Chagas - another neglected disease

  12,000 people die from Chagas every year. It kills more people in Latin America than any other parasitic disease, including malaria.

 6 to 7 million people around the world who are infected with the parasite, Trypanosoma cruzi, that causes the life-threatening disease. 

Chagas, named after Carlos Ribeiro Justiniano Chagas, a Brazilian physician and researcher who discovered the disease in 1909, is endemic in 21 countries in Latin America, and also present in North America, Europe, Japan and Australia. It is included on the World Health Organization’s list of neglected tropical diseases; the aim is to achieve elimination of Chagas by 2030.

Chagas is most commonly transmitted by contact with the faeces of blood-sucking insects, known as kissing bugs, that are infected with the parasite. These bugs live in the walls of poorly built homes in rural or suburban areas. The insect bites the skin, then defecates close by. The parasites enter the body when the person instinctively smears the faeces or urine into the bite, the eyes or the mouth.

It can be between 10 and 30 years before people develop symptoms so most are unaware they have Chagas, often called a “silent and silenced disease”. Some will never develop symptoms but up to a third suffer heart damage, which can lead to progressive heart failure or sudden death. 

The global case detection rate is low (estimated to be about 10%), posing a substantial barrier to accessing treatment and care and in preventing transmission. Only 30% of people with the disease are diagnosed, with 75 million people at risk around the world.

Elvira Idalia Hernández Cuevas is president of the International Federation of Chagas patients, explained, “In Mexico, the authorities say that there aren’t many people affected by Chagas and that it’s under control, but that’s not the situation. Medical professionals don’t receive any training and mistake Chagas for other heart diseases. The majority don’t realise there is Chagas in Mexico.” The same is true in other countries, she adds.

Colin Forsyth, a research manager at the Drugs for Neglected Diseases Initiative (DNDi), says Chagas is neglected partly because it is a disease that affects poor populations in rural areas. “The people affected just don’t have the power to influence healthcare policy.”

Chagas can be treated with two medicines, benznidazole and nifurtimox, both developed more than 50 years ago. They are more effective if given soon after infection. They can cure a baby. For adults, there is no guarantee but the medications can at least prevent or curb disease progression. In adults, the treatment, taken over two months, can produce severe side-effects. 

Professor David Moore, a consultant at the Hospital for Tropical Diseases in London, says of the drugs: “They’re practically alchemy – they’re toxic, unpleasant, not particularly effective.”

There’s a desperate need for new drugs, he adds, but pharmaceutical companies won’t develop any because there’s no financially appealing market. 

He says “Our main problem is that this isn’t a population that people are interested in. It’s a neglected tropical disease, even in places where it’s common.” He thinks the WHO target for elimination by 2030 is “a huge challenge”. “I can’t imagine that we’ll be remotely close by 2030. That seems highly unlikely.”

‘The silent disease’: Chagas is a killer. Now carriers want their voices heard | Global health | The Guardian