Except in Metro Manila, the use of ovicidal-larvicidal (OL) traps provided by the Department of Science and Technology has significantly reduced dengue cases across the country.
In select barangays nationwide where the DOST distributed the relatively cheap OL trap kits last year, the number of dengue cases dropped by 32 to 90 percent compared to the same period in 2010.
“The OL trap system has reduced the transmission that may have resulted in reduced dengue cases,” Dr. Nuna Almanzor, executive director of the DOST’s Industrial Technology Development Institute, said in a news conference on Friday.
But the installation of OL traps in some households in select barangays in Metro Manila barely had an effect.
In the cities of Caloocan, Parañaque, Malabon, Mandaluyong and San Juan, dengue cases went down by a mere 6.4 percent—from 6,156 to 5,761 from June to December last year when the OL traps were used—compared to the same period the previous year.
Almanzor said the OL trap—which is designed to collect the eggs of dengue-carrying mosquitos—was only one of the tools used to reduce the population of Aedes aegypti mosquitoes, particularly the adult females which carry the deadly dengue hemorrhagic fever virus.
The OL trap kit consists of a black cup and a small strip of lawanit (shaped like a popsicle stick) for the Aedes aegypti mosquito to lay eggs on. The DOST said one household should have at least four traps that should be placed in dark corners to attract mosquitoes.
Almanzor said people obviously still failed to clean mosquito breeding sites like drums and used tires where water stagnates for long periods.
“People must also clean their surroundings. We have to educate the people to clean up,” she said.
Before the resumption of classes in June, the DOST distributed one million OL trap kits to public elementary and high schools.
Dengue cases nationwide increased by 16 percent from Jan. 1 to July 14 this year compared to the same period last year. The number of deaths also rose to 328 from 293 during the period.
The Department of Health has recorded 51,597 cases from the start of the year to July 14, compared to 44,315 in the same period last year.
Most of the cases were recorded in Metro Manila with 11,476, followed by Calabarzon with 7,265 and Central Luzon with 7,044.
With the distribution of OL traps, the DOST reported the highest reduction in dengue cases in Eastern Visayas, where cases in nine barangays went down by 94.4 percent.
Dengue cases in barangays in Western Visayas that used the OL traps went down by 89 percent; 85 percent in eight barangays in Calabarzon; and 81.3 per cent in 25 barangays in Northern Mindanao.
The DOST also reported that dengue cases went down by 70 percent in two barangays that pilot-tested the OL traps in Puerto Princesa City by 70 percent; 69 percent in three barangays in Western Mindanao; 59 percent in select barangays in Southern Mindanao; and 56 percent in the Cordillera Administrative Region.