Experts find way to make mosquitoes dengue-free

MANILA, Philippines - The Department of Health (DOH) yesterday raised an alert over a supposed hyperactive strain of dengue monitored in the Ilocos region.

The dengue strain, health officials said, hits usually dark-skinned people, particularly children.?Health Secretary Enrique Ona said the Research Institute of Tropical Medicine (RITM) has been conducting tests on blood samples of four dengue strains to determine under which type the new strain can be classified.?

“For the moment we are calling it an Ilocano strain,” Ona told a news forum in Quezon City.

Ona noted reports that the hyperactive strain of dengue targets dark-skinned people and the initial sign of nose bleeding, apart from fever, would manifest in an affected individual.

Ona said the resurgence of the new strain was discovered by RITM, which is also developing a new anti-dengue vaccine.

Dr. Rose Capeding, chief of the dengue research group of the RITM, said that since dengue is endemic in the Philippines they have already raised an alert of the possible outbreak of the disease in certain parts of the country.

At the same time, Capeding added, the RITM is developing a vaccine now in its clinical test stage.?

Capeding said they are still in the process of determining if there is a fifth strain, but so far the type 3 and 4 strains are the most prevalent.?

She said the clinical tests showed that the new vaccine being developed is safe but stressed the need for more tests to determine possible side effects.?

“So far the vaccine is working but (it still) needs at least two years before it can be commercially available in the market,” Capeding said.?

Ona said at least a hundred patients are now the subject of the clinical test and all are responding positively. He added the tests are expensive and time consuming.?

Ona stressed the ultimate objective is to produce a vaccine that can combat the recurrent dengue outbreaks that have already killed thousands of people over the past several years.?

There is also a global effort to eradicate the disease.

More than 50 million people in over 100 countries fall sick and 20,000 die each year from dengue fever. There is no vaccine or specific treatment for the disease.

The only way of prevention is to control mosquito populations through eliminating breeding sites.

Scientists said injecting a bacteria into mosquitoes can block them from transmitting the dengue virus and help control the spread of the disease.

In two papers published in the journal Nature on Thursday, researchers in Australia showed how female mosquitoes infected with the Wolbachia bacteria passed the bug easily to their offspring, making them all dengue-free.

They said such infected mosquitoes should be released into the wild, so that the spread of dengue to people may be reduced.

Scientists in Austrialia injected the bacteria into more than 2,500 embryos of so-called Aedes aegypti mosquitoes that can spread dengue. After they hatched, they were treated to blood meals laced with the dengue virus, and none picked up the virus.

Anti-dengue financing

The DOH, on the other hand, is eyeing the use of calamity funds of local government units to finance dengue prevention programs.

The DOH sought cooperation from the Department of the Interior and Local Government (DILG) for the release of funds.

Interior Secretary Jesse Robredo said they wanted to intensify efforts to prevent dengue but admitted the budget is an issue for many areas in the country.?

Robredo said he and Ona had agreed to ask permission from Malacañang to allow the use of the LGUs’ calamity funds to prevent dengue cases.?

“Secretary Ona and I agreed that if an area is becoming a hot spot for dengue, we’ll request that the calamity funds be used to contain cases… this will enable barangay leaders to do intensified information and containment efforts,” Robredo said.?

DOH records showed that from Jan. 1 to Aug. 20, there were 56,005 cases, 24.35 percent lower than the 74,028 cases during the same period in 2010.

Death tolls are 321 and 517, respectively.?In Metro Manila, Quezon City accounts for most of the cases with 3,992, followed by Caloocan City with 1,558 and Manila with 1,340. ?But in terms of increase from last year’s figures, Taguig City actually posted the highest increase at 310.83 percent or from 120 to 493 cases; followed by Pasig at 235.71 percent or from 224 to 752 cases.?

Yesterday, the DOH, DILG, Quezon City government, the Metropolitan Manila ?Development Authority, Department of Science and Technology (DOST) and Department of Education launched an anti-dengue campaign “Aksyon Barangay Kontra Dengue (ABaKaDa)” in Novaliches, Quezon City.?

ABaKaDa seeks to reinforce nationwide efforts to curb dengue by going back to the basics of comprehensive vector control through regular weekly cleanup drives, fogging, spraying of insecticides and larviciding.?

The DOST, for its part, has partnered with a private company for the mass production of its Mosquito Ovicidal/Larvicidal Trap (OL Trap) in a bid to prevent the spread of dengue cases in the country. ?

Raymund Liboro, director of the DOST’s Science and Technology Information Institute, said they have partnered with the Heritage Veterinary Corp., a distributor of agricultural and veterinary chemicals based in Bulacan.?

Liboro said the company could produce about 16 million sachets of OL pellets a month.?

He said the pellets would be commercially available next month at the price of P1.50 per sachet.

The OL-pellet is not yet commercially available since the Industrial Technology Development Institute of the DOST is the only producer of the OL-pellet.

Liboro said the DOST will continue to produce the OL pellets even if they would be commercially available.

“I think they (Heritage Veterinary Corp.) will be better, more efficient because we don’t have the capacity to produce more OL-pellets,” Liboro said.

The OL Trap is a device used to help control the population of dengue-carrying mosquitoes.

The device is a black container, with a small strip of “lawanit” or wooden board inside resembling a large ice drop stick for mosquitoes to lay their eggs on. – With Helen Flores, Sheila Crisostomo, Cecille Suerte Felipe