Efficacy of directly-observed chloroquine-primaquine treatment for uncomplicated acute Plasmodium vivax malaria in northeast Myanmar: A prospective open-label efficacy trial

Abstract

Background: Chloroquine (CQ) and primaquine (PQ) remain the frontline drugs for radical cure of uncomplicated P. vivax malaria in the Greater Mekong Sub-region (GMS). Recent reports of decreased susceptibility of P. vivax to CQ in many parts of the GMS raise concerns.Methods: From April 2014 to September 2016, 281 patients with uncomplicated P. vivax infection attending clinics in border settlements for internally displaced people in northeast Myanmar were recruited into this study. Patients were treated with standard regimen of 3-day CQ and concurrent 14-day PQ (3.5 mg/kg total dose) as directly observed therapy, and followed for recurrent parasitemia within 28 days post-patency.Results: Within the 28-day follow-up period, seven patients developed recurrent parasitemia, resulting in a cumulative rate of parasite recurrence of 2.6%. Five of the seven parasitemias recurred within two weeks, and two of those failed to clear within seven days, indicating high-grade resistance. Conclusion:Although failure of CQ/PQ treatment of P. vivax was relatively infrequent in northeast Myanmar, this study nonetheless confirms that CQ/PQ-resistant strains do circulate in this area, some of them of a highly resistant phenotype. It is thus recommended that patients who acquire vivax malaria in Myanmar be treated an artemisinin-combination therapy along with hypnozoitocidal primaquine therapy to achieve radical cure.

Molecular surveillance for drug resistance markers in Plasmodium vivax isolates from symptomatic and asymptomatic infections at the China–Myanmar border

“…Drug resistance in P. falciparum and P. vivax isolates of asymptomatic malaria carriers has also been reported in high-and low-endemic regions of Myanmar [8,9]. Recently, along the China-Myanmar border, the therapeutic responses of P. vivax malaria to CQ treatment were declining [14,15]. Thus, this study compared the potential markers for CQR and antifolate resistance in asymptomatic and symptomatic P. vivax infections from this region.…”

Population genomics identifies a distinct Plasmodium vivax population on the China-Myanmar border of Southeast Asia

“…Therefore, mutations in these genes could be resulted from selection by chloroquine, given chloroquine/primaquine has remained the frontline treatment for vivax malaria in the GMS. It would be interesting to see whether the mutations in these genes are correlated with drug resistance, as there is clear evidence of emerging chloroquine resistance in the northeastern Myanmar P. vivax population [46,47].…”

Dynamics of Plasmodium vivax populations in border areas of the Greater Mekong sub-region during malaria elimination

“…Moreover, the parasite populations studied here have undergone apparent population bottlenecks, suggesting population reduction, or limited vectors or human movement within the defined geographic areas. At the CMB, the epidemic malaria transmission documented in the camps for internally displaced people and surrounding villages in 2013 and the detected reduction of effective population size may result from expansion of certain parasite isolates such as those that are resistant to the frontline treatment [77,78]. Interestingly, the TMB 2015 samples were quite genetically distinct, and even differed considerably from the 2012 parasite from the same region, which may suggest population replacement.…”