VIT脫RIA LA暮S DE SOUZA GOMES, a shy 14-year-old with long, dark hair, pulls aside cables hanging from a lamp post and climbs on a platform with a view over her neighbourhood, Complexo da Mar茅. With more than 130,000 residents, this sprawl of 16 favelas, or slums, is one of the largest and most densely packed parts of Rio de Janeiro, Brazil.
Vit贸ria jumps down and leads me into a house. It is cramped, humid and hot. Vit贸ria pushes past her mother, into the kitchen, and pulls out an empty margarine tub from a drawer 鈥� it is her mosquito breeding station.
The tub is home to Aedes aegypti, the species that transmits several viral infections, including dengue, chikungunya and Zika. Dengue is the fastest spreading viral disease on the planet, with a 30-fold rise in incidence over the past 50 years. About 390 million people get infected each year and . Brazil is the , and Complexo da Mar茅, with its densely packed houses and poor sanitation, is particularly vulnerable to outbreaks.
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Which begs the question as to why Vit贸ria is encouraging the insects that can spread the disease to live in her home. But Vit贸ria鈥檚 mosquitoes are different. Her breeding station is part of a unique anti-mosquito movement dreamed up by a German dentist and brought to life with the help of the Brazilian Ministry of 午夜福利1000集合 and hundreds of local children. From such humble beginnings, it is now a crucial part of the country鈥檚 most successful anti-dengue programme, one that could inspire much-needed action to save lives globally.
I am in Complexo da Mar茅 to find out more, to discover how this movement is setting an example to other hard-to-access neighbourhoods on how to defeat deadly viral infections 鈥� in Brazil and beyond.
The story starts in 2005 with Norbert Lehmann. The recently retired German dentist was visiting a clinic in Complexo da Mar茅, donating dental X-ray equipment and offering free treatment. During his time there, a patient told him a neighbour鈥檚 child was sick. Lehmann told her to bring the child to the clinic. 鈥淭he next morning there was screaming outside the clinic,鈥� he says. The child had died in the night from severe fever and internal bleeding due to dengue. 鈥淭his death left a mark,鈥� says Lehmann.
Dengue, Zika and chikungunya are all treatable if you catch them early enough and you have access to the right medicine. But in parts of Rio de Janeiro, particularly in the city鈥檚 favelas, where houses pile on top of each other and alleys turn into tunnels, infections spread easily and healthcare is hard to come by. 鈥淒engue originates where people live densely,鈥� says Claudia Code莽o, head of virology at Brazilian health institute Fiocruz. 鈥淥nce the virus goes around, you can鈥檛 get it contained.鈥�
Vit贸ria tells me about a neighbour who was expanding his second floor. She says he went away for a few days and it started to rain. Water collected in a tarpaulin on the construction site, mosquitoes laid eggs in it and thousands of larvae hatched. 鈥淔irst Russo was sick, then Nordestina,鈥� says Vit贸ria, using nicknames for those affected, 鈥渢hen Juju, then Pardo.鈥� Within a week, everyone in the alley was sick.
When Lehmann returned to his home city of Karlsruhe, which sits beside the Rhine river, he thought a lot about the impact of dengue that he had witnessed. He then remembered a project around Karlsruhe in the 1960s whose name translates as . 鈥淲hen I was a kid, I played soccer on the floodplains of the Rhine,鈥� says Lehmann. 鈥淭here was always this time of day, half past four, when the sky would turn black and you鈥檇 be standing in a cloud of mosquitoes.鈥� It was the reason why the area was deemed uninhabitable back then.
Lehmann recalls the unique way that the mosquitoes were eventually controlled. Children who still went to the floodplains to play football told their parents about the areas most affected. They, in turn, alerted local administrators. Helicopters 鈥� borrowed from the likes of fire departments and the police 鈥� were used to throw crushed ice containing the bacterium Bacillus thuringiensis israelensis into parts of the river closest to where the children reported the plagues of insects. The mosquito larvae ate these bacteria, which made them infertile, and the problem was solved. You don鈥檛 need to treat the disease if you can control the carriers.
He was convinced that children could be the answer to Complexo da Mar茅鈥檚 mosquito problem too. Much of the neighbourhood is controlled by gun-wielding gangs, meaning adults who don鈥檛 live there are unable to come in to educate the community about mosquitoes. But there were hundreds of children who could walk freely around the neighbourhoods. Over the next decade, Lehmann raised money in Germany, and in 2014, he hired social workers within the complex to educate children about the role of mosquitoes in spreading disease. The children walked through the favelas, explaining to other children and adults about how to stop the spread: don鈥檛 leave water standing, check surfaces after rain and so on. They educated communities about the symptoms of disease, where to get tested and when symptoms become critical. The campaign was called Heroes Against Dengue, and word spread. Within months, dozens of children, including Vit贸ria, had joined up.
It is difficult to say how successful the campaign was at this point, as collecting data from inside complexes like Mar茅 is challenging. However, just before the 2014 men鈥檚 football World Cup in Brazil, Zika broke out across Rio. Thousands of people fell ill and hundreds of children were later born with neurological conditions directly related to infection with the virus responsible. The government didn鈥檛 collect official figures from Complexo da Mar茅 at this time, but according to anecdotal data from researchers at Fiocruz, doctors in the neighbourhood and in hospitals in the region saw fewer cases from within Mar茅 than expected.
Yet education can only take you so far in the fight against vector-borne diseases. In 2014, an opportunity arose to possibly wipe out these diseases altogether. Shortly after the World Cup, Brazil began small trials of an anti-mosquito programme using what is known as the Wolbachia method. It involves infecting mosquitoes with a naturally occurring bacterium called Wolbachia from a fruit fly. This suppresses the dengue virus and others in two ways. First, the bacteria occupy the part of cells that viruses use to reproduce. 鈥淭here is competition in the cell between the virus and Wolbachia,鈥� says Wesley Oliveira at Fiocruz. If a mosquito infected with both the dengue virus and Wolbachia bites you, the risk it will transmit dengue is only 5 per cent, compared with an 80 per cent chance from the bites of mosquitoes infected with the dengue virus alone. Second, when Wolbachia-infected males mate with uninfected females, those females will lay eggs that won鈥檛 hatch. When females with Wolbachia mate, their offspring are born with the bacterium, no matter whether the male had it or not. Gradually, the entire population of mosquitoes become affected.
This technique was originally developed by the in the early 2000s. In 2018, Australia released 3 million mosquitoes inoculated with Wolbachia in three North Queensland communities. By 2021, populations of mosquitoes had been suppressed by , virtually wiping out dengue in areas where the technique was most successful.
I visit Fiocruz, situated on the edge of the Complexo da Mar茅, where Brazil鈥檚 own Wolbachia mosquitoes are bred. Inside its insectarium, gauze cages house millions of mosquitoes. White nets streaked with red hang from the ceiling 鈥� they are soaked in human blood, fresh from a blood bank, which female mosquitoes must feed on to form their eggs.
On the countertop, researchers place a nutritious mix of fish and liver meal, charcoal and yeast into thimble-sized holes. They drizzle mosquito eggs taken from the Wolbachia mosquitoes on top. These will be manufactured into thousands of small, black capsules.
Having seen promising results in smaller trials in 2014, three years later, Fiocruz began a large-scale deployment of these capsules in breeding stations in parks, railway stations and residential areas around Rio and the neighbouring city of Niter蠈i. An , which compared the incidence of disease in areas of Niter蠈i where capsules were deployed with an untreated control zone, showed a 69 per cent reduction in dengue, a 56 per cent fall in chikungunya and 37 per cent less Zika. The preliminary data suggested that the numbers would be comparable in Rio 鈥� with a few exceptions: favela neighbourhoods, including Complexo da Mar茅.
Defending against dengue
In 2019, Oliveira showed Lehmann Fiocruz鈥檚 most recent data. Lehmann was curious as to why the programme wasn鈥檛 working in Mar茅. Oliveira said his researchers had tried to get vaccinated mosquitoes into the neighbourhood. They installed breeding stations in schools and clinics, but those are often on the borders of the favelas. They had even tried to blow the mosquitoes over the barricaded areas of the neighbourhood with a long pipe. It was out of the question to ask the drug gangs that control Mar茅 for permission to go further in, said Oliveira. With mosquitoes not tending to spread too far from where they breed, Mar茅 remained undersupplied. When Lehmann heard Oliveira鈥檚 explanations, he said that Heroes Against Dengue may be able to help.
After their meeting, Lehmann asked his heroes to help put mosquito eggs in places around the favelas where they knew mosquitoes liked to breed. Breeding Wolbachia-carrying mosquitoes has now become popular, says Oliveira 鈥� parents call Fiocruz because their children want a kit.
Back in Vit贸ria鈥檚 house, I watch as she fills a new margarine tub with water and places two black capsules inside. Her mother helps her punch holes in the lid with a screwdriver. She carries the box to the entrance of her home and stows it in the rafters. Later, hundreds of mosquitoes fly through the holes.
Today, the Wolbachia programme is considered the most successful anti-dengue measure in Brazil, says , also at Fiocruz, and Lehmann and his troop of heroes are a big part of making it work. Dengue outbreaks happen in waves, so figuring out the incidence can be tricky, but cases seem to be significantly down inside the favelas and around the city more generally, he says. In 2015, before the widespread deployment of the inoculated mosquitoes, there were 18,070 officially recorded cases of dengue in Rio de Janeiro. In 2017, this dropped to 3684, and in 2021, .
The programme is now being exported to other cities in Brazil, including Belo Horizonte, Campo Grande, Petrolina and Maric谩, as well as to other countries, such as Indonesia. In Belo Horizonte particularly, researchers will probably encounter similar accessibility issues as they faced in Rio, since a similar percentage of its population live in favelas. The answer is that, where necessary, Lehmann鈥檚 heroes programme will be included in the plan. 鈥淚n Rio, the help of local children has been essential,鈥� says Oliveira. The approach is already being replicated in other favelas in Rio, such as Jacar茅zinho, one of the most violent neighbourhoods in the country.
On my last day with Vit贸ria, she packs a small backpack and walks down an alley close to her home. It has been raining, ankle-deep puddles have formed in the asphalt, water stands in plastic plates and old car tyres. She kicks over every tin can she sees to pour out the water. The wrong kind of mosquitoes could be breeding in there.
Vit贸ria strolls down the street, constantly greeting people. She goes door to door every week to educate people about mosquitoes. A white container building looms in the distance, a government health clinic. Just in front are heavy concrete pillars, a barricade set up by a drug gang. I stop. Young men with guns strapped to their chest stand around.
On the tables in front of them lie a pile of drugs. Vit贸ria walks past the gunmen unimpressed, bypassing the barricade. She is allowed through because she is from Mar茅.
In the clinic grounds stands another table. On this one are hundreds of bags of black capsules. A crowd of people are waiting for a medical appointment. Vit贸ria hands out dozens of mosquito kits that day. She is incredibly proud of what she is doing, she says. A 14-year-old-girl from a favela, saving hundreds of lives.
Reporting for this feature was supported by the Pulitzer foundation
