Rockville: A US scientist is leading an international team of researchers using an army of blood-sucking mosquitos to produce a potentially potent vaccine against malaria.

Stephen Hoffman, 58, founded Sanaria Inc, a biotech firm solely dedicated to the production of a vaccine against malaria, a mosquito-borne disease that kills one million people a year, many of them African children.

Hoffman officially opened a manufacturing facility on Friday in the Washington suburb of Rockville, Maryland, where he said he aims to produce 75 to 100 million doses a year to vaccinate the 25 million infants born every in year in sub-Saharan Africa. "The opening of this facility is an important step in the process to develop a whole-parasite malaria vaccine," he said.

The scientist told reporters touring the facility he was optimistic that the vaccine could be tested in clinical trials by late 2008.

His goal, which has received US government support, was given a major boost in late 2006 when the Bill and Melinda Gates Foundation donated US $ 29.3 million through the PATH Malaria Vaccine Initiativem, Hoffman said.

Hoffman knows the debilitating effects of malaria all too well.

In the 1980s, when he was director of the US Navy's malaria research programme, he was so confident in a new vaccine that he reportedly let himself be bitten by mosquitos carrying Plasmodium falciparum, the malaria parasite responsible for more than 95 per cent of severe malarial illnesses and deaths worldwide. Sure enough, he came down with malaria symptoms days after being bitten. The vaccine did not work. 

Despite the failure of 20 years ago, the researcher has taken the same approach and hopes that a vaccine can be mass produced and maintain its potency.

At his lab, researchers feed mosquitos capable of transmitting malaria to humans with blood contaminated with Plasmodium falciparum. Two weeks later, the parasites spread into the mosquitoes' intestines and then to their salivary gland. The mosquitos are then delicately taken to a new chamber
where they are briefly treated with radiation to weaken the parasites.

Researchers extract the weakened parasites and purify them. Used in the vaccine, the weakened parasites trigger an immune reaction powerful enough to protect against malaria more than 90 per cent of the time for at least 10 months, Hoffman said. Those results were based on a trial conducted among 16 adults, he said.

Hoffman said there is still much work to be done proving the treatment. But through this system, the firm is "turning the mosquitos into the production factories for the vaccine," he said, adding that each mosquito can produce two doses of the vaccine.

Source : PTI