What is malaria?
Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected mosquitoes. It can be fatal. Occurring in the tropics, about half the world’s population live in areas where malaria is present. In 2012 there were 207 million malaria cases, causing an estimated 627,000 deaths, mostly in Sub-Saharan Africa. Malaria causes fever, headaches and vomiting about two weeks after a person has been infected. It needs to be treated with drugs to avoid it becoming life-threatening. Prevention and control of malaria can be through limiting mosquito breeding areas of stagnant water, spraying around homes, preventing mosquito bites, and sleeping under mosquito nets treated with insecticide.
How is malaria transmitted?
Malaria is caused by tiny Plasmodium parasites that enter the red blood cells and lodge in the liver where they multiply rapidly and quickly infect other red blood cells. In the hours between dusk and dawn, when the female Anopheles mosquito sucks blood from an infected person and then bites others, she spreads the tiny parasites that cause malaria, continuing the cycle of infection. Bouts of fever coincide with the parasites bursting out of the red blood cells. Infected red blood cells can clump together, blocking blood flow and damaging the liver, kidneys and brain. It can lead to chronic anaemia.
Who does malaria affect?
Those most at risk of malaria are people who have not been exposed to the virus, especially young children, pregnant women and people living with HIV (who have depleted immune systems). Healthy adults who live in malaria-prone areas are likely to have developed a degree of resistance and their symptoms may be less severe than those with no immunity. Malaria mostly affects poor people who cannot afford treatment or have limited access to healthcare. It traps families and communities in a downward spiral of poverty.
Combating malaria requires a multi-pronged approach: tackling the parasite that causes malaria, the mosquito that transmits it and the infected human whose blood multiplies it.
The life cycle of the Plasmodium parasite occurs partly in the mosquito carrier and partly in the human host. Limiting the numbers of mosquitoes and their biting of humans is important for preventing the spread of malaria.
Mosquitoes breed in shallow fresh water, such as puddles and irrigation channels. Limiting breeding grounds by reducing standing water, clearing drains, using sea water rather than fresh water to flush toilets and introducing Gambusia fish to freshwater ponds to eat mosquitoes and their larvae reduces the spread of malaria.
‘If you don't get bitten, you won't get malaria.’
Preventing mosquitoes from biting humans is vital to limiting the spread of malaria. People can sleep under bed nets that have been treated with long-lasting insecticide, tucking them under bedding even though they may be hot and stuffy, and ensuring to check them for holes. They need to seek healthcare quickly if they have malaria in order to limit its spread to others.
Mosquitoes can be prevented from entering houses by spraying insecticide on the walls and ceilings. Burning mosquito coils made from pyrethrum daisies (most commonly chrysanthemums) and coconut husks also limits mosquito bites at night.
Early treatment reduces the severity and length of the illness. Quinine harvested from the bark of the cinchona tree in present-day Peru and Ecuador was traditionally the main form of treatment. While quinine interrupts the parasites’ breeding cycle, it is short acting and can have serious side effects.
In the 1940s a synthetic medicine, chloroquine, was introduced. It was inexpensive, safe and provided long-lasting protection against all forms of malaria. However, poor usage led to the development of resistance.
Since the 1980s a new drug based on a traditional Chinese herb, qinghaosu, has been used. The active ingredient is artemisinin, and it has significantly contributed to the decline of malaria. Artemisinin is used in combination with other drugs to reduce the development of resistance.
Major eradication campaigns
The global malaria eradication campaign, launched by the World Health Organization in 1955, was effective in eliminating malaria in many temperate and subtropical-zone countries through treatment, swamp drainage and spraying walls with DDT. Lack of funding prevented the expansion of these programs to tropical countries.
Recently the Roll Back Malaria Campaign and the Millennium Development Goals have renewed efforts to tackle malaria.
Malaria in Solomon Islands
The Solomon Islands Government has supported malaria elimination programs for more than 40 years, but difficult terrain, use of outdated drug regimes and lack of finance led to a peak number of cases (153,359) in 1992.
New programs, treating those infected quickly, distributing treated bed nets, indoor spraying, drain clearing and community education, are reducing the incidence of malaria. A network of medical centres, with doctors, researchers and other medical staff using radios to communicate across the country can respond rapidly when high numbers of malaria cases are reported.
Progress is being made. In 2012 only 75 cases per 1,000 people were recorded, compared to 199 per 1,000 people in 2003.