Dengue becoming global public health threat - experts

MANILA, Philippines - Health experts have warned that dengue is becoming a global public health threat, owing to rapid urbanization, growing population, increasing international travel and climate change.

Dr. Duane Gubler, director of Program on Emerging Infectious Diseases at Duke-NUS Graduate Medical School in Singapore, said dengue is no longer confined to tropical countries and is spreading rapidly across the globe.

Gubler noted that in the 1960s, less than 10 countries were reporting dengue cases to the World Health Organization but this grew to some 65 nations in 2007.

He added that the “global movement of dengue” was driven by uncontrolled urbanization and “increased movement of people, animals, commodities and pathogens” brought about by modern transportation.

“The world has become urbanized... People are moving to cities to find jobs so dengue is also moving to cities,” he claimed during the opening of the Novartis Institute for Tropical Disease Symposium on Dengue Fever last Monday.

Gubler said that dengue has reached epidemic proportions also because of “lack of effective mosquito control.”

Dengue is spread by the bites of infected stegomyia aegypti and stegomyia albopticus – previously known as Aedes Aegypti – mosquitoes.

Climate change is also being eyed as a “driver” for expanding geographical distribution of dengue.

A handout released by Novartis showed that “temperature limits the range of the mosquito that carries dengue fever” and that “frost kills both adults (mosquitoes) and larvae.”

“In the past, this has prevented the disease from spreading from the tropics, but rising temperatures are changing that. It has moved steadily north in recent decades and to higher elevations. In the United States, the mosquitoes that carry dengue have reached as far north as Chicago,” the handout stated.

There is no available treatment for dengue fever yet but supportive treatments like bed rest, fluid administration and analgesic are given to patients.

Gubler added that efforts are now underway to develop vaccines but this might take at least seven years.

According to Dr. Lyndon Lee Suy, head of the Department of Health (DOH)’s National Dengue Program, the development of vaccines drags on because there are four strains of dengue that surface at any given time.

Health Secretary Francisco Duque III said the Philippines had already experienced its “second worst year of dengue outbreak since we reported the first one in 1998.”

“In 2007, we had over 45,300 cases and 416 deaths. It was also the third straight year that the country had been trying to push back an alarming rise in reported dengue cases... a pattern that was unusual because we were reporting dengue even at the start of the year – outside of the peak dengue season,” he added.