Mefloquine for preventing malaria in pregnant women

Anemia in Pregnant Women and Children Aged 6 to 59 Months Living in Mozambique and Portugal: An Overview of Systematic Reviews

INTRODUCTION

Globally, anemia is still a public health issue faced by people in low and high-income countries. This study gives an overview of published scientific articles related to the prevalence, nutritional indicators, and social determinants of anemia in pregnant women and children aged 6 to 59 months living in Mozambique and Portugal.

METHODS

We performed a review of scientific literature in April 2021, searching for published indexed articles in the last 15 years (2003-2018) in electronic databases. Subsequently, quality assessment, data extraction, and content analysis were performed.

RESULTS

We have identified 20 relevant publications. Unsurprisingly, anemia plays a relevant role in disability and life imbalances for these subgroups in Mozambique compared with Portugal. For both countries, data on anemia and iron deficiency in pregnant women and children aged 6 to 59 months old are either outdated or remain unclear. Similarly, studies on social determinants and anemia are also still scarce.

CONCLUSIONS

A gap of information on anemia, other nutritional indicators, and social determinants in pregnant women and children between 6 and 59 months of age living in Mozambique and Portugal is highly observed. More research is crucial to help achieve the goals established by the Sustainable Development Goals.

Malaria chemoprevention and drug resistance: a review of the literature and policy implications

Chemoprevention strategies reduce malaria disease and death, but the efficacy of anti-malarial drugs used for chemoprevention is perennially threatened by drug resistance. This review examines the current impact of chemoprevention on the emergence and spread of drug resistant malaria, and the impact of drug resistance on the efficacy of each of the chemoprevention strategies currently recommended by the World Health Organization, namely, intermittent preventive treatment in pregnancy (IPTp); intermittent preventive treatment in infants (IPTi); seasonal malaria chemoprevention (SMC); and mass drug administration (MDA) for the reduction of disease burden in emergency situations. While the use of drugs to prevent malaria often results in increased prevalence of genetic mutations associated with resistance, malaria chemoprevention interventions do not inevitably lead to meaningful increases in resistance, and even high rates of resistance do not necessarily impair chemoprevention efficacy. At the same time, it can reasonably be anticipated that, over time, as drugs are widely used, resistance will generally increase and efficacy will eventually be lost. Decisions about whether, where and when chemoprevention strategies should be deployed or changed will continue to need to be made on the basis of imperfect evidence, but practical considerations such as prevalence patterns of resistance markers can help guide policy recommendations.

Poor Birth Outcomes in Malaria in Pregnancy: Recent Insights Into Mechanisms and Prevention Approaches

Pregnant women in malaria-endemic regions are susceptible to malaria in pregnancy, which has adverse consequences on birth outcomes, including having small for gestational age and preterm babies. These babies are likely to have low birthweights, which predisposes to infant mortality and lifelong morbidities. During malaria in pregnancy, Plasmodium falciparum-infected erythrocytes express a unique variant surface antigen, VAR2CSA, that mediates sequestration in the placenta. This process may initiate a range of host responses that contribute to placental inflammation and dysregulated placental development, which affects placental vasculogenesis, angiogenesis and nutrient transport. Collectively, these result in the impairment of placental functions, affecting fetal development. In this review, we provide an overview of malaria in pregnancy and the different pathological pathways leading to malaria in pregnancy-associated low birthweight. We also discuss current prevention and management strategies for malaria in pregnancy, and some potential therapeutic interventions that may improve birth outcomes. Lastly, we outline some priorities for future research that could bring us one step closer to reducing this health burden.

Assessment of perinatal outcomes of pregnant women with severe versus simple malaria

Objective

Malaria in pregnancy is associated with adverse perinatal outcomes. The objective was to compare outcomes of simple and severe malaria and to determine whether they vary by trimester or severity of infection.

Methods

Prospective cohort study performed in 3 hospitals in Rwanda. Both hospitalized and non-hospitalized pregnant patients with confirmed malaria were enrolled and followed until 7 days postpartum. Demographic, clinical manifestations and perinatal outcomes were recorded.

Results

There were 446 pregnant women with confirmed malaria and outcome data; 361 (80.9%) had simple malaria. Severe malaria was more common as pregnancy progressed; out of 85 with severe malaria, 12.9%, 29.4% and 57.6% were in the 1^st, 2^nd and 3^rd trimesters (p<0.0001). Overall, a normal term delivery occurred in 57.6%, with preterm delivery in 24.9% and abortion in 13.5%. Adverse perinatal outcomes increased with trimester of infection (p<0.0001). Eight of the 9 early neonatal deaths had 3^rd trimester infection (p<0.0001). There were 27 stillbirths; 63.7% were associated with 3^rd trimester infection. A significant difference in perinatal outcomes between simple and severe malaria was seen: 64% of women with simple malaria had a normal term delivery as compared to 30.6% with severe malaria (p<0.0001). All complications were significantly greater with severe malaria.

Conclusion

Overall poor outcomes are seen in malaria with significant differences in perinatal outcomes between simple and severe malaria and by trimester of infection. In addition to vector control and exposure prevention, efforts need to be made in screening, treatment education and monitoring pregnancies affected by malaria.

The Effectiveness of the Revised Intermittent Preventive Treatment with Sulphadoxine Pyrimethamine (IPTp-SP) in the Prevention of Malaria among Pregnant Women in Northern Ghana

This study investigated the effectiveness of the World Health Organization (WHO)-revised Intermittent Preventive Treatment using Sulphadoxine Pyrimethamine (IPTp-SP) dosage regimen in the prevention of malaria infections in pregnancy. The study involved a prospective cohort of pregnant women who attended the antenatal clinic in four health facilities (Tamale Teaching Hospital, Tamale West Hospital, Tamale Central Hospital, and Tamale SDA Hospital) within the Tamale metropolis. Data collection spanned a period of 12 months, from September 2016 to August 2017, to help account for seasonality in malaria. The study included 1181 pregnant women who attended antenatal clinics in four hospitals within the metropolis. The registers at the facilities served as a sampling frame, and the respondents were randomly sampled out from the number of pregnant women available during each visit. They were enrolled consecutively as they kept reporting to the facility to receive antenatal care. The participants were stratified into three groups; the no IPTp-SP, <3 doses of IPTp-SP, and ≥3 doses of IPTp-SP. The participants were followed up until 36 weeks of gestation, and blood samples were analyzed to detect the presence of peripheral malaria parasites. At the end of the study, 42.4% of the women had taken at least 3 doses of SP based on the revised WHO IPTp-SP policy. Pregnant women who had taken at least 3 doses of IPTp-SP had a malaria prevalence of 16.9% at 36 weeks of gestation, compared to 35.8% of those who had not taken IPTp-SP. In the multivariable logistic regression, those who had taken ≥3 doses of SP were associated with 56% reduced odds (aOR 0.44, CI 0.27-0.70, P = 0.001) of late gestational peripheral malaria, compared with those who did not take SP. IPTp-SP served under three or more doses provided a dose-dependent protection of 56% against maternal peripheral malaria parasitaemia detectable at the later stages of gestation (36 weeks). Since the dose-dependent potency of IPTp-SP depletes with time, there is the need for research into more sustainable approaches that offer longer protection.

Prevalence and factors associated with carriage of Pfmdr1 polymorphisms among pregnant women receiving intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) and artemether-lumefantrine for malaria treatment in Burkina Faso

Background

Single nucleotide polymorphisms occurring in the Plasmodium falciparum multidrug resistant gene 1 (pfmdr1) are known to be associated with aminoquinoline resistance and, therefore, represent key P. falciparum markers for monitoring resistance both in susceptible groups (children under 5 years old and pregnant women) and in the general population. This study aimed to determine prevalence and factors associated with the carriage of pfmdr1 N86Y, Y184F and D1246Y polymorphisms among pregnant women in a setting of high malaria transmission in Burkina Faso.

Methods

Plasmodium falciparum isolates were collected at the first antenatal care visit (ANC-1) as well as at delivery from pregnant women participating in the COSMIC trial (NTC01941264), which assessed malaria preventive interventions during pregnancy in the Nanoro Health District. Here, pregnant women received intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) and malaria infections and/or diseases were treated using artemether-lumefantrine (AL) during the trial. Parasite DNA was extracted from dried blood spots and the presence of pfmdr1 mutations at positions 86, 184 and 1246 was determined using nested PCR, followed by restriction fragment length polymorphism (RFLP) analysis.

Results

A prevalence of 13.2% (20/151) and 12.1% (14/116) of the pfmdr1 86Y mutant allele was found at ANC-1 and at delivery, respectively, while no mutant allele was observed for Y184F and D1246Y codons at both ANC-1 and at delivery. There were no significant factors associated with pfmdr1 86Y mutant allele carriage at ANC-1. However, malaria infections at delivery with a parasite density above the median (2237.2 (IQR: 613.5–11,425.7) parasites/µl) was associated with an increase risk of pfmdr1 86Y mutant allele carriage (AOR = 5.5 (95% CI  1.07–28.0); P = 0.04). In contrast, both three or more IPTp-SP doses (AOR = 0.25 (95% CI 0.07–0.92); P = 0.04) and one or more AL treatment (AOR = 0.25 (95% CI 0.07–0.89); P = 0.03) during pregnancy were associated with a significant reduce risk of pfmdr1 86Y mutant allele carriage at delivery.

Conclusion

These findings suggest that both high coverage of IPTp-SP and the use of AL for the treatment of malaria infection/disease during pregnancy select for pfmdr1 N86 wild-type allele at delivery.

Assay validation and determination of in vitro binding of mefloquine to plasma proteins from clinically normal and FIP-affected cats

The antimalarial agent mefloquine is currently being investigated for its potential to inhibit feline coronavirus and feline calicivirus infections. A simple, high pressure liquid chromatography assay was developed to detect mefloquine plasma concentrations in feline plasma. The assay’s lower limit of quantification was 250 ng/mL. The mean ± standard deviation intra- and inter-day precision expressed as coefficients of variation were 6.83 ± 1.75 and 5.33 ± 1.37%, respectively, whereas intra- and inter-day accuracy expressed as a percentage of the bias were 11.40 ± 3.73 and 10.59 ± 3.88%, respectively. Accordingly, this validated assay should prove valuable for future in vivo clinical trials of mefloquine as an antiviral agent against feline coronavirus and feline calicivirus. However, the proportion of mefloquine binding to feline plasma proteins has not been reported. The proportion of drug bound to plasma protein binding is an important concept when developing drug dosing regimens. As cats with feline infectious peritonitis (FIP) demonstrate altered concentrations of plasma proteins, the proportion of mefloquine binding to plasma proteins in both clinically normal cats and FIP-affected cats was also investigated. An in vitro method using rapid equilibrium dialysis demonstrated that mefloquine was highly plasma protein bound in both populations (on average > 99%).

In vitro hepatic metabolism of mefloquine using microsomes from cats, dogs and the common brush-tailed possum (Trichosurus vulpecula)

Feline infectious peritonitis (FIP) is a systemic, fatal, viral-induced, immune-mediated disease of cats caused by feline infectious peritonitis virus (FIPV). Mefloquine, a human anti-malarial agent, has been shown to inhibit FIPV in vitro. As a first step to evaluate its efficacy and safety profile as a potential FIP treatment for cats, mefloquine underwent incubation in feline, canine and common brush-tailed possum microsomes and phase I metabolism cofactors to determine its rate of phase I depletion. Tramadol was used as a phase I positive control as it undergoes this reaction in both dogs and cats. Using the substrate depletion method, the in vitro intrinsic clearance (mean ± S.D.) of mefloquine by pooled feline and common brush-tailed possum microsomes was 4.5 ± 0.35 and 18.25 ± 3.18 μL/min/mg protein, respectively. However, phase I intrinsic clearance was too slow to determine with canine microsomes. Liquid chromatography-mass spectrometry (LC-MS) identified carboxymefloquine in samples generated by feline microsomes as well as negative controls, suggesting some mefloquine instability. Mefloquine also underwent incubation with feline, canine and common brush-tailed possum microsomes and phase II glucuronidative metabolism cofactors. O-desmethyltramadol (ODMT or M1) was used as a positive control as it undergoes a phase II glucuronidation reaction in these species. The rates of phase II mefloquine depletion by microsomes by all three species were too slow to estimate. Therefore mefloquine likely undergoes phase I hepatic metabolism catalysed by feline and common brush-tailed possum microsomes but not phase II glucuronidative metabolism in all three species and mefloquine is not likely to have delayed elimination in cats with clinically normal, hepatic function.