Heart problems - that's how Chagas disease may manifest itself. But by then, the infection will have been in a patient's body for many years. That’s why the disease is rarely treated. But it also has to do with poverty.
This story may start with a bug bite somewhere in rural Bolivia. In a ramshackle home with cracked walls that offer shelter to a bug called the 'kissing bug.' "Kissing bug," because it likes to bite its victim's face at night.
The bite itself wouldn't be so bad, if it wasn't for the fact that the bug defecates or urinates after biting. Caught unaware, the sleeping victim will itch and scratch, rubbing a parasite into its body that transmits Chagas disease.
Infections go unnoticed
In most cases, the infection will go unnoticed. "Some 90 percent of those infected with Chagas disease show no symptoms, " says Doctor Jaime Altcheh, a pediatrician who heads up the department of parasitology and Chagas disease at a major children's hospital in the Argentinian capital of Buenos Aires.
It may be 20 or 30 years after that initial bug bite that a person may start having serious heart problems, or digestive problems. By then, the disease has become very difficult to cure. What's more, a woman is very likely to have passed the infection on to her children during pregnancy or birth, or a blood donor may have unknowingly passed on the infection.
Bolivia: Most cases per 100 inhabitants
With some 1.5 million people infected - according to data compiled by the World Health Organization (WHO)- Argentina has the most cases of Chagas disease. But it is Bolivia that has the highest number of cases relative to the size of its population.
"If you look at how big Chagas disease is in terms of being a public health problem on the national level, it is Bolivia that ranks top," says Maria Jesus Pinazo, a doctor at Institudo de Salud Global in Barcelona, who has spent the past four years of her career helping to combat Chagas disease in Bolivia.
One part of her and her team's work in Bolivia is to educate people about the disease and reduce the stigma associated with it.
"There are many negative connotations to this disease on the level of the population at large, " says Pinazo, "and health care professionals also hang on to antiquated ideas that it is a disease which cannot be treated. So we have to work to overcome these preconceptions."
No demand for treatment
There are various factors that hamper the effective treatment of Chagas disease, says Jaime Altcheh. "The health care system which doesn't focus on poor people. Then, the doctors who don't know enough about Chagas disease to diagnose and treat it properly. And also, it's the patients who don't demand to be treated."
"A patient with HIV will, generally speaking, call for proper treatment. But we don't see that with Chagas patients," says Altcheh. "Often, they are people that migrated from very poor, rural areas to the bigger cities, and they feel they don't have a right to demand treatment."
Spreading from Latin America to the world
Chagas is endemic in 21 countries on the Latin American continent. The overwhelming majority of people living with Chagas disease live in Latin America. At least six million people are infected with Chagas disease according to WHO.
But the disease has long spread to countries where the "kissing bug" doesn't exist. The WHO estimates that around 100,000 people in Europe are infected with Chagas disease.
"Latin Americans, particularly people from Bolivia and Ecuador, started leaving their country in search for better economic opportunities," explains Jaime Althcheh.
Leaving for Europe in search of a better life
Many people from South America first migrated to Spain, but also to other countries.
"It was in the late 1990s, early 2000s, that we saw an increased mobility,. This came following social unrest in Latin America, and at the time that the economic situation in Spain was improving," says Yves Jackson, a doctor based in Geneva, Switzerland, who has written his thesis about how Chagas disease spread to Europe.
A prototypical patient, he explains, "would be a middle-aged woman, still in child-bearing age, coming from rural Bolivia. A woman who would have grown up in a semi-urban area, left her country in hope for better possibilities in Spain, and in the wake of the economic crisis there would have gone to live in Switzerland as an undocumented immigrant."
Of course, Latin American immigrants did not actually bring the parasite-bearing "kissing bug" with them. But because blood wasn't routinely screened for Chagas, those that were infected with the disease were able to pass it on if they donated blood, and, to a lesser extent, organs. Also, women were likely to transmit the infection to their child during pregnancy or birth.
Prepared for bull fights, but not for Chagas
But while more and more people at risk of being infected with Chagas were coming to Europe, says Yves Jackson, doctors and other medical staff there were not prepared: "There was no system of detection, no health care policy and no awareness among health care professionals."
The Vinchuca bug spreads Chagas disease through the urine and feces it leaves behind after biting its victim
Barcelona-based Dr. Maria Jesus Pinazo comes to the same conclusion. "In Spain, we have fewer toreros, or bull fighters, than we have immigrants from Latin America," she says.
"But despite that fact, I got trained and even examined in treating wounds from a bull fight, something I have never actually had to do in my entire career. But not once throughout my medical training was I taught anything about Chagas disease."
Over the past few years, says Yves Jackson, the situation has started to improve.
"Several countries now try to implement strategies and respond to health needs, so we have been able to identify many more cases and we have realized that it is a new emerging disease in Western Europe," he says.
Jackson is not alone in advocating uniform rules governing the screening of blood donations, and in pregnancy. Indeed, the WHO aims to increase screening and help prevent the transmission of Chagas from mother to child.
But on the ground, progress is piece-meal, as Doctor Pinazo explains.
"A few years ago, the Spanish government passed a law introducing that blood of donors potentially infected with Chagas be screened," she says, going on to explain that the same requirements do not apply for blood screening during pregnancy.
"We do have this kind of mandatory screening in four regions, and it is covered by public health care and works reasonably well," she explains. "But the challenge remains to bring this to the national level."
A neglected disease on many levels
For Pinazo, Chagas qualifies as a neglected disease for many reasons.
"There are only very few resources to diagnose this disease, and in terms of treating it, we only have two drugs which date back to the 1970s and have considerable side effects," she says.
Yves Jackson in Geneva agrees, saying he is not aware of any other disease with so few options of treatment. Chagas disease, he says, is a disease that gets neglected even more than other so-called neglected diseases.
Impetus for change?
But for Jackson, the problem goes beyond the world of medicine.
"It's a very political disease," he says. "Look at the United States, where it is estimated that nearly half a million have Chagas disease, but there is hardly any program because the infected are undocumented immigrants, and there is no incentive to develop tools against this disease."
"In Europe, it's very much the same because Chagas disease affects people who are at the margins of social and health care systems."
Despite some efforts to address the problem, politicians as well as pharmaceutical companies don't care enough about Chagas patients to bring about change, the Argentinian doctor Jaime Althcheh believes.
"Until the patients start seriously demanding help," he says, "Chagas will never be a priority."