Failure to treat Chagas disease will progress the disease to the second, chronic, phase.

Chronic Phase

An estimated 30 percent of people with Chagas disease will proceed to the chronic phase. It can take up to 20 years for symptoms to show up, and sometimes symptoms never manifest. If they do occur, the most severe complications arise with the heart and digestive system.

Heart problems include:

• Enlarged heart

 

• Irregular heartbeat

 

• Sudden heart attack

 

• Heart failure

Digestive problems include:

• Enlarged esophagus, making it hard to swallow

 

• Enlarged colon, resulting in constipation and trouble eating

Diagnosis

If a person suspects Chagas disease, they should visit a doctor immediately. The doctor will look for an enlarged liver or spleen, or swollen glands, which can be found during the acute phase. A blood test is also performed. The blood test is effective especially during the acute phase, where many parasites are present.

For a diagnosis of chronic Chagas disease, serologic tests are performed. A serologic test is a form of blood test used to specifically identify antibodies in the blood against microorganisms. If the body is producing antibodies to the T. cruzi parasite, this is a good indication of Chagas disease.

A diagnosis of chronic Chagas disease may mean further tests are necessary to determine if any damage to the heart or digestive system has occurred. This includes an electrocardiogram to monitor the heart, an X-ray to create images of the stomach, and an upper endoscopy, which uses a tube with a camera to view the esophagus.

Prevention

Areas at high risk for Chagas disease are generally poor quality homes such as adobes and structures built from mud and thatched roofs where the triatomine bug can hide. There is no vaccine for Chagas disease, so removing insects through improvement of living conditions is the best prevention. Plastering walls or replacing the roof can decrease the population of bugs in the home. Sleeping under a bug net can also stop the bug from biting while you are asleep and defenseless. In addition, the use of insecticides can drive insects out of the home.

Eliminating bugs from the home is the most effective way to prevent Chagas disease. People living in high-risk environments should recognize the symptoms of Chagas and seek medical attention before the disease becomes chronic.