Identifying targets of protective antibodies against severe malaria in Papua, Indonesia using locally expressed domains of Plasmodium falciparum Erythrocyte Membrane Protein 1.

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), a diverse family of multi-domain proteins expressed on the surface of malaria-infected erythrocytes, is an important target of protective immunity against malaria. Our group recently studied transcription of the var genes encoding PfEMP1 in individuals from Papua, Indonesia with severe or uncomplicated malaria. We cloned and expressed domains from 32 PfEMP1s including 22 that were upregulated in severe malaria and 10 that were upregulated in uncomplicated malaria, using a wheat germ cell-free expression system. We used Luminex technology to measure IgG antibodies to these 32 domains and control proteins in 63 individuals (11 children). At presentation to hospital, levels of antibodies to PfEMP1 domains were either higher in uncomplicated malaria or were not significantly different between groups. Using principal components analysis, antibodies to three of 32 domains were highly discriminatory between groups. These included two domains upregulated in severe malaria, a DBLβ13 domain and a CIDRα1.6 domain (which has been previously implicated in severe malaria pathogenesis), and a DBLδ domain that was upregulated in uncomplicated malaria. Antibody to control non-PfEMP1 antigens did not differ with disease severity. Antibodies to PfEMP1 domains differ with malaria severity. Lack of antibodies to locally expressed PfEMP1 types, including both domains previously associated with severe malaria and newly identified targets, may in part explain malaria severity in Papuan adults. Importance Severe Plasmodium falciparum malaria kills many African children, and lack of antibody immunity predisposes to severe disease. A critical antibody target is the P. falciparum erythrocyte membrane 1 (PfEMP1) family of multidomain proteins, which are expressed on the infected erythrocyte surface and mediate parasite sequestration in deep organs. We previously identified var genes encoding PfEMP1 that were differentially expressed between severe and uncomplicated malaria in Papua, Indonesia. Here, we have expressed domains from 32 of these PfEMP1s and measured IgG antibody responses to them in Papuan adults and children. Using Principal Component Analysis, IgG antibodies to three domains distinguished between severe and uncomplicated malaria and were higher in uncomplicated malaria. Domains included CIDRα1.6, implicated in severe malaria; a DBLβ13 domain; and a DBLδ domain of unknown function. Immunity to locally relevant PfEMP1 domains may protect from severe malaria. Targets of immunity show important overlap between Asian adults and African children.

Assessment of Vitamin D Status in Patients Suffering from Uncomplicated Malaria in a Health Center in the District of Abidjan (Côte d’Ivoire)

Aims: The pathophysiology of Plasmodium falciparum infection is most often associated with anemia and immune deficiency. Given the important role of vitamin D in the synthesis of hemoglobin and in the stimulation of the immune system, it would be essential to assess the vitamin D status of patients with malaria in order to improve the quality of treatment management. Methodology: A thick drop and a blood smear were used to determine parasite density and parasite species respectively. The complete blood count was performed using an automated analyzer labelled Sysmex XN 1000i. Biochemical parameters such as calcium and phosphorus were determined using the Cobas C311 Hitachi. The Vidas was used to determine the concentrations of 25 (OH) -vitamin D. Results: The results showed a decrease in 25 (OH) -vitamin D concentrations in relation to the parasite density and anemia observed in patients with uncomplicated malaria. Conclusion: Vitamin D status in patients with uncomplicated malaria could represent an essential biomarker in the monitoring of antimalarial treatment.

The Impact of Covid-19 on Malaria Services in Three High Endemic Districts in Rwanda – A Mixed-Method Study

Background: Rwanda has achieved impressive reductions in malaria morbidity and mortality over the past two decades. However, the disruption of essential services due to the current Covid-19 pandemic can lead to a reversal of these gains in malaria control unless targeted, evidence-based interventions are implemented to mitigate the impact of the pandemic. The extent to which malaria services have been disrupted has not been fully characterized. In this study, we thus assessed the impact of Covid-19 on malaria services in Rwanda. Methods: We conducted a mixed-methods study in three purposively selected districts in Rwanda. The quantitative data included malaria aggregated data reported at the health facility level and the community level. The data included the number of malaria tests, uncomplicated malaria cases, severe malaria cases, and malaria deaths. We collected qualitative data using focus group discussions with community members and community health workers, as well as in-depth interviews with health care providers and staff working in the malaria program. We conducted interrupted time series analysis to compare changes in malaria presentations between the pre-Covid-19 period (January 2019 to February 2020) and Covid-19 periods (from March 2020 to November 2020). We used the constant comparative method in qualitative thematic analysis. Results: Compared to pre-Covid-19 period, there was a monthly reduction in patients tested in health facilities of 5.09 per 1000 population and a monthly increase in patients tested in the community of 3.13 per 1000 population during the Covid-19 period. There was no change in presentation rate for uncomplicated malaria or severe malaria. Additionally, although healthcare providers continued to provide malaria services, they were fearful that this would expose them and their families to Covid-19. Covid-19 mitigation measures limited the availability of transportation options for the community to seek care in health facilities and delayed the implementation of some key malaria interventions. The focus on Covid-19-related communication also reduced the amount of health information for other diseases provided to community members. Conclusion The Covid-19 pandemic resulted in patients increasingly seeking care in the community and poses challenges to maintaining delivery of malaria services in Rwanda. Interventions to mitigate these challenges should focus on strengthening programming for community and home-based care models and integrating malaria messages into Covid-19-related communication. Additionally, implementation of the interrupted interventions should be timed and overlap with the malaria transmission season to mitigate Covid-19 consequences on malaria.

Exploring patients’ viewpoints on uncomplicated malaria and its management in primary healthcare facilities of Plateau State, Nigeria: a qualitative study

Malaria infection is a major public health problem in Nigeria. The present study explored patients’ thoughts and feelings on uncomplicated malaria and its management practices in some primary healthcare (PHC) facilities of Plateau state, Nigeria. An in-depth interview was conducted on patients receiving treatment in some of the facilities in the state, who were recruited through purposive sampling method up to saturation point. All the information was audio-recorded and transcribed verbatim before analysis using the principles of thematic content analysis of inductive method. Generally, their views on malaria-related issues were categorised into four main themes based on their relevancies as: patients’ perceptions on malaria infection and anti-malarial drugs, the role of healthcare workers and family during treatment, medications taken and socio-economic-related factors, as well as their general views on healthcare facilities-related factors. The study showed patients’ perceptions of the aforementioned factors as influencing their treatment and management practices of the disease in the study area. Necessary interventions that would improve patients’ quality of management of the disease toward achieving the desired outcome of therapy are recommended.

Use of Rasch Wright map to understand the quality of Healthcare Workers’ Knowledge, Attitudes, and Practices for Uncomplicated Malaria (HKAPIUM)

The present study assessed the dimensionality and item difficulty targeting to person ability of HKAPIUM scale using Rasch Wright map approach. A HKAPIUM instrument (Cronbach’s alpha = 0.71) containing eighteen (18)-items was administered to 121 trained healthcare professionals involved in the management of uncomplicated malaria in 24 selected primary health care (PHC) facilities in Plateau state, Nigeria. The respondents filled and returned the instrument and the data was analyzed using Bond&Fox software®. The Rasch principal components analysis (Rasch-PCA) of the item residuals indicated variance explained values of 52 (knowledge), 41.1 (attitudes), and 55.4 (practices) and eigenvalues of the first contrast as 1.2, 1.8, and 1.5, respectively, which were within acceptable values thatindicated the unidimensionality of the three constructs of the HKAPIUM scale. The result showed moderate items difficulty levels for all the three constructs. The mean person ability levels of respondents with-respect-to knowledge-related items were low, while their mean person ability levels in endorsing the attitudes and practices-related items were good. The study revealed unidimensionality of the 3 constructs of HKAPIUM scale, with observed mismatch between item difficulty levels of the constructs with most of the person ability levels of the respondents.

Efficacy and safety of artemether-lumefantrine and dihydroartemisinin-piperaquine for the treatment of uncomplicated Plasmodium falciparum malaria and prevalence of molecular markers associated with artemisinin and partner drug resistance in Uganda

Background In Uganda, artemether-lumefantrine (AL) is first-line therapy and dihydroartemisinin-piperaquine (DP) second-line therapy for the treatment of uncomplicated malaria. This study evaluated the efficacy and safety of AL and DP in the management of uncomplicated falciparum malaria and measured the prevalence of molecular markers of resistance in three sentinel sites in Uganda from 2018 to 2019. Methods This was a randomized, open-label, phase IV clinical trial. Children aged 6 months to 10 years with uncomplicated falciparum malaria were randomly assigned to treatment with AL or DP and followed for 28 and 42 days, respectively. Genotyping was used to distinguish recrudescence from new infection, and a Bayesian algorithm was used to assign each treatment failure a posterior probability of recrudescence. For monitoring resistance, Pfk13 and Pfmdr1 genes were Sanger sequenced and plasmepsin-2 copy number was assessed by qPCR. Results There were no early treatment failures. The uncorrected 28-day cumulative efficacy of AL ranged from 41.2 to 71.2% and the PCR-corrected cumulative 28-day efficacy of AL ranged from 87.2 to 94.4%. The uncorrected 28-day cumulative efficacy of DP ranged from 95.8 to 97.9% and the PCR-corrected cumulative 28-day efficacy of DP ranged from 98.9 to 100%. The uncorrected 42-day efficacy of DP ranged from 73.5 to 87.4% and the PCR-corrected 42-day efficacy of DP ranged from 92.1 to 97.5%. There were no reported serious adverse events associated with any of the regimens. No resistance-associated mutations in the Pfk13 gene were found in the successfully sequenced samples. In the AL arm, the NFD haplotype (N86Y, Y184F, D1246Y) was the predominant Pfmdr1 haplotype, present in 78 of 127 (61%) and 76 of 110 (69%) of the day 0 and day of failure samples, respectively. All the day 0 samples in the DP arm had one copy of the plasmepsin-2 gene. Conclusions DP remains highly effective and safe for the treatment of uncomplicated malaria in Uganda. Recurrent infections with AL were common. In Busia and Arua, the 95% confidence interval for PCR-corrected AL efficacy fell below 90%. Further efficacy monitoring for AL, including pharmacokinetic studies, is recommended. Trial registration The trail was also registered with the ISRCTN registry with study Trial No. PACTR201811640750761

Trends and predictive factors for treatment failure following artemisinin-based combination therapy among children with uncomplicated malaria in Ghana: 2005–2018

Background Since the introduction of artemisinin-based combination therapy (ACT) in Ghana in 2005 there has been a surveillance system by the National Malaria Control Programme (NMCP) and the University of Ghana Noguchi Memorial Institute for Medical Research (UG-NMIMR) to monitor the therapeutic efficacy of ACTs for the treatment of uncomplicated malaria in the country. We report trends and determinants of failure following treatment of Ghanaian children with artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) combinations. Methods Per protocol analyses as well as cumulative incidence of day 28 treatment failure from Kaplan Meier survival analyses were used to describe trends of failure over the surveillance period of 2005–2018. Univariable and multivariable cox regression analyses were used to assess the determinants of treatment failure over the period. Results Day 28 PCR-corrected failure, following treatment with ASAQ, significantly increased from 0.0% in 2005 to 2.0% (95% CI: 1.1–3.6) in 2015 (p = 0.013) but significantly decreased to 0.4% (95% CI: 0.1–1.6) in 2018 (p = 0.039). Failure, following treatment with AL, decreased from 4.5% (95% CI: 2.0–9.4) in 2010 to 2.7% (95% CI: 1.4–5.1) in 2018, though not statistically significant (p = 0.426). Risk of treatment failure, from multivariable cox regression analyses, was significantly lower among children receiving ASAQ compared with those receiving AL (HR = 0.24; 95% CI: 0.11–0.53; p < 0.001); lower among children with no parasitaemia on day 3 compared with those with parasitaemia on day 3 (HR = 0.02; 95% CI: 0.01–0.13; p < 0.001); and higher among children who received ASAQ and had axillary temperature ≥ 37.5 °C on day 1 compared with those with axillary temperature < 37.5 °C (HR = 3.96; 95% CI: 1.61–9.75; p = 0.003). Conclusions Treatment failures for both ASAQ and AL have remained less than 5% (below WHO’s threshold of 10%) in Ghana since 2005. Predictors of treatment failure that need to be considered in the management of uncomplicated malaria in the country should include type of ACT, day 3 parasitaemia, and day 1 axillary temperature of patients being treated.

Artemether–lumefantrine and dihydroartemisinin–piperaquine treatment outcomes among children infected with uncomplicated Plasmodium falciparum malaria in Mwanza, Tanzania

Background Artemisinin based combination therapies (ACTs) have been a cornerstone in the treatment of malaria in the world. A rapid decline in dihydroartemisinin piperaquine (DHP) and artemether lumefantrine (ALU) efficacies has been reported in some parts of South East Asia, the historical epicenter for the antimalarial drug resistance. Prolonged drug use is associated with selection of resistant parasites due to exposure to inadequate drug levels hence effects on treatment outcomes in malaria. ALU and DHP are used as first line and alternative first line, respectively, in Tanzania. This study was carried in Igombe, Tanzania to assess the efficacies of ALU and DHP in routine treatment of uncomplicated malaria among children. Methods This was a prospective study involving children up to 10 years and followed up for 28 and 35 days as per the WHO protocol, 2015 for monitoring antimalarial drug efficacy. The primary end points were crude and adjusted Adequate Clinical and Parasitological Response (ACPR), parasite clearance rate and reported adverse events. Results A total of 205 children with uncomplicated malaria were enrolled. One hundred and sixteen participants were treated with ALU, while 89 participants were treated with DHP. Two participants in the ALU group were lost within the 24 h of follow-up. The PCR unadjusted ACPR was108 (94.7%) for ALU and 88 (98.9%) for DHP, while the PCR adjusted ACPR was 109(95.6%) and 88(98.9%) for ALU and DHP, respectively, at 28 day follow-up. No treatment failure was observed in both groups. Cumulative risk of recurrent parasitemia was similar in both groups (p = 0.32). Age and parasite density were strong predictors for persistent day 1 parasitemia (p = 0.034 and 0.026, respectively). Nausea and vomiting, abdominal pain and headache were the most clinical adverse events reported in both groups of patients. Conclusion The present study shows that ALU and DHP are still efficacious after more than a decade of use with PCR corrected efficacies greater than 95% implying a failure rate less than 5% which is below the WHO minimum threshold requirement for recommendation of a change in the treatment policy. Both drugs were well tolerated with no major adverse events reported.