Chagas disease
Chagas in the Americas

U.S.: Increasing Prevalence, Continued Neglect

Chagas disease has traditionally been characterised as a Latin American phenomenon, endemic only to the 21 countries south of the United States border. However, recent studies have shown that the prevalence of Chagas disease outside of Latin America is increasing, in large part due to population flows, and Chagas disease is becoming an important global health issue.(1) Caryn Bern and Sue Montgomery of Centres for Disease Control (CDC) estimate that in 2005 there were 300,167 individuals infected with Chagas disease living in the U.S.(2) This is more than six times the estimated prevalence of Chagas in Spain (47,743)(3) – the country with the next highest population of Latin American immigrants.

Modes of transmission in the U.S.
According to Bern and Montgomery, “the U.S. cannot be classified as an area of non-endemicity for Chagas in the same sense as Europe or Asia” due to the fact that eleven Chagas-carrying triatomine species live in the U.S. Although the likelihood of vector-borne transmission is rare, due to modern housing conditions and lower efficiency of vectors, there have been seven reported cases of autochthonous Chagas disease in the U.S.(4)
In January 2007, the U.S. began routinely screening blood donations for Chagas disease, and organ donation screening has now begun in some areas. According to the American Red Cross, 1 in 30,000 blood donations nationwide – and roughly 1 in 300 donations from Latin Americans in Southern California – continue to test positive for Chagas disease, even though donations from individuals with a known history of Chagas disease are not accepted.(5)

A case of neglect
CDC estimates of the prevalence of Chagas disease is based on demographic data, not actual diagnoses. This raises the question: of the 300,000 plus people who are estimated to be infected with Chagas disease in the U.S., how many have been – or will be – diagnosed? Testing for Chagas disease is not routine in the U.S., and the populations most at risk often do not have access to healthcare.

Health practitioners unfamiliar with Chagas disease
Even when patients are diagnosed, healthcare providers in the U.S. are largely unaware of Chagas disease and are unfamiliar with treatment protocols. Dr Meymandi, director of the Centre of Excellence for Chagas Disease, regularly sees patients who have been referred to her from around the country because of a lack of knowledge in the wider medical community.
In 2007, CDC published practical recommendations for the evaluation and treatment of Chagas disease in the U.S.(7) in an effort to address the lack of knowledge and standardisation in this area, but more education and training in the healthcare community is needed to ensure adequate surveillance, diagnosis and treatment of Chagas disease in the U.S.
Bern and Montgomery also estimate that every year, 63 to 315 babies may be born with Chagas disease. Despite the fact that these levels are in the range of other congenital conditions that appear in the American College of Genetics’ recommended newborn screening panel, screening for congenital transmission of Chagas disease is rarely conducted, suggesting a lack of awareness among obstetricians and gynecologists. To date, no congenital cases have been recorded in the U.S.
Furthermore, Bern and Montgomery conservatively project that up to 45,000 cases of heart disease could be attributed to the disease - in many cases, without the patients or their healthcare providers ever realising the cause.(8) The healthcare community’s lack of awareness may contribute to an increased burden on the healthcare system from patients with serious heart complications caused by Chagas, who may require aggressive treatments, such as defibrillators or heart transplants. These complications are, in large part, preventable if the disease is treated early.

U.S. global health policies neglect Chagas
Though more than 100 million people are at risk from Chagas in the Americas, the disease is often neglected in U.S. global health and neglected disease policies and programmes for disease control. For example, neglected disease programmes such as the President’s NTD Initiative and the Food and Drugs Administrations’s priority review voucher system do not include Chagas. In 2007, less than US$ 2.5 million of the federal(9) budget was spent on research and development (R&D) for new Chagas drugs and diagnostics - a negligible amount for a disease affecting more than 8 million people. (10)
President Obama’s five-year Global Health Initiative could change this by including Chagas disease programmes in its efforts to control NTDs, including: support for increasing surveillance, diagnosis, and treatment programmes; investment in R&D for new drugs and diagnostics; regulatory agency support; and measures to strengthen research capacity in disease-endemic countries. Increased attention is also needed to improve the situation for those living with Chagas disease in the U.S.. Public leadership is needed to ensure Chagas disease is appropriately addressed in international policies (i.e. WHO and PAHO), which should reflect the urgent needs for prevention, treatment, and development of new diagnostics and medicines. Over the long term, the emphasis must be on working with our Latin American neighbours to control the disease. With the Chagas disease burden concentrated in marginalised populations, Chagas patients do not have the political clout necessary to move this silent disease out of the shadows. DNDi’s Chagas campaign aims to raise awareness about this important public health issue, push for policy changes, and encourage R&D investments that will make a difference for Chagas patients in the future.

(1) Tarleton RL, Reithinger R, Urbina JA, Kitron U, Gürtler RE, 2007 The Challenges of Chagas Disease - Grim Outlook or Glimmer of Hope?. PLoS Med 4(12): e332. doi:10.1371/journal.pmed.0040332.
Bern C, Montgomery SP, An Estimate of the Burden of Chagas Disease in the United States, CID 2009; 49 e52-54 DOI: 10.1086/609509.
Gascon, J., et al., Chagas disease in Spain, the United States and other non-endemic countries. Acta Trop. (2009), doi:10.1016/j.actatropica.2009.07.019.
Bern & Montgomery, 2009.
Based on 147 confirmed positives since screening began in 2007 divided by the total estimated number of Latino Blood donors (40 000 – 50 000) in that period. Information provided by Cliff Numark and Ross Herron of the American Red Cross Blood Services.
(6) Centres for Disease Control and Prevention (CDC). (2007). Blood donor screening for Chagas disease-United States, 2006-2007. Morbidity and Mortality Weekly Report, 56, 141-143.
Bern C, Montgomery SP, Herwaldt BL, Rassi A, Jr, Marin-Neto JA, et al. Evaluation and treatment of Chagas disease in the United States: A systematic review. JAMA. 2007;298:2171–81. [PubMed].
Bern & Montgomery, 2009.
(9) This includes Centre for Disease Control, Department of Defense, National Institutes of Health and United States Agency for International Development.
(10) Families USA, “The World Can’t Wait: More Funding Needed for Research on Neglected Infectious Diseases.” December 2008.
Maira Gutierrez, an El Salvador native and an U.S. resident of 29 years, was diagnosed with Chagas disease by the Red Cross in 1997 after donating blood. At the time, the Red Cross was conducting exploratory screening of the disease (routine blood screening for Chagas was not implemented in the U.S. until 2007).(6) In the following years, Gutierrez repeatedly sought treatment without success – the doctors she contacted either did not know of Chagas disease or did not know how to treat it. Despite suffering from heart palpitations, Gutierrez gave up her search. In 2007, a decade later, her sister called to tell her that there was a story on the evening news about the opening of the Centre of Excellence for Chagas Disease, at Olive View-UCLA Medical Centre in Los Angeles County. Gutierrez subsequently underwent treatment for Chagas disease at the Centre, but she still doesn’t know if she’s cured, because no definitive “test of cure” currently exists. The American Red Cross now refers blood donors who test positive for Chagas to the Olive View-UCLA Centre of Excellence for Chagas Disease for treatment – still the only centre of its kind in the US. The Centre has implemented one of the only programmes in the country that proactively screens at-risk individuals for Chagas disease through outreach programmes in Hispanic communities in the Los Angeles area.

Treatment access in the U.S.

In the U.S., nifurtimox is available to physicians through special Centres for Disease Control (CDC) protocols, but benznidazole is more difficult to obtain and is rarely used. According to Dr Sheba Meymandi, director of the Centre of Excellence for Chagas Disease, “We can get [benznidazole], but it is a very laborious process through the FDA. Hopefully the CDC will have access to benznidazole soon.” Dr. Meymandi adds, “The difference, in terms of the treatments, is that benznidazole is a shorter course - two months - with a better side effect profile. Nifurtimox, which we have easier access to in the U.S., is a three-month course, and the side effect profile is pretty abysmal. It is like giving chemotherapy. Major side effects are nausea, vomiting, memory loss, neuropathies, and the list goes on.”

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