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Chagas Disease

Written by Sophie Keshishian, Peer Reviewed by Olivia McCollum, Edited by Courtney Coleman

 

It is frightening to be unknowingly living with an infection, especially when its effects are potentially life-threatening, and access to treatment is scarce. Unfortunately, this is the case for approximately 8 million people living in Mexico, Central, and South America who are infected with Chagas disease (1). Chagas disease, also known as American trypanosomiasis, is a disease caused by the parasite Trypanosoma cruzi. The disease was discovered in 1908 by bacteriologist Carlos Chagas as a result of his dissection of blood-sucking insects that conglomerated in certain regions of Brazil (2). T. cruzi is transmitted from insects to humans and animals, leading to higher infection rates in rural areas with poor housing conditions (1). With the rising rural-to-urban movement of Latin American populations, it is necessary that prevention is prioritized in order to maintain the control of Chagas disease and protect vulnerable populations in low- and middle-income countries.


Transmission and Symptoms

There are multiple ways in which people may become infected with Chagas disease. The most common mode of transmission is through something called “vector-borne transmission.” Insects known as “kissing bugs,” or triatomine bugs, act as the vector and are infected when they bite an infected animal or human. Following infection, the parasite is spread through the feces of the triatomine bugs without affecting the insects themselves. These bugs often hide in crevices of mud, adobe, straw, and palm thatch homes, emerging at night and biting their hosts’ faces. After biting, the bugs defecate on the person, leaving the person vulnerable to infection if the feces enters the body through the bite wound, eyes, or mouth (1).


Some other modes of transmission include: congenital transmission (from pregnant person to baby), blood transfusions, organ transplantation, laboratory exposure, and consumption of uncooked food contaminated with the feces of infected triatomine bugs. For those who may be nursing, it is generally safe to breastfeed while infected with Chagas disease, unless the mother’s nipples show signs of bleeding or cracking, in which case the mother should pump her breast milk, discard it, and wait to heal prior to breastfeeding again (1). Chagas disease cannot be transmitted through any casual contact with infected people or animals in the way a typical flu would be transmitted.


The symptoms of Chagas disease evolves with the progression of the infection. The initial (acute) phase lasts for approximately two months after infection. While this phase has a high amount of parasite circulation within the bloodstream, the symptoms are either nonexistent, or mild and unspecific. Approximately < 50% of people bitten by an infected triatomine bug may exhibit skin lesions, purple swelling of one of the eyelids, fever, headache, swollen lymph nodes, pallor, muscle pain, trouble breathing, inflammation, and/or abdominal/chest pain. Once progressed to the chronic phase, the parasites are often found in the heart and digestive muscles, which can consequently cause cardiac arrhythmias, heart failure, or death (2).


The steps in which a person takes following infection are crucial, yet, being that Chagas disease prevalence is highest in impoverished regions, proper diagnosis and treatment is not easily accessible.


Screening, Treatment, and Accessibility Concerns

Upon detecting symptoms of Chagas disease, it is important to visit a doctor and schedule a consultation to inquire about the factors which may have put a person at risk for infection. If symptoms develop, blood tests would be the initial method of detection for the presence of the T. cruzi parasite or antibodies which fight off the parasite in the immune system. If the parasite or antibodies are detected, the following tests may be performed to determine whether the disease is chronic, or if it has caused other cardiac or digestive complications: electrocardiogram, chest X-ray, echocardiogram, abdominal X-ray, and/or upper endoscopy (3). From that point forward, treatment for Chagas disease is focused on managing symptoms and attempting to kill the parasite. During the acute phase of infection – which begins approximately 8 days after infection and lasts 4-6 weeks – the medications benznidazole and nifurtimox (Lampit) are typically prescribed (3, 4). These medications may also be suggested for infected persons younger than 18 years of age, women of reproductive age, and adults over 50 years of age with signs of chronic infection. While the medications have been developed, accessibility remains a concern. In April of 2021, the Assistant Director-General of the Division for Universal Health Coverage stated: “It is sad to note that despite progress, millions of people remain undiagnosed, with limited or no access to healthcare… [detection and diagnosis of Chagas disease] are currently at unacceptably low levels and we need to provide equitable access to treatment and health services to everyone.” (5).

Fig. 1. Roadblocks in Chagas disease care in endemic and nonendemic countries: Argentina, Colombia, Spain, and the United States. (6)


As summarized in Figure 1, countries such as Argentina, Columbia, Spain, and the United States face barriers with regard to prevention, diagnosis, and treatment (6). Overcoming these barriers is important, because the longer that treatment is delayed, the more likely the disease will become chronic and medications will be ineffective.


Therefore, raising awareness about the lack of access to comprehensive treatment for Chagas disease remains a major responsibility for global health leaders, as well as concerned citizens who wish to see an improvement in public health.

 

References


1. “Parasites - American Trypanosomiasis (also known as Chagas Disease).” Centers for Disease Control and Prevention, 13 April 2022,

https://www.cdc.gov/parasites/chagas/index.html. Accessed 26 February 2023.


2. “Chagas Disease (also known as American trypanosomiasis).” World Health Organization, 13 April 2022,

https://www.who.int/news-room/fact-sheets/detail/chagas-disease-(american-trypanosomi asis). Accessed 26 February 2023.


3. “Chagas disease.” Mayo Clinic, 12 November 2020,

https://www.mayoclinic.org/diseases-conditions/chagas-disease/symptoms-causes/syc-20 356212. Accessed 26 February 2023.


4. “The history of Chagas disease.” Parasites & vectors vol. 7 317. NIH National Library of Medicine, 10 July 2014, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4105117/. Accessed February 28 2023.


5. “WHO calls for comprehensive, equitable access to healthcare for every Chagas disease patient.” World Health Organization, 14 April 2022,

https://www.who.int/news/item/14-04-2021-who-calls-for-comprehensive-equitable-acce ss-to-healthcare-for-every-chagas-disease-patient. Accessed March 10 2023.


6. “Roadblocks in Chagas disease care in endemic and nonendemic countries: Argentina, Colombia, Spain, and the United States. The NET-Heart project.” PLOS Neglected Tropical Diseases, 30 December 2021, https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0009954. Accessed March 10 2023.

 

This post is not a substitute for professional advice. If you believe that you may be experiencing a medical emergency, please contact your primary care physician, or go to the nearest Emergency Room. Results from on going research is constantly evolving. This post contains information that was last updated on April 10, 2023.

 

Sophie Keshishian is currently a Molecular & Cell Biology and Business Administration major undergraduate at UC Berkeley.


Olivia McCollum is a first-year MPH Candidate in the Department of Epidemiology at the University of Washington-Seattle. She is currently studying epidemiology of infectious and zoonotic disease specifically in children and women residing in low- and middle-income countries.


Courtney Coleman is a master's degree candidate in biology at Harvard and Co-President of Students vs Pandemics.

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