Jariyanart Gaywee

Bio: Jariyanart Gaywee is an academic researcher. The author has contributed to research in topics: Malaria. The author has an hindex of 1, co-authored 1 publications receiving 16 citations.

Malaria ecology along the Thailand–Myanmar border

Abstract: Malaria in Southeast Asia frequently clusters along international borders. For example, while most of Thailand is malaria free, the border region shared with Myanmar continues to have endemic malaria. This spatial pattern is the result of complex interactions between landscape, humans, mosquito vectors, and malaria parasites. An understanding of these complex ecological and socio-cultural interactions is important for designing and implementing malaria elimination efforts in the region. This article offers an ecological perspective on the malaria situation along the Thailand–Myanmar border. This border region is long (2000 km), mountainous, and the environment ranges from thick forests to growing urban settlements and wet-rice fields. It is also a biologically diverse region. All five species of malaria known to naturally infect humans are present. At least three mosquito vector species complexes, with widely varying behavioural characteristics, exist in the area. The region is also a hub for ethnic diversity, being home to over ten different ethnolinguistic groups, several of which have been engaged in conflict with the Myanmar government now for over half a century. Given the biological and ethnic diversity, as well as the complex socio-political context, malaria control and elimination in the region is challenging. Despite these complexities, multipronged approaches including collaborations with multiple local organizations, quick access to diagnosis and treatment, prevention of mosquito bites, radical cure of parasites, and mass drug administration appear to be drastically decreasing Plasmodium falciparum infections. Such approaches remain crucial as the region moves toward elimination of P. falciparum and potentially Plasmodium vivax.

Atovaquone-Proguanil in Combination With Artesunate to Treat Multidrug-Resistant P. falciparum Malaria in Cambodia: An Open-Label Randomized Trial.

Abstract: Background Recent artemisinin-combination therapy failures in Cambodia prompted a search for alternatives. Atovaquone-proguanil (AP), a safe, effective treatment for multidrug-resistant Plasmodium falciparum (P.f.), previously demonstrated additive effects in combination with artesunate (AS). Methods Patients with P.f. or mixed-species infection (n = 205) in Anlong Veng (AV; n = 157) and Kratie (KT; n = 48), Cambodia, were randomized open-label 1:1 to a fixed-dose 3-day AP regimen +/-3 days of co-administered artesunate (ASAP). Single low-dose primaquine (PQ, 15 mg) was given on day 1 to prevent gametocyte-mediated transmission. Results Polymerase chain reaction-adjusted adequate clinical and parasitological response at 42 days was 90% for AP (95% confidence interval [CI], 82%-95%) and 92% for ASAP (95% CI, 83%-96%; P = .73). The median parasite clearance time was 72 hours for ASAP in AV vs 56 hours in KT (P < .001) and was no different than AP alone. At 1 week postprimaquine, 7% of the ASAP group carried microscopic gametocytes vs 29% for AP alone (P = .0001). Nearly all P.f. isolates had C580Y K13 propeller artemisinin resistance mutations (AV 99%; KT 88%). Only 1 of 14 treatment failures carried the cytochrome bc1 (Pfcytb) atovaquone resistance mutation, which was not present at baseline. P.f. isolates remained atovaquone sensitive in vitro but cycloguanil resistant, with a triple P.f. dihydrofolate reductase mutation. Conclusions Atovaquone-proguanil remained marginally effective in Cambodia (≥90%) with minimal Pfcytb mutations observed. Treatment failures in the presence of ex vivo atovaquone sensitivity and adequate plasma levels may be attributable to cycloguanil and/or artemisinin resistance. Artesunate co-administration provided little additional blood-stage efficacy but reduced post-treatment gametocyte carriage in combination with AP beyond single low-dose primaquine.

Significance of training, monitoring and assessment of malaria workers in achieving malaria elimination goal of Malaria Elimination Demonstration Project.

Abstract: The Malaria Elimination Demonstration Project (MEDP) maintained a workforce of 235 Village Malaria Workers (VMWs) and 25 Malaria Field Coordinators (MFCs) to conduct disease surveillance, case management, IEC/BCC activities, capacity building, and monitoring of vector control activities in 1233 villages of Mandla, a high malaria endemic district of Madhya Pradesh in central India. The induction training was conducted for 3 days on malaria diagnosis, treatment, prevention, and ethics. All trainings were assessed using a pre and post-training assessment questionnaire, with 70% marks as qualifying threshold. The questionnaire was divided into three thematic areas viz. general knowledge related to malaria (KAP), diagnosis and treatment (DXRX), and vector control (PVC). In 2017, the project trained 330 candidates, followed by 243 and 247 candidates in 2018 and 2019, respectively. 94.3% candidates passed after a single training session. Almost all (95%) candidates showed improvement in knowledge after the training with 4% showing no effect and 1% showing deterioration. Progressive improvement in scores of 2017 cohort was seen along with significant improvement in performance of candidates in 2019 after the introduction of systematic monitoring and ‘shadowing’ training exercises. The project has successfully demonstrated the value of recruitment of workers from the study area, outcome of training, and performance evaluation of field staff in malaria elimination programme. This careful strategy of recruitment and training resulted in a work-force that was capable of independently conducting surveillance, case management, vector control, and Information Education Communication/Behaviour Change Communication (IEC/BCC). The learnings of this study, including the training modules and monitoring processes, can be used to train the health delivery staff for achieving national goal for malaria elimination by 2030. Similar training and monitoring programmes could also be used for other public health delivery programmes.

Malaria prevalence, knowledge, perception, preventive and treatment behavior among military in Champasak and Attapeu provinces, Lao PDR: a mixed methods study

Abstract: Malaria is a major health problem in Lao People’s Democratic Republic (Lao PDR) with high transmission in remote and forest areas, particularly in the South. The military is at risk of malaria infection especially those deployed in forest areas. This study determined the prevalence of malaria infection and assessed knowledge, perception, and preventive and treatment behavior regarding malaria among military personnel in two southern provinces in Lao PDR. Quantitative and qualitative approaches were undertaken in Champasak and Attapeu provinces in 2017. From 313 military personnel, quantitative data were collected through questionnaire-based interviews and blood samples used for parasite detection by polymerase chain reaction (PCR). Qualitative data were collected through 7 focus group discussions and 17 in-depth interviews among 49 military personnel. Fisher’s exact test and Mann-Whitney U test were used to assess the association between malaria infection and participant characteristics. Content analysis for qualitative data was performed to explore perception and treatment behaviors regarding malaria. The prevalence of malaria infection was 11.2% (Plasmodium falciparum: 1.3%, Plasmodium vivax: 9.3% and mixed infections: 0.6%). Many participants understood that malaria is transmitted through mosquito bites, although they did not necessarily know the name of vector mosquitoes (Anopheles). Surprisingly, more than a half also believed that malaria is transmitted through drinking stream water. One-third of the participants used long-lasting insecticidal nets. Due to limited supply, participants were often unable to use mosquito repellent and coils when necessary. Because participants were unable to receive timely diagnosis and appropriate treatment for malaria in their camps, they commonly practiced self-treatment using antibiotics, painkillers, and/or traditional medicines. They only go to a healthcare facility through their supervisor if their conditions worsen. The prevalence of symptomatic and asymptomatic malaria was conspicuous among military in forest areas. Many participants believed that malaria is transmitted not only by mosquito bites but also from drinking stream water. Preventive equipment was often insufficient. Self-treatment was practiced before referring to healthcare facility. To further prevent military from contracting malaria, the National Malaria Control Program and military body should provide adequate and suitable health education, protective equipment, and on-site malaria case management.

Combination therapies for malaria are failing--what next?

Abstract: Antimalarial drug resistance in southeast Asia has reached a critical new level in the past year. In The Lancet Infectious Diseases, Chanaki Amaratunga and colleagues present what is now the third report of signifi cant clinical failure of dihydroartemisinin–piperaquine in Cambodia. In a meticulous study of adults in three geographically distinct provinces, they found that resistance is not evenly distributed, seemingly worst in the western province of Pursat. They link treatment failure with both the presence of kelch13 resistance mutations and in vitro piperaquine resistance, although both were uncommon in northern and eastern provinces in their study. In addition, their reports of com plementary patterns of markers of molecular resistance for piperaquine and mefl oquine accord with earlier reports suggesting that reversion to treatment with mefl oquine or even combinations including both mefl oquine and piperaquine may be eff ective. These latter fi ndings should not be cause for complacency however, given that clinical dihydroartemisinin–piperaquine failure has appeared in only a few years. The high proportions of patients with detectable concentrations of piperaquine at enrolment evidenced here and elsewhere, suggest that insuffi cient treatment might be to blame. Although some progress has been made in combating counterfeit drugs, continued reliance on the private sector to supply antimalarial drugs in Cambodia raises several challenges. Although reversion to mefl oquine combination therapies might serve as a temporary solution, failures of artesunate–mefl oquine in Cambodia have been reported as recently as 2009. Resistance to mefl oquine is likely to return quickly now that artesunate–mefl oquine has replaced dihydroartemisinin–piperaquine as the fi rstline treatment in areas where resistance to artemisinin is common in Cambodian treatment guidelines. Although triple therapies combining mefl oquine and piperaquine with an artemisinin could ultimately prove eff ective, the potential for simultaneously compromising both drugs and potential safety concerns have yet to be evaluated in monitored settings. Unfavourable fi ndings in such studies would argue for rotation of therapies, but this could prove logistically challenging. There are few remaining alternative regimens available. Atovaquone–proguanil has been used in selected areas of Cambodia with limited success, although its expense and modelling data showing that resistance could emerge quickly argue against its widespread use. Artesunate–pyronaridine has been introduced in Cambodia in the past year, but when it was fi rst trialled in Cambodia in 2007, treatment failures occurred in substantial proportions of patients. New drugs in development are still at least several years away from clinical use. Although the research community has kept pace by conducting high-quality studies to defi ne and monitor the extent of the problem, practical approaches to stem the rising tide of resistance are less apparent. Successful implementation of novel drug combinations will require improved regulation of antimalarial drugs, greater fl exibility of drug procurement and distribution networks, and an enhanced public health response. A potentially eff ective though seldom-discussed approach would be to admit to hospital all patients with malaria in Cambodia, ensuring directly observed adherence to treatment. Such a strategy is already used in Cambodia’s long-established tuberculosis control programme, in which active case detection coupled with directly observed therapy is both feasible and cost eff ective. We and colleagues have described the involvement of regional militaries in malaria elimination, highlighting the Philippine military’s success with mandated hospital admission to ensure adequate treatment, which has coincided with falling incidence. This approach should be considered in Cambodia, where the number of patients with malaria has declined rapidly over the past decade. Universal inpatient treatment for malaria might now be attainable, particularly given the far shorter length of stay needed compared with tuberculosis treatment. Directly observed inpatient treatment would not only reduce the selection pressure for resistance arising from inadequate treatment, but would enable confi rmation of parasitological cure before discharge. It would also reduce transmission by enabling haemolytic safety monitoring of primaquine treatment, and sequester patients in discrete locations where concentrated vector control measures could be applied while they recover. Combining this approach with an active follow-up Lancet Infect Dis 2016