User login
Image by Ute Frevert
and Margaret Shear
Results of a new study confirm that dihydroartemisinin-piperaquine, the first-line treatment for Plasmodium falciparum malaria infection in Cambodia, has failed in certain provinces due to parasite resistance to both artemisinin and piperaquine.
Dihydroartemisinin-piperaquine is an artemisinin combination therapy (ACT) that combines fast-acting artemisinin with a long-acting partner drug, piperaquine.
Resistance to artemisinin in parts of Southeast Asia is well-documented, but, until now, only a few studies have presented clear evidence of piperaquine resistance.
Additional results from this study suggest that artesunate, a form of artemisinin, plus mefloquine, a different long-acting partner drug, should be the first-line ACT in areas where dihydroartemisinin-piperaquine treatment has failed.
Chanaki Amaratunga, PhD, of the National Institute of Allergy and Infectious Diseases in Rockville, Maryland, and colleagues reported these results in The Lancet Infectious Diseases.
The researchers assessed the efficacy of dihydroartemisinin-piperaquine treatment in 241 malaria-afflicted participants ages 2 to 65. The subjects lived in 3 different Cambodian provinces with varying levels of artemisinin resistance.
After monitoring parasite levels in the blood for 63 days, the researchers found that parasites had reemerged despite initial clearance in 45.7% of participants in Pursat, 15.9% of participants in Preah Vihear, and 1.67% of participants in Ratanakiri.
The results indicate the ACT is failing in Pursat and Preah Vihear, where artemisinin resistance is common, but remains highly efficacious in Ratanakiri, where resistance is uncommon.
Laboratory tests showed the parasites from dihydroartemisinin-piperaquine failures contained a genetic marker of artemisinin resistance and had a decreased susceptibility to piperaquine, demonstrating that both artemisinin and piperaquine resistance contributed to treatment failures.
However, the parasites also showed an increased susceptibility to mefloquine and completely lacked the molecular marker for mefloquine resistance.
These findings informed new World Health Organization guidelines reinstating artesunate plus mefloquine as the first-line ACT in Cambodia where dihydroartemisinin-piperaquine treatment has failed.
The researchers said the findings also provide evidence to initiate surveillance programs to track the spread of piperaquine resistance and clinical trials to test alternative combination therapies. 
Image by Ute Frevert
and Margaret Shear
Results of a new study confirm that dihydroartemisinin-piperaquine, the first-line treatment for Plasmodium falciparum malaria infection in Cambodia, has failed in certain provinces due to parasite resistance to both artemisinin and piperaquine.
Dihydroartemisinin-piperaquine is an artemisinin combination therapy (ACT) that combines fast-acting artemisinin with a long-acting partner drug, piperaquine.
Resistance to artemisinin in parts of Southeast Asia is well-documented, but, until now, only a few studies have presented clear evidence of piperaquine resistance.
Additional results from this study suggest that artesunate, a form of artemisinin, plus mefloquine, a different long-acting partner drug, should be the first-line ACT in areas where dihydroartemisinin-piperaquine treatment has failed.
Chanaki Amaratunga, PhD, of the National Institute of Allergy and Infectious Diseases in Rockville, Maryland, and colleagues reported these results in The Lancet Infectious Diseases.
The researchers assessed the efficacy of dihydroartemisinin-piperaquine treatment in 241 malaria-afflicted participants ages 2 to 65. The subjects lived in 3 different Cambodian provinces with varying levels of artemisinin resistance.
After monitoring parasite levels in the blood for 63 days, the researchers found that parasites had reemerged despite initial clearance in 45.7% of participants in Pursat, 15.9% of participants in Preah Vihear, and 1.67% of participants in Ratanakiri.
The results indicate the ACT is failing in Pursat and Preah Vihear, where artemisinin resistance is common, but remains highly efficacious in Ratanakiri, where resistance is uncommon.
Laboratory tests showed the parasites from dihydroartemisinin-piperaquine failures contained a genetic marker of artemisinin resistance and had a decreased susceptibility to piperaquine, demonstrating that both artemisinin and piperaquine resistance contributed to treatment failures.
However, the parasites also showed an increased susceptibility to mefloquine and completely lacked the molecular marker for mefloquine resistance.
These findings informed new World Health Organization guidelines reinstating artesunate plus mefloquine as the first-line ACT in Cambodia where dihydroartemisinin-piperaquine treatment has failed.
The researchers said the findings also provide evidence to initiate surveillance programs to track the spread of piperaquine resistance and clinical trials to test alternative combination therapies.
Image by Ute Frevert
and Margaret Shear
Results of a new study confirm that dihydroartemisinin-piperaquine, the first-line treatment for Plasmodium falciparum malaria infection in Cambodia, has failed in certain provinces due to parasite resistance to both artemisinin and piperaquine.
Dihydroartemisinin-piperaquine is an artemisinin combination therapy (ACT) that combines fast-acting artemisinin with a long-acting partner drug, piperaquine.
Resistance to artemisinin in parts of Southeast Asia is well-documented, but, until now, only a few studies have presented clear evidence of piperaquine resistance.
Additional results from this study suggest that artesunate, a form of artemisinin, plus mefloquine, a different long-acting partner drug, should be the first-line ACT in areas where dihydroartemisinin-piperaquine treatment has failed.
Chanaki Amaratunga, PhD, of the National Institute of Allergy and Infectious Diseases in Rockville, Maryland, and colleagues reported these results in The Lancet Infectious Diseases.
The researchers assessed the efficacy of dihydroartemisinin-piperaquine treatment in 241 malaria-afflicted participants ages 2 to 65. The subjects lived in 3 different Cambodian provinces with varying levels of artemisinin resistance.
After monitoring parasite levels in the blood for 63 days, the researchers found that parasites had reemerged despite initial clearance in 45.7% of participants in Pursat, 15.9% of participants in Preah Vihear, and 1.67% of participants in Ratanakiri.
The results indicate the ACT is failing in Pursat and Preah Vihear, where artemisinin resistance is common, but remains highly efficacious in Ratanakiri, where resistance is uncommon.
Laboratory tests showed the parasites from dihydroartemisinin-piperaquine failures contained a genetic marker of artemisinin resistance and had a decreased susceptibility to piperaquine, demonstrating that both artemisinin and piperaquine resistance contributed to treatment failures.
However, the parasites also showed an increased susceptibility to mefloquine and completely lacked the molecular marker for mefloquine resistance.
These findings informed new World Health Organization guidelines reinstating artesunate plus mefloquine as the first-line ACT in Cambodia where dihydroartemisinin-piperaquine treatment has failed.
The researchers said the findings also provide evidence to initiate surveillance programs to track the spread of piperaquine resistance and clinical trials to test alternative combination therapies.