Publications by authors named "Ric Price"

Article Synopsis
  • This study investigates the effectiveness and safety of different primaquine dosing strategies in preventing relapsing Plasmodium vivax malaria in children under 15 years.
  • A systematic review was conducted, analyzing various studies involving children treated with primaquine, focusing on those who received treatment over multiple days and were followed up for at least 28 days.
  • The findings from 3514 children across 27 studies were compiled to analyze different dosing regimens, assess the risk of recurrent malaria, and evaluate tolerability and safety concerning adverse effects.
View Article and Find Full Text PDF
Article Synopsis
  • The study focuses on the effectiveness of 8-aminoquinolines (primaquine and tafenoquine) in curing Plasmodium vivax malaria by targeting hypnozoites, with a specific look at the role of methaemoglobin levels as a potential indicator for preventing malaria recurrence.
  • The researchers conducted a systematic review of clinical studies from 2000 to 2022 and examined data from 1,747 patients treated with primaquine to analyze the relationship between methaemoglobin concentration and the time to malaria recurrence.
  • Their findings suggest that higher methaemoglobin levels may correlate with a lower risk of P. vivax recurrence, indicating the potential use of methaemoglobin as
View Article and Find Full Text PDF

Challenges in classifying recurrent Plasmodium vivax infections constrain surveillance of antimalarial efficacy and transmission. Recurrent infections may arise from activation of dormant liver stages (relapse), blood-stage treatment failure (recrudescence) or reinfection. Molecular inference of familial relatedness (identity-by-descent or IBD) can help resolve the probable origin of recurrences.

View Article and Find Full Text PDF

Plasmodium vivax remains a challenge for malaria elimination since it forms dormant liver stages (hypnozoites) that can reactivate after initial infection. 8-aminoquinolone drugs kill hypnozoites but can cause severe hemolysis in individuals with Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency. The STANDARD G6PD test (Biosensor) is a novel point-of-care diagnostic capable of identifying G6PD deficiency prior to treatment.

View Article and Find Full Text PDF

Quantitative diagnosis of glucose-6-phosphate dehydrogenase (G6PD) deficiency is essential for the safe administration of 8-aminoquinoline based radical cure for the treatment of Plasmodium vivax infections. Here, we present the PreQuine Platform (IVDS, USA), a quantitative biosensor that uses a dual-analyte assay for the simultaneous measurement of Hemoglobin (Hgb) levels and G6PD enzyme activity within the same sample. The platform relies on a downloadable mobile application.

View Article and Find Full Text PDF

To combat the global burden of malaria, development of new drugs to replace or complement current therapies is urgently required. Here, we show that the compound is a selective, nanomolar inhibitor of both and aminopeptidases M1 and M17, leading to inhibition of end-stage hemoglobin digestion in asexual parasites. can kill sexual-stage , is active against murine malaria, and does not show any shift in activity against a panel of parasites resistant to other antimalarials.

View Article and Find Full Text PDF

Background: The WHO recommends routine testing of G6PD activity to guide radical cure in patients with Plasmodium vivax malaria. Females may have intermediate G6PD enzyme activity and to date, only complex diagnostics are able to reliably identify them. The semi-quantitative G6PD diagnostic "One Step G6PD Test" (Humasis, RoK; "RDT") is a lateral flow assay that can distinguish deficient, intermediate, and normal G6PD status and offers a simpler diagnostic alternative.

View Article and Find Full Text PDF

Health policy processes should be evidence-informed, transparent and timely, but these processes are often unclear to stakeholders outside the immediate policymaking environment. We spoke to 36 international malaria stakeholders to gain insights on the processes involved in the World Health Organization's Global Malaria Programme's recommendations for their treatment guidelines of P. vivax malaria.

View Article and Find Full Text PDF

Background: Plasmodium vivax remains a major challenge for malaria control and elimination due to its ability to cause relapsing illness. To prevent relapses the Indian National Center for Vector Borne Diseases Control (NCVBDC) recommends treatment with primaquine at a dose of 0.25 mg/kg/day provided over 14 days.

View Article and Find Full Text PDF

In remote communities, diagnosis of G6PD deficiency is challenging. We assessed the impact of modified test procedures and delayed testing for the point-of-care diagnostic STANDARD G6PD (SDBiosensor, RoK), and evaluated recommended cut-offs. We tested capillary blood from fingerpricks (Standard Method) and a microtainer (BD, USA; Method 1), venous blood from a vacutainer (BD, USA; Method 2), varied sample application methods (Methods 3), and used micropipettes rather than the test's single-use pipette (Method 4).

View Article and Find Full Text PDF

Background: Malaria continues to pose a significant burden in endemic countries, many of which lack access to molecular surveillance. Insights from malaria cases in travellers returning to non-endemic areas can provide valuable data to inform endemic country programmes. To evaluate the potential for novel global insights into malaria, we examined epidemiological and molecular data from imported malaria cases to Australia.

View Article and Find Full Text PDF

Background: The optimal dosing of primaquine to prevent relapsing malaria in South Asia remains unclear. We investigated the efficacy and safety of different primaquine regimens to prevent relapse.

Methods: A systematic review identified efficacy studies from South Asia published between 1 January 2000 and 23 August 2021.

View Article and Find Full Text PDF

Ethiopia has the greatest burden of Plasmodium vivax in Africa, but little is known about the epidemiological landscape of parasites across the country. We analysed the genomic diversity of 137 P. vivax isolates collected nine Ethiopian districts from 2012 to 2016.

View Article and Find Full Text PDF
Article Synopsis
  • Splenomegaly, or spleen enlargement, is commonly found in patients with malarial anemia caused by Plasmodium falciparum or P. vivax, but the reasons for this connection are not fully understood.
  • A study in Papua, Indonesia measured red blood cell (RBC) concentrations in the spleens of 37 patients, discovering that spleen size correlated positively with the amount of red-pulp and negatively with white-pulp, indicating a relationship between spleen composition and size.
  • The research revealed that retained RBCs, primarily uninfected, accounted for significant blood loss in P. falciparum infections, and this retention correlated negatively with hemoglobin levels and circulating RBC counts, highlighting the impact
View Article and Find Full Text PDF

Background: In areas co-endemic for Plasmodium vivax and Plasmodium falciparum there is an increased risk of P vivax parasitaemia following P falciparum malaria. Radical cure is currently only recommended for patients presenting with P vivax malaria. Expanding the indication for radical cure to patients presenting with P falciparum malaria could reduce their risk of subsequent P vivax parasitaemia.

View Article and Find Full Text PDF

Colombia aims to eliminate malaria by 2030 but remains one of the highest burden countries in the Americas. Plasmodium vivax contributes half of all malaria cases, with its control challenged by relapsing parasitaemia, drug resistance and cross-border spread. Using 64 Colombian P.

View Article and Find Full Text PDF

Half of all pregnancies at risk of malaria worldwide occur in the Asia-Pacific region, where Plasmodium falciparum and Plasmodium vivax co-exist. Despite substantial reductions in transmission, malaria remains an important cause of adverse health outcomes for mothers and offspring, including pre-eclampsia. Malaria transmission is heterogeneous, and infections are commonly subpatent and asymptomatic.

View Article and Find Full Text PDF

Introduction: Screening for G6PD deficiency can inform disease management including malaria. Treatment with the antimalarial drugs primaquine and tafenoquine can be guided by point-of-care testing for G6PD deficiency.

Methods And Findings: Data from similar clinical studies evaluating the performance of the STANDARD G6PD Test (SD Biosensor, South Korea) conducted in Bangladesh, Brazil, Ethiopia, India, Thailand, the United Kingdom, and the United States were pooled.

View Article and Find Full Text PDF

Background: Imperfect adherence is a major barrier to effective primaquine radical cure of Plasmodium vivax. This study investigated the effect of reduced adherence on the risk of P. vivax recurrence.

View Article and Find Full Text PDF
Article Synopsis
  • The study investigates the safety of primaquine, a medication used to eliminate dormant liver-stage parasites of Plasmodium vivax, focusing on its impact on hemolysis risk.
  • Researchers conducted a systematic review and meta-analysis of clinical studies published from 2000 to 2023, including data on patients treated with different primaquine regimens.
  • The main outcome measured was the significant reduction in hemoglobin levels (more than 25% to below 7 g/dL) by day 14 post-treatment, with analysis based on the G6PD enzyme activity levels in patients.
View Article and Find Full Text PDF

Background: Primaquine is used to eliminate Plasmodium vivax hypnozoites, but its optimal dosing regimen remains unclear. We undertook a systematic review and individual patient data meta-analysis to investigate the efficacy and tolerability of different primaquine dosing regimens to prevent P vivax recurrence.

Methods: For this systematic review and individual patient data meta-analysis, we searched MEDLINE, Web of Science, Embase, and Cochrane Central for prospective clinical studies of uncomplicated P vivax from endemic countries published between Jan 1, 2000, and June 8, 2023.

View Article and Find Full Text PDF

Background: The World Health Organization recommends that primaquine should be given once weekly for 8-weeks to patients with Plasmodium vivax malaria and glucose-6-phosphate dehydrogenase (G6PD) deficiency, but data on its antirelapse efficacy and safety are limited.

Methods: Within the context of a multicentre, randomised clinical trial of two primaquine regimens in P. vivax malaria, patients with G6PD deficiency were excluded and enrolled into a separate 12-month observational study.

View Article and Find Full Text PDF

Introduction: Symptoms reported following the administration of investigational drugs play an important role in decisions for registration and treatment guidelines. However, symptoms are subjective, and interview methods to quantify them are difficult to standardise. We explored differences in symptom reporting across study sites of a multicentre antimalarial trial, with the aim of informing trial design and the interpretation of safety and tolerability data.

View Article and Find Full Text PDF

Primaquine (PQ) kills Plasmodium vivax hypnozoites but can cause severe hemolysis in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. We conducted two systematic reviews. The first used data from clinical trials to determine the variety of definitions and frequency of hematological serious adverse events (SAEs) related to PQ treatment of vivax malaria.

View Article and Find Full Text PDF