New weapon to fight malaria

Saturday,  February 21,   2004

Plastic sheeting, treated with insecticide, could be a promising new weapon in the fight against malaria in Africa, according to latest reports from Johns Hopkins University, Baltimore, United States.

 Researchers from Malaria Emergency Technical and Operational Response, (MENTOR) the new malaria response program of the institution’s School of Public Health Center for International Emergency, Disaster and Refugee Studies (CIEDRS) are evaluating the insecticide-treated plastic’s effectiveness at two camps in Sierra Leone.

According to Richard Allan, MENTOR’s director initiative, plastic sheeting is an essential survival tool for refugees in Africa seeking shelter, the release said. Allan helped develop the insecticide-treated sheeting as a practical method of keeping malaria-spreading mosquitoes out of refugee shelters.

 ‘Each year, 300 to 500 million people worldwide are infected with malaria according to the World Health Organization and it is the number one killer of refugees in many war-torn countries of Africa.’

Unlike blankets or mosquito netting, few people are willing to part with their plastic shelters. ‘I’ve seen refugees trade their children for rice and keep their plastic,’ recalled Allan. Because plastic sheeting is so highly valued, refugees are more likely to use it continuously, which could help reduce the spread of the disease.

Allan said the preliminary results are promising. ‘If tests are successful, the insecticide-treated sheeting could replace the standard shelter material distributed by the United Nations (UN). Insecticide treatment is also being considered for blankets and wallpaper to further protect against malaria and other diseases.’

MENTOR was established in October 2002, when the UN turned some of its malaria-fighting efforts to an independent organization. According to Allan, CIEDRS was selected to manage the program because of its cooperation with other non-governmental organizations and experience in training and emergency relief. The program provides technical assistance, guidance, and support to relief workers in the field. Additional training courses are conducted at the School of Public Health.

In addition to work in Sierra Leone, the initiative is active in Liberia, where malaria accounts for 30 to 45 percent of all illnesses among displaced people, according to health officials. Allan said the group is working closely with the Liberian Ministry of Health and other agencies to develop a national malaria control strategy and improve public health.

 ‘Each year, 300 to 500 million people worldwide are infected with malaria according to the World Health Organization (WHO) and it is the number one killer of refugees in many war-torn countries of Africa.’

 ‘Malaria kills an African child every 30 seconds, the WHO has said severally. Malaria is a life-threatening parasitic disease transmitted by mosquitoes. It was once thought that the disease came from fetid marshes, hence the name mal aria, ((bad air). In 1880, scientists discovered the real cause of malaria a one-cell parasite called plasmodium. Later they discovered that the parasite is transmitted from person to person through the bite of a female Anopheles mosquito, which requires blood to nurture her eggs.’

Today it is reported that ‘approximately 40 percent of the world's population mostly those living in the world's poorest countries is at risk of malaria. The disease was once more widespread but it was successfully eliminated from many countries with temperate climates during the mid 20th century. Malaria is currently found throughout the tropical and sub-tropical regions of the world and causes more than 300 million acute illnesses and at least one million deaths annually.’

There are four types of human malaria Plasmodium vivax, P. malariae, P. ovale and P. falciparum. P. vivax and P. falciparum are the most common and falciparum the most deadly type of malaria infection. Plasmodium falciparum malaria is most common in Africa, south of the Sahara, accounting in large part for the extremely high mortality in this region. There are also worrying indications of the spread of P. falciparum malaria into new regions of the world and its reappearance in areas where it had been eliminated.

The malaria parasite enters the human host when an infected Anopheles mosquito takes a blood meal. Inside the human host, the parasite undergoes a series of changes as part of its complex life-cycle. Its various stages allow plasmodia to evade the immune system, infect the liver and red blood cells, and finally develop into a form that is able to infect a mosquito again when it bites an infected person. Inside the mosquito, the parasite matures until it reaches the sexual stage where it can again infect a human host when the mosquito takes her next blood meal, 10 to 14 or more days later.

Malaria symptoms appear about 9 to 14 days after the infectious mosquito bite, although this varies with different plasmodium species. Typically, malaria produces fever, headache, vomiting and other flu-like symptoms. If drugs are not available for treatment or the parasites are resistant to them, the infection can progress rapidly to become life threatening. Malaria can kill by infecting and destroying red blood cells (anaemia) and by clogging the capillaries that carry blood to the brain (cerebral malaria) or other vital organs.

Malaria, together with HIV/AIDS and TB, is one of the major public health challenges undermining development in the poorest countries in the world. Malaria parasites are developing unacceptable levels of resistance to one drug after another and many insecticides are no longer useful against mosquitoes transmitting the disease. Years of vaccine research have produced few hopeful candidates and although scientists are redoubling the search, an effective vaccine is at best years away.

Till date science seems not to have any magic bullet for the disease and many doubt that such a single solution will ever exist. Nevertheless, WHO believes that effective low-cost strategies are available for its treatment, prevention and control and the Roll Back Malaria global partnership is vigorously promoting them in Africa and other malaria-endemic regions of the world. ‘Mosquito nets treated with insecticide reduce malaria transmission and child deaths. Treatment  and the use of insecticide-treated nets, results in improvement in maternal health, infant health and survival. Prompt access to treatment with effective up-to-date medicines, also saves lives.’

There is no doubt that the effective implementation of these robust measures will significantly reduce the burden of malaria in Nigeria and other endemic countries.