Currently, 219 million cases of malaria are estimated to occur around the world each year. Of that number, about 660,000 die each year, mostly children under the age of 5, according to the Geneva-based World Health Organization (WHO).
The figure is expected to increase as world temperature continues to rise. Models suggest, although conservatively, that risk of malaria will increase 5 percent to 15 percent by 2100 due to climate change.
Mosquitoes, which can carry the virus that causes malaria, are very sensitive to temperature changes. “Warming of their environment—within their viable range—boosts their rates of reproduction and the number of blood meals they take; prolongs their breeding season, and shortens the maturation period for the microbes they disperse,” wrote Dr. Paul R. Epstein in The New England Journal of Medicine.
“In highland regions, as permafrost thaws and glaciers retreat, mosquitoes and plant communities are migrating to higher ground,” added Epstein, who is the associate director of the Center for Health and the Global Environment of Harvard Medical School in Boston.
Malaria is caused by a bite of a mosquito, which has about 2,000 species. The species that transmit malaria are classified in the genus Anopheles. There are some 400 species of Anopheles mosquitoes, but only about 70 species are known to be responsible for transmitting malaria.
About 30 are of major importance, responsible for a significant amount of all malaria cases around the world. On the other hand, malaria is caused by four types of plasmodium, a single-cell parasite transmitted by the bite of the female Anopheles. Of these four types, Plasmodium falciparum produces the greatest number—and the most lethal—of infections.
Dr. Dominic Garcia, an infectious specialist, said malaria can also be transmitted accidentally by blood transfusion, or through contaminated needles or syringes. “During pregnancy, fetuses can become infected with parasites from the blood of the mother,” he cautioned.
According to a WHO publication, Rural Health, the malaria parasite is not simply transferred from one person to another but must live part of its life in the mosquito. It is for this reason that malaria is such a threat to health in the tropics but not in cooler countries or at high altitudes (where the temperature is lower).
“The cycle of malarial infection begins when a female mosquito bites a person with malaria,” The Merck Manual of Medical Information explained. “The mosquito ingests blood that contains malarial parasites. Once inside the mosquito, the parasite multiplies and migrates to the mosquito’s salivary gland. When the mosquito bites another person, the parasites are injected along with the mosquito’s saliva. Inside the person, the parasites move to the liver and multiply again. They typically mature over an average of one to three weeks, then leave the liver and invade the person’s red blood cells.”
It is at this point that the bitten person begins to feel the symptoms. The first signs are usually fever and a general feeling of aching and being unwell, often with a bad headache.
Many people who have had malaria feel that they can tell it from other illnesses, but this is a dangerous belief in reality, since, at this stage, malaria is easily confused with many other illnesses, such as an attack of flu. Other symptoms, such as cough, vomiting or diarrhea, may lead the patient to think the problem is a chest infection or a stomach upset.
If treatment is not started quickly, the patient gets more ill. “Malaria can kill an individual in just an hour, if the one being infected is not aware that he’s been bitten,” the WHO points out.
The symptoms are caused by the destruction of the red cells, causing anemia, the release of toxins into the bloodstream as the parasite bursts out of the red cells, and the blocking of small blood vessels throughout the body.
The patient becomes weaker. Danger signs include persistent vomiting, becoming confused, increasing difficulty in breathing, or having an epileptic fit. The patient may become unconscious, a condition known as “cerebral malaria.”
Any of these symptoms is a sign of serious problem, and the patient needs urgent admission to a hospital or health center with the facilities for good inpatient care.
An ounce of prevention is better than a pound of cure, so goes a saying. Filipinos must remember these simple prevention steps from the UN health agency:
- Sleep in a room that has screens that can protect you from mosquitoes.
- If there are a lot of mosquitoes in your place, be sure to have mosquito-repellent sprays or lotion for protection.
- Practice hygiene and sanitation.
- If you see some signs and symptoms of malaria, rush the individual to the nearest clinic or hospital.
- Make sure that the authorities in your place will know about the malaria outbreak (if there is such) as soon as possible.