Every 30 seconds, a child dies of malaria – that is the sobering fact coming from the World Health Organisation.
We may not be at too much risk in most parts of SA, but there are those like Peter Agre, director of the Johns Hopkins Malaria Research Institute in Maryland, US, who tell us we still have to be worried – very worried.
“There are more people infected with malaria now than ever before,” he says. “We know how to handle it, but the fear is the resistance to current drugs of choice, may spread.”
Agre was a guest speaker at the Mandela School of Medicine this week where he spoke of the pressing work that still needs to be done in Africa.
It was in 2003 that Agre won the Nobel Prize in Chemistry for his discovery of aquaporins, the pumping system and water channels contained in cell membranes.
“It wasn’t something I had set out to do,” he explains. “As a blood specialist my interest was studying malaria in red blood cells. But scientists will always tell you that while research takes you in one direction, your work sometimes leads you elsewhere.”
Agre says that where he left off, many other scientists have continued aquaporin research in the development of new drugs.
“When I had done as much as I could on the initial aquaporin front, malaria became my major focus.”
Although he spends a third of his year in regions where malaria is endemic – mostly Zimbabwe and rural Zambia – he has never had the disease himself.
“I am very careful, always sleep under nets and take the appropriate drugs. Even here in South Africa I hear people say malaria is no longer a threat. South Africa has done very well in its eradication programmes, but vigilance is not the only factor.”
The Anopheles vector mosquito, the main carrier, he explains, is a past master at developing resistance.
“We are seeing the devastating results everywhere. I don’t say we’re staring at defeat, but there is certainly no sign of victory.”
Globally, malaria infects 300 million to 500 million people and kills more than one million every year, according to the World Health Organisation.
“Those are huge figures. That is why we are encouraging young scientists to come on board. We need fresh approaches.
“Like everyone else I used to take chloroquine to prevent malaria. It was a very good drug. But within a decade resistance has emerged across the planet.”
He says it is no longer useful for the most common malarial parasite Plasmodium falciparum.
“We have new drugs, but the risk of resistance is still present.”
While he believes that a malaria vaccine is a possibility, he cannot suggest a time line to it.
“It would be nice if a vaccine emerged in the next year but I don’t think we’re close. This is not a simple virus or a bacterium; this is a complex parasite, and vaccines for parasites have not been successful generally.
“The tragedy is the number of young children who contract malaria. We know that people who have had repeated bouts can develop partial immunity, but young children don’t have time to build up that immunity, which is why the death rate is so high.”
Malaria, says Agre, is perhaps even tougher to combat than HIV or TB because of its many life-cycle stages. The genetic complexity allows the parasites to adapt rapidly to drugs and to the immune system’s efforts to make it ineffective.
With billions of parasites circulating in a single human host, one infected person can transmit to hundreds of others within months, far outstripping the infectiousness of HIV or TB.
He said that while the prevalence of malaria in some parts of Zambia had been reduced by 98 percent because of interventions, other areas were not doing well.
“We’re starting a field station in eastern Zimbabwe, where malaria was once well-controlled. Today that is not the case. Eighty percent of clinic visits are due to malaria. It is out of control.”
Back in the US, Agre’s research team at the John Hopkins lab are looking at a number of ways to block the parasite transmission from mosquito to man and from man to mosquito.
A genetically-modified mosquito whose parasite transmission has been compromised is just one of those investigative avenues. So too, are the mosquito aquaporins, where Agre’s journey of discovery first began, and their role in parasite transmission.
“Our team members are a bit like medical Indiana Joneses. It’s not straightforward. It’s adventurous. Even fun.”
His big wish is that actor George Clooney would become an ambassador for malaria awareness.
“While in the Sudan Clooney got it for the second time. He said he recovered because he was able to get modern medicines that others don’t have, but they should. That was a powerful statement, and so accurate.”
l Peter Agre was hosted in SA by the Vice Chancellor of UKZN Malegapuru Makgoba and KwaZulu-Natal Research Institute into TB and HIV.
Efforts in SA:
According to the National Institute for Communicable Diseases in SA, December and January are the malaria season in Southern Africa, with many travellers exposed during holidays, particularly in Zimbabwe and Mozambique.
Drug-resistant malaria strains, says the institute, are an increasing problem globally, with drugs like chloroquine and Fansidar now largely ineffective.
An artemesinin-based combination drug, Coartem, is described as “a state-of-the-art treatment” and first choice for uncomplicated malaria in the public malaria programmes in Mpumalanga, Limpopo and KwaZulu-Natal.
SA’s malaria programmes have reduced the malaria risk in SA, with reported cases decreasing from 60 000 in 2000 to an average of 7 000 cases annually. - Sunday Tribune