The female Anopheles mosquito

A report by the world's leading international health organisations on Monday called for joint action to accelerate the development and licensing of a highly-effective malaria vaccine.

The Malaria Vaccine Technology Roadmap, a new global strategy, was launched Monday in Bangkok at the Global Vaccine Research Forum taking place from December 3 to 6.

"Having a highly-protective malaria vaccine and putting it into widespread use in affected areas would be a true achievement for public health. It would fulfill an urgent need," said Dr. Marie-Paule Kieny, director of the Initiative for Vaccine Research, World Health Organisation (WHO). "The roadmap marks the first concerted global attempt at mapping out a shared plan of action for making a preventive malaria vaccine reality."

The roadmap is a pathway towards reaching the goal of developing a malaria vaccine by 2025 that would have a protective efficacy of more than 80 per cent against clinical disease and would provide protection for longer than four years. An interim landmark would be to develop and license a first-generation vaccine by 2015 with 50 per cent protective efficacy against severe disease and death that would last longer than one year.

Every year, there are 300-500 million cases of malaria and the disease kills more than one million people, mainly African children. The plan calls for the malaria vaccine community - scientists, funding organisations, policy experts and national and global decision-makers - to work together to develop an effective vaccine that prevents severe disease and death caused by Plasmodium falciparum, the most deadly form of the malaria parasite.

Challenges in creating a malaria vaccine include scientific unknowns such as the lack of full understanding of mechanisms of malaria infection; disease and immunity; inadequate resources; limited private-sector involvement; and uncertain mechanisms for procuring and distributing a successful vaccine.

More than 230 experts representing 100 organisations from 35 countries collaborated to develop and publish the roadmap over a two-year period.

The malaria parasite

Public health experts describe malaria as the infection of red blood cells with a single-cell parasite, Plasmodium. Normal disease spread is through the bite of an infected female Anopheles mosquito.

Four species of the malaria-causing parasites can infect people:

1. Plasmodium falciparum

2. Plasmodium vivax

3. Plasmodium ovale

4. Plasmodium malariae.

P. vivax and P. ovale can stay dormant in the liver, releasing, periodically, mature parasites into the blood stream causing recurring attacks of symptoms. P. falciparum and P. malariae do not persist in the liver, however, the latter can persist in the blood stream for months or years causing symptoms.

Malaria is endemic in parts of Asia, Africa, Central and South America, Oceania, and certain Caribbean islands.

Symptoms

When infected blood cells rupture and release the malaria-causing parasite, the infected individual will experience symptoms of shaking, chills, followed by fever that can exceed 104 degrees Fahrenheit; the infected individual may also experience headache, body aches and nausea. The Plasmodium may also cause enlarged spleen and anaemia.

Prevention

The United States Centres for Disease Control recommends preventing infection by:

1. Avoiding bites by parasite-carrying mosquitoes.

2. Using antimalarial drugs prophylactically to prevent the development of the malaria parasites in the blood.