It all started from a simple technology to control the population of dengue carrying mosquitoes – the ovicidal larvicidal mosquito trap or popularly known as OL trap. Today, dengue prevention and control is now one of the major programs of the Department of Science and Technology (DOST) to help the country alleviate the chronic problem of dengue.
“When we talk about dengue prevention and control, we need to focus on two specific aspects: the vector and the host,” said Dr. Jaime Montoya, Executive Director of the Philippine Council for Health Research and Development (PCHRD) of DOST, who presented the project framework of DOST on dengue prevention and control during the Dengue Summit held at DOST Executive Launch, Bicutan, Taguig City on 8 September 2011.
“In an infectious disease like dengue, there are always two parties involved – the host and the virus or the organism which, in this case, is carried by an Aedes mosquito. The DOST efforts are actually based on this principle to widely address the problem on dengue,” said Dr. Montoya.
Controlling the vector
DOST has completed several projects related to vector control and management. This includes the development of the OL mosquito trap from laboratory testing to field testing in Quezon City and Marikina, and its roll-out in all the regions of the country.
“Likewise, another project is underway to determine the effect of OL trap system in reducing dengue incidence in Tacloban City. This will compare the baseline and monthly dengue fever incidence between the experimental and control communities in Tacloban City,” shared Dr. Montoya.
DOST is also looking at the organic and aqueous extracts and essential oils of pepper (Piper nigrum) to scientifically establish the compounds and associated mechanism for its larvicide activity and compare the bioactivity on the duration of eggs, larval and pupal development stages of Aedes and Anopheles mosquitoes to further understand its mechanism of action and effects to mosquitoes.
“Another interesting study is the research being done in the University of San Carlos in Cebu City about the “transovarial transmission” or natural transmission of dengue virus to its offspring without biting an infected human. The study will determine and compare the serotypes of dengue virus collected from the mosquito vector during the rainy and dry seasons,” said Dr. Montoya.
DOST will also implement SRO Philippines or School-based Roll-out of OL traps and the Program DEWS or Program on Dengue Early Warning System.
SRO Philippines is the deployment of DOST OL traps in approximately 900,000 classrooms in pre-elementary, elementary and high schools nationwide. The program has four components, namely: OL trap production by the Industrial Technology Development Institute (ITDI – DOST), deployment and monitoring of OL traps headed by the DOST National Capital Region, surveillance in sentinel sites and community engagement.
Program DEWS, on the other hand, is about the development of Dengue Decision Support System (DDSS) that can be used to forecast dengue disease outbreaks. The technology can be used by frontline personnel in the formulation of information-based decisions relevant in the prevention, management and control of dengue.
Most of the imported dengue diagnostic kits available in the country have low sensitivity when it comes to application in the Philippines. To address this, DOST is pursuing a project to locally develop a diagnostic kit for the early diagnosis of dengue. The diagnostic kit will detect dengue and its stereotype at a specific temperature within an hour.
Another ongoing project on diagnostics is the development of Point-of-Care (POC) diagnostic testing kit for detecting dengue infections. This project employs the lateral flow technology that can be administered at bedside and produces results in 15 minutes. The kit will be designed to detect both dengue virus antigen and antibodies in the patient, thus, allowing detection of dengue in both early and acute phase.
“Despite decades of research, there are no drugs yet developed for dengue,” said Dr. Montoya. The DOST now is looking for possibilities to create drugs from the medicinal plants that are suspected to help dengue patients.
Among these plants include tawa-tawa (Euphorbia hirta), kamote (Ipomea batatas), bawang (Allium sativum), papaya (Carica Papaya), tanglad (Cymbopogon citrates), luyang dilaw (Curcuma longa), ampalaya (Momordica charantia) and oregano (Coleus aromaticus Benth).(Edmon B. Agron)