Dengue Mosquitoes Spreading Widely to More Regions, Countries

Lisa Schelein

The World Health Organization warns dengue fever is spreading to more regions and countries around the world due to the increased movement of people, urbanization, and climate-related issues.

"About half of the world's population is at risk of dengue," Raman Velayudhan, a top official of the WHO's global program on the control of neglected tropical diseases, told journalists at a briefing Friday in Geneva. "Dengue affects about 129 countries. We estimate about 100 to 400 million cases are reported every year. This is basically an estimate."

The disease, which is spread by the Aedes species of mosquito, thrives mainly in tropical and subtropical climates. WHO reports it has grown dramatically worldwide in recent decades, with cases increasing from half a million in 2000 to more than 4.2 million in 2022.

Last year, the Latin American region reported 2.8 million cases and 1,280 deaths. Just seven months into 2023, the region has already matched those figures, with nearly three million cases and an almost equal number of deaths.

Velayudhan said dengue is a global disease, noting that the mosquito which causes dengue has been found in 24 European countries.

He said that in Africa there recently have been reports of more than 2,000 cases and 45 deaths in Sudan, as well as new reports within the past week of dengue being present in Egypt.

He said the presence of dengue in Africa is of special concern, noting that the figure of over 200,000 cases reported annually from the continent is likely an underestimate.

He added that the reporting of dengue cases in Africa must be improved.

"We know it is there," said Velayudhan. "But it has been masked by other diseases. But now that [the battle against] malaria, in particular, has made great strides and has reduced in Africa, we have seen an increasing percent of dengue, and this is something we really encourage the governments [to address]."

He said this is already happening as the WHO is currently tracking cases of the disease reported in Sudan, Ethiopia, Senegal, Kenya, Nigeria and Sao Tome.

The monsoon season has begun in Asia, a situation that health officials find very worrying as the region accounts for about 70 percent dengue cases. The WHO has issued an alert to governments to take preventive measures to control the spread of the disease.

Velayudhan said the monsoon already has hit many of the dengue endemic regions in the Indian sub-continent, where high precipitation, increased temperature and even water scarcity favor mosquitoes and pose a real threat.

"So, we really need to be better prepared and make sure that all our health facilities are alerted and as the water recedes, we need to prevent [mosquito] breeding. And this is the key message," he said.

He said people can protect themselves by eliminating stagnant water and other possible breeding areas around their homes.

Most people with dengue do not have symptoms and get better in one to two weeks. However, those who develop severe cases often require hospital care.

While there is no specific treatment for dengue, WHO says patients can be treated with medicines to lower the temperature and ease body pain.

The World Health Organization says new tools, such as diagnostics, antivirals, and vaccines for preventing and controlling dengue, are under development. Indeed, it notes one vaccine is in the market, and two are in the final phase three clinical trial and review.

Meanwhile, Velayudhan noted that the mosquito that transmits dengue tends to bite during the day. So, his advice to people is "to cover up during the day to lower their risk of being bitten and getting dengue."

[VM/VOA]

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