Thursday, June 30, 2016

How do you solve a problem like malaria?

(Published in Enrich magazine, 2013)

THEY SAY THAT NO NEWS is good news, and when it comes to that dreaded disease called malaria, this adage is spot on.

Once one of the most feared killer diseases in the Philippines, malaria no longer makes news the way it did during the latter half of the 20th century. Its incidence has been steadily reduced to a point where the Department of Health is confident enough to predict the Philippines will be malaria-free by 2020.

The impending “death” of malaria as a killer of Filipinos is really good news. And it will be a historic success the government and its local and international partners involved in malaria’s eradication can be proud of.

For the generations born in the 21st century, however, malaria is an unknown danger. The mosquito-borne menace that frightens them is dengue fever or “H-fever” (Hemorrhagic fever) as it was known in the 1950s.

History’s greatest mass murderer
But malaria is a far more fearsome terror—by far the deadliest killer of humans since modern humans surfaced on this planet 200,000 years ago. Scientists estimate malaria has caused 50% of all human deaths in the 2,000 centuries of human existence. That makes the female anopheles mosquito—the sole carrier of this deadly disease—the greatest mass murderer in history.

Exactly how many deaths has malaria caused? Scientists estimate that the total number of human beings that have ever populated the Earth (including today’s population) at some 107 billion persons. Malaria killed over 53 billion of these persons. These are far, far more deaths than all the wars in recorded history.

Malaria was the scourge of pre-Hispanic Filipinos whose chronicles note malaria-type symptoms among victims. It continued to remain one of the deadliest diseases during the Spanish colonial occupation. At the start of the American occupation in1903, malaria caused some 118,500 Filipino deaths in a total population of only seven million. Preventive measures such as the introduction of quinine caused the death toll to plunge to some 20,000 persons in 1935 out of a population that had risen to 13 million Filipinos.

Health authorities at the time noted that over 70% of “malarious” areas were located near mountains or hills, and that malaria was almost always associated with streams, which are the favored breeding grounds of the female anopheles mosquito.

A national anti-malaria campaign by the Philippine and U.S. governments in 1948 introduced DDT in an effort to stamp out malaria. It was called off in 1954 after studies showed no significant decreases in the malaria infection rate.
A commitment by the World Health Organization in the 1950s to eradicate malaria worldwide helped the Philippines in its fight against this deadly menace. New malaria eradication and control programs were initiated and implemented by successive Philippine administrations.

The importance this Administration attaches to eliminating malaria can be seen in its strong support for the sixth most important goal of the Philippines’ Millennium Development Plan: halting and reversing the incidence of malaria by 2015.

Secretary of Health Enrique Ona said this goal is definitely within reach. He cited data that shows an 80% drop in malaria cases in 2011 as compared to 2003.

“This decrease is the lowest malaria level on record for the country in 42 years, with only 9,642 cases in 2011 as compared to 43,441 in 2003,” Ona said.

That malaria does not continue inflicting massive losses on Filipinos today is one of the greatest triumphs of collective action and modern medical science. But the 9,642 malaria cases in 2011 show that a lot has to be done before the Philippines can claim total victory over the female anopheles mosquito.

You have a role to play in this ongoing war against malaria. But first you have to learn more about your deadly adversary. Human malaria is a disease caused by a parasite called Plasmodium that is mostly transmitted via the bites of infected female Anopheles mosquitoes. Gorillas and some apes are also known to have been victims of malaria.

The word malaria, by the way, comes from the medieval Italian word “mal aria,” meaning “evil air.” The ancient Romans believed malaria was caused by vapors emitted by swamps, leading to malaria’s nickname, “swamp fever.”

Human malaria symptoms include high fever, shaking chills, flu-like symptoms, bloody stools, nausea and vomiting. The alternating episodes of high fever and severe shaking are the best known symptoms of malaria.

This “paroxysm” is a cyclical occurrence of sudden coldness followed by fever and sweating. How often this paroxysm occurs depends on the type of mosquito that caused the malaria. An infection by the parasite called P. falciparum can cause a recurrent fever every 36 to 48 hours.

Malaria parasites belong to the genus Plasmodium. In humans, malaria is commonly caused by P. falciparum, P. vivax,  P. malariae, P. ovale and P. knowlesi. Among those infected, P. falciparum is the most common predator. It accounted for three-fourths of cases while P. vivax infected some 20%. P. falciparum also causes the majority of deaths.

Severe human malaria is usually caused by P. falciparum, and is often called falciparum malaria. Symptoms of falciparum malaria are manifest from nine to 30 days after infection. Along with P. vivax, P. falciparum is the most common form of malaria in the Philippines. Infection with P. falciparum might also result in cerebral malaria, a form of severe malaria.

A. flavirostris: the usual suspect
The chief “vector” or carrier of malaria in the Philippines is “Anopheles minimus flavirostris” or “A. flavirostris.”  The female of this mosquito bites only at night. It breeds in shaded areas of rapidly flowing rivers, streams and irrigation ditches. A. flavirostris prefers shady places and clear, fresh water.

This mosquito does not normally breed in salt water, rice paddies or in water above 2,000 feet altitude. In many malaria hit areas in the Philippines, malaria is contracted in the foothills, mostly between flat coastal plains and higher ground below 2,000 feet altitude.

Today, only two provinces—Palawan and Tawi-Tawi—report more than 1,000 malaria cases a year. Four more (Sulu, Maguindanao, Mindoro Occidental and Zambales) have more than 100 cases but less than 500 cases annually. Most of those infected by malaria are boys between the ages of one and 10 years old.

Palawan accounts for over 80% of malaria cases. It stands to reason that reducing malaria in Palawan will greatly reduce the total incidence of malaria in the Philippines. The government and allied organizations are doing just that and in mid-2012 reported the incidence of malaria Palawan hit its lowest level.

Palawan reported some 5,000 cases in 2011 compared to 20,000 cases in 1991, a drop of 300%. Malaria in Palawan is confined mostly to the southern part of the island, specifically the municipalities of Quezon, Rizal and Narra. Palawan accounted for 55% of all malaria cases in 2011. Total malaria cases nationwide for the first ten months of 2012 fell to 5,000 compared to 9,124 cases of 2011.

Worldwide, malaria affects 216 million people and kills about 655,000 each year, according to WHO. Most of these deaths are among children in Africa, which is home to over 90% of all malaria cases in the world.

Malaria transmission can be reduced by preventing mosquito bites. This can be achieved by using mosquito nets and insect repellent, or by implementing mosquito-control measures such as spraying insecticides.

Sadly, no effective vaccine against malaria has been developed A variety of anti-malarial medications are available, however. Severe malaria is treated with intravenous or intramuscular quinine or with the artemisinin derivative, artesunate. This drug is superior to quinine in both children and adults and is given in combination with a second anti-malarial such as mefloquine.

Artemisinin became the treatment of choice for malaria in 2006. Thereafter, WHO called for an immediate halt to single-drug artemisinin preparations in favor of combinations of artemisinin with another malaria drug to reduce the risk of malarial parasites developing resistance.

A lot of kids these days are going on eco-tours, adventure tours, nature tours and heritage tours to the provinces. This boost to local tourism is great, but the smart traveler always plans his trips and always prepares for emergencies.

So be prepared if your sojourns take you to those six provinces where malaria is still a problem. Insect repellent should be a must bring necessity on all your trips. And if you decide to sleep outdoors, do so underneath that quaint piece of cloth called the mosquito net or “kulambo.” WHO estimates that the use of “insecticide-treated mosquito nets” can reduce malaria cases by half.