Niterói, Brazil — Since Rio de Janeiro declared a public health emergency following a dengue outbreak In the past month, the city has increased testing capacity, opened a dozen dengue health centers and trained medical staff to address the growing needs of its population.
But in the sister city of this city of Brazil, Niterói, on the other side of Guanabara Bay, is a completely different situation. With a population of half a million people, Niterói has had some 403 cases of dengue so far this year, and its per capita incidence is one of the lowest in the state, with 69 confirmed cases per 100,000 inhabitants.
In comparison, the city of Rio has an incidence of 700 cases per 100,000 people, with more than 42,000 cases.
The dengue virus is passed between humans by infected mosquitoes, but a type of bacteria called Wolbachia can interrupt the transmission of the disease.
Health officials noted that a pilot program launched in Niterói in 2015, in which Scientists bred mosquitoes carrying the Wolbachia bacteria, has helped the city in its fight against dengue.
The strategy used by Wolbachia was promoted in the last decade by the non-profit organization World Mosquito Program. It was first tested in Australia in 2011 and has since been The group has carried out rehearsals in more than a dozen countries, including Brazil. The initiative offers an attractive alternative at a time when the health agency of the The UN warns that dengue cases recorded around the world have multiplied tenfold in the last generation.
In Niterói, Mayor Axel Grael said he was looking to help after the 2012 dengue epidemic, when officials received thousands of notifications and one person died. The city signed a collaboration with the state institute Fiocruz, the World Mosquito Program and the Ministry of Health, and cases have been decreasing since then.
“It was a moment of great concern in the country and in Rio,” Grael recalled in an interview Friday with The Associated Press in Niterói. “Today, after applying the Wolbachia technique, we have much better results.”
Mosquitoes transmit dengue to humans. Many infected never develop symptoms, but others have high fever, headaches, body aches, nausea, and a rash. Although most improve within a week, some develop a severe form that requires hospitalization. and it can be deadly.
Frequent rains and high temperatures, which accelerate the hatching of mosquito eggs and the development of larvae, make the famously hot city of Rio especially susceptible. Every two years, outbreaks become epidemics.
Despite the low number of cases, the city of Niterói, like its neighbors, continues to invest heavily in prevention. Every day, hundreds of the city's health workers are sent to inspect neighborhoods, streets, rooftops, wooded areas, small businesses and junkyards to promote best practices, especially by keeping an eye out for any standing water where mosquitoes can deposit their eggs.
On Friday, in the scorching heat, Augusto César, 63, climbed into the Morro da Penha favela. For more than two decades, this municipal agent has entered neighbors' houses, climbed the roofs, collected garbage and inspected every corner of the favela in search of stagnant water. Even the cap of a plastic bottle, if filled with rainwater, can become a breeding ground for larvae, he explains.
“The biggest challenge is access,” says César, with beads of sweat running down his face. Favelas, often informally built, can be difficult to navigate, like mazes. After spotting a large plastic water tank on a roof that he would like to inspect, César makes his way down a tiny alley, squeezed between two concrete and red brick walls, but cannot find a way to the roof.
Later, he discovers two more unclosed water tanks. He climbs a wall and begins to remove the loose sheets that cover them. He installs mosquito nets and replaces the sheets. In a shady alley, he lifts the tops of two water tanks, grabs a flashlight, and checks the surface for any trace of mosquito larvae.
According to Luciano Moreira, a Fiocruz researcher, another challenge is security, since vast areas of the city are controlled by drug traffickers or militias. Moreira directs the Wolbachia project in Brazil.
According to César and Moreira, dozens of municipalities have contacted national and municipal authorities, eager to apply the Wolbachia method in their own territory. The Ministry of Salud announced plans at the end of last year to build a large breeding factory for Wolbachia-carrying mosquitoes that, over the next 10 years, will be able to produce 100 million eggs a week, ten times Fiocruz's current capacity.