Mônica Bergamo: Anvisa approves a kit for molecular diagnosis of Chagas disease made by Fiocruz

Anvisa (National Health Surveillance Agency) granted this Monday (20) the registration for the first molecular diagnostic kit for Chagas disease in the country. Developed by researchers at Fiocruz, the product is a kind of quick test to identify Trypanosoma cruzi, the parasite that causes the disease.

Due to its high sensitivity, the kit detects the protozoan even if its presence in an organism is low or even from a fragment. As most of those infected are asymptomatic, the mechanism can make more diagnoses possible and prevent the development of the disease in its severe forms.

According to researcher Constança Britto, head of the Laboratory of Molecular Biology and Endemic Diseases at the Oswaldo Cruz Institute who led the project alongside researcher Otacílio Moreira, about 80% of people affected by the disease do not have access to diagnosis or treatment.

“Chagas disease is a neglected disease. There is no investment in vaccine because it affects a more vulnerable population. In South America, it is associated with vulnerable living conditions and can perpetuate poverty”, says Britto.

Currently, Chagas disease is more easily identified in its acute phase, when the parasites multiply. But considering that about 70% of cases are asymptomatic, the 30% who have symptoms may find themselves in a stage with no turning point with late diagnosis. “The parasite forms nests in the tissue of the heart muscle”, explains the researcher.

Chagas disease can still affect the digestive system and even the neurological part of the human body, requiring surgical intervention.

“Most of our Brazilian patients are chronic [que convivem há muito tempo com a doença]. As they feel nothing and have no diagnosis, they are considered chronic patients. And when it’s treated, they’re given an ancient drug that doesn’t heal. It can reduce the number of parasites, but it will not be cured”, says Britto.

“The drugs, from 1970, are effective when the disease is detected early. If the person is diagnosed early and is treated, the chance of cure is 100%”, he continues.

This is where the importance of the Chagas NAT Kit lies, as the test developed by Fiocruz was named. If distributed in regions where the disease has a higher incidence, more Brazilians could receive treatment sooner.

“The whole problem [atualmente] it’s you diagnosing more than 80% of patients who are chronic and are unattended, living in places where they don’t have access to the health center”, says Britto.

Another innovation brought with the novelty is its national origin, which eliminates the need to import inputs and makes the testing process cheaper.

The most widespread test for the detection of Chagas disease today consists of a PCR-type test, which seeks the genetic material of the pathogen from a blood sample.

With the molecular tool developed by Fiocruz, it will be possible not only to have a faster response —between four and five hours after sample collection— and more accurate, but also to monitor the parasite load throughout a treatment.

Currently, the most recurrent transmission of Chagas disease occurs orally, when a person consumes some food infected with parts of the barbeiro, its vector, or with its excrements.

“People have an açaí tree in their backyard. They collect the fruit, put it on a paneira, clean it with water and leave it under the light to dry the fruit. The next day, it takes that dry product and hits it in the blender to make juice. If the barber falls into the middle of the açaí — it is not an animal that moves a lot —, the next day the person will drink Trypanosoma cruzi broth”, exemplifies Britto.

Constança Britto still remembers when Italian tourists contracted the disease while drinking sugarcane juice during a trip to Santa Catarina, in 2005. Deaths were recorded at the time.

According to the head of the Molecular Biology and Endemic Diseases Laboratory at the Oswaldo Cruz Institute, oral infection causes even more aggressive symptoms than when someone is bitten by a barber, the more classic form of transmission. “It’s a radically new thing and people aren’t being careful,” she warns.

Between 2007 and 2019, Brazil recorded, on average, about 200 new cases of acute Chagas disease per year. “Usually, by the oral outbreak”, says the researcher.

The molecular kit was developed in partnership with the Institute of Molecular Biology of Paraná (IBMP), linked to Fiocruz, and with the government of Paraná.

Registration with Anvisa is a requirement for the exam to be incorporated into the SUS (Unified Health System). The adoption of the methodology still depends on a cost-benefit assessment by the National Commission for the Incorporation of Technologies in the Unified Health System (Conitec) and a final decision by the Ministry of Health.

_{with BIANKA VIEIRA, KARINA MATIAS and MANOELLA SMITH}