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WHO warns of increased risk of vector-borne diseases in tsunami-affected areas

Scaling up of prevention activities key to prevent outbreaks

SEA/PR/1385

WHO/Dermot Tatlow

The World Health Organization (WHO) warned about increased risk of vector-borne diseases such as malaria and dengue fever across tsunami-affected areas in Southeast Asia. Nearly four weeks after the disaster struck the region on 26 December, the organization is strengthening its disease surveillance, stagnant water conditions creating conditions for mosquito vectors to multiply to sufficient levels, to potentially cause severe public health problems.

Most affected countries in the region are endemic for dengue fever and malaria except the Maldives, which has no malaria cases but does have dengue cases. With the onset of the rainy season, particularly in Indonesia and Sri Lanka, a rise in the cases can be expected at this time of the year.

Indonesia suffered a major dengue outbreak last year. This year too, many cases have been reported in Jakarta, since December and the national authorities have installed control measures for these. However, given the extent of destruction due to the tsunami, WHO and the Ministry of Health are concerned about the increased risk of Dengue in Aceh and are carefully monitoring the situation. Concerns for malaria remain high, too. Although there is no information to suggest an increase in malaria cases in Banda Aceh, the area is endemic for the disease. "At present, we are dealing with a lot of unknowns because of the violent environmental changes that have taken place here," explained Dr Jack Chow, Assistant Director-General responsible for malaria at WHO Headquarters during a visit to Banda Aceh today. "For example, we do not know whether mosquitoes - which generally mostly live and bite outdoors - will start biting indoors more frequently. We have to monitor for these situations and support the communities so they are protected from disease, and have access to treatment when they need it".

"To reduce the risk of a dengue fever or malaria cases, WHO is strengthening its support to national authorities to implement effective vector-borne disease prevention and control activities", said Dr Samlee Plianbangchang, WHO Regional Director for South-East Asia Region. "WHO is working with national authorities and international teams in the region to conduct entomological surveys in affected districts with local staff being trained on the job. WHO is also making accessible insecticide-treated bed-nets, vector control supplies, and equipment for larviciding and fogging with insecticides as a stopgap measure. In addition, health workers are starting to involve the community to clean up the Aedes mosquito breeding sites in the open water containers and debris around camps and homes", added Dr Samlee.

Experts have been deployed and an Early Warning and surveillance systems has been established in affected regions. Public health laboratory services are being restored including provision of rapid diagnostic kits, medical supplies and equipment, and training of local health workers.

WHO, with national authorities, are increasing awareness among national and international personnel regarding risk of dengue infection. "Proper management of dengue hemorrhage fever can reduce fatality rates and save many lives", said Dr Samlee.

In Sri Lanka, WHO and UNICEF have provided long-lasting insecticidal nets (LLINs) to displaced individuals and families for malaria prevention, along with other key supplies such as insecticides, fogging machines and spray tanks (as well as the hiring of vehicles for spraying activities). WHO also assists in the clean-up of debris in which water collects, to prevent the formation of dengue breeding sites.

In India, a number of anti-vector measures are being implemented, including the strengthening of vector surveillance measures, while family-sized insecticide impregnated bed-nets have been distributed to families living in displacement camps. In Thailand, in addition to prevention activities, the ministry of health has stockpiled anti-malarial treatments in hospitals across the affected areas. And in the Maldives, which is not endemic for malaria and dengue fever, the ministry of health continues to conduct its routine vector-control activities.

A generous outpouring of donations targeting vector-control efforts is facilitating the task. In Banda Aceh alone, some 100,000 insecticide-treated mosquito nets, 20,000 rapid diagnostic tests for malaria and 150,000 treatment courses of artemisinin-based combination therapy - the most effective available antimalarial treatment - have been made available by private donors and UN agencies.

Providing support to countries to implement vector control strategies including establishment of a proper drainage system and engineering methods are key components of WHO's long-term strategy to rehabilitate the damaged or destroyed public health infrastructure. To implement this health system rehabilitation strategy, WHO urgently requires US$67 million for activities through the next six months.

Notes to editors

The tsunami in Southeast Asia, has at least in some areas, led to environmental disturbance of the kind that would typically be associated with increased mosquito breeding. While pools of salt water would not support mosquitoes by themselves, but once diluted by rains, they can become ideal breeding places for the malaria vector. Drinking water storage around temporary dwellings can also become a breeding place for vectors. Exposure is further increased if displaced populations live in temporary conditions without proper shelter.

Different mosquitoes cause different vector-borne diseases. Dengue fever is carried by the Aedes aegypti mosquito (a day-time biting mosquito, hence the utility of insecticide treated bed-nets is very limited as a specific prevention tool), while malaria is spread through the bite of a female Anopheles mosquito.

With no medical treatment available for dengue fever, case management should focus on:

  • Rapid diagnosis - persons suspected of having dengue fever must see a doctor at once. Dengue haemorrhagic fever is a deadly disease and early recognition and treatment can save lives. Unless proper treatment is given promptly, the patient may go into shock and die.
  • Severe abdominal pains (black stools), bleeding on the skin or from the nose or gums, sweating, cold skin are danger signs. If any one of them is noticed, the patient should be taken to a hospital immediately.
  • The patient should be given fluids to drink during transfer to the hospital.
  • The patient should be provided nutritious food and fluids.
  • The patient should be kept under a mosquito net or in a screened room during the period of illness.
  • Doctors and health workers treating cases of dengue fever should also notify the health authorities.
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For more information contact:

Mrs Harsaran Pandey
WHO Regional Office for South-East Asia
Mobile phone: +91 9810695878
E-mail: pandeyh@whosea.org

Mr Bob Dietz
Banda Aceh
Telephone: + 62-0651-6370-28
Mobile phone: + 62-0815-135-13039
E-mail: dietzr@whosea.org

Ms Christine McNab
Communications Officer
Director-General’s Office - WHO
Telephone: +41 22 791 4688
Mobile phone: +41 79 254 6815
E-mail: mcnabc@who.int

Mr Iain Simpson
Communications Officer
Director-General’s Office - WHO
Telephone: +41 22 791 3215
Mobile phone: +41 79 475 5534
E-mail: simpsoni@who.int

Dr Fadéla Chaib
Director-General’s Office/Media and Communications
WHO/Geneva
Telephone: +41 22 791 3228
Mobile phone: +41 79 477 1738
E-mail: chaibf@who.int