MyMedR

Displaying all 8 publications

Abstract:

Sort:

Fulltext A study protocol for a randomised open-label clinical trial of artesunate-mefloquine versus chloroquine in patients with non-severe Plasmodium knowlesi malaria in Sabah, Malaysia (ACT KNOW trial)

Grigg MJ, William T, Dhanaraj P, Menon J, Barber BE, von Seidlein L, et al.

BMJ Open, 2014 Aug 19;4(8):e006005.
PMID: 25138814 DOI: 10.1136/bmjopen-2014-006005

INTRODUCTION: Malaria due to Plasmodium knowlesi is reported throughout South-East Asia, and is the commonest cause of it in Malaysia. P. knowlesi replicates every 24 h and can cause severe disease and death. Current 2010 WHO Malaria Treatment Guidelines have no recommendations for the optimal treatment of non-severe knowlesi malaria. Artemisinin-combination therapies (ACT) and chloroquine have each been successfully used to treat knowlesi malaria; however, the rapidity of parasite clearance has not been prospectively compared. Malaysia's national policy for malaria pre-elimination involves mandatory hospital admission for confirmed malaria cases with discharge only after two negative blood films; use of a more rapidly acting antimalarial agent would have health cost benefits. P. knowlesi is commonly microscopically misreported as P. malariae, P. falciparum or P. vivax, with a high proportion of the latter two species being chloroquine-resistant in Malaysia. A unified ACT-treatment protocol would provide effective blood stage malaria treatment for all Plasmodium species.
METHODS AND ANALYSIS: ACT KNOW, the first randomised controlled trial ever performed in knowlesi malaria, is a two-arm open-label trial with enrolments over a 2-year period at three district sites in Sabah, powered to show a difference in proportion of patients negative for malaria by microscopy at 24 h between treatment arms (clinicaltrials.gov #NCT01708876). Enrolments started in December 2012, with completion expected by September 2014. A total sample size of 228 is required to give 90% power (α 0.05) to determine the primary end point using intention-to-treat analysis. Secondary end points include parasite clearance time, rates of recurrent infection/treatment failure to day 42, gametocyte carriage throughout follow-up and rates of anaemia at day 28, as determined by survival analysis.
ETHICS AND DISSEMINATION: This study has been approved by relevant institutional ethics committees in Malaysia and Australia. Results will be disseminated to inform knowlesi malaria treatment policy in this region through peer-reviewed publications and academic presentations.
TRIAL REGISTRATION NUMBER: NCT01708876.
Fulltext Factors that are associated with the risk of acquiring Plasmodium knowlesi malaria in Sabah, Malaysia: a case-control study protocol

Grigg MJ, William T, Drakeley CJ, Jelip J, von Seidlein L, Barber BE, et al.

BMJ Open, 2014 Aug 22;4(8):e006004.
PMID: 25149186 DOI: 10.1136/bmjopen-2014-006004

INTRODUCTION: Plasmodium knowlesi has long been present in Malaysia, and is now an emerging cause of zoonotic human malaria. Cases have been confirmed throughout South-East Asia where the ranges of its natural macaque hosts and Anopheles leucosphyrus group vectors overlap. The majority of cases are from Eastern Malaysia, with increasing total public health notifications despite a concurrent reduction in Plasmodium falciparum and P. vivax malaria. The public health implications are concerning given P. knowlesi has the highest risk of severe and fatal disease of all Plasmodium spp in Malaysia. Current patterns of risk and disease vary based on vector type and competence, with individual exposure risks related to forest and forest-edge activities still poorly defined. Clustering of cases has not yet been systematically evaluated despite reports of peri-domestic transmission and known vector competence for human-to-human transmission.
METHODS AND ANALYSIS: A population-based case-control study will be conducted over a 2-year period at two adjacent districts in north-west Sabah, Malaysia. Confirmed malaria cases presenting to the district hospital sites meeting relevant inclusion criteria will be requested to enrol. Three community controls matched to the same village as the case will be selected randomly. Study procedures will include blood sampling and administration of household and individual questionnaires to evaluate potential exposure risks associated with acquisition of P. knowlesi malaria. Secondary outcomes will include differences in exposure variables between P. knowlesi and other Plasmodium spp, risk of severe P. knowlesi malaria, and evaluation of P. knowlesi case clustering. Primary analysis will be per protocol, with adjusted ORs for exposure risks between cases and controls calculated using conditional multiple logistic regression models.
ETHICS: This study has been approved by the human research ethics committees of Malaysia, the Menzies School of Health Research, Australia, and the London School of Hygiene and Tropical Medicine, UK.
Fulltext Artesunate-mefloquine versus chloroquine for treatment of uncomplicated Plasmodium knowlesi malaria in Malaysia (ACT KNOW): an open-label, randomised controlled trial

Grigg MJ, William T, Menon J, Dhanaraj P, Barber BE, Wilkes CS, et al.

Lancet Infect Dis, 2016 Feb;16(2):180-188.
PMID: 26603174 DOI: 10.1016/S1473-3099(15)00415-6

BACKGROUND: The zoonotic parasite Plasmodium knowlesi has become the most common cause of human malaria in Malaysia and is present throughout much of southeast Asia. No randomised controlled trials have been done to identify the optimum treatment for this emerging infection. We aimed to compare artesunate-mefloquine with chloroquine to define the optimum treatment for uncomplicated P knowlesi malaria in adults and children.
METHODS: We did this open-label, randomised controlled trial at three district hospitals in Sabah, Malaysia. Patients aged 1 year or older with uncomplicated P knowlesi malaria were randomly assigned, via computer-generated block randomisation (block sizes of 20), to receive oral artesunate-mefloquine (target dose 12 mg/kg artesunate and 25 mg/kg mefloquine) or chloroquine (target dose 25 mg/kg). Research nursing staff were aware of group allocation, but allocation was concealed from the microscopists responsible for determination of the primary endpoint, and study participants were not aware of drug allocation. The primary endpoint was parasite clearance at 24 h. Analysis was by modified intention to treat. This study is registered with ClinicalTrials.gov, number NCT01708876.
FINDINGS: Between Oct 16, 2012, and Dec 13, 2014, we randomly assigned 252 patients to receive either artesunate-mefloquine (n=127) or chloroquine (n=125); 226 (90%) patients comprised the modified intention-to-treat population. 24 h after treatment, we recorded parasite clearance in 97 (84% [95% CI 76-91]) of 115 patients in the artesunate-mefloquine group versus 61 (55% [45-64]) of 111 patients in the chloroquine group (difference in proportion 29% [95% CI 18·0-40·8]; p<0·0001). Parasite clearance was faster in patients given artesunate-mefloquine than in those given chloroquine (18·0 h [range 6·0-48·0] vs 24·0 h [6·0-60·0]; p<0·0001), with faster clearance of ring stages in the artesunate-mefloquine group (mean time to 50% clearance of baseline parasites 8·6 h [95% CI 7·9-9·4] vs 13·8 h [12·1-15·4]; p<0·0001). Risk of anaemia within 28 days was lower in patients in the artesunate-mefloquine group (71 [62%; 95% CI 52·2-70·6]) than in those in the chloroquine group (83 [75%; 65·6-82·5]; p=0·035). Gametocytaemia as detected by PCR for pks25 was present in 44 (86%) of 51 patients in the artesunate-mefloquine group and 41 (84%) of 49 patients in the chloroquine group at baseline, and in three (6%) of 49 patients and two (4%) of 48 patients, respectively, at day 7. Fever clearance was faster in the artesunate-mefloquine group (mean 11·5 h [95% CI 8·3-14·6]) than in the chloroquine group (14·8 h [11·7-17·8]; p=0·034). Bed occupancy was 2426 days per 1000 patients in the artesunate-mefloquine group versus 2828 days per 1000 patients in the chloroquine group (incidence rate ratio 0·858 [95% CI 0·812-0·906]; p<0·0001). One (<1%) patient in the artesunate-mefloquine group had a serious neuropsychiatric event regarded as probably related to study drug.
INTERPRETATION: Artesunate-mefloquine is highly efficacious for treatment of uncomplicated P knowlesi malaria. The rapid therapeutic response of the drug offers significant advantages compared with chloroquine monotherapy and supports a unified treatment policy for artemisinin-based combination therapy for all Plasmodium species in co-endemic areas.
FUNDING: Malaysian Ministry of Health, Australian National Health and Medical Research Council, and Asia Pacific Malaria Elimination Network.
Fulltext Trends in malaria research in 11 Asian Pacific countries: an analysis of peer-reviewed publications over two decades

Andersen F, Douglas NM, Bustos D, Galappaththy G, Qi G, Hsiang MS, et al.

Malar J, 2011 May 18;10:131.
PMID: 21586174 DOI: 10.1186/1475-2875-10-131

BACKGROUND: Quantitative data are lacking on published malaria research. The purpose of the study is to characterize trends in malaria-related literature from 1990 to 2009 in 11 Asian-Pacific countries that are committed to malaria elimination as a national goal.
METHODS: A systematic search was conducted for articles published from January 1990 to December 2009 in PubMed/MEDLINE using terms for malaria and 11 target countries (Bhutan, China, North Korea, Indonesia, Malaysia, Philippines, Solomon Islands, South Korea, Sri Lanka, Thailand and Vanuatu). The references were collated and categorized according to subject, Plasmodium species, and whether they contained original or derivative data.
RESULTS: 2,700 articles published between 1990 and 2009 related to malaria in the target countries. The annual output of malaria-related papers increased linearly whereas the overall biomedical output from these countries grew exponentially. The percentage of malaria-related publications was nearly 3% (111/3741) of all biomedical publications in 1992 and decreased to less than 1% (118/12171; p < 0.001) in 2009. Thailand had the highest absolute output of malaria-related papers (n = 1211), followed by China (n = 609) and Indonesia (n = 346). Solomon Islands and Vanuatu had lower absolute numbers of publications, but both countries had the highest number of publications per capita (1.3 and 2.5 papers/1,000 population). The largest percentage of papers concerned the epidemiology and control of malaria (53%) followed by studies of drugs and drug resistance (47%). There was an increase in the proportion of articles relating to epidemiology, entomology, biology, molecular biology, pathophysiology and diagnostics from the first to the second decade, whereas the percentage of papers on drugs, clinical aspects of malaria, immunology, and social sciences decreased.
CONCLUSIONS: The proportion of malaria-related publications out of the overall biomedical output from the 11 target Asian-Pacific countries is decreasing. The discovery and evaluation of new, safe and effective drugs and vaccines is paramount. In addition the elimination of malaria will require operational research to implement and scale up interventions.
Fulltext Individual-level factors associated with the risk of acquiring human Plasmodium knowlesi malaria in Malaysia: a case-control study

Grigg MJ, Cox J, William T, Jelip J, Fornace KM, Brock PM, et al.

Lancet Planet Health, 2017 Jun 09;1(3):e97-e104.
PMID: 28758162 DOI: 10.1016/S2542-5196(17)30031-1

BACKGROUND: The emergence of human malaria due to the monkey parasite Plasmodium knowlesi threatens elimination efforts in southeast Asia. Changes in land use are thought to be driving the rise in reported P knowlesi cases, but the role of individual-level factors is unclear. To address this knowledge gap we assessed human and environmental factors associated with zoonotic knowlesi malaria risk.
METHODS: We did this population-based case-control study over a 2 year period in the state of Sabah in Malaysia. We enrolled cases with microscopy-positive, PCR-confirmed malaria who presented to two primary referral hospitals serving the adjacent districts of Kudat and Kota Marudu. We randomly selected three malaria-negative community controls per case, who were matched by village within 2 weeks of case detection. We obtained questionnaire data on demographics, behaviour, and residential malaria risk factors, and we also assessed glucose-6-phosphate dehydrogenase (G6PD) enzyme activity. We used conditional logistic regression models to evaluate exposure risk between P knowlesi cases and controls, and between P knowlesi and human-only Plasmodium spp malaria cases.
FINDINGS: From Dec 5, 2012, to Jan 30, 2015, we screened 414 patients and subsequently enrolled 229 cases with P knowlesi malaria mono-infection and 91 cases with other Plasmodium spp infection. We enrolled 953 matched controls, including 683 matched to P knowlesi cases and 270 matched to non-P knowlesi cases. Age 15 years or older (adjusted odds ratio [aOR] 4·16, 95% CI 2·09-8·29, p<0·0001), male gender (4·20, 2·54-6·97, p<0·0001), plantation work (3·50, CI, 1·34-9·15, p=0·011), sleeping outside (3·61, 1·48-8·85, p=0·0049), travel (2·48, 1·45-4·23, p=0·0010), being aware of the presence of monkeys in the past 4 weeks (3·35, 1·91-5·88, p<0·0001), and having open eaves or gaps in walls (2·18, 1·33-3·59, p=0·0021) were independently associated with increased risk of symptomatic P knowlesi infection. Farming occupation (aOR 1·89, 95% CI 1·07-3·35, p=0·028), clearing vegetation (1·89, 1·11-3·22, p=0·020), and having long grass around the house (2·08, 1·25-3·46, p=0·0048) increased risk for P knowlesi infection but not other Plasmodium spp infection. G6PD deficiency seemed to be protective against P knowlesi (aOR 0·20, 95% CI 0·04-0·96, p=0·045), as did residual insecticide spraying of household walls (0·52, 0·31-0·87, p=0·014), with the presence of young sparse forest (0·35, 0·20-0·63, p=00040) and rice paddy around the house (0·16, 0·03-0·78, 0·023) also associated with decreased risk.
INTERPRETATION: Adult men working in agricultural areas were at highest risk of knowlesi malaria, although peri-domestic transmission also occurrs. Human behavioural factors associated with P knowlesi transmission could be targeted in future public health interventions.
FUNDING: United Kingdom Medical Research Council, Natural Environment Research Council, Economic and Social Research Council, and Biotechnology and Biosciences Research Council.
Fulltext Plasmodium vivax population structure and transmission dynamics in Sabah Malaysia

Abdullah NR, Barber BE, William T, Norahmad NA, Satsu UR, Muniandy PK, et al.

PLoS One, 2013;8(12):e82553.
PMID: 24358203 DOI: 10.1371/journal.pone.0082553

Despite significant progress in the control of malaria in Malaysia, the complex transmission dynamics of P. vivax continue to challenge national efforts to achieve elimination. To assess the impact of ongoing interventions on P. vivax transmission dynamics in Sabah, we genotyped 9 short tandem repeat markers in a total of 97 isolates (8 recurrences) from across Sabah, with a focus on two districts, Kota Marudu (KM, n = 24) and Kota Kinabalu (KK, n = 21), over a 2 year period. STRUCTURE analysis on the Sabah-wide dataset demonstrated multiple sub-populations. Significant differentiation (F ST = 0.243) was observed between KM and KK, located just 130 Km apart. Consistent with low endemic transmission, infection complexity was modest in both KM (mean MOI = 1.38) and KK (mean MOI = 1.19). However, population diversity remained moderate (H E = 0.583 in KM and H E = 0.667 in KK). Temporal trends revealed clonal expansions reflecting epidemic transmission dynamics. The haplotypes of these isolates declined in frequency over time, but persisted at low frequency throughout the study duration. A diverse array of low frequency isolates were detected in both KM and KK, some likely reflecting remnants of previous expansions. In accordance with clonal expansions, high levels of Linkage Disequilibrium (I A (S) >0.5 [P<0.0001] in KK and KM) declined sharply when identical haplotypes were represented once (I A (S) = 0.07 [P = 0.0076] in KM, and I A (S) = -0.003 [P = 0.606] in KK). All 8 recurrences, likely to be relapses, were homologous to the prior infection. These recurrences may promote the persistence of parasite lineages, sustaining local diversity. In summary, Sabah's shrinking P. vivax population appears to have rendered this low endemic setting vulnerable to epidemic expansions. Migration may play an important role in the introduction of new parasite strains leading to epidemic expansions, with important implications for malaria elimination.
Fulltext The challenges of introducing routine G6PD testing into radical cure: a workshop report

Ley B, Luter N, Espino FE, Devine A, Kalnoky M, Lubell Y, et al.

Malar J, 2015 Sep 29;14:377.
PMID: 26416229 DOI: 10.1186/s12936-015-0896-8

The only currently available drug that effectively removes malaria hypnozoites from the human host is primaquine. The use of 8-aminoquinolines is hampered by haemolytic side effects in glucose-6-phosphate dehydrogenase (G6PD) deficient individuals. Recently a number of qualitative and a quantitative rapid diagnostic test (RDT) format have been developed that provide an alternative to the current standard G6PD activity assays. The WHO has recently recommended routine testing of G6PD status prior to primaquine radical cure whenever possible. A workshop was held in the Philippines in early 2015 to discuss key challenges and knowledge gaps that hinder the introduction of routine G6PD testing. Two point-of-care (PoC) test formats for the measurement of G6PD activity are currently available: qualitative tests comparable to malaria RDT as well as biosensors that provide a quantitative reading. Qualitative G6PD PoC tests provide a binomial test result, are easy to use and some products are comparable in price to the widely used fluorescent spot test. Qualitative test results can accurately classify hemizygous males, heterozygous females, but may misclassify females with intermediate G6PD activity. Biosensors provide a more complex quantitative readout and are better suited to identify heterozygous females. While associated with higher costs per sample tested biosensors have the potential for broader use in other scenarios where knowledge of G6PD activity is relevant as well. The introduction of routine G6PD testing is associated with additional costs on top of routine treatment that will vary by setting and will need to be assessed prior to test introduction. Reliable G6PD PoC tests have the potential to play an essential role in future malaria elimination programmes, however require an improved understanding on how to best integrate routine G6PD testing into different health settings.
Fulltext Challenges for achieving safe and effective radical cure of Plasmodium vivax: a round table discussion of the APMEN Vivax Working Group

Thriemer K, Ley B, Bobogare A, Dysoley L, Alam MS, Pasaribu AP, et al.

Malar J, 2017 04 05;16(1):141.
PMID: 28381261 DOI: 10.1186/s12936-017-1784-1

The delivery of safe and effective radical cure for Plasmodium vivax is one of the greatest challenges for achieving malaria elimination from the Asia-Pacific by 2030. During the annual meeting of the Asia Pacific Malaria Elimination Network Vivax Working Group in October 2016, a round table discussion was held to discuss the programmatic issues hindering the widespread use of primaquine (PQ) radical cure. Participants included 73 representatives from 16 partner countries and 33 institutional partners and other research institutes. In this meeting report, the key discussion points are presented and grouped into five themes: (i) current barriers for glucose-6-phosphate deficiency (G6PD) testing prior to PQ radical cure, (ii) necessary properties of G6PD tests for wide scale deployment, (iii) the promotion of G6PD testing, (iv) improving adherence to PQ regimens and (v) the challenges for future tafenoquine (TQ) roll out. Robust point of care (PoC) G6PD tests are needed, which are suitable and cost-effective for clinical settings with limited infrastructure. An affordable and competitive test price is needed, accompanied by sustainable funding for the product with appropriate training of healthcare staff, and robust quality control and assurance processes. In the absence of quantitative PoC G6PD tests, G6PD status can be gauged with qualitative diagnostics, however none of the available tests is currently sensitive enough to guide TQ treatment. TQ introduction will require overcoming additional challenges including the management of severely and intermediately G6PD deficient individuals. Robust strategies are needed to ensure that effective treatment practices can be deployed widely, and these should ensure that the caveats are outweighed by the benefits of radical cure for both the patients and the community. Widespread access to quality controlled G6PD testing will be critical.