Southeast Asia’s Covid-19 lockdowns may be driving another virus wave: dengue fever

Getting people to hunker down at home has helped stem the coronavirus pandemic, but in parts of Southeast Asia, it’s spurred another potentially deadly disease: dengue.

The mosquito-borne viral illness, sometimes known as break-bone fever because of the joint pain it inflicts, has skyrocketed in the tropical region just as the usual dengue-spreading season begins. Singapore reported an average of 165 cases a day in the week through June 13, a record which authorities said may herald the largest dengue outbreak in the city state’s history.

Dengue is transmitted by the bite of a female Aedes mosquito. The insect species is widespread in Southeast Asia and thrives in sources of stagnant water in and around dwellings. People have spent more time in their homes to reduce transmission of Covid-19, and the World Health Organisation said the movement restrictions may be preventing communities and households from cleaning up potential mosquito-breeding sites in their neighbourhood.

“Lockdowns are placing more people at home than they normally would,” said Cameron Simmons, director of the Institute of Vector-Borne Disease at Melbourne’s Monash University, who studied dengue in Vietnam. “While no evidence has emerged proving a direct link, lockdowns could potentially have created an environment where mosquitoes are interacting more with the population than they would otherwise.”

Movement curbs probably worsened the dengue outbreak, said Siti Nadia Tarmizi, the director for vector-borne and zoonotic disease at Indonesia’s health ministry. As of Wednesday, the country had recorded some 64,251 dengue cases in 2020, almost 60 per cent more than at the same time last year. Bali, the popular tourist destination, has almost 9,000 infections.

In neighbouring Malaysia, weekly cases have climbed to 1,927, according to its health ministry, which expects the current wave to last until September. A longer than expected rainy season in the region is contributing to the increase in cases.