A drugs programme which slashed malaria infections in parts of Cambodia is being extended to an African island, with Chinese scientists aiming to simultaneously treat all 40,000 residents, an expert said.
Although malaria-infected mosquitoes pass the parasite from person to person, the scientists say the real source of the disease is people, some of whom can carry it in their bodies for a long time without showing clear symptoms.
Moheli island, the test location, is among the Comoros group of islands at the northern mouth of the Mozambique Channel, about two-thirds of the way between northern Madagascar and northern Mozambique.
While the average carrier rate in the 10 most seriously affected villages on Moheli is 50 percent, the rate is as high as 94.4 percent in some villages and as low as 6.5 percent in other areas. Malaria is the most common cause of death for children under the age of 5.
"This project is to eradicate the parasite in humans because the real source are the humans," said Li Guoqiang, a professor at the Tropical Medicine Institute at Guangzhou University of Traditional Chinese Medicine (GUTCM) in southern China.
"When it is driven out of humans, mosquitoes will not carry it since mosquitoes get it from humans. And once the parasite is not around, malaria will be exterminated."
Li disclosed the plan at an anti-malaria conference in Guangzhou and told Reuters later that GUTCM and the Comoros were expected to sign an agreement soon.
The project would probably kick off in the first half of 2007.
Under the plan, the islanders will be prescribed a single dose of arteminisin-based combination therapy (ACTs) and primaquine, which they will all consume at the same time to clear the parasite from their bodies.
The World Health Organisation recommends ACTs as the drug of choice against malaria. Artemisinin is a compound extracted from a herb, mostly grown in China.
Primaquine, another anti-malaria drug, blocks transmission of the parasite after 24 hours.
But some experts were cautious about the plan, saying frequent use of primaquine may bring drug resistance, something the world can ill afford given what is already a limited arsenal against malaria, which kills more than 1 million people a year.
Drugs to Cut Parasite Pool
Li expects the total pool of malaria parasites in the islanders to drop sharply after the mass administration of drugs.
But because infected mosquitoes -- which have a 30-day life span -- may still be lurking and transmit the disease, a second round of mass drug intake will be carried out 40 days later.
"That would bring the (malaria parasite) carrier rate down by at least 99 percent," Li said.
The plan also involves everyone taking primaquine every 10 days for the first six months.
Li and colleagues implemented similar schemes in two places in Cambodia in recent years and the results were impressive.
Malaria infections fell by 90 percent in one district and in the other, only 2 to 3 percent of villagers tested positive for the parasite on the 40th day. Prior to that 57 percent of villagers carried the parasite.
"The projects have been going fine. Infection rates have plunged sharply and people have had no adverse side effects," said Duong Socheat, the director of the National Malaria Centre in Cambodia who oversaw the two projects there.
While some experts said a malaria-free environment would be near impossible to maintain as outsiders could bring in the parasite, Li insisted a more creative solution to malaria was needed.
"The traditional method is to kill the mosquitoes, but we have been doing that for 50 years and it doesn't work," he said.
Source: Bio - Bio Technology