Gene clues point to Cambodia for resistant malaria

April 28, 2013

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.

Explore further: Artemisinin-resistant untreatable malaria increasing rapidly along the Thailand-Myanmar border: study

More information: Paper:

Related Stories

WHO hopeful drug-resistant malaria can be contained

April 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

September 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.

Recommended for you

New class of RNA tumor suppressors identified

November 23, 2015

A pair of RNA molecules originally thought to be no more than cellular housekeepers are deleted in over a quarter of common human cancers, according to researchers at the Stanford University School of Medicine. Breast cancer ...

Batten disease may benefit from gene therapy

November 11, 2015

In a study of dogs, scientists showed that a new way to deliver replacement genes may be effective at slowing the development of childhood Batten disease, a rare and fatal neurological disorder. The key may be to inject viruses ...


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.