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Pinoy towards a malaria-free world

A Filipino scientist makes a huge leap in developing a vaccine against the disease.

 By Yves St. James Aquino, M.D.

APRIL 2011

A teenage boy comes in the emergency room, complaining that he has been experiencing high-grade fever and fatigue for the past few days. There is no remarkable information in his medical history, but he says he recently vacationed in Palawan. With the boy’s travel history, exposure to mosquito bites, and a laboratory exam, he was diagnosed with malaria. He was given an antimalarial drug, recovered, and was discharged a few days later.

Even if cases have decreased, malaria remains one of the top 10 causes of deaths and diseases in the Philippines. In fact, Palawan is one of more than 50 provinces considered to be an endemic area for malaria, meaning, in these areas, malaria cases are prevalent and may occur in steady cycles all throughout the year.

The novelty in vaccination

Uncomplicated malaria, like the one experienced by the teenage boy, usually subsides with proper treatment, but there are cases when malaria leads to complications, including death. This is the reason why the medical community has been aggressive in developing a vaccine against malaria.

In this field, Rhoel Dinglasan, a U.S.-based Filipino entomologist and biologist at Johns Hopkins University Hospital has risen to the difficult challenge of creating a new vaccine. Under collaboration between PATH Malaria Vaccine Institute and Johns Hopkins Bloomberg School of Public Health and the Sabin Vaccine Institute, the new vaccine is aimed not at protecting humans per se, but at preventing mosquitoes from spreading the disease.

Vaccines traditionally work by introducing a killed or weakened version of a disease into an individual to stimulate the development of immunity. But, the new vaccine developed by Dinglasan is meant to fight the parasite inside the gut of the mosquito. The Pinoy scientist discovered an antigen (any foreign substance that stimulates production of antibody), called AnAPN1, which makes humans produce antibodies that prevent mosquitoes from transmitting the disease.

Creating an antimalarial vaccine is difficult because the disease is made complicated by the fact that the malaria-causing parasite needs two hosts to survive and cause infection: mosquitoes and humans. Unlike bacteria and viruses, parasites are far more complex, with their evolving structures and life cycles. According to PATH MVI, a global program of international nonprofit organization PATH that aims to accelerate the development of malaria vaccines, there are no measurable “signs” of immunity for malaria vaccines. Unlike in viral infections like measles, the amount of antibodies in a person is a reliable “sign” of immunity. This requires expensive and time-consuming human clinical (some might say, hit-and-miss) trials. The difficulty in developing vaccines does not make it an impossibility, though. It’s been noted that individuals who live in endemic areas and exposed to malaria develop immunity against active disease and/or death, so there’s hope.

Re-infection, however, is not prevented, allowing an immune individual to harbor parasites but show no symptoms of the disease. This is the reason Filipinos traveling abroad (especially to the West) are required to take prophylactic antimalarial medications even if they aren’t sick. This requirement is less for our protection than it is about keeping the citizens of the country we are going to visit safe. In cases when travelers have asymptomatic (symptom-free) parasites in their blood—and they get bitten by mosquitoes—the mosquitoes can transmit the parasite and cause a

malarial outbreak in that country.

For more information about malaria in the Philippines, check out the April 2011 issue of Health Today now available on the newsstands.

pinoy and a malaria free world
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