Surge in dengue cases leaves Brazilian health officials rattled

Summer means Carnaval in Brazil, but it also means outbreaks of dengue fever. The two are unrelated, but the latter is due to the climate: warm, rainy days help fill the standing water where the Aedes aegypti mosquito — the vector of dengue, Zika, and chikungunya — lays its eggs. 

This time, mosquito season could be worse than usual. 

The Health Ministry expects dengue fever cases to break all previous records. In the worst-case scenario, the number of infections could top 4.2 million. The rapidly escalating numbers have prompted several local governments across the country to declare states of emergency, allowing them to expedite the procurement of equipment and personnel.

In a partnership with Brazil’s Air Force, the government in capital city Brasília set up a field hospital for dengue patients last week, a stark reminder of the worst moments of the Covid pandemic. The facility was expected to serve up to 600 patients per day; in its first three days of operation, it had more than 3,500 consultations, as several citizens without dengue symptoms also sought health services.

The states of Acre, Goiás, and Minas Gerais — the latter is the second-most populous state in Brazil, with more than 20 million residents — also declared emergencies. So did the city of Rio de Janeiro, home to 6.2 million people, where Mayor Eduardo Paes appealed to the community for help.

“Unlike the Covid pandemic, where individual citizens could not do much other than demand that governments get the vaccine, in the case...