The Public Library of Science (PLOS) Journal of Neglected Diseases, a peer-reviewed journal, released an editorial in May about a little-known illness called Chagas. The infectious disease which is transmitted through parasites, can cause substantial damage to the long-term health and quality of life of those afflicted. While the editorial ignited some controversy due to its comparison of the disease to that of the HIV virus, it has managed to attract attention to a disease which has frequently been overlooked despite its prevalence in Latin America.
Chagas disease: basic facts
Chagas was first discovered in 1909 by a Brazilian doctor, Carlos Chagas. Also known as American Trypanosomiasis, the disease is the result of infection by a parasite called Trypanosoma cruzi, found in kissing bugs (triatomine insects). These insects are native to Latin America, and as such, Chagas is primarily limited to this region. However, due to high levels of immigration from Latin America, concern about Chagas has recently been voiced in the United States as well.
The disease, transmitted through contact with the feces of infected insects, often occurs when the kissing bugs infest human homes, allowing the parasite to come into contact with broken skin, mucosal surfaces on the body or the eye. Once the parasite has entered the body, it multiplies within the cells, entering the bloodstream and lymphomatic system, and eventually making its way throughout the body. Chagas can also spread through blood transfusions, organ donation, or from mother to child during childbirth. There have also been reports of infection from contaminated food.
Infection occurs in three periods. Following initial infection, the disease enters into an “acute” phase, which is presented by an elevated presence of parasites in the blood. The disease often goes unnoticed in this phase due to its lack of overt symptoms and poor access to healthcare amongst those infected. After 3-8 weeks, the disease enters the indeterminate phase, but still no symptoms appear. The final phase results in the manifestation of symptoms, mostly in the form of heart complications such as inflammatory cardiopathy, stroke, or problems with the gastrointestinal tract. This final phase generally occurs in only 10-30% of those infected, but those who do not display symptoms can still spread the disease to others.
The new AIDS?
Dr. Peter Hoetz, the dean of Baylor College of Medicine’s National School of Tropical Medicine and author of the editorial, compares the Latin American disease to the early days of the HIV pandemic. The article states “that a patient living with Chagas disease faces formidable challenges that resemble those faced by someone living with HIV/AIDS, especially the challenges that occurred in the early years of the HIV/AIDS epidemic.” In addition, Dr. Hoetz highlights the socio-economic situation of those most susceptible to disease, its chronic nature, the length of treatment and the manner in which it spreads through blood transfusion and organ transplant as examples of similarities between Chagas and the HIV virus.
Not all experts agree with Dr. Hoetz’s analysis. One of the most prominent individuals to question the parallel between Chagas and HIV is Rick Tarleton, the president of the Chagas Disease Foundation. In a statement to ABC News, he said that he does not believe “the comparison toHIV/AIDS is a realistic one, and I don’t expect it to serve the situation terribly well.” However, ABCalso noted that the author of the editorial, Dr. Hoetz, said that he had intentionally used the comparison as a mechanism to ignite controversy and thus generate greater awareness of Chagas.“I believe that Chagas disease is every bit as important as the AIDS problem, but no one’s ever heard of the disease.” says Dr. Hoetz.
Chagas: the neglected tropical disease
The World Health Organization (WHO) states that around 10 million people have Chagas, and is thus one of the major health challenges facing Latin America. The Pan American Health Organization (PAHO), the regional officer of the WHO, states that throughout the 1990’s, Chagas was the most widespread tropical disease in Latin America.
Neglected Tropical Diseases are diseases that take a high human and physical toll on populations, but receive less attention and funding on the international level. In particular, the United Nations Millennium Goals have been criticized for focusing on the “big three”, HIV/AIDS, malaria and tuberculosis, at the expense of other regional diseases that also incur high economic and human costs.
Of these diseases, Chagas has the highest rate of infection. PAHO states that throughout the 1990s the disease was five times more common than malaria, and that the burden Chagas caused was higher than any of the other disease in the region.
International responses to chagas
Although concern about Chagas is certainly valid, there have been relatively successful scientific, political and social responses to the disease, and neglected tropical diseases in general. Signs of progress began to show in 2008 when the Global Network for Neglected Tropical Diseases, the Inter-American development Bank and the Pan-American Health Organization (the regional officer of the World Health Organization) agreed to work together to end diseases associated with poverty. In 2009 they established the target date of 2015 for reducing the impact of these diseases, which included Chagas. The following year, the WHO Global Network for Chagas Elimination was formed to further combat the disease.
In response to these initiatives, Dr. Mirta Rosas Periago, the director of PAHO, has stated that, “It is possible to achieve elimination of certain diseases that still affect our populations, for which we already have knowledge and the tools to control and eliminate. It is also an ethical imperative that we make the necessary efforts to eliminate those diseases.”
Recent advances have also been made in the specific treatment of Chagas. Two drugs, Benznidazole and Nifurtimox, have been shown to be effective in curing the disease in its acute stage. Both are taken for four to twelve weeks, costing around $1000 a month.
However, the authors of the PLOS editorial expressed concern over the limited availability of the treatment and the lack of multiple manufactures of the drugs. These concerns are primarily based on a report issued by Medicins Sans Frontieres that outlined a lack of will and coordination amongst politicians and drug manufactures. These weaknesses ultimately contributed to a drug shortage in 2010 and 2011. Additionally, the drugs are only confirmed to be effective in the acute stage of the disease, and beyond treatment of emergent symptoms, there is no definitive cure or treatment for those with the chronic form of the disease.
The other face of Chagas
Because Chagas is a disease of poverty, merely focusing on scientific remedies is ineffective in both treating the disease, as well as ultimately reducing its infection rate. Dr. Louis V. Kirchoff who writes for Medscape, an online repository of medical information, states that preventing the spread of Chagas is no longer an issue of further technological or medical advances; instead, the focus should be the socio-economic issues which aid in the spread of the disease. The intergovernmental organization focused on problems related to poor access to healthcare, UNHCO, especially recommends further focus on the issue of substandard housing in the creation of a preventative strategy to tackle the transmission of the disease.
Consequently, preventative measures play a vital role in the response to Chagas, emphasizing the need for a modification of public health strategies to fight against the disease. Through the use of insecticide and mosquito nets, improved hygiene, and better methods of food transport, preparation and storage, the transmission rates of the disease have been lowered drastically. Uruguay, Chile and Brazil have been declared transmission free and other countries in Latin America have drastically lowered rates of transmission. Additionally, a test for screening the blood for the disease has been created to reduce its transmission through blood transfusion, organ transplant and childbirth. Thus far, twenty out of twenty-one of the countries impacted by Chagas have implemented this screening process.
While the response and success of current regional public health strategies give reason to be optimistic about the future eradication of the disease, heightened international involvement and effort will be essential to ensure Chagas never reaches similar proportions of HIV infection rates.