Molecular Epidemiology of Parasitic Diseases: The Chagas Disease Model

Abstract

Parasitic diseases represent one of the most important issues in public health. More than one billion people worldwide are infected by parasites causing different disease scenarios. Parasitic diseases are closely related to geographic, social and economic factors driving the prevalence and incidence of these pathologies (WHO, 2010). These represent a broad group of eukaryotic organisms that may cause severe diseases in animal and human populations. Parasites are the causative agents of pathologies such as Malaria. In 2008, there were 247 million cases of Malaria and nearly one million deaths from the disease, mostly among children living in Africa. In Africa, a child dies of Malaria every 45 seconds; the disease accounts for 20% of all childhood deaths. Leishmaniasis threatens approximately 350 million men, women and children in 88 countries around the world. As many as 12 million people are believed to be currently infected by this disease, with approximately 1–2 million estimated new cases occurring every year. Additionally, an estimated of 10 million people are infected worldwide by Chagas disease (American trypanosomiasis), mostly in Latin America, where Chagas disease is endemic. More than 25 million people are at risk of acquiring this disease. It is estimated that in 2008, Chagas disease killed more than 10,000 people. Schistosomiasis is a chronic, parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma. More than 207 million people are infected with these organisms worldwide, with an estimated 700 million people at risk in 74 endemic countries. Lymphatic filariasis affects more than 1.3 million people in 81 countries. Approximately 65% of those infected live in Southeast Asia, 30% in Africa and the remainder in other tropical areas. Lymphatic filariasis afflicts over 25 million men with genital disease and over 15 million people with lymphoedema. Because the prevalence and intensity of infection are linked to poverty, elimination can contribute to achieving the United Nations Millennium Development Goals. Human African Trypanosomiasis (HAT) affects mostly poor populations living in remote rural areas of Africa. If untreated, it is usually fatal. Travellers also risk becoming infected if they venture through regions where the insect vector (tse tse flies) is common. Generally, the disease is not found in urban areas, although some cases have been reported in suburban areas of Kinshasa, the capital of the Democratic Republic of Congo, and Luanda, the capital city of Angola. In 2004, the number of new reported cases fell to 17,616, which the WHO considered to be due to increased control, estimating the cumulative rate to be between 50,000 and 70,000 cases (WHO, 2010). These trends show the