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 Table of Contents  
Year : 2022  |  Volume : 8  |  Issue : 2  |  Page : 71-73

What's new in academic international medicine? The perils of neglecting diseases

1 Department of Biochemistry, University of Cambridge, Cambridge, England, UK
2 Department of International Health, Johns Hopkins School of Public Health, Baltimore, Maryland, USA

Date of Submission01-Jun-2022
Date of Acceptance02-Jun-2022
Date of Web Publication21-Jun-2022

Correspondence Address:
Dr. Brandon N Mercado-Saavedra
Department of Biochemistry, University of Cambridge, Cambridge, England
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijam.ijam_47_22

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How to cite this article:
Mercado-Saavedra BN, Ribas E, Detoy K. What's new in academic international medicine? The perils of neglecting diseases. Int J Acad Med 2022;8:71-3

How to cite this URL:
Mercado-Saavedra BN, Ribas E, Detoy K. What's new in academic international medicine? The perils of neglecting diseases. Int J Acad Med [serial online] 2022 [cited 2022 Sep 26];8:71-3. Available from: https://www.ijam-web.org/text.asp?2022/8/2/71/347824

The World Health Organization defines neglected tropical diseases (NTDs) as a group of 20 parasitic, bacterial, and viral conditions predominantly present in the destitute areas of the tropics.[1] Affecting the lives of billions of people, they result annually in a loss of billions of dollars in direct costs and reduced worker productivity.[1],[2] Although they do not receive much attention from the international health community, NTDs cause a loss of 19 million disability-adjusted life years each year.[1]

Chagas disease (CD) or American trypanosomiasis is a vector-borne NTD endemic in many Latin American countries. It is caused by a flagellated protozoan, Trypanosoma cruzi, which is primarily transmitted to humans by blood-sucking triatomine bugs. Contact with the contaminated feces of the bug – which may infect mucosal membranes and broken skin, including the bug's bite wound is the main mode of transmission.[3] However, it can also be transmitted through other routes, including congenital, oral (ingestion of contaminated food or drink), blood transfusion, and organ transplantation.

Although most patients infected with CD do not present any symptoms, it is a potentially fatal infection that can have an acute and chronic phase. The acute phase occurs after an incubation period of around 2 weeks and can last 2–3 months.[4] During this phase, patients have high parasitemia, and the majority experience nonspecific symptoms such as fever, malaise, myalgia, and headache. Some patients develop more severe and potentially fatal manifestations such as meningoencephalitis and myocarditis. During this initial phase, antiparasitic treatment with benznidazole or nifurtimox is most beneficial and effective, although they are associated with high rates of adverse side effects in adults. Parasitological cure can occur in 60%–85% of patients treated during the acute phase.[4]

Following the acute phase, untreated patients progress to a chronic phase, which is characterized by low parasitemia as the parasites at this time have formed amastigote nests and remain mostly embedded in tissue rather than circulating in the blood. Many patients remain in the “indeterminate” chronic phase with positive serology but no symptoms. However, 20%–40% of chronically infected patients will develop serious cardiac and/or gastrointestinal complications.[5],[6] While the pathogenesis of Chagas cardiomyopathy is not entirely understood, it is believed that parasite-induced neuronal damage, microvascular dysfunction, and autoimmunity contribute to tissue fibrosis, remodeling, and dysautonomia, leading to heart failure, arrhythmias, and thromboembolic events.[3],[4] A similar pathophysiological mechanism may be responsible for the gastrointestinal complications associated with CD. More frequently identified in the Southern Cone of South America, the digestive CD is characterized by dysmotility and severe dilatation of the gastrointestinal tract, especially the esophagus and colon (“megaesophagus” and “megacolon”). Clinically, patients present with progressive constipation, bloating, and pain. In severe cases, volvulus (twisting of the colon) and secondary bowel ischemia with necrosis can occur.

It is estimated that around 6–7 million people have CD, and the majority affected are in endemic regions of Latin America.[4] Although the parasite and vector can both be found in an extensive geographical area from Argentina to the Southern United States (US), the greatest burden of CD remains in more tropical locations and particularly in impoverished communities and rural areas with poor housing conditions, high exposure to vectors, and lack of access to health care. CD causes more morbidity and mortality than any other parasitic disease in the Americas, including malaria.[7]

It has been almost 80 years since the first Chagas case was reported in Bolivia, and as of now, Bolivia has one of the highest prevalence of Chagas in Latin America.[5],[6] CD is particularly prevalent in poor and rural areas – studies in 2007 and 2011 found a seroprevalence in adults as high as 80% in endemic regions in Bolivia.[8],[9] Even though the prevalence of T. cruzi infection has decreased in the past decades, CD remains a significant public health problem.[3],[10] The INCOSUR-Chagas initiative to eliminate Triatoma infestans and transfusional transmission of the American trypanosomiasis established in 1992 has prevented vectorial transmission in Chile, Uruguay, and parts of Argentina and Brazil.[11] Vector control programs work to decrease infestation of houses by T. infestans which can occur even after insecticide treatment due to insecticide resistance observed mainly in the Gran Chaco region at the border of Argentina and Bolivia.[12],[13]

Additional public health interventions aimed at preventing infection, including laws promoting proper food storage and programs to expand prenatal screening for pregnant women, have helped decrease the incidence of chronic Chagas cardiomyopathy in endemic settings. Additional reductions in disease burden have been achieved by policies aimed at facilitating the prompt diagnosis and proper treatment of both acute and chronic infections and increasing public awareness and screening programs.[9] However, public health interventions must also be prepared to meet the challenges of demographic and ecologic changes contributing to a changing distribution of CD and new challenges in Chagas prevention and control.[14]

Autochthonous transmission of CD in the US is rare but possible, with 11 known triatomine species spread throughout the southern 2/3 of the country.[15] However, the reporting is sparse, and <10 known vector-borne cases are acquired in the US.[16] This is likely related to an increased sylvatic association in these species compared to T. infestans. There is some concern that climate change will lead to the spread of vector species further north, and models have shown that by 2050, vector distribution will significantly increase, with a likely concomitant increase in autochthonous transmission.[17]

The vast majority of cases in the US are related to immigration, with an estimated >300,000 cases of Chagas in the US[18] leading to an estimated health cost of over $31 billion in health-care costs and lost productivity in the US and Canada.[19] In spite of this massive potential cost to society, Chagas continues to be largely underappreciated by the US medical establishment. Surveys of health-care providers have demonstrated a discouraging lack of awareness, with 47% of obstetrician-gynecologists (OB/GYNs) and 23% of cardiologists having never heard of CD.[18] At the very least, all OB/GYNs, pediatricians, cardiologists, and transplant specialists should be aware of the risks of CD in patients originating from Latin American countries.

In addition to the severe lack of awareness among health-care providers, there are numerous other systemic, clinical, and social barriers to appropriate diagnosis and treatment of CD in the US, many of which are common to most NTDs. This includes lack of access to care, health insurance, poverty, social/legal marginalization of immigrants, language barriers, gold standard in diagnosis, and changing treatment guidelines.[18] There are also research-related barriers such as lack of data, funding for NTDs in general, and logistical challenges to collaborating in research and capacity building abroad in the most affected countries.[16],[18]

While research and interventions for NTDs have always come with challenges, many of these barriers have become notably worse during the COVID pandemic. At this time, we have not yet fully comprehended the wide-ranging health and social costs of the severe and prolonged disruptions caused by COVID-19. These costs have been especially severe for those suffering from NTDs, and include disruption of community-based interventions, delays in diagnosis and care from health-care centers that either closed or were preoccupied with treating COVID patients, suspension of research and surveillance of NTDs; supply chain disruptions for research materials, diagnostics, and medications; and diversion of personnel and resources from NTDs toward COVID-19 research and management.[20]

We have witnessed all these disruptions and costs affecting Chagas patients in the US and Bolivia. Rapid tests used for screening pregnant women and cardiac patients for Chagas abruptly halted production for over a year so that companies could focus on the development and manufacture of COVID antigen tests; prolonged travel restrictions severely hampered field operations and exchange programs for training and capacity building; and research and clinical staff were diverted to urgently-needed COVID surveillance. In addition, plans for developing improved community awareness and screening programs for Latin American immigrant communication in the US were indefinitely put on hold.

Like many other researchers and public health workers, we are working to rebuild our labs, field sites, and collaborative relationships with our research partners in the US and abroad. There is much discussion about how COVID-19 laid bare many stark health inequities, including the greater morbidity and mortality in poorer communities and the profound lack of access to tests, vaccines, and treatments for low- and middle-income countries. What remains to be seen is the other “ripple” effects COVID-19 will continue to have that will disproportionately affect people in impoverished or marginalized communities. The loss of years of research, training, capacity building, and work toward awareness and prevention of this severely neglected disease will have effects for years to come and show how precarious our current systems are in the face of a global challenge.

Financial support and sponsorship

BNMS is supported by a Gates Cambridge Scholarship

Conflicts of interest

There are no conflicts of interest.

Ethical conduct of research

The authors declare that this editorial does not require an Institutional Review Board/Ethics assessment.

  References Top

World Health Organization. Neglected Tropical Diseases. WHO; 2021. Available from: https://www.who.int/health-topics/neglected-tropical-diseases#tab=tab_1. [Last accessed on May 30th, 2022].  Back to cited text no. 1
Huppatz C, Durrheim DN. Control of neglected tropical diseases. N Engl J Med 2007;357:2407-8.  Back to cited text no. 2
Vieira JL, Távora FR, Sobral MG, Vasconcelos GG, Almeida GP, Fernandes JR, et al. Chagas cardiomyopathy in Latin America review. Curr Cardiol Rep 2019;21:8.  Back to cited text no. 3
Bern C. Chagas' disease. N Engl J Med 2015;373:456-66.  Back to cited text no. 4
Torrico RA. Current Knowledge on the Epidemiology of Chagas Disease in Bolivia; 1950. Available from: https://iris.paho.org/handle/10665.2/11775. [Last accessed on May 29th, 2022].  Back to cited text no. 5
Medrano-Mercado N, Ugarte-Fernandez R, Butrón V, Uber-Busek S, Guerra HL, Araújo-Jorge TC, et al. Urban transmission of Chagas disease in Cochabamba, Bolivia. Mem Inst Oswaldo Cruz 2008;103:423-30.  Back to cited text no. 6
Global Health Estimates: Life expectancy and leading causes of death and disability. Available at: https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates. [Last accessed on May 30th, 2022]  Back to cited text no. 7
Samuels AM, Clark EH, Galdos-Cardenas G, Wiegand RE, Ferrufino L, Menacho S, et al. Epidemiology of and impact of insecticide spraying on Chagas disease in communities in the Bolivian Chaco. PLoS Negl Trop Dis 2013;7:e2358.  Back to cited text no. 8
Chippaux JP, Postigo JR, Santalla JA, Schneider D, Brutus L. Epidemiological evaluation of Chagas disease in a rural area of southern Bolivia. Trans R Soc Trop Med Hyg 2008;102:578-84.  Back to cited text no. 9
WHO. Chagas Disease (American Trypanosomiasis). n.d. Available from: https://www.who.int/health-topics/chagas-disease#tab=tab_1.[Last accessed on May 30th, 2022].  Back to cited text no. 10
PAHO. INNCOSUR-Chagas: Southern Cone Initiative to Control/Eliminate Chagas Disease. n.d. Available from: https://www.paho.org/english/AD/DPC/CD/incosur.htm. [Last accessed on May 30th, 2022].  Back to cited text no. 11
Picollo MI, Vassena C, Orihuela PS, Barrios S, Zaidemberg M, Zerba E. High resistance to pyrethroid insecticides associated with ineffective field treatments in Triatoma infestans (Hemiptera: Reduviidae) from Northern Argentina. J Med Entomol 2005;51:637-42.  Back to cited text no. 12
Germano MD, Santo-Orihuela P, Roca-Acevedo G, Toloza AC, Vassena C, Picollo MI, et al. Scientific evidence of three different insecticide-resistant profiles in Triatoma infestans (Hemiptera: Reduviidae) populations from Argentina and Bolivia. J Med Entomol 2012;49:1355-60.  Back to cited text no. 13
Echavarría NG, Echeverría LE, Stewart M, Gallego C, Saldarriaga C. Chagas disease: Chronic Chagas cardiomyopathy. Curr Probl Cardiol 2021;46:100507.  Back to cited text no. 14
Busselman RE, Hamer SA. Chagas disease ecology in the United States: Recent advances in understanding trypanosoma cruzi transmission among triatomines, wildlife, and domestic animals and a quantitative synthesis of vector-host interactions. Annu Rev Anim Biosci 2022;10:325-48.  Back to cited text no. 15
Bern C, Messenger LA, Whitman JD, Maguire JH. Chagas disease in the United States: A public health approach. Clin Microbiol Rev 2019;33:e00023-19.  Back to cited text no. 16
Graves, Brittany “Climate Change and Chagas Disease in the Americas: A Qualitative Systematic Review”. UT School of Public Health Dissertations (Open Access); 2019. p. 87. Available from: https://digitalcommons.library.tmc.edu/uthsph_dissertsopen/87. [Last accessed on May 30th, 2022].  Back to cited text no. 17
Forsyth C, Meymandi S, Moss I, Cone J, Cohen R, Batista C. Proposed multidimensional framework for understanding Chagas disease healthcare barriers in the United States. PLoS Negl Trop Dis 2019;13:e0007447.  Back to cited text no. 18
Lee BY, Bacon KM, Bottazzi ME, Hotez PJ. Global economic burden of Chagas disease: A computational simulation model. Lancet Infect Dis 2013;13:342-8.  Back to cited text no. 19
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