ASIA NEWS
Dengue Fever Outbreaks Strike Asia
Southern China, Japan, Taiwan Battle Potentially Deadly Disease

    Though much of the world is focused on the Ebola virus, pockets of Asia are struggling with record outbreaks of a mosquito-borne infectious disease called dengue fever, which has no specific drug treatment.
    Guangdong Province in southern China is facing its largest outbreak of the virus in more than 20 years. There have been more than 44,000 confirmed cases in Guangdong, with more than 15,500 people hospitalized and six deaths as of Nov.12, according to the Provincial Health and Family Planning Commission.

    On Nov. 3, the U.S. Centers for Disease Control and Prevention warned travelers to the region about the outbreak, advising them to prevent mosquito bites.
    The Taiwanese city of Kaohsiung, with more than 9,000 cases, is battling its largest-ever outbreak of laboratory-confirmed infections. In Hong Kong on Nov.7, officials confirmed a third case of locally acquired dengue, after last month discovering its first in four years. Earlier this fall, Japan faced its first outbreak in 70 years.

    In Kaohsiung, “the number will exceed 10,000 in the near future,” said Min-Nan Hung, a medical officer at Taiwan’s Centers for Disease Control,in an interview. “Fortunately, the turning point was noticed just a few days ago and the incidence of dengue cases seemed decreasing.”
    Officials in Hong Kong expressed concern about finding multiple locally acquired cases of dengue. Though a fair number of its residents contract dengue fever each year, nearly all are infected while traveling abroad. As of Nov. 13, 102 cases of dengue had been confirmed in the city this year, 99 of which originated elsewhere, officials said Friday.
 “The Centre for Health Protection is very concerned about the recent occurrence of two local confirmed cases of dengue fever,” said Wing-man Ko, Secretary for Food and Health, at a briefing earlier this month. “Even a single local case of dengue fever is enough to prove that certain populations of mosquitoes are carrying the virus of dengue fever, therefore we have to continue our effort in mosquito control.”

    While the virus can’t be spread directly from person to person, a mosquito that has bitten an infected human can transmit the disease to others.
    Within a few days of the first locally acquired case of dengue in Hong Kong,which is known for its meticulous public-health and mosquito-control practices, officials had questioned about 300 people in the vicinity of the place where the patient was believed to have contracted the illness and other sites he hadfrequented, and held two meetings to educate the public about the virus.
    Dengue fever cases world-wide have climbed dramatically since the 1960s, with some 50 million people infected annually. Some 500,000 are estimated to contract more-severe dengue that requires hospitalization, leading to about 22,000 deaths each year, according to the World Health Organization.
    The virus is regularly found in several countries across southeast Asia, including Thailand, Vietnam, Indonesia and the Philippines, but less commonly strikes more-affluent countries that employ tight mosquito-control strategies. When it does, however, more people tend to fall ill because they don’t have the immunity that many in endemic countries have built up.
  “There’s a very good chance if dengue-infected mosquitoes feed on anyone in Japan or South China, that person will get infected,” said Cameron Simmons, a professor of infectious disease at the University of Melbourne who studies dengue.

    The economic and public-health impact of dengue in Southeast Asia is substantial, with one analysis published last year in PLOS Neglected Tropical Diseases suggesting its disease burden outstrips that of hepatitis B, upper respiratory infections and ear infection in the region.
    Predicting which areas will experience dengue outbreaks and why those hot spots crop up is difficult. One factor is weather, which has been warmer and rainier than normal, creating better breeding grounds for mosquitoes. Experts in Taiwan and mainland China say climate conditions have contributed to the current outbreaks in those areas.
     Mosquitoes also tend to hatch after a shorter period and live longer in urban areas compared with those in rural areas, which may exacerbate the problem in cities, according to recent research by Xiao-Guang Chen, head of the department of pathogen biology at Southern Medical University in Guangzhou, China. The work was published Thursday in PLOS Neglected Tropical Diseases.
    There are four known types of the dengue virus, and the strains responsible for illness wax and wane cyclically. In regions where dengue is common, one or two strains tend to dominate for three to four years at a time, according to Dr.Simmons. People in the region appear to acquire immunity for those strains and the number of cases will dip for a few years before another strain takes over and infections flare up again.
    Taiwan, for instance, experiences an outbreak every four years or so, according to the Taiwan CDC’s Dr. Hung. However, this year’s outbreak is much larger than predicted, he said. In 2010, there were just 1,000 cases on the island, Dr.Hung said.
    Treatment for dengue includes rest and fluids and the use of pain relievers with acetaminophen, according to the U.S. CDC.