FIGHTING DENGUE ON ALL FRONTS

“We can control dengue if we work together.”  — Dr. Allan Schapira, an epidemiologist with the regional office of the World Health Organization

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Three weeks ago, I was catapulted from my deep sleep when I heard my phone ringing.  It was already 10 o’clock at night and I was so tired since I had been busy for the past two days.  But it was my sister Jean talking and she seemed to be crying.  “What’s the problem?” I inquired. 

“Ashley has dengue fever,” Jean explained.  “The doctor said her blood platelet has gone down dramatically.  I went panic so we decided to bring her to a hospital in Digos City, just in case something will go wrong with her.”

Before I left for Davao City to attend a five-day live-in seminar, I learned that 5-year-old Ashley had an off-and-on fever.  Her parents brought her to a hospital in our small town because they thought it was just an ordinary fever.

But it wasn’t; it was dengue fever, the most widespread mosquito viral disease in the world which infects up to 51 million people a year.

Recalling an assignment I wrote for Reader’s Digest a couple of years back, I wrote: “Symptoms vary according to the age and health of the patient.  Generally, the sickness starts with a high temperature, rash, agonizing headache, and muscle and joint pain. Nausea, vomiting and loss of appetite are common, and a rash usually appears three or four days after the fever starts.  The worst symptoms can last up to ten days, and complete recovery can take a month.”

But the deadly form of the infection, called dengue hemorrhagic fever (DHF), is another story.  In this variant, cells release chemicals that trigger leakage of plasma from blood vessels. 

Dr. Lulu Bravo, a professor at the University of the Philippines College of Medicine, told me this bit of information as what would happen when DHF attacks: “Fluids accumulate in body cavities, causing profound shock.  Death often results from bleeding in the brain, intestines or other organs.”

“After a dengue patient has gone into shock, it’s usually a matter of time before multi-organ failure occurs and death becomes inevitable,” pointed out Professor Zulkifli Ismail, a pediatrician at the Hospital Universiti Kebangsaan Malaysia in Kuala Lumpur. 

Just recently, dengue cases and deaths are surging in the country.  So much so the Department of Health has issued a national dengue epidemic.

The problem with dengue is: people respond only if there are already deaths. Most Filipinos know that when rainy season starts, that’s the time also when dengue-carrying mosquitoes proliferate.

An ounce of prevention is a pound of cure, so goes a saying.  An ounce of prevention is better than a pound of cure, so goes a popular saying. “Prevention is crucial,” Dr. Bravo said.  “Unless we take concerted action to educate our people now, dengue will continue to take its toll in the country.”

The best way to beat dengue fever is not to be bitten by dengue-carrying mosquitoes.  When going out, people are advised to wear long-sleeved shirts and long pants.  When indoors, it is advisable to stay in air-conditioned or screened areas.  All windows and doors must have screens to avoid mosquitoes from getting in.  Children must not play near still water.

Eliminating breeding sites for mosquitoes is another way.  “While government has an important role in dengue control, families and communities have a greater responsibility,” says Dr. Eric Tayag, one of the country’s foremost experts on dengue.  “Mosquitoes breed in our homes. While government reminds, the people should mind.”

But there are other ways of beating the day-biting mosquitoes that carry the dengue virus.  This is through biological control or “the introduction of organisms that prey upon, parasitize, compete with or otherwise reduce populations of the target species,” to quote the explanation of Geneva-based World Health Organization (WHO).

Some larvivorous species and predatory small freshwater crustaceans are effective against the immature larval stages of the dengue-carrying Aedesmosquitoes. “The biological control organisms are bred and distributed into water-storage containers or wells,” the WHO says.

In Dagupan City, about 6,000 mosquito fish have been released in the stagnant waters in some barangays “as part of the city’s dengue prevention measures,” the state-run Philippine News Agency reported.

“Mosquito fish is classified as lavivorous fish,” explained Dr. Westly Rosario, director of the National Integrated Fisheries Technology Development Center (NIFTDC).  “It thrives even in hospitable areas like shallow waters, freshwater, brackishwater or even in areas that have doubled salinity.”

According to Rosario, the mosquito fish stocks are propagated and distributed by the center, which is a line agency of the Bureau of Fisheries and Aquatic Resources (BFAR).  The Gambusia affinis was first introduced into the country in 1905 and was instituted again during the World War II in more than 30 countries to prevent malaria, another contagion spread by mosquitoes.

Some years back, the Manila-based Asian Development Bank also promoted the use of the larvae-eating guppy fish as “a low-cost, year-round, safe way of reducing the spread of dengue in which the whole community can participate.”

Gerard Servais, then ADB’s health specialist said: “(The guppy fish) offers a viable alternative to using chemicals and can reduce the scale of costly emergency response activities to contain epidemics.”

The 25 to 60 millimeter-long guppy fish (scientific name: Poecilia reticulata) is also known as million fish.  It is considered as one of the most popular freshwater aquarium fish species in the world because of its colorful, mermaid-like tail.

But beyond its being cute, the fish can eat up to 102 mosquito larvae a day, according to one study.  Servais said one or two guppy fish can keep a tank of water larvae-free for three to four months. 

“It offers a viable alternative to using chemicals and can reduce the scale of costly emergency response activities to contain epidemics,” Servais said in a press statement. “The study we’ve made has shown that the guppy fish don’t have an impact on the biological quality of the water. It’s safe, even for drinking water.”

Aside from fish, frogs can also help control the population of mosquitoes. A toad reportedly can consume up to 100 mosquito larvae per night. In the past, frogs were common; they could be found in canals, creeks, irrigations, vacant lots, and rice fields.  But these days, they are nowhere to be found. Their population has dwindled due to the filthy waters in canals; those in rice fields are harvested for food.

Bats are another predator of mosquitoes.  “A single bat can eat up to a thousand mosquitoes in just one hour,” said a fact sheet published by the Philippine Bat Conservation, Inc.  “A single large bat colony can eat up to half a million pounds of insect pests in one night.”

Meanwhile, the Department of Science and Technology (DOST) is promoting dengue prevention kits called Ovidical Larvicidal Traps (OL Traps).  OL Trap is composed of a black canister, a lawanit paddle, and pellets (which can be made into a larvicidal solution that can kill the mosquito larvae).

“The scent of the solution invites female mosquitoes to the trap where they lay eggs on the stick and on the solution itself,” the DOST explained.  “The stick, moistened by the solution through capillary action, is highly attractive for mosquitoes to lay eggs on.  As the eggs and the hatched larvae get exposed to the solution, they die.

“The trap does not kill the adult mosquitoes,” it added.  “Instead, its ovicidal and larvicidal effect prevent the next generation of mosquitoes from reaching adulthood, thus curbing the population of Aedes mosquitoes.”

Dengue is a water-vector disease and so the antidote may also be the water itself.  According to Dr. Richard Mata, dengue is one of the most misunderstood diseases in this planet. Most people are terrified of denguebecause when the blood platelets decrease, it causes severe bleeding andultimately death.  This thinking, he says, is very wrong. 

Dr. Mata, a consultant with WHO, says that what really kills a person withdengue is not due to low platelet counts but dehydration.  It occurs when a person loses more fluid and his body doesn’t have enough water and other fluids to carry out its normal functions. 

Dehydration causes intestinal ulcer that causes bleeding. “And because the platelets are low, the bleeding becomes severe.  But if there was no dehydration, there will be no ulcer and thus no bleeding – even if the platelets are low,” he explains.  “So, it still boils down to dehydration.”

Dehydration also causes kidney failure, which result from the decrease inurine output.  “This causes the water to be retained in the lungs thereby creating congestion that can kill the patients,” he says.

Many people believe congestion is caused by over hydration.  “But the truth is, it is caused by kidney failure due to dehydration,” he says.  “That’s ironic, right?”

According to Dr. Mata, Thailand and Sri Lanka has zero casualties when it comes to dengue (compared to 1,000 deaths annually in the Philippines). “These countries never said they got a drug from herbs or something; they said its about correct fluid management,” he says.

Research in the aforementioned countries are focused more on fluid management.  In comparison, most Filipino researchers “focused on herbs which are actually or are already being used by many but still the deaths are high,” Dr. Mata laments.

“In severe dengue, the blood vessels leak of fluids until the blood pressure drops,” says Dr. Mata, a pediatrician who has a clinic in Panabo City in Davao del Norte. “Dehydration is the killer; low platelet is only secondary.”

Thus, he advises to hydrate the patient with oral rehydrating solution or other fluids like coconut water, fruit juices and water.   “Monitor urine output and record the amount and the time.

Once the patient is no longer urinating regularly, it is already a red flag.  “A clear urine with good amount and less than four to six hours in intervals is a good sign of hydration,” he explains. 

Not all cases of dengue are the same.  “Some can be managed by oral hydration, some need intravenous hydration,” Dr. Mata points out.  “Let the doctor decide during early consultation.” – ###

FIGHTING DENGUE ON ALL FRONTS