The number of dengue fever cases in the southern Taiwan city of Tainan has surpassed 3,000, accounting for the bulk of cases in the country this year. Taiwan’s Centers for Disease Control (CDC) said today that Tainan now accounts for 3,003 of the 3,446 dengue infections reported nationwide since May 1.

Aedes aegypti/CDC
Aedes aegypti/CDC

Of this total, four dengue-related deaths have been reported in Tainan City.

In addition to the massive increase in dengue cases in 2015, public health experts say those infected with the mosquito borne viral disease are suffering with symptoms like a fever for a week, as opposed to the usual 2-3 days typically seen.

In an effort for more timely diagnosis, Tainan City health officials said last week they will introduce 5,000 paper-based dengue NS1 antigen test kits for early diagnosis of dengue fever.

Tainan’s Department of Health chief, Lin Sheng-che said, “The tests, which use a color change to indicate the positive presence of the dengue NS1 antigen, will be able to identify patients at an early stage and thus prevent the disease from spreading.”

Lastly, a retired CDC researcher pointed to a lack of leadership as a problem with getting the dengue outbreak under control. Hsia Wei-tai said he attributed the problem to a lack of expertise and competent leaders who can map out strategies and guidelines.

Dengue virus is transmitted by female mosquitoes mainly of the species Aedes aegypti and, to a lesser extent, A. albopictus.

The World Health Organization says there are 4 distinct, but closely related, serotypes of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4). Recovery from infection by one provides lifelong immunity against that particular serotype.

However, cross-immunity to the other serotypes after recovery is only partial and temporary. Subsequent infections by other serotypes increase the risk of developing severe dengue.

Although the World Health Organization (WHO) says on their recent fact sheet that they currently estimate there may be 50–100 million dengue infections worldwide every year, researchers from the University of Oxford and the Wellcome Trust, using cartographic approaches, estimate there to be 390 million dengue infections per year worldwide.

There are three types of dengue fever in order of less severe to most: the typical uncomplicated dengue fever, dengue hemorrhagic fever (DHS) and dengue shock syndrome (DSS).

There is not a vaccine for dengue fever. There is no treatment for dengue, just treat the symptoms.

Robert Herriman is a microbiologist and the Editor-in-Chief of Outbreak News Today

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