Laos grapples with high dengue infection rates amid rainy season

More than 8,400 people have been infected with dengue during the first seven months of the year, eight of whom have died of the mosquito-borne illness, according to figures issued by Lao health authorities in late July.

Though this year’s infection rate is high, it is a dramatic decrease from the 15,851 reported infections during the same seven-month period in 2023, according to the Centre of Information and Education for Health under Laos’ Ministry of Health. No reasons were given for this year’s lower figure.

The actual number of infections could be higher because not all Laotians seek help from medical centers or hospitals that would record and report their illnesses.

The country’s capital, Vientiane, has seen the most reported infections this year with 2,138 cases and three deaths, compared to 1,461 cases and one death during the first seven months of 2023.

Sekong province in southern Laos has the second-highest infection rate with 2,045 cases and three deaths, compared to 96 cases and no deaths during the same period in 2023.

RELATED STORIES

COVID-19 crisis complicates dengue prevention efforts in Southeast Asia

Laos gripped by deadly dengue fever surge

Dengue ravages region

The number of dengue infections, caused by the bite of infected female Aedes species mosquitoes, is usually higher in central and southern provinces of Laos because these areas are warmer and have higher humidity levels than other parts of the country, said an official who works in the infectious disease control office under the Health Ministry.

A persistent threat

Despite the decrease in this year’s infection rate, dengue continues to pose a threat to residents of the tropical, landlocked country. Monsoons during the wet season from May to November bring significant rainfall and high humidity that are ideal breeding grounds for mosquitoes.

Exacerbating the problem are growing populations in cities with poor sanitation systems and ineffective preventive measures, said the infectious disease control official.

“It is because it is quite crowded in some cities now as many people move to live in the city,” he said.

A lack of sanitation means mosquitoes spawn in stagnant water that collects in discarded bottles and other containers as well as in canals without proper water flows, he said.

Dengue infections plague Sekong city where many Laotians have moved to seek jobs in sectors such as construction, said an official from Sekong province’s Department of Public Health.

Residents and workers often carelessly discard cans and bottles, which sit in the open, fill with water and draw mosquitoes, he added.

“Also, water tanks without proper closures in restrooms are ideal places for the spread of mosquitoes,” he said.

Preventing the spread

During the rainy season, authorities in Vientiane usually spray insecticides in communities, but one villager observed that they have not yet done so this year in her community and others.

“There are many mosquitoes around our communities this year, and this rainy season the numbers of them is getting much too high,” she said, citing poor water flows in canals and an abundance of discarded bottles and cans.

The woman, however, said she saw workers spraying insecticide around hotels, hospitals and large buildings in the city.

Many provincial health departments send public health workers to villages to educate residents about preventing dengue infections and destroying places where mosquitoes lay eggs.

In 2023, Laos’ Health Ministry and Vientiane’s public health department with support from Save the Children launched a pilot program in two districts of Vientiane to reduce the spread of dengue by releasing mosquitoes with the Wolbachia bacteria to mate with domestic mosquitos.

The natural bacteria that is harmless to ecosystems and humans makes it difficult for the bugs to transmit viruses, including dengue, to humans.

But the effects of the program would not be immediate, according to Save the Children.

Translated by Phouvong. Edited by Roseanne Gerin and Matt Reed.