PAE reports greater disease threat: Dengue-lamok attacks during the day and at night

The Philippine Association of Entomologists (PAE) reports an increased threat of dengue against communities. Through a clinical study conducted by Filipino entomologists, it has been confirmed that a dengue-lamok species (dengue-carrying mosquitoes) bite not only during the day but at night as well.

This breakthrough discovery debunks a common belief that dengue-lamok only bite at daytime, and that there is little or no threat of dengue at night.

“Many people believe that dengue lamok only bite during the day. This makes them feel more complacent at night, as they think there’s no more risk of dengue infection.



However, this new study shows that the danger of dengue is now more serious, since infection can occur both during the day and at night,” said Dr. Barbara Laviña Caoili, PAE Secretary.

Double Threat: Day and Night Dengue Lamok
The most common source of dengue infection in the Philippines is a mosquito species called Aedes aegypti. Ae. aegypti bite most aggressively during the day, so this gave rise to the belief that dengue infection occurs only at daytime.

Filipino entomologists have observed that another dengue lamok, the Aedes albopictus, is increasingly present in human dwelling places. In a laboratory study, Ae. albopictus was found bite most aggressively from late afternoon until night. According to Dr. Caoili, the presence of both Ae. aegypti and Ae. albopictus in places where people live will make dengue a round-the-clock threat.

“Previously, researchers weren’t paying a lot of attention to Ae. Albopictus because Ae. aegypti, being the primary dengue virus vector, was known to be the most common source of dengue infections in humans. Results of the study however, show that Ae. albopictus, known as a secondary vector of dengue virus, presents a danger to humans as well.

Ae. albopictus is now present in places where humans are staying. This dengue lamok bites most aggressively from late afternoon hours and this biting behavior stretches until nighttime. We may face an increase in dengue infections if we are not prepared for this.

Factors raising dengue threat
Several factors may have contributed to the increasing threat of dengue. One crucial factor is the encroachment of human populations into the natural habitat of dengue lamok. Ae. albopictus is known to live in forested areas. With more forested areas being turned into residential developments, people are moving into the natural habitats of these dengue-lamok. This increases exposure of people to Ae. albopictus.

The other contributing factors are environmental and biological. These include:
Climate change and global warming. Across the world, climate change is raising temperatures, as well as increasing humidity and rainfall. This creates tropical and sub-tropical conditions that are ideal for day and night dengue-lamok to thrive in.

Widespread travel. More and more people are traveling to countries where dengue is endemic. Travelers who get infected become incubators of the virus and carry it from one country to another.

Global trade. Dengue-lamok are able to travel along with goods and cargo that are transported across countries.

Weak mosquito control. Dengue-lamok thrive when there are inadequate measures in place to control their breeding and their contact with humans.

Changing survival capabilities. Over time, dengue-lamok develop survival mechanisms that help them thrive even in hostile environments. They are able to develop resistance to some insecticides, or they change their feeding and breeding habits.

Year-long, round the clock
All these factors make dengue in the Philippines an even bigger threat than the AH1N1 virus that caused widespread panic a few years back. In 2011, a total of 110,257 cases of dengue were reported, resulting in the deaths of 580 people. Twenty-five percent of the total dengue cases were in Metro Manila.

By comparison, the incidence and mortality rate of dengue is much higher than AH1N1, as the latter has a nearly 100 percent recovery rate, and fewer Filipinos get infected with it.

As of March 2012, there are already a number of dengue hot spots in the Philippines including Central Visayas (Region VIII); SOCSARGEN (Region XII); CALABARZON (Region IV-A) and the National Capital Region (NCR). The most vulnerable residents in these areas are the children who have underdeveloped immune systems. Dengue is, in fact, the leading cause of childhood hospitalizations in the country.

Dr. Caoili added that dengue is can be a year-long threat in the Philippines, during both the dry and wet seasons as long as there are breeding sites for the dengue-lamok. It has also become a round-the-clock threat, with dengue lamok biting during the day as well as at night. For these reasons, we also need year-long, round the clock protection from dengue.

Level Up Protection Versus Day and Night Dengue Lamok
Based on the discovery reported by the experts, the increased dengue threat also requires increased protection and prevention measures. These must be in place during the day and through the night. One such measure is the use of insect repellent lotion. The ideal insect repellent lotion is one that is effective against dengue-lamok that bite during daytime and nighttime.

The new Green Cross Insect Repellent Lotion is endorsed by the Philippine Association of Entomologists as effective against dengue lamok that bite during the day and at night. It provides longer protection time compared to other brands and provides anti-dengue and anti-bacterial protection. Green Cross Insect Repellent Lotion is hypoallergenic and kid-friendly as well.

The breakthrough discovery by Filipino entomologists regarding day and night dengue-lamok teaches us to act on an urgent threat: we must now level up our anti-dengue measures. This requires changing our mindsets and using an insect repellent lotion that effectively protects against both day and night dengue-lamok.

-30-