Chagas

Chagas disease owes its name to Brazilian doctor Carlos Chagas, who discovered it in 1909. This disease is caused by the parasite Trypanosoma cruzi, which is transmitted to mammals and humans by insect vectors (triatoma) that are found only in the Americas, specifically in rural areas where poverty is widespread. Chagas disease (infection by T. cruzi) is also known as American trypanosomiasis.

Chagas disease is a major public health problem, as it is one of the causes of significant morbidity and mortality in the Americas. It is estimated that eight to eleven million people in Mexico, Central and South America have Chagas disease, and most of them are not aware that they are infected. If the infection goes untreated, this disease may be lifelong and life-threatening.

This endemic disease was thought to be limited to rural areas, however now a days it is known that its impact is bigger than those areas. The migration of populations from rural to urban areas in Latin American and/or other regions of the globe, have increased the geographic distribution and changed the epidemiology of Chagas disease worldwide. In Venezuela, for example, the disease has spread over a large number of urban areas in recent years, which means it is no longer a disease exclusively associated with poverty, although it still affects more impoverished people in both rural and urban areas. In the United States and other countries outside of the Americas where there is Chagas disease, although not at endemic levels, transmission is caused by blood transfusions, organ transplants and congenitally from mother to child during pregnancy.

Committed to contributing to studies in endemic diseases in Venezuela, Dr. Convit, collaborated with epidemiological and scientific research related to Chagas and its parasite Trypanosoma cruzi. He identified reservoirs of T. cruzi in endemic areas of the country, and participated in basic studies of bioquemical and cellular characteristics of the parasite that helped acquire more knowledge of the parasite's system and possible targets for the search of new treatments.

The Foundation aims to diagnose Chagas through its new Molecular Diagnostic Unit, in order to contribute to an early and more precise identification of the disease in the patient. This will be done in collaboration with other public health institutions.

¿How do people get Chagas disease?

People can become infected in various ways. In areas where Chagas disease is endemic, the main form of transmission is through vectors. The insect vectors are called triatomine bugs ("kissing bugs"). These blood-sucking bugs get infected by biting an infected animal or person. Once infected, the bugs pass T. cruzi parasites in their feces. After they bite and ingest blood, they defecate on the person at the moment. The person may inadvertently scratch the bite and the parasites enter the body either through the bite, the surrounding mucous membranes or breaks in the skin. The bugs can be found in houses made from materials such as mud, adobe, straw, and palm thatch. However, they can also be found in urban abodes, hiding in humid and dark areas behind furniture, picture frames, boxes, under mattresses, or near the trash. During the day, the bugs remain in hiding and during the night, when the inhabitants are sleeping, the bugs emerge to feed. Because they tend to bite people's faces, triatomine bugs are also known as "kissing bugs". They sometimes bite the areas close to the eyes causing the usual "Romagna's sign", which is a swelling of the eye area caused by the bite.

People also can become infected through:

• Consumption of uncooked food contaminated with feces from infected bugs (oral consumption)

• Congenital transmission (from a pregnant woman to her baby);

• Blood transfusions

• Organ transplants

• Accidental laboratory exposure

It is generally considered safe to breastfeed even if the mother has Chagas disease. However, if the mother has cracked nipples or blood in the breast milk, she should pump and discard the milk until the nipples heal and the bleeding stops.

¿What are the signs and symptoms of Chagas disease?

There are two phases of Chagas disease: the acute phase and the chronic phase. Both phases can be symptom free or potentially fatal.

The acute phase lasts for the first few weeks or months of the infection. It usually goes unnoticed because it is symptom free or exhibits only mild symptoms and signs that are not unique to Chagas disease. The symptoms noted by the patient can include fever, fatigue, body aches, headache, rashes, loss of appetite, diarrhea, and vomiting. The signs on physical examination can include mild enlargement of the liver or spleen, swollen glands, and local swelling (a chagoma) where the parasite entered the body. The most recognized marker of acute Chagas disease is called Romaña's sign, which includes swelling of the eyelids on the side of the face near the bite wound or where the bug feces were deposited or accidentally rubbed into the eye. Even if symptoms develop during the acute phase, they usually disappear on their own, within a few weeks or months. Although the symptoms disappear, the infection persists if left untreated. Young children rarely die (<5%) from severe inflammation or infection of the heart muscle (myocarditis) or the brain (meningoencephalitis). The acute phase can be fatal in people with weakened immune systems.

During the chronic phase, the infection may remain asymptomatic for decades or even for life. However, some people develop cardiac complications, which can include an enlarged heart (cardiomyopathy), heart failure, altered heart rate or rhythm, and cardiac arrest (sudden death); and/or intestinal complications, which can include an enlarged esophagus (megaesophagus) or colon (megacolon) and can lead to difficulties with eating or with passing stool. The average life-time risk of developing one or more of these complications is about 30%, so that not all the persons infected with T. cruzi develop the disease with the characteristics of the chronic phase, but may remain in a phase known as "unspecified".

The severity and course of infection might be different in people infected at other times of life, in other ways, or with different strains of the T. cruzi parasite.

¿What should I do if I suspect I have Chagas disease?

You should discuss these concerns with your doctor, who will examine you and ask questions to guide you regarding the chances of infection and refer you to take the diagnostic test (for example, about your health and the places where you have lived). Chagas disease is diagnosed through a blood test. If it is determined that you have Chagas disease, you should get in touch with a cardiologist who will conduct a complete check-up of your heart, even if you are feeling fine. This type of control is important to monitor the patient's progress and timely identify any change in the heart's activity, thus allowing for early action to be taken before serious and irreversible damage occurs in the heart muscle.

¿How is Chagas disease treated?

There are two approaches to therapy, both of which can save the patient's life: antiparasitic treatment, to kill the parasite; and symptomatic treatment, to control the symptoms and signs of infection.

Symptomatic treatment may help people who have cardiac or intestinal problems caused by Chagas disease. For example, pacemakers and medications for irregular heartbeats may be life saving for some patients with chronic cardiac disease, allowing persons to lead a normal life despite the disease.

The currently available antiparasitic treatment is most effective in the early phase of infection. In Venezuela, this type of treatment is available through the consolidated public health system; however, the medications currently used are highly toxic and cause a number of serious side effects.