HEALTH: Dengue Threatens Asia Pacific Region

By IPS Correspondents Reprint | | Print |

Stella Gonzales

MANILA, Oct 1 2008 (IPS) - Over the past three decades, dengue fever has affected more and more countries in the Asia-Pacific region and is now regarded as the fastest of emerging mosquito-borne diseases.

From 1991-2004, a dengue pandemic emerged in the World Health Organisation’s (WHO) Western Pacific region which covers 37 states and areas. It severely affected 10 countries: Vietnam, Malaysia, the Philippines, Cambodia, Laos, Singapore, French Polynesia, Fiji, New Caledonia and China.

Since 2007, there have been an unusually high number of dengue cases in Cambodia, the Philippines, Singapore and Kiribati. The disease is now so widespread in the region that the WHO estimates that 1.8 billion people are at risk of contracting dengue.

Over the last three months, the Indian capital of New Delhi reported 600 cases of dengue of which two turned fatal.

Yet, according to the WHO, dengue is a "neglected disease" that attracts public attention and government commitment only during epidemics. And by then it is usually already too late for effective action.

The WHO says mortality due to dengue is highest during the initial period of an epidemic, and children are particularly at high risk of death as a result of complications and lack of access to prompt treatment.

Dengue was one of the major areas of concern discussed by health ministers and representatives from the region during a meeting held in Manila, late September. The delegates agreed that there was a need to find long-term solutions to the problem and reverse the rising trend of the disease.

Participants noted that while some countries have had some success in controlling the spread of the disease, it was the opposite situation in others.

Vietnam is one of the countries that have suffered from dengue outbreaks.

Dr. Nguyen Huy Nga of the ministry of health said Vietnam started having dengue cases in 1959, and it now averages 50,000 cases a year. The doctor said the ministry has been able to pinpoint the principal breeding areas of the Aedes aegypti, the mosquito species that carries the dengue virus, in containers used by residents to store water in the Mekong Delta.

For Fiji, the WHO regional meeting could not have come at a more opportune time. It is currently experiencing a major dengue outbreak, with about 1,000 cases reported.

"And there are no signs that the situation is abating," Fiji’s representative told the meeting.

In Brunei Darussalam, dengue cases were minimal before 2002. But in 2006, the country experienced dengue outbreaks and the disease has since remained endemic there.

Increased global travel and trade have contributed to the spread of dengue in countries that previously were not troubled by the disease. This is why, the WHO believes, the occurrence of dengue in one country poses a threat to others.

In Hong Kong, there were no locally acquired dengue cases as of 2003 and infections originated with people who had travelled to South-east Asia and came back home, said Dr. Lawrence Wong Yu-shing of the department of health.

The WHO said dengue cannot be controlled if efforts were limited only to a few countries. It said there must be regional collaboration to enable countries to implement measures.

The spread of dengue in the region has been attributed by the WHO to "unplanned urban development," human migration and high population density. The more crowded an area is, the more opportunities there are for the transmission of the virus.

Also to blame are human practices such as inappropriate disposal of used tyres, plastic containers and metal cans. The Aedes aegypti breeds in the clear stagnant water that accumulates in these materials.

WHO said that while some interventions have been known for decades to be effective against dengue, their implementation remains a big challenge for many countries because of the lack of resources for dengue control programmes.

When government do pend scarce resources on dengue, most of it goes into insecticide sprays and chemical larvicides that have little impact on epidemics.

In contrast, the most effective measures in preventing dengue include controlling the Aedes aegypti through reducing its breeding areas and ensuring a sanitary environment.

Climate change is also believed to be responsible for the high incidence of the disease. The WHO says vector-borne diseases such as dengue and malaria, water-borne and food-borne diseases, and respiratory diseases are just some of the current and potential health risks related to climate change.

Dr. Shigeru Omi, WHO regional director for the Western Pacific, acknowledged that more research was needed on the effects of climate change on health. But, he said, countries "should not wait for all evidence to be available…and must act now to minimise potential health consequences of climate change with the existing knowledge and technologies available to us."

During the regional meeting, the participants approved a Dengue Strategic Plan for the Asia-Pacific region that will help countries enhance their outbreak preparedness and response and limit epidemics through prevention and control.

Among others, the plan includes measures to reduce fatality rates, improve surveillance and reporting of data to the authorities, provide guidance on environmental management of urban development and control the spread of the Aedes aegypti, and educate people on recognising dengue fever and the need for prompt medical care.

Studies show that fatality rates can be reduced to one percent or less if dengue cases are admitted early and treated appropriately.

The strategic plan also recognises the need for vaccine development, improved diagnostics and other innovations for the treatment of dengue.