KUALA
LUMPUR, Malaysia (AP) — Malaysia released about 6,000 genetically
modified mosquitoes into a forest in the first experiment of its kind in
Asia aimed at curbing dengue fever, officials said Wednesday.

The
field test is meant to pave the way for the use of genetically
engineered Aedes aegypti male mosquitoes to mate with females and
produce no offspring or ones with shorter lives, thus curtailing the
mosquito population. Only female Aedes aegypti mosquitoes spread dengue
fever, which killed 134 people in Malaysia last year.

A
similar trial in the Cayman Islands last year — the first time
genetically modified mosquitoes have been set loose in the wild after
years of laboratory experiments and hypothetical calculations — resulted
in a dramatic drop in the mosquito population in a small area studied
by researchers.

The
plan has sparked criticism by some Malaysian environmentalists, who
fear it might have unforeseen consequences, such as the inadvertent
creation of uncontrollable mutated mosquitoes. Critics also say such
plans could leave a vacuum in the ecosystem that is then filled by
another insect species, potentially introducing new diseases.

Government
authorities have tried to allay the concerns by saying they are
conducting small-scale research and will not rush into any widespread
release of mosquitoes.

The
Malaysian government-run Institute for Medical Research said it
released about 6,000 sterile male lab mosquitoes in an uninhabited
forest area in eastern Malaysia on Dec. 21. Another 6,000 wild male
Aedes aegypti mosquitoes were also placed in the area for scientific
comparison, it said in a statement.

The
institute provided few details of the experiment, but said it was
“successfully” concluded Jan. 5, and that all the mosquitoes were killed
with insecticide. It said it is not planning to release any more
mosquitoes until it analyzes the results.

It
was the first such trial in Asia, an official in the Ministry of
Natural Resources and Environment said on condition of anonymity because
he was not authorized to make public statements.

Duane
Gubler, a professor specializing in infectious diseases at Singapore’s
Duke-NUS Graduate Medical School who was not involved with the research,
said the plan is likely to be effective in fighting dengue if it is
combined with other biological control methods.

“We need new tools. Nothing we’ve done in the past 40 years has had an impact” on dengue, Gubler told the AP.

Using
genetically altered sterile male insects against fruit flies and other
flies that cause damage in cattle has been successful in places like the
United States, Gubler said. He added that environmentalists should not
be concerned, because the genetically modified mosquitoes would die
quickly.

In
the Cayman Islands, genetically altered sterile male mosquitoes were
also set loose by scientists in a 40-acre (16-hectare) region between
May and October last year. By August, mosquito numbers in that area
dropped by 80 percent compared with a neighboring area where no sterile
mosquitoes were released.

Malaysian
Prime Minister Najib Razak said last year the project was an
“innovative” way to fight dengue after a lack of success in campaigns
urging Malaysians to keep neighborhoods free of stagnant water where
mosquitoes can breed.

The
number of dengue-linked deaths in Malaysia increased 52 percent last
year from 88 in 2009. The total dengue infections rose 11 percent from
2009 to more than 46,000 cases last year.

Dengue
fever is common in Asia and Latin America. Symptoms include high fever,
joint pains and nausea, but in severe cases, it can lead to internal
bleeding, circulatory shutdown and death. There is no known cure or
vaccine.

Associated Press writer Sean Yoong contributed to this report.

SOURCE: The Associated Press