From: Secretary of Health, Bolivia

Alexandra Bono
Chagas Disease in Bolivia

From: Secretary of Health, Bolivia

To: Minister of Finance, Bolivia

Introduction

Bolivia has the highest prevalence and incidence ratesof Chagas disease in the world, with approximately 1.8 million infected and 3.7 million at risk for infection.12Annually, 45,000 Bolivian deaths can be attributed to Chagas.14The disease disproportionately affects individuals of low socioeconomic status residing in rural areas.37The risk factors for Chagas include poor-quality housing, endemic residential location, lack of education, and receipt of blood or organ transplants.2589The repercussions of Chagas are the annual loss of over $255 million in both medical costs and lost revenue and the debilitating infections of millions.15 Consequently, our ability to develop a productive workforce is diminishing, along with the nation’s economic and social progress. In order to combat this growing problem, we must both utilize prevention methods and invest in research to improve our diagnostics and treatments.

Nature and Magnitude of the Problem

The prevalence of Chagas disease in Bolivia is the highest in the world, affecting approximately 1.8 million Bolivians—15% of our population.[1]An additional 3.7 million Bolivians are at risk of infection.2In Bolivia, Chagasis ranked the fourth most common disease.4Mortality related to T. Cruziinfection is 8.9 per 1000.[2]Annually, 45,000 deaths can be attributed to chronic Chagas, an advanced stage of the disease are developed by 20-30% of the infected.1[3]Diagnostic tests lack specificity and sensitivity, often requiring multiple blood tests before diagnosis.[4]Only half of people who are treated will be successfully cured, and no treatments exist for pregnant women and children.6When left untreated,the T. cruziparasite attacks the cardiac and digestive systems, leading to permanent heart, esophagus, and colon damage and/or death.[5]In young adults, heart failure is a common cause of death when the disease is untreated.56Healthy adults most often die of complications from Chagas without knowledge of their seropositive status.1

Affected Populations
Chagas disease affects many Bolivians. However, individuals of low socioeconomic status residing in rural areas have disproportionally high prevalence rates.2[6]Impoverished populations are 30% more likely to be infected via triatomine bug transmission and to develop chronic Chagas than higher socioeconomic classes. This is due to higher frequency rate of home infestation by infected bugs in addition to limited access to diagnostics and/or necessary treatment.59The endemic area spans 60% of Bolivia, with T. cruzi-infected vectorsfound in seven of nine Bolivian departments. In these regions, nearly 50% of residences have triatomine infestation, with over 30% of those vectors carrying the T. cruziparasite.2In Cochabamba, Chuquisaca, Tarija, and Santa Cruz, prevalence of Chagas is 100% in individuals over 40.1[7]Throughout Bolivia, seroprevalenceof T. cruziantigens ranges from 16 to 71% in children aged one to six years old and 32 to 93.5% in adults.1 Prevalence among pregnant women ranges from 25 to 50%, and 8 to 38% in neonates born to infected mothers.12[8]

Risk Factors

The primary risk factors contributing to the contraction of Chagas disease include endemic residential location, poor-quality housing, lack of education, and receipt of blood or organ transplants.2589Many Chagas-endemic areas are located in rural regions of Bolivia, limiting access to medical services that provide diagnostic and treatment services. Many houses owned by poor Bolivians consist of adobe or straw.2This type of housing greatly increases the likelihood of infection due to structural cracks and crevices that can shelter the triatomine bug.5These two risk factors contribute to greater than 80% of Chagas cases.1The lack of education increases diseaseprevalence because individuals are unaware ofthe various means of transmission and the ways by which they can prevent infection.5

Although less prevalent, mother-to-child transmissionand receiptof a blood transfusion or organ transplant from an infected individualsignificantly increase an individual’s risk of developing Chagas.Currently, no treatment exists for pregnant mothers to cure Chagas, and consequently her infant often contracts the disease during gestation, labor or while breastfeeding.[9]Additionally, 63% of potential donors in Bolivian blood banks carry the infectious parasite.8 Blood transfusions and organ transplants seropositive for the T. cruziantigens are estimated to have a 14.8% and 7.2% risk of transmission, respectively.25

Economic and Social Consequences

Chagas has significant negative impacts onBolivia’s progress and development, both economically and socially. The physical disability and illness caused by Chagas preventour people from working, costing Bolivia revenue from productivity and earnings from days lost due to illness. Due to high rates of absenteeism among workers with chronic Chagas, Bolivia loses an estimated $5 million annually from potential profits.5On average, these workers are 25 years old—our most economically productive age group.32 In addition to lost revenue, the annual cost of medical care in Bolivia due to Chagas is $250 million.1The World Health Organization estimates that disability adjusted life years lost due to Chagasin Latin America are 2,740,000, the majority from Bolivia.2Social effects emerging due to Chagas include psychological stress on individuals living in infested residences, in addition to the burden on families infected with Chagas. Research shows a decline in mental health as a result of home infestation, associated with thefear of infection.6 Lack of knowledge about disease status also harms mental health.26The burden and stress of Chagas on an individual or household also harms the overall health and well-being of a family.2

Priority Action Steps

Priority action steps to combat Chagas disease must include prevention and research. In order to prevent Chagas disease, priority must be placed on utilizing insecticides, replacing common structural materials, and providing education. Insecticides must be used to kill insect vectors within residences, limiting the amount of insect-transmitted disease. Replacing standard materials such as adobe and straw in homes with plaster and metal will also help prevent the colonization of vectors. Additionally, by providing education on Chagas, awareness will be raised about prevention, diagnostics, and treatment.

Currently, both diagnostics and treatment for Chagas are expensive, inaccessible, and inefficient. Because the majority of the Chagas-infected population are impoverished and reside in rural areas, new methods for ensuring both cheap and accessible diagnostics and treatment are imperative. Diagnostics and treatment should be subsidized and medical centers should also provide mobile medical services that provide diagnostics and treatment to all remote areas. By helping individuals to learn their disease status transmission, we can reduce transmission via pregnancy, blood transfusion or organ transplant.

Presently, we must continue to utilize available diagnostics and treatment. However, research is crucial in order to find more efficient methods to improve the health of our people. Diagnostics must be developed so that one test is sufficient to diagnose, eliminating the present method of multiple serological tests. More efficient treatments must be developed that have both high cure rates and can be given to infected mothers and infants. The long-term effects of this research would be an increase in awareness of the disease and effective treatments that can be given to all, thus decreasing Chagas prevalence in Bolivia.

Bibliography

[1]Medrano-Mercado, N., Ugarte-Fernandez, R., Butrón, V., Uber-Busek, S., Guerra, H., Araújo-Jorge, T., & Correa-Oliveira, R. (2008).Urban transmission of Chagas disease in Cochabamba, Bolivia.Memórias Do InstitutoOswaldo Cruz, 103(5), 423-430.

[2]Bolivia ncap project: Vallegrande findings. (2011, March 30). Retrieved from

[3]Bolivia. (2005). Retrieved from

[4]Time to treat chagas. (2009). Retrieved from

[5]Chagas in Bolivia: In pursuit of an effective treatment. (2008, August 07). Retrieved from

[6]UNDP / WORLD BANK / WHO Special Program for Research and Training in Tropical Disease (TDR). Tropical Disease Progress in Research 1991-1992, WHO, Geneva

[7]Arata AA, Balderrama F, Bermudez H, Navin T, Ormsby G, Torrico F, Velarde R 1994. Trabajo de la SNS CCH/ProgramaPiloto de Control de Chagas. La Paz, Bolivia, MinisteriodelDesarolloHumano, SecretariaNacional de Salud, 94 pp.

[8]Pless M, Juranek D, Kozarsky P, Steurer F, Tapia G, Bermudez H 1992. The epidemiology of Chagas disease in a hyperendemic area of Cochabamba, Bolivia: A clinical study including electrocardiography, seroreactivityto Trypanosomacruzi, xenodiagnosis, and domiciliary triatomine distribution. Am J Trop Med Hyg 47: 539-546

[9]Chagas disease. (2010). Retrieved from