100 Years of Chagas Disease
Updated: Feb 19, 2021
Chagas disease: American Trypanosomiasis
Today we focus on another parasite! A disease that many are unfamiliar with; Chagas disease.
Chagas Disease, also known as American Trypanosomiasis - is an illness caused by a protozoan parasite called Trypanosoma Cruzi (T. cruzi).
Named after Carlos Chagas, who diagnosed the first human case in 1909, Chagas disease is a neglected tropical disease (NTD). Though it was identified over 100 years ago, it still remains somewhat ignored, continuing to impact many countries.
Chagas disease is endemic to 21 countries in Latin America  and infects approximately 6-7 million people globally, killing 10,000 annually .
Most transmission of T.cruzi is by an insect called the triatomine bug, transmitting the disease to both animals and humans . Triatomine bugs feed at night and tend to bite areas of the faces, lending them the name ‘kissing bugs’. The triatomine bug is only found in the Americas, so vector-borne spread of Chagas can only occur in this region .
This is not the only way the disease can spread - transmission can also occur without the triatomine bug by:
Congenital transmission (pregnant women to baby)
Consumption of triatomine feces i.e. on contaminated food
Diagram adapted from https://www.cdc.gov/parasites/chagas/disease.html
The triatomine bugs feed and release parasites in their feces, parasites enter the body via the bite wound or via mucus membrane, such as the eyes.
Once in the body the parasites enter cells and multiply.
Parasites then exit the cells and enter the bloodstream.
Now in the blood they can infect cells from other tissues, where they will multiply and cause symptoms of the disease. Parasites circulating in the blood may be taken up by a triatomine bug - infecting the bug.
The parasites develop into the infective stage in the bug, ready to be transmitted to another person/ animal
Burden of Disease
The disease is associated with some serious health issues, with the annual economic burden of health care costs estimated to be $627.5 million globally.
The disease has an acute and chronic stage.
Acute stage: occurs soon after infection, usually lasting up to a couple of months. This stage is asymptomatic (no symptoms) or associated with mild symptoms which can include; headache, swollen lymph glands, muscle, abdominal or chest pain . As these symptoms are general and mild, disease may go undetected and if left untreated it can lead to serious health issues- associated with the chronic stage.
Chronic stage: is accompanied with more severe symptoms such as cardiac disorders, and neurological and digestive issues, which in later stages of the disease may lead to death .
Impacts of the disease are not limited to physical issues, there is a stigma associated with the disease. This includes social rejection and difficulties finding work due to association of the illness with poor health, decreased ability and the risk of unexpected death being a concern to employers.
With growing globalisation and urbanisation individuals are able to move across countries and continents with relative ease. This has brought to attention a public health concern regarding the spread of Chagas disease to new areas, including Europe, Africa and Western Pacific countries .
Increasing the awareness and monitoring, such as routine screening for the disease will increase chances of identifying the disease early, before it can cause serious disease and/ or be transmitted. However, this as with every disease, will require increased awareness and funding! In line with increasing public awareness of Chagas disease globally - April the 14th has been declared World Chagas day!
Impressive progress is being made in Latin America, with almost all endemic countries conducting compulsory screening of blood (for transfusion), in order to prevent spread. In addition NGO’s (non governmental organisations) have increased their involvement in endemic areas, in 2015-2016 the number of individuals that were diagnosed and treated increased by almost 100%.
Interestingly, a modern approach to combating the disease has been implemented in areas across Bolivia. A system has been developed using a mobile app in aim to control the disease! Using this app, people can contact regional teams and inform them of locations where triatomine bugs have been spotted, the teams then use this information to locate and exterminate the bugs. This real-time method shows an impressive advancement using technology in the prevention and control of Chagas disease. Perhaps success of this method may see it used in other endemic areas of Latin America!
There is much to be done, but things are moving in the right direction. With increased awareness and support, let's hope this disease soon becomes a disease of the past!
Chagas disease is a neglected tropical disease (NTD) endemic to Latin America, but can be found in other countries
It is caused by protozoan parasite Trypanosoma Cruzi (T.cruzi)
The disease is spread by Triatomine bug - only found in Latin America. It can also be transmitted by blood transfusion, contaminated food, and from mother to baby during pregnancy.
There are approximately 6-7 million people infected globally with approximately 10 million deaths a year
There is increasing awareness of the disease in public health, with April 14th declared world Chagas day
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World Health Organisation, (2020). Chagas disease https://www.who.int/news-room/fact-sheets/detail/chagas-disease-(american-trypanosomiasis)
Centers for Disease Control and Prevention,(2020). Parasites- American Trypanosomiasis https://www.cdc.gov/parasites/chagas/gen_info/detailed.html#intro
Centres for Disease Control and Prevention, (2020) Chagas Disease https://www.cdc.gov/parasites/chagas/disease.html
Medecins Sans Frontieres Doctors Without Borders,(2020) Bolivia: Exterminating Chagas "kissing bugs. https://msf.org.uk/article/bolivia-exterminating-chagas-kissing-bugs?fbclid=IwAR1d9sIgiQzY-x1IqAzyvgooAvlBrpHm9CQKGO58g0egKNaOKUm9tEz0uME
World Health Organisation, (2020) World Chagas Disease Day: bringing a forgotten disease to the fore of global attention https://www.who.int/news/item/14-04-2020-world-chagas-disease-day-bringing-a-forgotten-disease-to-the-fore-of-global-attention?fbclid=IwAR2deqGlHtBlY3eygjecep7apZUNhWvpbzjCuJYBxh9_y_yIH9Z6gP8fM2k
Lee, B.Y., Bacon, K.M., Bottazzi, M.E. and Hotez, P.J., (2013). Global economic burden of Chagas disease: a computational simulation model. The Lancet infectious diseases, 13(4), pp.342-348.l https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3763184/
Uniting To Combat Neglected Tropical Disease(2021) https://unitingtocombatntds.org/reports/5th-report/chagas-disease-progress/