Dengue: cases increased 4 times in Brazil

The number of fever cases dengue in Brazil as of January 1 is four times higher than in the same period last year, government data showed on Saturday, ahead of the launch of a vaccination campaign.

In the first four weeks of 2024, 262,247 probable cases were registered, compared to 65,366 in the same period last year, according to the latest data available in the Brazilian Ministry of Health database.

Dengue: an emergency not to be overlooked

Fabio Baccheretti, president of the National Council of Health Secretaries, indicated high temperatures as the main factor in the spread of the disease transmitted by mosquitoes“The record temperatures at the end of last year, with the El Niño phenomenon, are a new and determining factor,” he told AFP.

Dengue fever has killed 29 people this year in Latin America's largest country and another 173 deaths are being investigated for possible links to the disease.

Mosquito-borne dengue, which can cause hemorrhagic fever, infects an estimated 100 to 400 million people worldwide each year, although most cases are mild or asymptomatic, the World Health Organization says.

“We are seeing that dengue is spreading in areas that were previously free in Brazil, so we need to follow this phenomenon closely,” warned Baccheretti.

Health services are already under pressure in many metropolitan areas of Brazil due to growing workloads. In the capital Brasilia district, a field hospital will begin accepting dengue patients starting next week.

The hardest-hit state so far is the southeast of Minas Gerais, Brazil's second most populous, with more than 88,587 probable cases reported.

Outside the state capital of Belo Horizonte, teams of fumigators are going door-to-door as part of a campaign against disease-spreading mosquitoes. Members are equipped with gas masks and dressed in white coveralls from head to toe.

“Sometimes it's hard to get into people's homes, but they're starting to see that there are a lot of cases around them and they're becoming more understanding,” Supervisor Katia Batista said.

Two weeks ago, the Brazilian government announced that a free vaccination campaign targeting 3.2 million people would take place in February, with priority given to children between 10 and 14 years old, the group with the highest number of hospital admissions . However, available doses are limited due to supply shortages from the vaccine's developer, Japanese pharmaceutical company Takeda, Brazil's Health Ministry said.

Overall, the nation of 203 million people expects to receive 6.5 million doses of the two-dose vaccine, tailored for children, this year.

Brazil began a vaccination campaign against dengue fever in February, authorities said, as a sharp increase in cases of the potentially deadly disease raised fears of an out-of-control epidemic.

The country of 203 million people, which approved the new “Qdenga” vaccine in December, will be the first in the world to offer it through the public health system, officials said.

However, the number of available doses remains limited due to supply shortages from its developer, Japanese pharmaceutical company Takeda, Brazil's Health Ministry said.

“The first shipment of 750,000 doses of dengue vaccine has arrived in Brazil,” the ministry said in a statement on Sunday.

Overall, Brazil expects to receive 6.5 million doses of the two-dose vaccine, tailored for children, this year.

Last year the World Health Organization recommended distributing Qdenga to children aged 6 to 16 living in dengue hotspots.

The European Union, Indonesia and Thailand have also approved the vaccine.

Brazil saw a 57% increase in dengue cases last year starting in 2022. And it recorded 56,000 cases in the first two weeks of 2024, double the number in 2023.

Six people have died from the disease so far this year in the South American country.

Mosquito-borne dengue, which can cause hemorrhagic fever, infects an estimated 100 to 400 million people each year, although most cases are mild or asymptomatic, the WHO says.

Climate change could help the disease spread. A recent report published in the medical journal The Lancet found that dengue transmission will increase by 36 percent if global temperatures rise by two degrees Celsius by 2100.

The United Nations health agency said Friday that reported cases of dengue fever globally have increased tenfold in the past generation, with climate change and the growing spread of virus-carrying mosquitoes partly responsible for transmission that remains prevalent in the Americas.

The World Health Organization said reported cases rose to a record 5.2 million in 2019, up from 500,000 in 2000, in 129 countries around the world, figures that likely underestimate the true toll.

In January, the WHO warned that dengue posed a pandemic threat and was the fastest-spreading mosquito-borne disease in the world. While there are vaccines and specially bred mosquitoes containing a bacteria called Wolbachia to fight dengue, there are no specific treatments for the virus once someone is infected.

More than 5 million cases and more than 5,000 deaths linked to dengue have been reported this year, the WHO said. Factors driving the increase were changing distribution patterns of mosquitoes that spread dengue, along with increases in
precipitation, humidity and heat linked to climate change.

Weaker health systems and poor surveillance have also played a role.

Most cases of dengue cause no symptoms or cause mild illness, although some infections can cause shock, severe bleeding and organ damage, symptoms that typically emerge after the fever has cleared, the WHO said.

Warning signs include intense abdominal pain, persistent vomiting, bleeding gums, fluid accumulation, lethargy or restlessness and enlarged liver, the agency said. Repeated infections can cause serious illness, which can cause bleeding and death.

This year, dengue has hit the Western Hemisphere. It is not widespread in Europe, although since 2010 there have been some locally widespread cases in the southern part of the continent.

Regions including the Americas, the Caribbean and Bangladesh reported record numbers of cases in 2023.

The Americas, which accounts for about four-fifths of the world's dengue cases, broke the previous regional dengue record earlier this year, with Brazil, Argentina, Paraguay and Peru reporting the most cases globally world. Peru has declared a state of emergency in some areas after reporting a historic number of cases.

There are two authorized vaccines against dengue, although experts say one of them should only be used on people who have been previously infected, otherwise they could run the risk of more severe disease.