Pham Thi Hoan, a member of the mosquito-raising team at the National Institute of Malariology, Parasitology and Entomology, helps mosquitoes mate under a microscope

Raising mosquitoes for vaccine research may not be the world’s most dangerous job, but scientists do risk catching malaria for the cause.

Though mosquito breeders like Hoan provide the insects for vaccine research at the National Institute of Malariology, Parasitology and Entomology, a few scientists have actually caught malaria this way.

But Hoan says they have no choice.

“We have to be very careful,” she says.

Whereas mosquito farms in other countries often feed the insects with a pre-prepared mix of human blood and chemicals, Hoan says the Vietnamese institute doesn’t have any of the special feed.

But she’s ready to give for the cause and make sacrifices, “just like raising your own babies,” she says.

All in a day’s work

After cleaning the insects’ water trays, checking the mosquitoes health and feeding the larvae a blend of ground green peas, breadcrumbs and dried shrimp, Hoan says she often helps around 10 pairs of mosquitoes mate each morning.

They need to be forced into it as they lose many natural instincts in the institute’s controlled environment.

To breed the mosquitoes, Hoan sedates a male and female with ether and must manually place the male’s appendage inside the female.

Hoan, who has worked here for more than 10 years, says another delicate task is ensuring that the room stays between 25 and 30 degrees Celsius at all times.

Otherwise, the insects might die.

“Some nights during the northeastern monsoons, we have to stay here all night adjusting the air conditioner or boiling water to increase the moisture and keep the mosquitoes warm.”

Mosquito hunters

Dr. Vu Dinh Chu, a colleague of Hoan’s, has recently returned from a mosquito hunting trip in the central province of Phu Yen.

Having collected some 100 mosquitoes on the week-long trip, he says he can catch about 20 bugs on a good day.

His recent catch includes Anopheles dirus, which carries malaria in the central region. Chu’s team has raised the species since 2006.

They have also bred Anopheles minimus and Anopheles epiroticus, other vectors of malaria in the south-central coastal province of Binh Thuan. They also breed Culex quinquefasciatus, which carries Japanese encephalitis.

But mosquito hunting is not easy.

To catch the insects, the hunters camp out in the forests for days at a time, usually only catching the bugs at night.

Hoan said they often have to use their legs as bait, again putting them at risk for malaria.

Hoa Binh Province in the north and Ho Chi Minh City’s Can Gio District are the prime hunting spots. The scientists often hide in pigpens and bushes, then catch the insects with nets.

But once they get the mosquitoes back to the institute, it’s very difficult to keep them alive.

Outside their natural environment, the mosquitoes sometimes don’t eat at all and die en masse immediately after being caught.

But thanks to the efforts of those like Hoan and Chu, the mosquito farm provides some 20,000 mosquitoes for vaccine research at the institute every year.

Source: TT, LD