Global Trends by Martin Khor

Monday 9 April 2012

Worrisome rise of Super Malaria

The danger of drug resistance is coming uncomfortably close to home, as scientists report the rapid spread of super malaria resistant to the best drugs, and warn of the need to contain this resistance.


Just a fortnight after the World Health Organisation chief warned about the possible end of modern medicine because of the resistance of disease-causing micro-organisms to drugs, there was alarming news last week of the rapid spread of a strain of malaria in Asia that is resistant to the most effective drugs.

A new study published last week found resistance growing in a malaria strain in the Thai-Myanmar border.  It had earlier been found in Western Cambodia.  The study’s authors warn that the deadly form of malaria could spread through Myanmar to other countries, unless swift action is taken.

Malaria is caused by parasites carried by mosquitoes, and killed 655,000 people worldwide in 2010.

It had earlier been treated with quinine then chloroquine.  When malaria developed resistance to chloroquine it was no longer effective and the new effective drug ingredient was artemisinin (derived from the sweet wormwood shrub), which is now mainly used in combination with other ingredients.

Resistance to artemisinin-based drugs is now causing alarm bells to ring, because there are no other effective drugs, and no new anti-malaria drug is expected to be in the market in the next several years.

Malaria that is resistant to artemisinin was first found in 2006 in Cambodia.  In Western Cambodia, 42% of malaria cases were found to be resistant in 2007-2010.  That’s a shockingly high percentage, and if this kind of prevalent resistance spreads to other regions, there will be a malaria emergency.

A team of British and Thai scientists studied 3,202 patients along Thailand’s northwestern border with Myanmar from 2001 and 2010 and measured the time it took them to clear malaria infections from their blood after treatment. An article in The Lancet journal reported that the number of slow-clearing infections rose from 0.6 per cent of cases treated in 2001 to 20 per cent in 2010, indicating a rapid rise in drug resistance.

In that period, the average time taken to reduce the number of parasites in the blood by half rose from 2.6 hours to 3.7 hours.   The proportion of slow-clearing infections rose from six to 200 out of every 1,000 cases, indicating resistance has reached 20% of cases.

According to a report by Sky News, the lead researcher, Professor Francois Nosten, director of the Shoklo Malaria Research Unit in Thailand, warned of a “race against time” to halt the resistance trend.

“If the situation continues to deteriorate then it could mean that the newest drugs that we have to treat malaria now which are the derivatives of artemisinin, will be progressively inefficient, ineffective.”

Nosten said the consequences, as seen in the past, would be increasing number of cases of malaria and more deaths.

He said the reason why the malaria strain has evolved resistance to the new treatments is probably because they have been used a lot over the last 20 years, as they were the only effective treatments.

“We can still treat the patient with these drugs and they get better and they get cured, it just takes longer for them to clear the disease,” he said.

“We have now seen the emergence of malaria resistant to our best drugs, and these resistant parasites are not confined to western Cambodia. This is very worrying indeed and suggests that we are in a race against time to control malaria in these regions before drug resistance worsens and develops and spreads further. The effect of that happening could be devastating.

“Malaria already kills hundreds of thousands of people a year – if our drugs become ineffective, this figure will rise dramatically.”

Another of the researchers, Prof. Nicholas White at the Faculty of Tropical Medicine in Mahidol University in Bangkok, urged that support be given to Myanmar to fight the spread of drug-resistant malaria there.

Support is needed to contain the resistance in this region, otherwise it is going to spread to India and Africa, said White.

The spread of resistant malaria is but one more example of a critical situation, one in which Margaret Chan, director general of the World Health Organisation waned of an emerging era of the end of modern medicine.

There should be a worldwide campaign to identify the sources of this problem and to contain drug resistance, including through the proper prescription and use of drugs.