Gene clues point to Cambodia for resistant malaria

Gene analysis of malaria parasites has pinpointed western Cambodia as the hotspot of strains that are dangerously resistant to artesiminin, the frontline drug against the disease, scientists said on Sunday.

An international consortium of researchers unravelled the genetic code of 825 samples of the Plasmodium falciparum parasite from , Gambia, Ghana, Mali, Thailand, Vietnam and from northeastern and western Cambodia.

The 166 samples from western Cambodia stood out, the team reported in the journal Nature Genetics.

Included in them were three sub-populations of parasites whose made them resistant to artesiminin.

These strains appear to be the wellspring for malarial resistance that is spreading to other countries.

"Clinical resistance to artemisinin and its derivatives is now well established in the P. falciparum population of western Cambodia and appears to be emerging in neighbouring regions," said the paper.

"These recent developments have grave implications for public health, as artemisinin derivatives are the mainstay of worldwide."

Western Cambodia has unleashed "successive global waves" of antimalarial , the investigators said.

Resistance to chloroquine drugs was observed there in the late 1950s before it spread around the world, and the most common forms of resistance to and sulfadoxine drugs are also thought to have originated there.

The study offers several reasons why such a relatively small geographical area should be so unusual.

Parasites are transmitted to humans by , and a crucial step in the process is the way in which the parasites swap genes within mosquito.

In the case of Cambodia, parasites experienced inbreeding that created lineages with drug-resistant mutations, the study ??found.

Such inbreeding typically comes from isolation.

One scenario is that a group of parasites became isolated in a remote area of jungle.

Another is that the 1979-1998 period of Khmer Rouge resistance in western Cambodia restricted human movement.

As the parasite could not move easily out of the area through infected humans, this provided excellent conditions for inbreeding.

Malaria causes around 650,000 deaths each year, mostly African children under five, according to the UN's World Health Organisation (WHO).

Artemisinin-resistant parasites emerged on the Thai-Cambodian border around nine years ago and were later discovered in western Thailand, Myanmar and Vietnam.

More information: Paper: dx.doi.org/10.1038/ng.2624

add to favorites email to friend print save as pdf

Related Stories

WHO hopeful drug-resistant malaria can be contained

Apr 24, 2012

The World Health Organisation said Tuesday it was optimistic drug-resistant malaria that has emerged along Thailand's borders with Cambodia and Myanmar could be contained within the region.

WHO urges action as drug-resistant malaria spreads

Sep 27, 2012

The World Health Organization said Thursday that governments in the Mekong region must act "urgently" to stop the spread of drug-resistant malaria which has emerged in parts of Vietnam and Myanmar.

Drug-resistant malaria has emerged in Cambodia

Jul 29, 2009

(PhysOrg.com) -- Malaria parasites in western Cambodia have become resistant to artemisinin-based therapies, the first-line treatment for malaria, according to a study published in the New England Journal of ...

Recommended for you

Changes in scores of genes contribute to autism risk

22 hours ago

Small differences in as many as a thousand genes contribute to risk for autism, according to a study led by Mount Sinai researchers and the Autism Sequencing Consortium (ASC), and published today in the journal Nature.

Dozens of genes associated with autism in new research

23 hours ago

Two major genetic studies of autism, led in part by UC San Francisco scientists and involving more than 50 laboratories worldwide, have newly implicated dozens of genes in the disorder. The research shows ...

Genetic link to kidney stones identified

Oct 29, 2014

A new breakthrough could help kidney stone sufferers get an exact diagnosis and specific treatment after genetic links to the condition were identified.

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.