In response to a surge in dengue fever cases during Rio de Janeiro's peak tourist season, local public health officials have escalated their efforts to curb the spread of the mosquito-borne illness. With nearly four times more cases reported compared to the same period last year, Brazil is facing a dengue epidemic, prompting urgent measures to protect both residents and visitors.

A small team of state public health workers recently scoured the streets, neighborhoods, and even junkyards of Rio de Janeiro in search of standing water where mosquitoes could lay their eggs. Delving into auto parts strewn across a junkyard, these dedicated workers discovered mosquito larvae swimming in shallow rainwater inside a car bumper. The prevalence of standing water in such locations contributes to the high presence of mosquitoes.

Earlier this month, just days before Rio's renowned Carnival festivities, the city, along with several states and the country's capital, declared a public health epidemic due to an unusually high number of dengue cases. Ethel Maciel, head of health surveillance at Brazil's Health Ministry, revealed that January registered the most cases ever recorded for that month.

This year alone, Brazil has reported 512,000 cases of dengue nationwide, encompassing both confirmed and likely cases. This figure represents a stark increase compared to the same period last year. Furthermore, there have been 75 confirmed deaths out of the 425 under investigation, with the number of fatalities on track to surpass the total for 2023.

High temperatures and frequent rains exacerbate the hatching of mosquito eggs and the development of larvae, making Rio de Janeiro particularly vulnerable to dengue outbreaks. While many infected individuals may be asymptomatic, dengue can cause severe symptoms such as high fever, headache, body aches, nausea, and a rash. In some cases, hospitalization may be required, and the disease can even prove fatal.

Equipped with masks and gloves, health workers like Paulo Cesar Gomes diligently combed through junkyards and other potential breeding sites for the Aedes aegypti mosquito – the primary carrier of dengue. Gomes collected mosquito larvae in white plastic containers to be tested for the virus at a city laboratory. Upon positive test results, health agents spray the area with mosquito-killing products and closely monitor the vicinity for subsequent weeks.

Maciel disclosed that the first warning of a possible epidemic arose in September. The esteemed Oswaldo Cruz Foundation, or Fiocruz, projected a potential 4.2 million dengue cases in Brazil this year, significantly surpassing the 1.6 million cases reported in 2023. Maciel also highlighted the circulation of four dengue virus serotypes concurrently, including one that had not been seen in 15 years.

With over 80% of mosquito breeding sites located in residential properties, health officials emphasize the crucial role of public awareness and individual efforts in combating dengue. State officials launched the "10 minutes that save lives" initiative, urging residents to inspect their homes, offices, and places of worship for any standing water. Health workers and volunteers went door-to-door in Rio's Tabajara neighborhood, distributing leaflets and inspecting rooftops for containers holding rainwater.

As part of their prevention efforts, health employees distributed free repellent to visitors during the recent Carnival festivities. A van adorned with a crossed-off mosquito emblem and the message "Against Dengue Everyday" highlighted the importance of dengue prevention during the parade, reaching millions of TV viewers.

The impact of Carnival on the spread of dengue remains to be seen, as increased tourism can potentially introduce the disease to previously unaffected areas. As public health officials intensify their efforts, it is crucial for both residents and tourists to remain vigilant and actively contribute to the prevention of dengue fever in Brazil.