6-7M
6-7 million people are affected worldwide
Chagas disease, also known as American trypanosomiasis, is a neglected tropical disease caused by a group of parasites called Trypanosoma cruzi.
First discovered more than 100 years ago, the disease continues to affect more than seven million people worldwide and is one of the most prevalent public health problems in Latin America. If left untreated, Chagas can cause irreversible damage to the heart and other vital organs.
About Chagas Disease
Chagas disease is found mainly in endemic areas of 21 continental Latin American countries. The most common way people are infected with Chagas is through the blood-sucking triatomine bugs, also known as ‘kissing bugs’ (or vinchuca, barbeiro, pito, chinche, chipo in different Latin American countries). The bugs typically live in wall or roof cracks of poorly constructed homes made of materials such as mud, straw and palm thatch. They come out at night to feed on people’s blood while they’re sleeping, then defecate close to the bite. Their faeces contain the parasite, which can then enter the person’s body when they inadvertently smear the bug’s waste into the bite or another skin break, the eyes or the mouth.
The parasite can also be transmitted from mother to child during pregnancy or childbirth, through contaminated food and beverages, blood transfusions, organ transplants or laboratory accidents.
Once entirely confined to the continental part of Latin America, in the last decades Chagas has been increasingly detected in the United States of America, Canada, many countries in Europe and some countries in Africa, the Middle East and the Western Pacific. The epidemiological pattern of Chagas has also changed from a rural to a mostly urban disease, mainly due to population mobility, urbanization and emigration.
Around 12,000 people die every year due to complications from Chagas disease, with only 1 in 10 being diagnosed. Of these, only a small percentage receive treatment. With an estimated 75 million individuals at risk of infection, Chagas remains a profound public health issue with significant social and economic burdens in Latin America and beyond.
There are two main stages of the disease: an acute phase and a chronic phase. In the acute phase, which lasts about two months, symptoms generally start to develop about one to two weeks following the bite. These are generally mild and unspecific, and may include fever, fatigue, body aches, headache, rash, loss of appetite, diarrhoea and vomiting. In people bitten by a triatomine bug, characteristic first visible signs of infection, such as a skin lesion or a purplish swelling of the lids of one eye (the so-called Romaña sign), can help in the diagnosis of new cases.
In the chronic phase, about 70-80% of people may not show any symptoms at all. However, in about 20-30% of people, the disease progresses, mainly affecting the heart or gastro-intestinal organs. This occurs 10 to 20 years after the initial infection. In the heart, the disease can cause enlargement of the heart muscle, leading to heart failure. Other common problems are arrythmias and sudden cardiac arrest. In the gastro-intestinal system, there can be enlargement of the colon or the oesophagus, leading to digestive problems.
Treatment is urgently indicated for anyone during the acute phase and for those in whom the infection has been reactivated. In these situations, treatment is almost 100% effective, and the disease can be completely cured.
During the acute phase, Chagas disease can be treated with two antiparasitic medicines: benznidazole* and nifurtimox*. Both medicines are nearly 100% effective in curing the disease if given soon after infection, including the cases of congenital transmission. The efficacy of both diminishes, however, the longer a person has been infected, and the risk of adverse reactions increases with age.
Once Chagas disease reaches the chronic phase, medications won’t cure the disease, but they may help slow the progression of the disease and its most serious complications. Adults, especially those with the indeterminate form of the disease, should be offered treatment, but its potential benefits in preventing or delaying the development of Chagas disease should be weighed against the long duration and frequent adverse events.
During the late chronic phase, when cardiac or digestive manifestations may occur, additional lifelong medical treatment and surgery are usually indicated.
*Benznidazole and nifurtimox should not be taken by pregnant women or by people with kidney or liver failure. Nifurtimox is also contraindicated for people with a background of neurological or psychiatric disorders.
In areas of Mexico, Central America, and South America, where the Trypanosoma cruzi parasite is present in triatomine bugs, improved housing and spraying insecticide inside housing to eliminate the bugs has significantly decreased the spread of Chagas disease. Screening of blood donations for Chagas is another important public health tool to help prevent spreading the disease through blood transfusions. Early detection and treatment of new cases, including mother-to-baby (congenital) cases, will also help reduce the burden of disease.
In other regions where Chagas disease is now found but is not widespread, control strategies should focus on preventing transmission from blood transfusion, organ transplantation, and mother to child.
