Risk factors associated with slide positivity among febrile patients in a conflict zone of north-eastern Myanmar along the China-Myanmar border

Li, Nana; Parker, Daniel M.; Yang, Zhaoqing; Fan, Qi; Zhou, Guofa; Ai, Guoping; Jian-hua, Duan; Lee, Ming‐Chieh; Yan, Guiyun; Matthews, Stephen A.; Cui, Liwang; Wang, Ying

doi:10.1186/1475-2875-12-361

Cited by 40 publications

(56 citation statements)

References 22 publications

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“…At our study site, we noticed a significant portion (76.63%) of the patients were children 15 years old and younger (20). Consequently, children were more likely to have recurrent vivax parasitemia during the follow-up.…”

Section: Discussionmentioning

confidence: 86%

“…In this subtropical region, malaria is hypoendemic, with an annual parasite incidence of ϳ57 per 1,000 people/year. Malaria transmission is seasonal, peaking in June to September, coincident with the rainiest months (20).…”

Section: Methodsmentioning

confidence: 99%

“…The study was conducted between March 2012 and December 2013 in two camps for internally displaced people, one nearby hospital, and four surrounding villages near Laiza City, Kachin State, Myanmar, along the China-Myanmar border (97.56°E, 24.75°N) (20). The camps were established in 2010 as a consequence of internal military conflict.…”

Section: Methodsmentioning

confidence: 99%

“…Currently, CQ and PQ remain the frontline therapy for vivax malaria in Myanmar. As in other regions of the GMS acting aggressively against becoming an area where falciparum malaria is endemic, the area of northeast Myanmar bordering China's Yunnan province experienced a significant increase in the prevalence of vivax malaria (20). This occurred despite ramped up control measures.…”

mentioning

confidence: 99%

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Therapeutic Responses of Plasmodium vivax Malaria to Chloroquine and Primaquine Treatment in Northeastern Myanmar

Yuan

Wang

Parker

et al. 2015

Antimicrob Agents Chemother

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h Chloroquine-primaquine (CQ-PQ) continues to be the frontline therapy for radical cure of Plasmodium vivax malaria. Emergence of CQ-resistant (CQR) P. vivax parasites requires a shift to artemisinin combination therapies (ACTs), which imposes a significant financial, logistical, and safety burden. Monitoring the therapeutic efficacy of CQ is thus important. Here, we evaluated the therapeutic efficacy of CQ-PQ for P. vivax malaria in northeast Myanmar. We recruited 587 patients with P. vivax monoinfection attending local malaria clinics during 2012 to 2013. These patients received three daily doses of CQ at a total dose of 24 mg of base/kg of body weight and an 8-day PQ treatment (0.375 mg/kg/day) commencing at the same time as the first CQ dose. Of the 401 patients who finished the 28-day follow-up, the cumulative incidence of recurrent parasitemia was 5.20% (95% confidence interval [CI], 3.04% to 7.36%). Among 361 (61%) patients finishing a 42-day follow-up, the cumulative incidence of recurrent blood-stage infection reached 7.98% (95% CI, 5.20% to 10.76%). The cumulative risk of gametocyte carriage at days 28 and 42 was 2.21% (95% CI, 0.78% to 3.64%) and 3.93% (95% CI, 1.94% to 5.92%), respectively. Interestingly, for all 15 patients with recurrent gametocytemia, this was associated with concurrent asexual stages. Genotyping of recurrent parasites at the merozoite surface protein 3␣ gene locus from 12 patients with recurrent parasitemia within 28 days revealed that 10 of these were the same genotype as at day 0, suggesting recrudescence or relapse. Similar studies in 70 patients in the same area in 2007 showed no recurrent parasitemias within 28 days. The sensitivity to chloroquine of P. vivax in northeastern Myanmar may be deteriorating. Plasmodium vivax has the widest geographical distribution among the four human-infecting species, stretching from the Korean Peninsula to northern Argentina. An estimated 2.48 billion people lived at risk of P. vivax malaria in 2010, of which a large majority was in Central and Southeast Asia (1). Each year, P. vivax infects an estimated 130 to 391 million people (2, 3). Past eradication campaigns have witnessed the resilience of vivax malaria to control efforts. In areas where P. vivax and P. falciparum are coendemic, intensified control efforts have led to major changes in malaria epidemiology, and the problem of vivax malaria has become more prominent (4). With emerging global interests in malaria elimination (5), many nations in which vivax malaria is endemic will inevitably face greater challenges for the control and elimination of this parasite. For example, among the 34 malariaeliminating countries, 26 have malaria burdens mainly or solely due to P. vivax (4).The relative resilience of vivax malaria may be attributed to the formation of dormant hypnozoites in the livers of patients. These hypnozoites awaken in the weeks and months following a primary attack and cause new attacks, called relapses. Thus, treatment of P. vivax malaria requires drugs that target both the ...

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Section: Discussionmentioning

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Therapeutic Responses of Plasmodium vivax Malaria to Chloroquine and Primaquine Treatment in Northeastern Myanmar

Yuan

Wang

Parker

et al. 2015

Antimicrob Agents Chemother

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“…20 Outpatients of falciparum malaria were treated with DP, and parasite clearance and clinical efficacy were determined. Our data confirmed the excellent clinical efficacy of this drug combination, and also revealed information about delayed parasite clearance.…”

Section: Introductionmentioning

confidence: 99%

Clinical Efficacy of Dihydroartemisinin–Piperaquine for the Treatment of Uncomplicated Plasmodium falciparum Malaria at the China–Myanmar Border

Wang¹,

Yang²,

Yuan³

et al. 2015

The American Society of Tropical Medicine and Hygiene

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Abstract. Artemisinin-based combination therapies (ACTs) are currently used as the first-line therapy for uncomplicated Plasmodium falciparum malaria. However, the recent emergence and/or spread of artemisinin resistance in parts of Greater Mekong Subregion (GMS) of southeast Asia requires close monitoring of the therapeutic efficacy of ACTs. This study was conducted from March 2012 to December 2013 in four clinics and seven villages along the China-Myanmar border. A total of 109 patients with uncomplicated falciparum malaria were treated with dihydroartemisinin-piperaquine (DP) and followed up on days 1, 2, 3, 7, 14, 21, 28, and 42 after treatment. A total of 71 patients (22 children and 49 adults) completed the 42-day follow-up. DP remained highly efficacious for treatment of uncomplicated falciparum malaria with an overall 42-day cure rate of 100%. The day 3 parasite-positive rate was 7.04% (5/71). Within 14 days of treatment, a total of 13 (18.31%) patients had detectable gametocytes and a large proportion of these were persistent from the first three days of treatment. The presence of gametocytes in patients through 14 days after DP treatment suggests that the incorporation of a single dose of primaquine for clearing gametocytemia should be considered for blocking parasite transmission.

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A more appropriate white blood cell count for estimating malaria parasite density in Plasmodium vivax patients in northeastern Myanmar

et al. 2016

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The conventional method of estimating parasite densities employs an assumption of 8000 white blood cells (WBCs)/µl. However, due to leucopenia in malaria patients, this number appears to overestimate parasite densities. In this study, we assessed the accuracy of parasite density estimated using this assumed WBC count in eastern Myanmar, where Plasmodium vivax has become increasingly prevalent. From 256 patients with uncomplicated P. vivax malaria, we estimated parasite density and counted WBCs by using an automated blood cell counter. It was found that WBC counts were not significantly different between patients of different gender, axillary temperature, and body mass index levels, whereas they were significantly different between age groups of patients and the time points of measurement. The median parasite densities calculated with the actual WBC counts (1,903/µl) and the assumed WBC count of 8,000/µl (2,570/µl) were significantly different. We demonstrated that using the assumed WBC count of 8000 cells/µl to estimate parasite densities of P. vivax malaria patients in this area would lead to an overestimation. For P. vivax patients aged five years and older, an assumed WBC count of 5,500/µl best estimated parasite densities. This study provides more realistic assumed WBC counts for estimating parasite densities in P. vivax patients from low-endemicity areas of Southeast Asia.

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Risk factors associated with slide positivity among febrile patients in a conflict zone of north-eastern Myanmar along the China-Myanmar border

Cited by 40 publications

References 22 publications

Therapeutic Responses of Plasmodium vivax Malaria to Chloroquine and Primaquine Treatment in Northeastern Myanmar

Therapeutic Responses of Plasmodium vivax Malaria to Chloroquine and Primaquine Treatment in Northeastern Myanmar

Clinical Efficacy of Dihydroartemisinin–Piperaquine for the Treatment of Uncomplicated Plasmodium falciparum Malaria at the China–Myanmar Border

A more appropriate white blood cell count for estimating malaria parasite density in Plasmodium vivax patients in northeastern Myanmar

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