Hvis den nye “tredje bølge” af modstandsdygtige parasitter fra malaria-myggen breder sig til Afrika – lige som det er sket to gange før – kan det få voldsomme konsekvenser for kampen mod tropelidelsen, der har kostet millioner af ofre og hvor man ikke har nogen vaccine.
PHNOM PENH, 29 August 2014 (IRIN): Public health experts and scientists warn history’s third major bout (omgang) of drug-resistant malaria could spread across Asia to Africa unless “radical action” is taken.
Artemisinin-resistant strains (sygdomsstammer) on the Thailand-Cambodia border threaten the treatment’s efficacy and pose containment (inddæmnings) challenges.
“The bad news is that drug-resistant parasites are actually found in a wider area than we previously thought,” said Nicholas White, professor of Tropical Medicine at the University of Oxford.
He is author of a July 2014 study that revealed drug-resistant malaria parasites have spread to critical border regions of Southeast Asia (including the Cambodia-Thailand and Burma-Thailand borders), and that resistance to Artemisinin, the world’s most effective anti-malarial drug, is now widespread in the region.
Must use several drugs
Artemisinin is effective against malaria, but it must be used in a combination of several drugs.
In 2007, the World Health Assembly (WHA) issued a resolution calling for the end of monotherapies (or using a single drug) to treat malaria as this practice was causing resistance.
A full dose of Artemisinin Combination Therapy (ACT) is now prescribed to prevent the development of drug resistance.
According to White, who also chairs the Worldwide Antimalarial Resistance Network, despite the new evidence of resistance along the Thailand-Cambodia border, not all hope for effective interventions is lost.
He told IRIN: “The good news is that we can still treat it using longer ACT courses and we can map its spread using a molecular marker.”
A “molecular marker” was identified in 2013 in western Cambodia, which for the first time allowed scientists to detect malaria parasites with resistance to drug treatments outside clinical trials.
However, despite these advances in malaria monitoring and the availability of treatment, some warn the containment of drug-resistant malaria will require “radical action” to prevent what history has shown to be a deadly inter-continental spread.
Tracking the threat
According to the Pasteur Institute, one of the partners in the research on malaria’s molecular marker, “the discovery of this marker will further our understanding of parasite resistance to Artemisinin derivatives (afledte midler), improved monitoring of the spread of resistant forms of malaria, and the swift adaptation of effective treatment methods to combat this disease.”
While almost 40 percent of the world’s population is exposed to malaria, no vaccine currently exists.
In 2012, it killed 627,000 people globally; WHO estimates that 207 million cases were detected worldwide that year. The mosquito-borne parasite mutates to resist popular treatment drugs.
From the late 1950s to the 1970s chloroquine was the most commonly-prescribed drug, but resistance spread across Asia to Africa, resulting in a resurgence (genopståen) of malaria infections and millions of deaths.
Chloroquine was replaced by sulphadoxine-pyrimethamine (SP) in 1973, but resistance to SP emerged in Thailand by the end of the 1980s and spread to Africa.
By 2006, ACT became the treatment of choice for malaria in many malaria endemic countries, replacing SP.
“Now we face the prospect of history repeating itself for a third time,” said the Bangkok-based Mahidol Oxford Research Unit (MORU) in a July 2014statement.
Patrick Kachur, a medical epidemiologist and chief of the Malaria Branch of the Centres for Disease Control and Prevention (CDC), warned:
“If the resistance observed in Southeast Asia were to intensify or spread to Africa, it could cripple efforts to control malaria there and reverse a decade of progress.”
“The massive global effort to scale up effective malaria treatment and prevention that has saved more than three million lives in the last decade could be reversed,” he said.
Resistance leads to “drug loss”
Læs videre på http://www.irinnews.org/report/100549/third-wave-of-malaria-resistance-lurks-on-thai-cambodia-border
