Acquired thrombotic thrombocytopenic purpura in a patient with plasmodium vivax malaria: A case report.

Acquired thrombotic thrombocytopenic purpura (TTP) is a rare life-threatening disorder characterized by microangiopathic hemolytic anemia, severe thrombocytopenia, and organ damage. We present the case of a 71-year-old man initially diagnosed with malaria-like symptoms and displaying markers of microangiopathic hemolytic anemia, severe thrombocytopenia, renal injury, and neurological impairment. Despite antimalarial treatment, acquired TTP was suspected. Plasma exchange and immunosuppressive therapy led to clinical improvement, normalizing the platelet count and hemolytic profile. Diagnostic confirmation revealed significantly reduced ADAMTS13 levels. Following the proposed treatment, the patient's ADAMTS13 levels normalized. This case illustrates acquired TTP linked to uncomplicated Plasmodium vivax malaria.

Contextual factors and G6PD diagnostic testing: a scoping review and evidence and gap map.

BACKGROUND: Testing for glucose-6-phosphate dehydrogenase (G6PD) deficiency is an important consideration regarding treatment for malaria. G6PD deficiency may lead to haemolytic anaemia during malaria treatment and, therefore, determining G6PD deficiency in malaria treatment strategies is extremely important. METHODS: This report presents the results of a scoping review and evidence and gap map for consideration by the Guideline Development Group for G6PD near patient tests to support radical cure of Plasmodium vivax. This scoping review has investigated common diagnostic tests for G6PD deficiency and important contextual and additional factors for decision-making. These factors include six of the considerations recommended by the World Health Organization (WHO) handbook for guideline development as important to determining the direction and strength of a recommendation, and included 'acceptability', 'feasibility,' 'equity,' 'valuation of outcomes,' 'gender' and 'human rights'. The aim of this scoping review is to inform the direction of future systematic reviews and evidence syntheses, which can then better inform the development of WHO recommendations regarding the use of G6PD deficiency testing as part of malaria treatment strategies. RESULTS: A comprehensive search was performed, including published, peer-reviewed literature for any article, of any study design and methodology that investigated G6PD diagnostic tests and the factors of 'acceptability', 'feasibility,' 'equity,' 'valuation of outcomes,' 'gender' and 'human rights'. There were 1152 studies identified from the search, of which 14 were determined to be eligible for inclusion into this review. The studies contained data from over 21 unique countries that had considered G6PD diagnostic testing as part of a malaria treatment strategy. The relationship between contextual and additional factors, diagnostic tests for G6PD deficiency and study methodology is presented in an overall evidence and gap, which showed that majority of the evidence was for the contextual factors for diagnostic tests, and the 'Standard G6PD (SD Biosensor)' test. CONCLUSIONS: This scoping review has produced a dynamic evidence and gap map that is reactive to emerging evidence within the field of G6PD diagnostic testing. The evidence and gap map has provided a comprehensive depiction of all the available literature that address the contextual and additional factors important for decision-making, regarding specific G6PD diagnostic tests. The majority of data available investigating the contextual factors of interest relates to quantitative G6PD diagnostic tests. While a formal qualitative synthesis of this data as part of a systematic review is possible, the data may be too heterogenous for this to be appropriate. These results can now be used to inform future direction of WHO Guideline Development Groups for G6PD near patient tests to support radical cure of P. vivax malaria.

Detection through the use of RT-MqPCR of asymptomatic reservoirs of malaria in samples of patients from the indigenous Comarca of Guna Yala, Panama: Essential method to achieve the elimination of malaria.

BACKGROUND: Plasmodium vivax is the main causative agent of malaria in Panama. However, the prevalence of asymptomatic infections in the different endemic regions remains unknown. Understanding the epidemiological behavior of asymptomatic infections is essential for the elimination of malaria. This study aimed to determine the prevalence of asymptomatic malarial infections in one of the main endemic regions of Panama using multiplex real-time reverse transcription RT-MqPCR. METHODS: A cross-sectional study was conducted in three communities in the Guna Yala Comarca. A total of 551 thick blood smears and their respective samples on filter paper were collected from volunteers of different ages and sexes from June 20 to 25, 2016. Infections by the Plasmodium spp. were diagnosed using microscopy and RT-MqPCR. All statistical analyses were performed using the R software. RESULTS: The average prevalence of asymptomatic infections by P. vivax in the three communities detected by RT-MqPCR was 9.3%, with Ukupa having the highest prevalence (13.4%), followed by Aidirgandi (11.1%) and Irgandi (3.3%). A total of 74 samples were diagnosed as asymptomatic infections using RT-MqPCR. Light microscopy (LM) detected that 17.6% (13/74) of the asymptomatic samples and 82.4% (61/74) were diagnosed as false negatives. A 100% correlation was observed between samples diagnosed using LM and RT-MqPCR. A total of 52.7% (39/74) of the asymptomatic patients were female and 85.1% (63/74) were registered between the ages of 1 and 21 years. Factors associated with asymptomatic infection were community (aOR = 0.38 (95% CI 0.17-0.83), p < 0.001) and age aOR = 0.98 (95% CI 0.97-1.00), p < 0.05); F = 5.38; p < 0.05). CONCLUSIONS: This study provides novel evidence of the considerable prevalence of asymptomatic P. vivax infections in the endemic region of Kuna Yala, representing a new challenge that requires immediate attention from the National Malaria Program. The results of this study provide essential information for the health authorities responsible for developing new policies. Furthermore, it will allow program administrators to reorient and design effective malaria control strategies that consider asymptomatic infections as a fundamental part of malaria control and move towards fulfilling their commitment to eliminate it.

Identification and serological responses to a novel Plasmodium vivax merozoite surface protein 1 (PvMSP-1) derived synthetic peptide: a putative biomarker for malaria exposure.

Background: The integration of diagnostic methods holds promise for advancing the surveillance of malaria transmission in both endemic and non-endemic regions. Serological assays emerge as valuable tools to identify and delimit malaria transmission, serving as a complementary method to rapid diagnostic tests (RDT) and thick smear microscopy. Here, we evaluate the potential of antibodies directed against peptides encompassing the entire amino acid sequence of the PvMSP-1 Sal-I strain as viable serological biomarkers for P. vivax exposure. Methods: We screened peptides encompassing the complete amino acid sequence of the Plasmodium vivax Merozoite Surface Protein 1 (PvMSP-1) Sal-I strain as potential biomarkers for P. vivax exposure. Here, immunodominant peptides specifically recognized by antibodies from individuals infected with P. vivax were identified using the SPOT-synthesis technique followed by immunoblotting. Two 15-mer peptides were selected based on their higher and specific reactivity in immunoblotting assays. Subsequently, peptides p70 and p314 were synthesized in soluble form using SPPS (Solid Phase Peptide Synthesis) and tested by ELISA (IgG, and subclasses). Results: This study unveils the presence of IgG antibodies against the peptide p314 in most P. vivax-infected individuals from the Brazilian Amazon region. In silico B-cell epitope prediction further supports the utilization of p314 as a potential biomarker for evaluating malaria transmission, strengthened by its amino acid sequence being part of a conserved block of PvMSP-1. Indeed, compared to patients infected with P. falciparum and uninfected individuals never exposed to malaria, P. vivax-infected patients have a notably higher recognition of p314 by IgG1 and IgG3.

Detection of Duffy blood group genotypes and submicroscopic Plasmodium infections using molecular diagnostic assays in febrile malaria patients.

BACKGROUND: Malaria remains a severe parasitic disease, posing a significant threat to public health and hindering economic development in sub-Saharan Africa. Ethiopia, a malaria endemic country, is facing a resurgence of the disease with a steadily rising incidence. Conventional diagnostic methods, such as microscopy, have become less effective due to low parasite density, particularly among Duffy-negative human populations in Africa. To develop comprehensive control strategies, it is crucial to generate data on the distribution and clinical occurrence of Plasmodium vivax and Plasmodium falciparum infections in regions where the disease is prevalent. This study assessed Plasmodium infections and Duffy antigen genotypes in febrile patients in Ethiopia. METHODS: Three hundred febrile patients visiting four health facilities in Jimma town of southwestern Ethiopia were randomly selected during the malaria transmission season (Apr-Oct). Sociodemographic information was collected, and microscopic examination was performed for all study participants. Plasmodium species and parasitaemia as well as the Duffy genotype were assessed by quantitative polymerase chain reaction (qPCR) for all samples. Data were analysed using Fisher's exact test and kappa statistics. RESULTS: The Plasmodium infection rate by qPCR was 16% (48/300) among febrile patients, of which 19 (39.6%) were P. vivax, 25 (52.1%) were P. falciparum, and 4 (8.3%) were mixed (P. vivax and P. falciparum) infections. Among the 48 qPCR-positive samples, 39 (13%) were negative by microscopy. The results of bivariate logistic regression analysis showed that agriculture-related occupation, relapse and recurrence were significantly associated with Plasmodium infection (P < 0.001). Of the 300 febrile patients, 85 (28.3%) were Duffy negative, of whom two had P. vivax, six had P. falciparum, and one had mixed infections. Except for one patient with P. falciparum infection, Plasmodium infections in Duffy-negative individuals were all submicroscopic with low parasitaemia. CONCLUSIONS: The present study revealed a high prevalence of submicroscopic malaria infections. Plasmodium vivax infections in Duffy-negative individuals were not detected due to low parasitaemia. In this study, an improved molecular diagnostic tool was used to detect and characterize Plasmodium infections, with the goal of quantifying P. vivax infection in Duffy-negative individuals. Advanced molecular diagnostic techniques, such as multiplex real-time PCR, loop-mediated isothermal amplification (LAMP), and CRISPR-based diagnostic methods. These techniques offer increased sensitivity, specificity, and the ability to detect low-parasite-density infections compared to the employed methodologies.

The PreQuine Platform: A novel diagnostic tool for measuring glucose-6-phosphate dehydrogenase (G6PD) activity and hemoglobin concentration.

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. The device requires 10µl of whole blood and works with a reflectance-based meter. Comparing the G6PD measurement normalized by Hgb of 12 samples from the PreQuine Platform with reference measurements methods (spectrophotometry, Pointe Scientific, USA and hemoglobin meter, HemoCue, Sweden) showed a positive and significant agreement with a slope of 1.0091 and an intercept of -0.0379 under laboratory conditions. Next steps will be to conduct field trials in Bangladesh, Cambodia, and the USA to assess diagnostic performance, user friendliness and acceptance.

Autochthonous Plasmodium vivax Infections, Florida, USA, 2023.

During May-July 2023, a cluster of 7 patients at local hospitals in Florida, USA, received a diagnosis of Plasmodium vivax malaria. Whole-genome sequencing of the organism from 4 patients and phylogenetic analysis with worldwide representative P. vivax genomes indicated probable single parasite introduction from Central/South America.

Field evaluation of a novel semi-quantitative point-of-care diagnostic for G6PD deficiency in Indonesia.

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. METHODS: G6PD status of participants enrolled in Malinau and Nunukan Regencies and the capital Jakarta was assessed with the RDT, and G6PD activity was measured in duplicate by reference spectrophotometry. The adjusted male median (AMM) of the spectrophotometry measurements was defined as 100% activity; 70% and 30% of the AMM were defined as thresholds for intermediate and deficient G6PD status, respectively. Results were compared to those derived from spectrophotometry at the clinically relevant G6PD activity thresholds of 30% and 70%. RESULTS: Of the 161 participants enrolled, 10 (6.2%) were G6PD deficient and 12 (7.5%) had intermediate G6PD activity by spectrophotometry. At the 30% threshold, the sensitivity of the RDT was 10.0% (95%CI: 0.3-44.5%) with a specificity of 99.3% (95%CI: 96.4-100.0%); the positive predictive value was 50.0% (95%CI: 1.3-98.7%) and the negative predictive value 94.3% (95%CI: 89.5-97.4%). The corresponding figures at the 70% threshold were 22.7% (95%CI: 7.8-45.4%), 100.0% (95%CI: 97.4-100.0%), 100.0% (95%CI: 47.8-100.0%) and 89.1% (95%CI: 83.1-93.5%), respectively. CONCLUSION: While there is a dire need for an easy-to-use, economical, semi-quantitative diagnostic for the point of care, the observed performance of the "One Step G6PD Test" in its current form was insufficient to guide antimalarial treatment.

Malaria Slide Bank to Strengthen and Improve the Quality of Malaria Diagnosis: A National Slide Repository in India.

Malaria elimination is one of the top health care priorities in India, necessitating accessible and accurate diagnosis for effective treatment. A malaria slide bank in India is a collection of quality-controlled malaria-positive and -negative slides and is considered a vital asset for quality diagnosis. The collection of blood samples, preparation of blood smears, staining, quality control, molecular characterizations, and slide validation were carried out according to standard operating procedures in accordance with the WHO reference laboratory. The true count and parasite density per microliter were computed in accordance with WHO guidelines. Over 27 months, 48 batches (8,196 slides) were prepared. Overall, the majority of slide batches were Plasmodium vivax (45.9%; 22/48), followed by Plasmodium falciparum (25%; 12/48), malaria-negative infections (25%; 12/48), and mixed infections (4.1%; 2/48). All 48 batches passed internal validation by WHO-certified level-1 microscopists. For a batch, the true count was the median of the validators' counts (range, 111-280,795 parasites/µL). Except for mixed infections, the PCR results agreed with the verified microscopy results. Malaria slide bank slides would be a valuable tool for quality control, assurance, and microscopist training.

Investigation of Sensitivity of Rapid Diagnosis Tests in Patients with Suspected Malaria

Objective: Malaria has been eradicated in Türkiye as of 2010, but there are imported cases. In this study, we aimed to compare the diagnostic value of two rapid tests; SD Bioline Malaria Ag Pf/Pan (SD-Pf/Pan) and SD Bioline Malaria Ag Pf/Pv (SD-Pf/Pv) with microscopy and real time-polymerase chain reaction (RT-PCR). Methods: Blood samples were taken from all participants. Thick drop smears were prepared. Thick drop smears were examined for malaria positive/negative distinction under the light microscopy. Then, two rapid diagnostic tests (SD-Pf/Pan and SD-Pf/Pv) were performed. After DNA extraction from blood samples, RT-PCR was typed. The data were evaluated with SPSS 21 program of statistics. Results: A total of 30 cases out of 66 suspected malaria cases were detected as positive with microscopy and RT-PCR. Twenty-seven patients were found positive with both SD-Pf/Pan and SD-Pf/Pv tests. Based on the microscopic results as a reference method, SD-Pf/Pan and SD-Pf/Pv rapid diagnostic tests had a 90% sensitivity, 100% specificity, 100% positive predictive value (PPV), and 92.86% negative predictive value (NPV). Based on the RT-PCR results as a reference method, for detection of P. falciparum, both tests had a 95.65% sensitivity, 100% specificity, 100% PPV, and 88.89% NPV. Moreover, while SD-Pf/Pv had a sensitivity, specificity, PPV, and NPV of 100% in detection of P. vivax; SD-Pf/Pan has a 77.78% sensitivity of, 61.90% specificity of, 46.67% PPV, and 86.67% NPV SD-Pf/Pan for detection of PAN. Conclusion: As a result, high sensitivity and specificity were detected in both kits in the diagnosis of malaria infections caused by P. falciparum and P. vivax. Rapid diagnostic tests can be used safely in diagnosis however the diagnosis should be supported by microscopy and RT-PCR methods when they are applicable.

Characterisation of Plasmodium vivax lactate dehydrogenase dynamics in P. vivax infections.

Plasmodium vivax lactate dehydrogenase (PvLDH) is an essential enzyme in the glycolytic pathway of P. vivax. It is widely used as a diagnostic biomarker and a measure of total-body parasite biomass in vivax malaria. However, the dynamics of PvLDH remains poorly understood. Here, we developed mathematical models that capture parasite and matrix PvLDH dynamics in ex vivo culture and the human host. We estimated key biological parameters characterising in vivo PvLDH dynamics based on longitudinal data of parasitemia and PvLDH concentration collected from P. vivax-infected humans, with the estimates informed by the ex vivo data as prior knowledge in a Bayesian hierarchical framework. We found that the in vivo accumulation rate of intraerythrocytic PvLDH peaks at 10-20 h post-invasion (late ring stage) with a median estimate of intraerythrocytic PvLDH mass at the end of the life cycle to be 9.4 × 10-3ng. We also found that the median estimate of in vivo PvLDH half-life was approximately 21.9 h. Our findings provide a foundation with which to advance our quantitative understanding of P. vivax biology and will facilitate the improvement of PvLDH-based diagnostic tools.

A randomised controlled trial to compare the efficacy, safety, and tolerability of low dose, short course primaquine in adults with uncomplicated P. vivax malaria in two hospitals in India.

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. Shorter treatment courses may improve adherence and treatment effectiveness. METHODS: This is a hospital-based, randomised, controlled, open-label trial in two centres in India. Patients above the age of 16 years, with uncomplicated vivax malaria, G6PD activity of ≥ 30% of the adjusted male median (AMM) and haemoglobin levels ≥ 8 g/dL will be recruited into the study and randomised in a 1:1 ratio to receive standard schizonticidal treatment plus 7-day primaquine at 0.50 mg/kg/day or standard care with schizonticidal treatment plus 14-day primaquine at 0.25 mg/kg/day. Patients will be followed up for 6 months. The primary endpoint is the incidence risk of any P. vivax parasitaemia at 6 months. Safety outcomes include the incidence risk of severe anaemia (haemoglobin < 8 g/dL), the risk of blood transfusion, a > 25% fall in haemoglobin and an acute drop in haemoglobin of > 5 g/dL during primaquine treatment. DISCUSSION: This study will evaluate the efficacy and safety of a 7-day primaquine regimen compared to the standard 14-day regimen in India. Results from this trial are likely to directly inform national treatment guidelines. TRIAL REGISTRATION: Trial is registered on CTRI portal, Registration No: CTRI/2022/12/048283.

Methemoglobin levels in malaria: a systematic review and meta-analysis of its association with Plasmodium falciparum and Plasmodium vivax infections and disease severity.

Reports indicate that Plasmodium infections influence methemoglobin levels. However, findings have been inconclusive or have varied across different geographic and demographic contexts. This systematic review and meta-analysis aimed to consolidate existing data regarding the association between Plasmodium infections and alterations in methemoglobin levels related to the severity of the infection. A comprehensive literature search of several databases, including Ovid, ProQuest, Embase, Scopus, MEDLINE, and PubMed, was conducted to identify relevant studies that examined methemoglobin levels in patients with malaria. Qualitative synthesis and meta-analysis of the pooled standardized mean difference were conducted to synthesize the differences in methemoglobin levels between: (1) patients with malaria and those without malaria and (2) patients with severe malaria and those with uncomplicated malaria based on various themes including publication year, study design, study area, Plasmodium species, age group, symptomatic status, severity status, and method of malaria detection. Of the 1846 studies that were initially identified from the main databases and additional searches on Google Scholar, 10 studies met the eligibility criteria and were selected for this review. The systematic review distinctly highlighted an association between malaria and elevated methemoglobin levels, an observation consistent across diverse geographical regions and various Plasmodium species. Furthermore, the meta-analysis confirmed this by demonstrating increased methemoglobin levels in patients with malaria compared to those without malaria (P < 0.001, Hedges' g 2.32, 95% CI 1.36-3.29, I2 97.27, 8 studies). Moreover, the meta-analysis found elevated methemoglobin levels in patients with severe malaria compared to those with uncomplicated malaria (P < 0.001, Hedges' g 2.20, 95% CI 0.82-3.58, I2 96.20, 5 studies). This systematic review and meta-analysis revealed increased methemoglobin levels in patients with P. falciparum and P. vivax infections, with a notable association between elevated methemoglobin levels and severe malaria. Future research should focus on elucidating the specific mechanisms by which changes in methemoglobin levels are related to infections by P. falciparum and P. vivax, particularly in terms of severity, and how these alterations could potentially impact patient management and treatment outcomes.

Benefits of Lot Testing to Improve the Quality of Malaria Rapid Diagnostic Tests in India.

Since 2010, malaria rapid diagnostic tests (RDTs) are widely used to detect malaria. The Indian Council of Medical Research-National Institute of Malaria Research performed lot testing (LT) according to WHO procedures since 2016. Lot testing is performed to evaluate the lot-to-lot variation in performance of malaria RDTs. Four sets of positive quality control (QC) panels for P. falciparum (Pf) and P. vivax (Pv) and 10 negative panels tested RDTs. RDTs were reported as pass, failed, or deferred on the basis of WHO criteria. In the past 5 years, 275 lots containing 15,488 RDT kits for malaria diagnosis were subjected to LT. The monovalent RDTs (n = 1,216), based on either Pf histidine rich protein 2 (HRP2) or Pan-Plasmodium lactate dehydrogenase (Pan-pLDH) antigens, showed 90.4% sensitivity and 100% specificity, whereas RDTs based on HRP2 + Pan-pLDH or HRP2 + pLDH (n = 13,924) had sensitivity 95.6% and specificity 99.5%, respectively. RDTs based on PfHRP2 + Pv-pLDH + Pan-pLDH (n = 348) had 100% sensitivity and specificity. In a comparison between HRP2 + pLDH or HRP2 + Pan-pLDH to HRP2 + pLDH + Pan-pLDH RDTs, it was found that the sensitivity of PfHRP2 with Pan-pLDH RDTs (n = 2,382) was only 83%. Of the 275 lots analyzed, 15 lots of PfHRP2 with Pan-pLDH were deferred. The QC panel for Pf revealed a faint Pan band in the tested lots, which is a cause for concern. The results of deferred lots were reported to concerned government agencies. Quality-compromised RDTs may lead to an incorrect diagnosis. It is critical to have a QC system in place for effective malaria management.

Using serological diagnostics to characterize remaining high-incidence pockets of malaria in forest-fringe Cambodia.

BACKGROUND: Over the last decades, the number of malaria cases has drastically reduced in Cambodia. As the overall prevalence of malaria in Cambodia declines, residual malaria transmission becomes increasingly fragmented over smaller remote regions. The aim of this study was to get an insight into the burden and epidemiological parameters of Plasmodium infections on the forest-fringe of Cambodia. METHODS: 950 participants were recruited in the province of Mondulkiri in Cambodia and followed up from 2018 to 2020. Whole-blood samples were processed for Plasmodium spp. identification by PCR as well as for a serological immunoassay. A risk factor analysis was conducted for Plasmodium vivax PCR-detected infections throughout the study, and for P. vivax seropositivity at baseline. To evaluate the predictive effect of seropositivity at baseline on subsequent PCR-positivity, an analysis of P. vivax infection-free survival time stratified by serological status at baseline was performed. RESULTS: Living inside the forest significantly increased the odds of P. vivax PCR-positivity by a factor of 18.3 (95% C.I. 7.7-43.5). Being a male adult was also a significant predictor of PCR-positivity. Similar risk profiles were identified for P. vivax seropositivity. The survival analysis showed that serological status at baseline significantly correlated with subsequent infection. Serology is most informative outside of the forest, where 94.0% (95% C.I. 90.7-97.4%) of seronegative individuals survived infection-free, compared to 32.4% (95% C.I.: 22.6-46.6%) of seropositive individuals. CONCLUSION: This study justifies the need for serological diagnostic assays to target interventions in this region, particularly in demographic groups where a lot of risk heterogeneity persists, such as outside of the forest.

Tafenoquine following G6PD screening versus primaquine for the treatment of vivax malaria in Brazil: A cost-effectiveness analysis using a transmission model.

BACKGROUND: Malaria transmission modelling has demonstrated the potential impact of semiquantitative glucose-6-phosphate dehydrogenase (G6PD) testing and treatment with single-dose tafenoquine for Plasmodium vivax radical cure but has not investigated the associated costs. This study evaluated the cost-effectiveness of P. vivax treatment with tafenoquine after G6PD testing using a transmission model. METHODS AND FINDINGS: We explored the cost-effectiveness of using tafenoquine after G6PD screening as compared to usual practice (7-day low-dose primaquine (0.5 mg/kg/day) without G6PD screening) in Brazil using a 10-year time horizon with 5% discounting considering 4 scenarios: (1) tafenoquine for adults only assuming 66.7% primaquine treatment adherence; (2) tafenoquine for adults and children aged >2 years assuming 66.7% primaquine adherence; (3) tafenoquine for adults only assuming 90% primaquine adherence; and (4) tafenoquine for adults only assuming 30% primaquine adherence. The incremental cost-effectiveness ratios (ICERs) were estimated by dividing the incremental costs by the disability-adjusted life years (DALYs) averted. These were compared to a willingness to pay (WTP) threshold of US$7,800 for Brazil, and one-way and probabilistic sensitivity analyses were performed. All 4 scenarios were cost-effective in the base case analysis using this WTP threshold with ICERs ranging from US$154 to US$1,836. One-way sensitivity analyses showed that the results were most sensitive to severity and mortality due to vivax malaria, the lifetime and number of semiquantitative G6PD analysers needed, cost per malaria episode and per G6PD test strips, and life expectancy. All scenarios had a 100% likelihood of being cost-effective at the WTP threshold. The main limitations of this study are due to parameter uncertainty around our cost estimates for low transmission settings, the costs of G6PD screening, and the severity of vivax malaria. CONCLUSIONS: In our modelling study that incorporated impact on transmission, tafenoquine prescribed after a semiquantitative G6PD testing was highly likely to be cost-effective in Brazil. These results demonstrate the potential health and economic importance of ensuring safe and effective radical cure.

An imported malaria case with repeated episodes of neurological syndromes resulting from different Plasmodium species.

BACKGROUND: Imported cerebral malaria (CM) cases in non-endemic areas are often misdiagnosed, which delays treatment. Post-malaria neurological syndrome (PMNS) after recovery from severe malaria can also complicate diagnosis. CASE: We report an imported malaria case from West Africa with two sequential episodes with neurological syndromes within about a month. The first episode was diagnosed as CM with microscopy-positive Plasmodium falciparum infection. The second episode, occurring a month after the recovery from the first CM episode, was consistent with PMNS, since malaria parasites were not detected by microscopy in peripheral blood smears. However, this diagnosis was complicated by the detection of Plasmodium vivax in peripheral blood by PCR, suggesting a potential cause of the second episode by P. vivax. CONCLUSION: This study suggests that PMNS often occurs after severe falciparum malaria. Concurrent P. vivax infection with pathogenic biomass being predominantly extravascular further complicates accurate diagnosis.

A visualized hybrid PCR-LAMP assay for the detection of human Plasmodium species.

Combining the advantages of PCR and LAMP, we described a new technique, namely PCR-LAMP, for malaria diagnosis. The whole process of DNA amplification can be completed in 35 min. This hybrid amplification technique markedly improved the sensitivity of detection compared to the classic single PCR or LAMP assay alone. PCR-LAMP assay had a detection limit of 1 copy/µL for P. knowlesi and P. ovale, 0.1 copy/µL for P. vivax, P. falciparum and P. malariae, respectively. To facilitate the endpoint detection, xylenol orange was added. Positive samples were indicated in orange while negative reactions were violet. The inclusion of xylenol orange into the LAMP reaction mix significantly reduces the post-amplification workload. Without relying on the use of specific instruments, the color changes of the amplicons could be visualized directly through the naked eye. In conclusion, PCR-LAMP poses the potential to be developed as a new malaria molecular diagnosis tool.

Clinical Profile and Treatment Outcomes of Patients with Malaria Complicated by Acute Kidney Injury.

As Odisha is an endemic region for malaria with many acute kidney injury (AKI) cases, this study evaluated the clinical profile and treatment outcomes of patients with malaria complicated by AKI. This prospective observational study was conducted between December 2015 and September 2017. Detailed histories and clinical examinations were recorded. On admission, tests for routine hematology, plasma glucose, liver function, renal function, serum electrolytes, thick smears, thin smears, and malarial parasites were performed. Of the 958 AKI malarial patients admitted, 202 (82.6 % males) were included in the study, with a mean age of 38.37 years. In total, 86.14%, 3.46%, and 10.39% of patients had Plasmodium falciparum, Plasmodium vivax, and mixed malaria, respectively. Headache and decreased urination (83.66% each) were the most common symptoms after fever (100%). Anuria and oliguria were reported in 5.95% and 67.82% of patients, respectively, whereas 26.23% reported a urine output of >400 mL/24 h. All patients had raised serum creatinine and urea levels, and >60% had anemia, proteinuria, and/or hyponatremia. Multiple organ dysfunction syndrome was observed in 62.87% of patients. Acute tubular necrosis was seen in 60% of renal biopsy specimens (n = 15). Of the 75.75% of patients requiring dialysis, 82.12% and 17.88% of patients required hemodialysis and peritoneal dialysis, respectively, during which 11 patients died. AKI, a serious complication of P. falciparum or P. vivax malaria, is a life-threatening condition. Fever, anemia, oligo/anuria, hepatic involvement, cerebral malaria, high serum creatinine and urea, and disseminated intravascular coagulation were the main predictors of mortality in our study.