COCHABAMBA , Bolivia ( CNN ) -- A hundred years ago a Brazilian physician , Carlos Chagas , showed that monkeys were susceptible to a rare parasitic illness carried by a particular Latin American bug . A mother and baby visit a clinic in Bolivia to get tested for Chagas . Today an estimated 16 to 18 million people are infected with Chagas , as the disease is now known , and it claims some 50,000 lives each year . Yet most people have never heard of it . Chagas disease is exclusive to Latin America , and kills more people there than any other parasitic illness , including malaria . In Bolivia , an estimated one in five people are infected . So why is so little known about the disease ? One crucial reason is that it only affects the poor . In the mud and thatch homes of rural villages and urban slums , bugs known locally as vinchuca , make their home in cracks in the walls and holes in the roofs . The bugs carry the parasite that causes chagas , in their saliva and their feces . Infection occurs when they bite , or if their are unknowingly eaten in uncooked food , or rubbed in the eye . Infected women can transfer chagas to their child during pregnancy , delivery or while breastfeeding . In its early stages , Chagas it is eminently treatable , but there are many problems . `` Most people do n't know they 've been infected , '' says Dr. Tom Ellman , who works in Bolivia with humanitarian agency , Doctors Without Borders . He told CNN : `` Many of them will drop down dead usually from heart problems cause by the disease 10 , 20 , 30 years after they 've been infected and no one will know why . '' For Dr. Ellman , this lack of effective treatment is a symptom of a much sadder cause . `` In terms of getting better treatment , you 're not going to have the interest of pharmaceutical companies , who will only investigate new drugs if there is a market that is willing to buy them . `` What we need now is more interest . We 're still using drugs invented over forty years ago , that have huge numbers of side effects and take sixty or ninety days to work , '' he told CNN . Even after these extensive courses of anti-parasitic drugs , there is no definitive test to see if the patient has been cured . Doctors can only advise patients to return in two years . Dr. Ellman also has particular concerns for children over the unavailability of new drugs : `` At the moment we have to cut adult doses of tablets into much smaller sizes for children which brings pricks of getting the dosage wrong and makes it much more complicated . '' Chagas can be detected via blood test . In the clinics where Doctors Without Borders work , they advise parents to have themselves and their children tested whenever they visit a clinic . But the challenge they face is vast . How to make a population wise to the threat of a disease that is already plaguing them , and that many have still never heard of . Tom Peck contributed to this report .
Chagas is a deadly disease that largely affects people in Latin America . An estimated 16 to 18 million people are infected with Chagas . The disease remains largely unknown , even where infection is rife . In the United States, there have been no reported cases of Chagas since it was first identified in 1976 by Dr. William Schaffner at Vanderbilt University Medical Center in Tennessee.