Chagas disease is a parasitic disease that occurs mainly in Central and South America. It can cause heart, nervous and/or digestive problems if the parasite is not identified and treated within days of transmission.
Definition: what is Chagas disease?
Chagas disease is a disease caused by the parasite Trypanosoma cruzitransmitted to humans by through bedbug excretions of the family Reduviidae. “This hematophagous insect feeds on the blood of humans/animals that it bites during the night. The itch caused by this bite will encourage them to scratch and spread the droppings of bedbugs, carriers of the parasite, all over their body and promote its circulation and incubation“, explains Paola Minoprio, research director at the Institut Pasteur.
Transmission usually takes place through the insect bite : the droppings deposited by the insect after its “blood meal” will be spread by scratching the skin and mucous membranes. “The parasite is present in excreta and because of the itching that the bite causes, the stung person will become contaminated by solution of continuity the place of the bite with the traces of fiantes under the nails, in the eyes if she rubs them… The parasite thus goes through the bite and/or at the level of the mucous membranes enter the bloodstream and grow within the cells“, she adds. Chagas disease can also be transmitted through blood transfusion or from mother to unborn child when the parasite is present in the bloodstream. “The French blood establishment offers people who wish to donate their blood an additional questionnaire when they come from endemic areas to avoid possible contamination.“, she specifies.
6 million people are affected worldwide by Chagas disease
By bed bugs?
“It’s not about bedbugs“. Bedbugs of the Reduviidae family are insects found only in South America and Central America, in forests, in rural and underprivileged areas. They can measure between 2 and 7 cm. As they are photophobic and evolve at night, you can protect yourself with a mosquito net on the bed and repellents when you live or are in an endemic area.
Can we catch it in France?
Chagas disease cannot, by definition, be caught in France, these insects evolving only in the southern United States. Chagas disease is endemic in Latin America, from Mexico to Argentina. Due to the strong immigration of these populations, we can find today some insects of the Reduviidae family in Texas which have adapted and perpetuated the evolutionary cycles of the Trypanosoma cruzi parasite.
What are the symptoms of Chagas disease?
The symptoms of Chagas disease are quite similar to those of the flu and therefore difficult to distinguish: poor general condition, fatigue, slightly high fever (39-40°C), vomiting and/or diarrhea. Depending on the entry point of the parasite, only a sign of inflammation in the eyes will be characteristic: bi-palpebral and uni-ocular conjunctivitis : “only one eye affected but both eyelids swollen”. One can also observe at the level of the swelling linked to the bite, on the arm or on the hand, an inflammation. The disease progresses in two phases.
► The acute phaseoften paucisymptomatic, usually goes unnoticed. “It is in this phase that the parasite will circulate in the blood, during first 30-60 days infection“.
► It is followed by the chronic phase. “The parasite will evolve at the level of tissues and organs: the heart, the muscles, the digestive system… and this for years, and will no longer be perceptible”. The majority of patients remain asymptomatic all their life.
A PCR test or serologye in the acute phase of the disease, during the symptoms, is the only possibility of identifying the parasite circulating in the blood. “If the test is not carried out, the disease will progress for years.“, insists Paola Minoprio. In almost a third of cases, cardiac, digestive or neurological complications occur 10 or 25 years later.
What is the treatment for Chagas disease?
A parasitic treatmente (“cytostatic, cytolytic“) must be carried out in the period of 30 to 60 days after the incubation of the parasite in the blood to stop its reproduction cycle in the cells of the organism. “Drug treatment will only act in the acute phase, then it is very ineffective“.
Is Chagas disease fatal?
Chagas disease is progressive and can cause after years a fatal disease such as a myocardial infarction. “We speak then sudden death : the parasite has evolved within the heart tissues for years and by multiplying has destroyed the cells, weakened the muscles of the myocardium. The heart suddenly drops“. According to the latest estimates, 6 million people are affected worldwide by Chagas disease and only 10% of them will die from it.
Thanks to Paola Minoprio, research director at the Institut Pasteur in Paris and head of the Trypanosomatid Infectious Processes laboratory at the Institut Pasteur in São Paulo, Brazil.