Malaria, erythrocytic infection, and anemia

Infectious and obstetric determinants of anemia among pregnant women in Southwest Ethiopia

Background

Anaemia, characterized by low red blood cell or haemoglobin levels, impairs oxygen transport in the body and poses a major global public health issue, particularly affecting pregnant women and children. This study focuses on identifying the factors contributing to anaemia among pregnant women receiving antenatal care (ANC) at Mizan-Tepi University Teaching Hospital (MTUTH) in southwest Ethiopia.

Methods

A hospital-based unmatched case-control study was conducted from July 1 to August 30, 2022, involving 370 pregnant women (90 with anaemia and 280 without). Data collection included questionnaires, laboratory tests (Hgb and stool examination), and anthropometric measurements. SPSS version 21 was used for data analysis, with binary logistic regression identifying factors associated with anaemia. The significance level was set at a p-value <0.05.

Results

The study achieved a 100% response rate for both cases and controls. Factors identified as determinants of anaemia among pregnant women included malaria infection (AOR = 7.83, 95% CI: 3.89-15.8), hookworm infection (AOR = 2.73, 95% CI: 1.39-5.34), short birth interval (AOR = 7.11, 95% CI: 3.59-14.2), and history of unsafe abortion (AOR = 5.40, 95% CI: 2.46-11.8).

Conclusion

This study found that malaria infection, hookworm infection, birth interval <33 months, and a history of unsafe abortion are factors contributing to anaemia in pregnant women. Strategies such as distributing insecticide-treated bed nets (ITNs) to combat malaria, improving sanitation, anthelmintic drugs, promoting family planning to prevent unwanted pregnancies and unsafe abortions, and providing preconception care can help reduce the incidence of anaemia.

Understanding the significance of oxygen tension on the biology of Plasmodium falciparum blood stages: From the human body to the laboratory

Plasmodium falciparum undergoes sequestration within deep tissues of the human body, spanning multiple organ systems with differing oxygen (O2) concentrations. The parasite is exposed to an even greater range of O2 concentrations as it transitions from the human to the mosquito host, suggesting a high level of plasticity as it navigates these different environments. In this review, we explore factors that may contribute to the parasite's response to different environmental O2 concentrations, recognizing that there are likely multiple pieces to this puzzle. We first review O2-sensing mechanisms, which exist in other apicomplexans such as Toxoplasma gondii and consider whether similar systems could exist in Plasmodium. Next, we review morphological and functional changes in P. falciparum's mitochondrion during the asexual-to-sexual stage transition and discuss how these changes overlap with the parasite's access to O2. We then delve into reactive oxygen species (ROS) as ROS production is influenced by O2 availability and oxidative stress impacts Plasmodium intraerythrocytic development. Lastly, given that the primary role of the red blood cell (RBC) is to deliver O2 throughout the body, we discuss how changes in the oxygenation status of hemoglobin, the RBC's O2-carrying protein and key nutrient for Plasmodium, could also potentially impact the parasite's growth during intraerythrocytic development. This review also highlights studies that have investigated P. falciparum biology under varying O2 concentrations and covers technical aspects related to P. falciparum cultivation in the lab, focusing on sources of technical variation that could alter the amount of dissolved O2 encountered by cells during in vitro experiments. Lastly, we discuss how culture systems can better replicate in vivo heterogeneity with respect to O2 gradients, propose ideas for further research in this area, and consider translational implications related to O2 and malaria.

Prevalence of Plasmodium and Soil-Transmitted Helminth Coinfection and Associated Factors among Malaria-Suspected Patients Attending Shewa Robit Health Center, North-Central Ethiopia

Plasmodium and soil-transmitted helminth (STH) coinfection is a major public health problem in developing countries. Its prevalence and associated factors are poorly addressed in the available research. Therefore, this study aimed to assess Plasmodium-STH coinfection prevalence and associated factors among malaria-suspected patients attending Shewa Robit Health Center, north-central Ethiopia. A cross-sectional study was conducted among 379 malaria-suspected patients attending Shewa Robit Health Center from April to May 2023. Stool and blood samples were collected from each participant. Plasmodium and STHs were detected from blood and stool samples by using blood film and the Kato-Katz method, respectively. Data were entered into Epi Info version 7 and analyzed by SPSS version 26. Descriptive statistics were used to compute Plasmodium-STH coinfection. Logistic regression was used to identify associated factors. Variables with a P-value <0.05 were considered statistically significant. Among the study participants, 27.9%, 20.3%, and 13.4% were positive for Plasmodium, STHs, and Plasmodium-STH coinfection, respectively. The prevalence of Plasmodium-Ascaris lumbricoides coinfection was high (7.6%). Unavailability of insecticide-treated bed nets (ITNs), improper use of ITNs, absence of indoor residual spraying, presence of stagnant water, and previous malaria infection were significantly associated (P <0.01) with Plasmodium infection. Being illiterate, using an unimproved latrine, having an untrimmed fingernail, and practicing open defecation were also significantly associated (P <0.03), with STH infection. Being male, illiterate, and living in rural areas were significantly associated (P <0.03) with Plasmodium-STH coinfection. The prevalence of Plasmodium-STH coinfection was high in malaria-endemic areas. Therefore, malaria-suspected cases should be checked for STH infection.

Prevalence and Associated Factors of Anemia in Children Aged 6 to 59 Months in the Eastern Region of Burkina Faso

Background. Anemia in children aged 6 to 59 months is a public health problem in Burkina Faso with a prevalence well above the 40% estimated by WHO globally for this age group. Aim. The objective of this study was to evaluate the prevalence and associated factors of anemia in children aged 6 to 59 months. Methods. This was a cross-sectional descriptive and analytical study. The rapid diagnostic test "hemocue" was used to measure the hemoglobin level in the blood of 486 children aged 6 to 59 months. The cut-off point for any anemia was a hemoglobin level of less than 11.0 g/dL. The chi-square test was used to analyze the anemia prevalence differences in different characteristic groups, and the multivariate logistic regression was used to analyze the relationship between the household and sociodemographic characteristics and anemia in children. The data was processed using the SPSS software. Results. Nine out of 10 children were anemic, with a prevalence of 90.9%. Prevalences were high in both Gnagna and Gourma, respectively 89.9% and 91.6%. The results of the bivariate analysis showed that the age of the child, the household head education level and the participation of the mother in activities to prevent malnutrition were significantly associated with anemia. In multivariate analysis, children aged 6 to 12 months were 3 times more likely to have anemia than children aged over 36 months. Those aged 13 to 36 months were twice as likely to have anemia as those aged over 36 months. Conclusion. There was a need to strengthen anemia interventions taking into account the age of children.

Association between telomere length and Plasmodium falciparum malaria endemicity in sub-Saharan Africans

Leukocyte telomere length (LTL) varies significantly across human populations, with individuals of African ancestry having longer LTL than non-Africans. However, the genetic and environmental drivers of LTL variation in Africans remain largely unknown. We report here on the relationship between LTL, genetics, and a variety of environmental and climatic factors in ethnically diverse African adults (n = 1,818) originating from Botswana, Tanzania, Ethiopia, and Cameroon. We observe significant variation in LTL among populations, finding that the San hunter-gatherers from Botswana have the longest leukocyte telomeres and that the Fulani pastoralists from Cameroon have the shortest telomeres. Genetic factors explain ∼50% of LTL variation among individuals. Moreover, we observe a significant negative association between Plasmodium falciparum malaria endemicity and LTL while adjusting for age, sex, and genetics. Within Africa, adults from populations indigenous to areas with high malaria exposure have shorter LTL than those in populations indigenous to areas with low malaria exposure. Finally, we explore to what degree the genetic architecture underlying LTL in Africa covaries with malaria exposure.

Antiplasmodial Activity of β-Ionone and the Effect of the Compound on Amelioration of Anaemia and Oxidative Organ Damage in Mice Infected with Plasmodium berghei

INTRODUCTION

Owing to evolution of parasite strains that are resistant to existing antimalarial drugs, research for novel antimalarial medicines is progressing on numerous fronts.

PURPOSE

Herein, we evaluated the in vivo anti-Plasmodium berghei activity of β-ionone including its ameliorative potential towards P. berghei-associated anaemia and oxidative organ damage.

METHODS

Mice were infected with chloroquine-sensitive strain of P. berghei and then treated with β-ionone at doses of 10 and 20 mg/kg body weight (BW) for seven days. The parasitemia, packed cell volume and redox sensitive biomarkers in the liver, brain and spleen were estimated.

RESULTS

Our result showed that β-ionone, in a dose-dependent fashion, significantly (p < 0.05) repressed the multiplication of P. berghei. More so, the compound, at doses of 10 and 20 mg/kg BW, significantly (p < 0.05) mitigated anaemia and organ damage induced by P. berghei.

CONCLUSION

Overall, the findings demonstrated that β-ionone has antiplasmodial actions and plays a mitigative role against P. berghei-induced anaemia and oxidative organ damage.

Plasmodium falciparum Malaria Presenting as a Thrombotic Thrombocytopenic Purpura (TTP) Mimic: A Case Report

Malaria can present with clinical manifestations overlapping with thrombotic thrombocytopenic purpura (TTP). We present the case of a 55-year-old female who presented with abdominal pain, fever, confusion, dehydration, and recent travel to Nigeria. Laboratory investigations were remarkable for low hemoglobin, decreased platelets, and elevated lactate. Suspicion for TTP occurred when the patient's platelet count and hemoglobin progressively decreased along with acute kidney injury and confusion. There was an elevated ADAMTS13 antibody level and mildly reduced ADAMTS13 activity suggesting possible TTP. However, Plasmodium falciparum was seen on peripheral blood smears. Treatment with artemether-lumefantrine was initiated which led to improvement in parasitemia, platelet count, and anemia. The similarity between malaria and TTP is mostly explained by thrombotic microangiopathic anemia (TMA) present in both diseases. Awareness of the common pathogenesis of TMA in both diseases and clinical judgment are pivotal in determining the timely initiation of appropriate treatment.

Dihydroartemisinin-piperaquine effectiveness for seasonal malaria chemoprevention in settings with extended seasonal malaria transmission in Tanzania

Effectiveness of dihydroartemisinin-piperaquine (DP) as seasonal malaria chemoprevention (SMC) was assessed in Nanyumbu and Masasi Districts. Between March and June 2021, children aged 3-59 months were enrolled in a cluster randomized study. Children in the intervention clusters received a monthly, 3-days course of DP for three consecutive months regardless of malaria infection status, and those in the control clusters received no intervention. Malaria infection was assessed at before the first-round and at 7 weeks after the third-round of DP in both arms. Malaria prevalence after the third-round of DP administration was the primary outcome. Chi-square tests and logistic regression model were used to compare proportions and adjust for explanatory variables. Before the intervention, malaria prevalence was 13.7% (161/1171) and 18.2% (212/1169) in the intervention and control clusters, respectively, p < 004. Malaria prevalence declined to 5.8% (60/1036) in the intervention clusters after three rounds of DP, and in the control clusters it declined to 9.3% (97/1048), p = 0.003. Unadjusted and adjusted prevalence ratios between the intervention and control arms were 0.42 (95%CI 0.32-0.55, p < 0.001) and 0.77 (95%CI 0.53-1.13, p = 0.189), respectively. SMC using DP was effective for control of malaria in the two Districts.Trial registration: NCT05874869, https://clinicaltrials.gov/ 25/05/2023.

Malaria in pregnancy in India: a 50-year bird's eye

Introduction

In 2021, India contributed for ~79% of malaria cases and ~ 83% of deaths in the South East Asia region. Here, we systematically and critically analyzed data published on malaria in pregnancy (MiP) in India.

Methods

Epidemiological, clinical, parasitological, preventive and therapeutic aspects of MiP and its consequences on both mother and child were reviewed and critically analyzed. Knowledge gaps and solution ways are also presented and discussed. Several electronic databases including Google scholar, Google, PubMed, Scopus, Wiley Online library, the Malaria in Pregnancy Consortium library, the World Malaria Report, The WHO regional websites, and ClinicalTrials.gov were used to identify articles dealing with MiP in India. The archives of local scientific associations/journals and website of national programs were also consulted.

Results

Malaria in pregnancy is mainly due to Plasmodium falciparum (Pf) and P. vivax (Pv), and on rare occasions to P. ovale spp. and P. malariae too. The overall prevalence of MiP is ~0.1-57.7% for peripheral malaria and ~ 0-29.3% for placental malaria. Peripheral Pf infection at antenatal care (ANC) visits decreased from ~13% in 1991 to ~7% in 1995-1996 in Madhya Pradesh, while placental Pf infection at delivery unit slightly decreased from ~1.5% in 2006-2007 to ~1% in 2012-2015 in Jharkhand. In contrast, the prevalence of peripheral Pv infection at ANC increased from ~1% in 2006-2007 to ~5% in 2015 in Jharkhand, and from ~0.5% in 1984-1985 to ~1.5% in 2007-2008 in Chhattisgarh. Clinical presentation of MiP is diverse ranging from asymptomatic carriage of parasites to severe malaria, and associated with comorbidities and concurrent infections such as malnutrition, COVID-19, dengue, and cardiovascular disorders. Severe anemia, cerebral malaria, severe thrombocytopenia, and hypoglycemia are commonly seen in severe MiP, and are strongly associated with tragic consequences such as abortion and stillbirth. Congenital malaria is seen at prevalence of ~0-12.9%. Infected babies are generally small-for-gestational age, premature with low birthweight, and suffer mainly from anemia, thrombocytopenia, leucopenia and clinical jaundice. Main challenges and knowledge gaps to MiP control included diagnosis, relapsing malaria, mixed Plasmodium infection treatment, self-medication, low density infections and utility of artemisinin-based combination therapies.

Conclusion

All taken together, the findings could be immensely helpful to control MiP in malaria endemic areas.

Co-infection of Plasmodium falciparum and Schistosoma mansoni is associated with anaemia

BACKGROUND

Malaria and schistosomiasis persist as major public health challenge in sub-Saharan Africa. These infections have independently and also in polyparasitic infection been implicated in anaemia and nutritional deficiencies. This study aimed at assessing asymptomatic malaria, intestinal Schistosoma infections and the risk of anaemia among school children in the Tono irrigation area in the Kassena Nankana East Municipal (KNEM) in the Upper East Region of Northern Ghana.

METHODS

A cross sectional survey of 326 school children was conducted in the KNEM. Kato Katz technique was used to detect Schistosoma eggs in stool. Finger-prick capillary blood sample was used for the estimation of haemoglobin (Hb) concentration and blood smear for malaria parasite detection by microscopy.

RESULTS

The average age and Hb concentration were 10.9 years (standard deviation, SD: ± 2.29) and 11.2 g/dl (SD: ± 1.39) respectively with 58.9% (n = 192) being females. The overall prevalence of infection with any of the parasites (single or coinfection) was 49.4% (n = 161, 95% confidence interval, CI [44.0-54.8]). The prevalence of malaria parasite species or Schistosoma mansoni was 32.0% (n = 104) and 25.2% (n = 82), respectively with 7.7% (n = 25) coinfection. The prevalence of anaemia in the cohort was 40.5% (95%CI [35.3-45.9]), of which 44.4% harboured at least one of the parasites. The prevalence of anaemia in malaria parasite spp or S. mansoni mono-infections was 41.8% and 38.6%, respectively and 64.0% in coinfections. There was no statistically significant difference in the odds of being anaemic in mono-infection with malaria (OR = 1.22, 95% CI 0.71-2.11, p = 0.47) or S. mansoni (OR = 1.07, 95% CI 0.58-1.99, p = 0.83) compared to those with no infection. However, the odds of being anaemic and coinfected with malaria parasite species and S. mansoni was 3.03 times higher compared to those with no infection (OR = 3.03, 95% CI 1.26-7.28, p = 0.013). Conclusion The data show a high burden of malaria, S. mansoni infection and anaemia among school children in the irrigation communities. The risk of anaemia was exacerbated by coinfections with malaria parasite(s) and S. mansoni. Targeted integrated interventions are recommended in this focal area of KNEM.

Therapeutic activity of eugenol towards mitigation of anaemia and oxidative organ damage caused by Plasmodium berghei

The parasite responsible for causing malaria infection, Plasmodium, is known to exhibit resistance to a number of already available treatments. This has prompted the continue search for new antimalarial drugs ranging from medicinal plant parts to synthetic compounds. In lieu of this, the mitigative action of the bioactive compound, eugenol towards P. berghei-induced anaemia and oxidative organ damage was investigated following a demonstration of in vitro and in vivo antiplasmodial effects. Mice were infected with chloroquine-sensitive strain of P. berghei and thereafter treated with eugenol at doses of 10 and 20 mg/kg body weight (BW) for seven days. The packed cell volume and redox sensitive biomarkers in the liver, brain and spleen were measured. Our result demonstrated that eugenol significantly (p < 0.05) ameliorated the P. berghei-associated anaemia at a dose of 10 mg/kg BW. In addition, the compound, at a dose of 10 mg/kg BW, significantly (p < 0.05) alleviated the P. berghei-induced organ damage. This evidently confirmed that eugenol plays an ameliorative role towards P. berghei-related pathological alterations. Hence, the study opens up a new therapeutic use of eugenol against plasmodium parasite.

The Impact of Co-Infections for Human Gammaherpesvirus Infection and Associated Pathologies

The two oncogenic human gammaherpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) cause significant disease burden, particularly in immunosuppressed individuals. Both viruses display latent and lytic phases of their life cycle with different outcomes for their associated pathologies. The high prevalence of infectious diseases in Sub-Saharan Africa (SSA), particularly HIV/AIDS, tuberculosis, malaria, and more recently, COVID-19, as well as their associated inflammatory responses, could potentially impact either virus' infectious course. However, acute or lytically active EBV and/or KSHV infections often present with symptoms mimicking these predominant diseases leading to misdiagnosis or underdiagnosis of oncogenic herpesvirus-associated pathologies. EBV and/or KSHV infections are generally acquired early in life and remain latent until lytic reactivation is triggered by various stimuli. This review summarizes known associations between infectious agents prevalent in SSA and underlying EBV and/or KSHV infection. While presenting an overview of both viruses' biphasic life cycles, this review aims to highlight the importance of co-infections in the correct identification of risk factors for and diagnoses of EBV- and/or KSHV-associated pathologies, particularly in SSA, where both oncogenic herpesviruses as well as other infectious agents are highly pervasive and can lead to substantial morbidity and mortality.

Metallic Nanoparticles and Core-Shell Nanosystems in the Treatment, Diagnosis, and Prevention of Parasitic Diseases

The usage of nanotechnology in the fight against parasitic diseases is in the early stages of development, but it brings hopes that this new field will provide a solution to target the early stages of parasitosis, compensate for the lack of vaccines for most parasitic diseases, and also provide new treatment options for diseases in which parasites show increased resistance to current drugs. The huge physicochemical diversity of nanomaterials developed so far, mainly for antibacterial and anti-cancer therapies, requires additional studies to determine their antiparasitic potential. When designing metallic nanoparticles (MeNPs) and specific nanosystems, such as complexes of MeNPs, with the shell of attached drugs, several physicochemical properties need to be considered. The most important are: size, shape, surface charge, type of surfactants that control their dispersion, and shell molecules that should assure specific molecular interaction with targeted molecules of parasites' cells. Therefore, it can be expected that the development of antiparasitic drugs using strategies provided by nanotechnology and the use of nanomaterials for diagnostic purposes will soon provide new and effective methods of antiparasitic therapy and effective diagnostic tools that will improve the prevention and reduce the morbidity and mortality caused by these diseases.

Unusual clinical spectra of childhood severe malaria during malaria epidemic in eastern Uganda: a prospective study

BACKGROUND

In sub-Saharan Africa (SSA), malaria remains a public health problem despite recent reports of declining incidence. Severe malaria is a multiorgan disease with wide-ranging clinical spectra and outcomes that have been reported to vary by age, geographical location, transmission intensity over time. There are reports of recent malaria epidemics or resurgences, but few data, if any, focus on the clinical spectrum of severe malaria during epidemics. This describes the clinical spectrum and outcomes of childhood severe malaria during the disease epidemic in Eastern Uganda.

METHODS

This prospective cohort study from October 1, 2021, to September 7, 2022, was nested within the 'Malaria Epidemiological, Pathophysiological and Intervention studies in Highly Endemic Eastern Uganda' (TMA2016SF-1514-MEPIE Study) at Mbale Regional Referral Hospital, Uganda. Children aged 60 days to 12 years who at admission tested positive for malaria and fulfilled the clinical WHO criteria for surveillance of severe malaria were enrolled on the study. Follow-up was performed until day 28. Data were collected using a customized proforma on social demographic characteristics, clinical presentation, treatment, and outcomes. Laboratory analyses included complete blood counts, malaria RDT (SD BIOLINE Malaria Ag P.f/Pan, Ref. 05FK60-40-1) and blood slide, lactate, glucose, blood gases and electrolytes. In addition, urinalysis using dipsticks (Multistix^® 10 SG, SIEMENS, Ref.2300) at the bedside was done. Data were analysed using STATA V15.0. The study had prior ethical approval.

RESULTS

A total of 300 participants were recruited. The median age was 4.6 years, mean of 57.2 months and IQR of 44.5 months. Many children, 164/300 (54.7%) were under 5 years, and 171/300 (57.0%) were males. The common clinical features were prostration 236/300 (78.7%), jaundice in 205/300 (68.3%), severe malarial anaemia in 158/300 (52.7%), black water fever 158/300 (52.7%) and multiple convulsions 51/300 (17.0%), impaired consciousness 50/300(16.0%), acidosis 41/300(13.7%), respiratory distress 26/300(6.7%) and coma in 18/300(6.0%). Prolonged hospitalization was found in 56/251 (22.3%) and was associated with acidosis, P = 0.041. The overall mortality was 19/300 (6.3%). Day 28 follow-up was achieved in 247/300 (82.3%).

CONCLUSION

During the malaria epidemic in Eastern Uganda, severe malaria affected much older children and the spectrum had more of prostration, jaundice severe malarial anaemia, black water fever and multiple convulsions with less of earlier reported respiratory distress and cerebral malaria.

Delayed Hemolysis With Parenteral Artesunate

Artesunate is an effective and first-line therapy option in patients with severe malaria caused by Plasmodium species. Among adverse effects of the drug is a phenomenon of delayed hemolysis. This usually occurs at least 7 days after initiation of therapy, and is characterized by reductions in hemoglobin and haptoglobin and an increase in lactate dehydrogenase. Here, we report an instance of delayed hemolysis in a patient probably attributed to parenteral artesunate therapy.

Parasites and childhood stunting - a mechanistic interplay with nutrition, anaemia, gut health, microbiota, and epigenetics

Globally, stunting affects approximately 149.2 million children under 5 years of age. The underlying aetiology and pathophysiological mechanisms leading to stunting remain elusive, and therefore few effective treatment and prevention strategies exist. Crucial evidence directly linking parasites to stunting is often lacking - in part due to the complex nature of stunting, as well as a lack of critical multidisciplinary research amongst key age groups. Here, based on available studies, we present potential mechanistic pathways by which parasitic infection of mother and/or infant may lead to childhood stunting. We highlight the need for future multidisciplinary longitudinal studies and clinical trials aimed at elucidating the most influential factors, and synergies therein, that can lead to stunting, and ultimately towards finding solutions to successfully mitigate against it.

TLR7 modulates extramedullary splenic erythropoiesis in P. yoelii NSM-infected mice through the regulation of iron metabolism of macrophages with IFN-γ

Splenomegaly is a prominent clinical manifestation of malaria and the causes remain incompletely clear. Anemia is induced in malaria and extramedullary splenic erythropoiesis is compensation for the loss of erythrocytes. However, the regulation of extramedullary splenic erythropoiesis in malaria is unknown. An inflammatory response could facilitate extramedullary splenic erythropoiesis in the settings of infection and inflammation. Here, when mice were infected with rodent parasites, Plasmodium yoelii NSM, TLR7 expression in splenocytes was increased. To explore the roles of TLR7 in splenic erythropoiesis, we infected wild-type and TLR7 ^-/- C57BL/6 mice with P. yoelii NSM and found that the development of splenic erythroid progenitor cells was impeded in TLR7 ^-/- mice. Contrarily, the treatment of the TLR7 agonist, R848, promoted extramedullary splenic erythropoiesis in wild-type infected mice, which highlights the implication of TLR7 on splenic erythropoiesis. Then, we found that TLR7 promoted the production of IFN-γ that could enhance phagocytosis of infected erythrocytes by RAW264.7. After phagocytosis of infected erythrocytes, the iron metabolism of RAW264.7 was upregulated, evidenced by higher iron content and expression of Hmox1 and Slc40a1. Additionally, the neutralization of IFN-γ impeded the extramedullary splenic erythropoiesis modestly and reduced the iron accumulation in the spleen of infected mice. In conclusion, TLR7 promoted extramedullary splenic erythropoiesis in P. yoelii NSM-infected mice. TLR7 enhanced the production of IFN-γ, and IFN-γ promoted phagocytosis of infected erythrocytes and the iron metabolism of macrophages in vitro, which may be related to the regulation of extramedullary splenic erythropoiesis by TLR7.

Erythropoiesis and Malaria, a Multifaceted Interplay

One of the major pathophysiologies of malaria is the development of anemia. Although hemolysis and splenic clearance are well described as causes of malarial anemia, abnormal erythropoiesis has been observed in malaria patients and may contribute significantly to anemia. The interaction between inadequate erythropoiesis and Plasmodium parasite infection, which partly occurs in the bone marrow, has been poorly investigated to date. However, recent findings may provide new insights. This review outlines clinical and experimental studies describing different aspects of ineffective erythropoiesis and dyserythropoiesis observed in malaria patients and in animal or in vitro models. We also highlight the various human and parasite factors leading to erythropoiesis disorders and discuss the impact that Plasmodium parasites may have on the suppression of erythropoiesis.

Micro-Raman spectroscopy study of optically trapped erythrocytes in malaria, dengue and leptospirosis infections

Malaria, dengue and leptospirosis are three tropical infectious diseases that present with severe hematological derangement causing significant morbidity and mortality, especially during the seasonal monsoons. During the course of these infectious diseases, circulating red blood cells are imperiled to the direct ill-effects of the infectious pathogen in the body as well as to the pro-inflammatory cytokines generated as a consequence of the infection. RBCs when exposed to such inflammatory and/or pathogenic milieu are susceptible to injuries such as RBC programmed eryptosis or RBC programmed necrosis. This research aimed to explore the Raman spectra of live red cells that were extracted from patients infected with malaria, dengue, and leptospirosis. Red cells were optically trapped and micro-Raman probed using a 785 nm Diode laser. RBCs from samples of all three diseases displayed Raman signatures that were significantly altered from the normal/healthy. Distinct spectral markers that were common across all the four groups were obtained from various standardized multivariate analytical methods. Following comprehensive examination of multiple studies, we propose these spectral wavenumbers as "Raman markers of RBC injury." Findings in our study display that anemia-triggering infections can inflict variations in the healthy status of red cells, easily identifiable by selectively analyzing specific Raman markers. Additionally, this study also highlights relevant statistical tools that can be utilized to study Raman spectral data from biological samples which could help identify the very significant Raman peaks from the spectral band. This approach of RBC analysis can foster a better understanding of red cell behavior and their alterations exhibited in health and disease.

Integrated Network Pharmacology Analysis and Serum Metabolomics to Reveal the Anti-malaria Mechanism of Artesunate

Artesunate is a widely used drug in clinical treatment of malaria. The aim of this study was to investigate the therapeutic mechanism of artesunate on malaria using an integrated strategy of network pharmacology and serum metabolomics. The mice models of malaria were established using 2 × 10⁷ red blood cells infected with Plasmodium berghei ANKA injection. Giemsa and hematoxylin-eosin (HE) staining were used to evaluate the efficacy of artesunate on malaria. Next, network pharmacology analysis was applied to identify target genes. Then, a metabolomics strategy has been developed to find the possible significant serum metabolites and metabolic pathways induced by artesunate. Additionally, two parts of the results were integrated to confirm each other. Giemsa and HE staining results showed that artesunate significantly inhibited the proliferation of Plasmodium and reduced liver and spleen inflammation. Based on metabolomics, 18 differential endogenous metabolites were identified as potential biomarkers related to the artesunate for treating malaria. These metabolites were mainly involved in the relevant pathways of biosynthesis of unsaturated fatty acids; aminoacyl-tRNA biosynthesis; valine, leucine, and isoleucine biosynthesis; and phenylalanine, tyrosine, and tryptophan biosynthesis. The results of the network pharmacology analysis showed 125 potential target genes related to the treatment of malaria with artesunate. The functional enrichment was mainly associated with lipid and atherosclerosis; pathways of prostate cancer and proteoglycans in cancer; and PI3K-Akt, apoptosis, NF-κB, Th17 cell, and AGE-RAGE signaling pathways. These findings were partly consistent with the findings of the metabolism. Our results further suggested that artesunate could correct the inflammatory response caused by malaria through Th17 cell and NF-κB pathways. Meanwhile, our work revealed that cholesterol needed by Plasmodium berghei came directly from serum. Cholesterol and palmitic acid may be essential in the growth and reproduction of Plasmodium berghei. In summary, artesunate may have an effect on anti-malarial properties through multiple targets.

Safety of Treating Malaria with Artemisinin-Based Combination Therapy in the First Trimester of Pregnancy

There have been recent calls for the use of artemisinin-based combination therapies (ACTs) for uncomplicated malaria in the first trimester of pregnancy. Nevertheless, the 2021 WHO Guidelines for Malaria reaffirmed their position that there is not adequate clinical safety data on artemisinins to support that usage. The WHO's position is consistent with several issues with the existing clinical data. First, first trimester safety results from multiple ACTs were lumped in a meta-analysis which does not demonstrate that each of the included ACTs is equally safe. Second, safety results from all periods of the first trimester were lumped in the meta-analysis which does not demonstrate the same level of safety for all subperiods, particularly gestational Weeks 6 to 8 which is likely to be the most sensitive period. Third, even if there is evidence of a lack of an effect on miscarriage for a particular ACT, it does not follow then there are no developmental effects for any ACT. In monkeys, artesunate caused marked embryonal anemia leading to embryo death but the long-term consequences of lower levels of embryonal anemia are not known. Fourth, there have been advances in the sensitivity and usage of rapid diagnostic tests that will lead to diagnoses of malaria earlier in gestation which is less well studied and more likely sensitive to artemisinins. Any clinical studies of the safety of ACTs in the first trimester need to evaluate the results of treatment with individual ACTs during different 1- to 2-week periods of the first trimester.

Effect of Allicin and Artesunate Combination Treatment on Experimental Mice Infected with Plasmodium berghei

Malaria is still a significant health problem in endemic countries and increases Plasmodium resistance to the available antimalarial drugs. Hence, this study aimed to investigate the antimalarial activity of allicin and its combination with artesunate (ART) against rodent malaria Plasmodium berghei ANKA (PbANKA) infected mice. Allicin was prepared in 20% Tween-80. Balb/c mice were inoculated intraperitoneally with 1×10⁷ PbANKA-infected erythrocytes and orally given by gavage with the chosen doses of 1, 10, 50, and 100 mg/kg of allicin and 1, 5, 10, and 20 mg/kg of ART once a day for 4 consecutive days. Effective dose 50 (ED₅₀) of allicin and ART was subsequently investigated. Moreover, the combination (1 : 1) of allicin and ART at the doses of their respective ED₅₀, ED₅₀ 1/2, ED₅₀ 1/4, and ED₅₀ 1/8 was also carried out. The untreated control was given 20% Tween-80. The results showed that allicin presented a dose-dependent antimalarial activity with significance (p < 0.05). The ED₅₀ values of allicin and ART were about 14 and 5 mg/kg, respectively. For combination, allicin and ART showed a synergistic effect at the combination doses of ED₅₀, ED₅₀ 1/2, and ED₅₀ 1/4 with significantly (p < 0.01) prevented reduction of packed cell volume, bodyweight loss, rapid dropping of rectal temperature, and markedly prolonged mean survival time, compared with the untreated control and single treatment. It can be concluded that allicin exerted potential antimalarial activity in single and its combination with ART.

Association between vitamin D serum levels and clinical, laboratory, and parasitological parameters in patients with malaria from an endemic area of the Amazon

BACKGROUND

Some studies have suggested the importance of vitamin D [25(OH)D] in malaria clinical practice. The prevalence of 25(OH)D deficiency in the Amazon population is not well known, and there are few studies in patients with malaria. This study aimed to evaluate 25(OH)D serum levels in patients with malaria and determine their relationships with epidemiological, clinical, laboratory, and parasitemia data.

METHODS

An analytical cross-sectional study of 123 patients with malaria and 122 individuals without malaria was performed in Itaituba, Pará, Brazil, from January 2018 to October 2019, by evaluating sociodemographic, clinical-epidemiological, parasitological, and laboratory data and adopting a 5% significance level. Parametric tests (Student's t-test), non-parametric tests (Mann-Whitney U), and Spearman's correlation ([rs], for non-parametric variables) were used according to the nature of the distribution of the variables. For the qualitative variables, Pearson's chi-square test, Fisher's exact test, and the G test were used. Spearman's correlation was used to compare the results of the 25(OH)D levels and blood counts performed among patients and the control group.

RESULTS

Malaria patients residing in a mining area had 25(OH)D serum levels that were significantly lower than those in the control group residing in the mining area, though both were within normal levels. Red blood cell counts had an inverse correlation with parasitemia (Plasmodium falciparum), and platelet levels had an inverse correlation with parasitemia (Plasmodium vivax). 25(OH)D deficiency was evidenced in Itaituba, in the state of Pará, which is an endemic area of malaria in the Amazon region.

Age-modified factors associated with placental malaria in rural Burkina Faso

BACKGROUND

Malaria in pregnancy can result in placental infection with fetal implications. This study aimed at assessing placental malaria (PM) prevalence and its associated factors in a cohort of pregnant women with peripheral malaria and their offspring.

METHOD

The data were collected in the framework of a clinical trial on treatments for malaria in pregnant women . Placental malaria (PM) was diagnosed by histopathological detection of parasites and/or malaria pigment on placenta biopsies taken at delivery. Factors associated with PM were assessed using logistic regression.

RESULTS

Out of 745 biopsies examined, PM was diagnosed in 86.8 % of women. Acute, chronic and past PM were retrieved in 11 (1.5 %), 170 (22.8 %), and 466 (62.6 %) women, respectively. A modifying effect was observed in the association of gravidity or anemia at the study start with pooled PM (presence of parasites and/or malaria pigment). In women under 30, gravidity ≤ 2 was associated with an increased prevalence of pooled PM but in women aged 30 years or more, gravidity was no more associated with pooled PM (OR 6.81, 95 % CI 3.18 - 14.60; and OR 0.52, 95 % CI 0.10 - 2.76, respectively). Anemia was associated with pooled PM in women under 30 (OR 1.96, 95 % CI 1.03 - 3.72) but not in women aged 30 years or more (OR 0.68, 95 % CI 0.31 - 1.49). Similarly, the association of gravidity with past-chronic PM depended also on age. A higher prevalence of active PM was observed in women under 30 presenting with symptomatic malaria (OR 3.79, 95 % CI 1.55 - 9.27), while there was no significant increase in the prevalence of active PM (presence of parasites only) in women with symptomatic malaria when aged 30 years or more (OR 0.42, 95 % CI 0.10 - 1.75). In women with chronic PM, the prevalence of low birth weight or prematurity was the highest (31.2 %) as compared with past PM or no PM.

CONCLUSION

Despite the rapid diagnosis and efficacious treatment of peripheral infection, the prevalence of placental malaria remained high in women with P. falciparum peripheral infection in Nanoro, especially in younger women This underlines the importance of preventive measures in this specific group.

Pseudoreticulocytosis by the ADVIA 2120 Hematology Analyzer and Other Hematologic Changes in a Cynomolgus Macaque (Macaca fascicularis) With Malaria

Important hematologic changes can be observed in nonhuman primates with malaria, including inaccurate reticulocyte counts by the ADVIA 2120 hematology analyzer. A 5-year-old male purpose-bred cynomolgus macaque ( Macaca fascicularis) imported from a commercial source in Cambodia was enrolled in a nonclinical toxicity study investigating the effects of an immunomodulatory pharmaceutical agent. On study day 22, an increase in large unstained cells (LUCs), due to increased monocytes (2.20 × 103/µl, reference interval: 0.17-0.76 × 103/µl), was reported by the analyzer during a scheduled hematologic evaluation, which prompted blood smear review and revealed that the macaque had a high burden of Plasmodium spp.. The macaque did not have clinical signs for the infection at this time point. Progressively higher parasite burdens and persistently increased monocytes (markedly increased by study day 56, 10.38 × 103/µl) were observed at subsequent hematologic evaluations. New Methylene Blue stain manual reticulocyte counts were performed on study day 43 and at later time points, and showed that the analyzer reported erroneous higher reticulocyte counts (study day 43: +6.7%, +266.2 × 109/L; study day 50: +18.9%, +409.8 × 109/L) compared with the manual reticulocyte counts (pseudoreticulocytosis). The magnitude of regenerative response was considered inadequate for the severity of anemia at these time points. Atypical reticulocyte scatter plot distributions from the analyzer were also observed at time points with high parasite burdens, and combined with increased LUCs, may suggest high burden parasitemia. Verification of automated reticulocyte counts is important in cases with high malarial parasite burdens and the recognition of pseudoreticulocytosis is prudent in assessing appropriateness of the regenerative response. Increases in monocytes correlated with higher parasite burdens and marked increases may be an indicator of advanced disease.

A single low dose of primaquine is safe and sufficient to reduce transmission of Plasmodium falciparum gametocytes regardless of cytochrome P450 2D6 enzyme activity in Bagamoyo district, Tanzania

BACKGROUND

Primaquine is a pro-drug and its active metabolite is potent against mature Plasmodium falciparum gametocytes. Primaquine is metabolized by a highly polymorphic cytochrome P450 2D6 (CYP2D6) enzyme. Mutations in the gene encoding this enzyme may lead to impaired primaquine activity. This study assessed if 0.25 mg/kg single-dose primaquine is safe and sufficient to reduce transmission of gametocytes in individuals with no, reduced, or increased CYP2D6 enzyme activity.

METHODS

Between June 2019 and January 2020 children aged 1-10 years, attending at Yombo dispensary, Bagamoyo district, with confirmed microcopy-determined uncomplicated P. falciparum malaria were enrolled in the study. The enrolled patients were treated with a standard artemether-lumefantrine regimen plus 0.25 mg/kg single-dose primaquine and followed up for 28 days for clinical and laboratory assessment. Primaquine was administered with the first dose of artemether-lumefantrine. Safety assessment involved direct questioning and recording of the nature and incidence of clinical signs and symptoms, and measurement of haemoglobin (Hb) concentration. Blood samples collected from 100 patients were used for assessment of post-treatment infectiousness on day 7 using mosquito membrane feeding assays. Molecular methods were used to determine CYP2D6 and glucose-6-phosphate dehydrogenase (G6PD) status. The primary outcome was the safety of 0.25 mg/kg single-dose primaquine based on CYP2D6 status.

RESULTS

In total, 157 children [median age 6.4 (Interquartile range 4.0-8.2) years] were recruited, of whom 21.0% (33/157) and 12.7% (20/157) had reduced CYP2D6 and deficient G6PD activity, respectively. Day 3 mean absolute Hb concentration reduction was 1.50 g/dL [95% confidence interval (CI) 1.10-1.90] and 1.51 g/dL (95% CI 1.31-1.71) in reduced and normal CYP2D6 patients, respectively (t = 0.012, p = 0.990). The day 3 mean absolute Hb concentration reduction in G6PD deficient, G6PD normal and heterozygous female was 1.82 g/dL (95% CI 1.32-2.32), 1.48 g/dL (95% CI 1.30-1.67) and 1.47 g/dL (95% CI 0.76-2.18), respectively (F = 0.838, p = 0.435). Sixteen percent (16/98) of the patients each infected at least one mosquito on day 7, and of these, 10.0% (2/20) and 17.9% (14/78) had reduced and normal CYP2D6 enzyme activity, respectively (x2 = 0.736, p = 0.513).

CONCLUSION

Single-dose 0.25 mg/kg primaquine was safe and sufficient for reducing transmission of P. falciparum gametocytes regardless of CYP2D6 or G6PD status. Trial registration Study registration number: NCT03352843.

CD4+ICOS+Foxp3+: a sub-population of regulatory T cells contribute to malaria pathogenesis

BACKGROUND

Regulatory T cells are known to play a key role to counter balance the protective immune response and immune mediated pathology. However, the role of naturally occurring regulatory cells CD4⁺CD25⁺Foxp3⁺ in malaria infection during the disease pathogenesis is controversial. Beside this, ICOS molecule has been shown to be involved in the development and function of regulatory T cell enhance IL-10 production. Therefore, possible involvement of the ICOS dependent regulatory CD4⁺ICOS⁺Foxp3⁺ T cells in resistance/susceptibility during malaria parasite is explored in this study.

METHODS

5 × 10⁵ red blood cells infected with non-lethal and lethal parasites were inoculated in female Balb/c mice by intra-peritoneal injection. Infected or uninfected mice were sacrificed at early (3rd day post infection) and later stage (10th day post infection) of infection. Harvested cells were analysed by using flow cytometer and serum cytokine by Bioplex assay.

RESULTS

Thin blood films show that percentages of parasitaemia increases with disease progression in infections with the lethal malaria parasite and mice eventually die by day 14th post-infection. Whereas in case of non-lethal malaria parasite, parasitaemia goes down by 7th day post infection and gets cleared within 13th day. The number of CD4⁺ ICOS⁺ T cells increases in lethal infection with disease progression. Surprisingly, in non-lethal parasite, ICOS expression decreases after day 7th post infection as parasitaemia goes down. The frequency of CD4⁺ICOS⁺FoxP3⁺ Tregs was significantly higher in lethal parasitic infection as compared to the non-lethal parasite. The level of IL-12 cytokine was remarkably higher in non-lethal infection compared to the lethal infection. In contrast, the level of IL-10 cytokines was higher in lethal parasite infection compared to the non-lethal parasite.

CONCLUSION

Taken together, these data suggest that lethal parasite induce immunosuppressive environment, protecting from host immune responses and help the parasite to survive whereas non-lethal parasite leads to low frequencies of Treg cells seldom impede immune response that allow the parasite to get self-resolved.

High-carbohydrate diet lacked the potential to ameliorate parasitemia and oxidative stress in mice infected with Plasmodium berghei

The search for a novel prophylactic agent against malaria is on the rise due to the negative socio-economic impact of the disease in tropical and subtropical regions of the world. Sequel to this, we evaluated the in vivo anti-Plasmodium berghei activity of a high-carbohydrate diet as well as the effects of the diet on parasite-associated anemia and organ damage. Mice were fed with either standard or a high-carbohydrate diet for 4 weeks and subsequently infected with chloroquine-sensitive strain of P. berghei. The levels of parasitemia, blood glucose, packed cell volume, and redox sensitive biomarkers of brain and liver tissues were measured. Data from this study showed that high-carbohydrate significantly (p < 0.05) aggravated the multiplication of P. berghei in the animals. Furthermore, our result demonstrated that blood glucose level in P. berghei-infected mice fed with a high-carbohydrate diet was insignificantly (p > 0.05) depleted. Additionally, our findings revealed that high-carbohydrate did not demonstrate a significant (p < 0.05) ameliorative potentials against P. berghei-induced anemia and oxidative stress in the brain and liver tissues. We concluded that high-carbohydrate diet was unable to suppress P. berghei upsurge and accordingly could not mitigate certain pathological alterations induced by P. berghei infection.

Malaria infection and anemia status in under-five children from Southern Tanzania where seasonal malaria chemoprevention is being implemented

BACKGROUND

Malaria and anemia remain major public health challenges in Tanzania. Household socioeconomic factors are known to influence these conditions. However, it is not clear how these factors influence malaria transmission and anemia in Masasi and Nanyumbu Districts. This study presents findings on malaria and anemia situation in under-five children and its influencing socioeconomic factors in Masasi and Nanyumbu Districts, surveyed as part of an ongoing seasonal malaria chemoprevention operational study.

METHODS

A community-based cross-sectional survey was conducted between August and September 2020. Finger-prick blood samples collected from children aged 3-59 months were used to test for malaria infection using malaria rapid diagnostic test (mRDT), thick smears for determination of asexual and sexual parasitemia, and thin smear for parasite speciation. Hemoglobin concentration was measured using a HemoCue spectrophotometer. A structured questionnaire was used to collect household socioeconomic information from parents/caregivers of screened children. The prevalence of malaria was the primary outcome. Chi-square tests, t-tests, and logistic regression models were used appropriately.

RESULTS

Overall mRDT-based malaria prevalence was 15.9% (373/2340), and was significantly higher in Nanyumbu (23.7% (167/705) than Masasi District (12.6% (206/1635), p<0.001. Location (Nanyumbu), no formal education, household number of people, household number of under-fives, not having a bed net, thatched roof, open/partially open eave, sand/soil floor, and low socioeconomic status were major risks for malaria infection. Some 53.9% (1196/2218) children had anemia, and the majority were in Nanyumbu (63.5% (458/705), p<0.001. Location (Nanyumbu), mRDT positive, not owning a bed net, not sleeping under bed net, open/partially open eave, thatched window, sex of the child, and age of the child were major risk factors for anemia.

CONCLUSION

Prevalence of malaria and anemia was high and was strongly associated with household socioeconomic factors. Improving household socioeconomic status is expected to reduce the prevalence of the conditions in the area.

Oxidative Stress and Pathogenesis in Malaria

Malaria is a highly inflammatory and oxidative disease. The production of reactive oxygen species by host phagocytes is an essential component of the host response to Plasmodium infection. Moreover, host oxidative enzymes, such as xanthine oxidase, are upregulated in malaria patients. Although increased production of reactive oxygen species contributes to the clearance of the parasite, excessive amounts of these free radicals can mediate inflammation and cause extensive damage to host cells and tissues, probably contributing to severe pathologies. Plasmodium has a variety of antioxidant enzymes that allow it to survive amidst this oxidative onslaught. However, parasitic degradation of hemoglobin within the infected red blood cell generates free heme, which is released at the end of the replication cycle, further aggravating the oxidative burden on the host and possibly contributing to the severity of life-threatening malarial complications. Additionally, the highly inflammatory response to malaria contributes to exacerbate the oxidative response. In this review, we discuss host and parasite-derived sources of oxidative stress that may promote severe disease in P. falciparum infection. Therapeutics that restore and maintain oxidative balance in malaria patients may be useful in preventing lethal complications of this disease.

Profiling the Quality and Quantity of Naturally Induced Antibody Responses Against Pfs230 and Pfs48/45 Among Non-Febrile Children Living in Southern Ghana: A Longitudinal Study

A clear understanding of the properties of naturally induced antibody responses against transmission-blocking vaccine candidates can accelerate the understanding of the development of transmission-blocking immunity. This study characterized the naturally induced IgG responses against two leading transmission-blocking vaccine antigens, Pfs230 and Pfs48/45, in non-febrile children living in Simiw, Ghana. Consecutive sampling was used to recruit 84 non-febrile children aged from 6 to 12 years old into the 6-month (November 2017 until May 2018) longitudinal study. Venous blood (1 ml) was collected once every 2 months and used to determine hemoglobin levels, P. falciparum prevalence using microscopy and polymerase chain reaction, and the levels and relative avidity of IgG responses against Pfs230 and Pfs48/45 using indirect ELISA. IgG levels against Pfs230 and Pfs48/45 decreased from the start (November) to the middle (January) and end (March) of the dry season respectively, then they began to increase. Participants, especially older children (10-12 years old) with active infections generally had lower antibody levels against both antigens. The relative avidities of IgG against both antigens followed the trend of IgG levels until the middle of the dry season, after which the relative avidities of both antigens correlated inversely with the antibody levels. In conclusion, although IgG antibody levels against both Pfs48/45 and Pfs230 began to increase by the early rainy season, they were inversely correlated to their respective relative avidities.

Artesunate-induced hemolysis in severe complicated malaria - A diagnostic challenge: A case report and literature review of anemia in malaria

Malaria infection, which results due to the parasitic protozoan Plasmodium, has several known etiologies of hemolytic anemia as a possible complication in cases such as concurrent G6PD deficiency, severe parasitemia, or use of parenteral antimalarials. Although artemisinin-based antimalarial therapies are generally well-tolerated, several cases of severe post-artemisinin delayed hemolysis (PADH) have been recently reported, which present a diagnostic challenge, and affect morbidity and mortality in patients with malarial infection. We highlight the case of a young lady with Plasmodium falciparum severe parasitemia who developed hemolytic anemia after parenteral artesunate therapy.

Confounding influences of malnutrition and Plasmodium falciparum and Schistosoma haematobium infections on haematological parameters in school children in Muyuka, Cameroon

Background

School-aged children (SAC) are a high-risk demographic group for infectious diseases and malnutrition. The objective of this study was to assess the burden and the effect of Plasmodium falciparum and Schistosoma haematobium infections on the haematological indices in SAC and the confounding influence of malnutrition on the outcomes.

Methods

This cross-sectional study was conducted in SAC 4–14 years old living in Ikata, Bafia and Mile 14-Likoko in Muyuka, Cameroon. Anthropometric measures of malnutrition were obtained and blood samples collected were used for detection of malaria parasites by Giemsa-stained blood films using light microscopy and complete blood count analysis using an automated haematology analyser. Urine samples collected were used to detect micro haematuria with the aid of reagent strips and the eggs of S. haematobium by urine filtration technique. Multiple linear regression model was used to examine influence of independent variables on haematological parameters.

Results

Out of the 606 SAC examined, the prevalence of single infections with Plasmodium or S. haematobium and co-infection with both parasites was 16.2, 16.3 and 8.3%, respectively. Overall, malaria parasite (MP), urogenital schistosomiasis, malnutrition, anaemia, haematuria, microcytosis and thrombocytopenia was prevalent in 24.4, 24.6, 25.9, 74.4, 12.2, 45.4 and 11.1% of SAC, respectively. A significant linear decline (P = 0.023) in prevalence of P. falciparum infection with the severity of stunting was observed. Factors that significantly influenced haematological parameters included haemoglobin: age, stunting and MP; haematocrit: age and MP; white blood cell count: age; red blood cell count; age and MP; lymphocyte counts: stunting; mean cell volume: age; mean cell haemoglobin: age and stunting; mean cell haemoglobin concentration: sex, stunting and red cell distribution width-coefficient of variation: sex, age and stunting.

Conclusions

Malnutrition, Plasmodium and S. haematobium infections are common while anaemia is a severe public health problem in Muyuka, Cameroon. The interaction between haematological parameters with malaria parasites as well as linear growth index was negative and other interactions indicate systemic inflammation. While findings provide contextual intervention targets to ensure the judicious use of the limited resources, there is need for regular monitoring and proper treatment to improve the health of the underserved population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06201-9.

Pancytopenia with hemophagocytic lymphohistiocytosis in Plasmodium falciparum: A unusual presentation

Hematological manifestations such as anemia and thrombocytopenia are known complications in malaria. Here, we report two cases presented as pancytopenia with hepatosplenomegaly and initial diagnosis kept as hematological malignancy like leukemia but later on its diagnosed as malaria-associated hemophagocytic lymphohistiocytosis which is a rare entity. The aim of this report is to draw the attention of physicians, especially in tropical countries such as India and Sub-Saharan nations to keep in mind this uncommon presentation of malaria, though the exact pathophysiological mechanism still remains obscure.

A systematic review and meta-analysis of asymptomatic malaria infection in pregnant women in Sub-Saharan Africa: A challenge for malaria elimination efforts

Background

In Sub-Saharan Africa (SSA), where malaria transmission is stable, malaria infection in pregnancy adversely affects pregnant women, fetuses, and newborns and is often asymptomatic. So far, a plethora of primary studies have been carried out on asymptomatic malaria infection in pregnant women in SSA. Nevertheless, no meta-analysis estimated the burden of asymptomatic malaria infection in pregnant women in SSA, so this meta-analysis was carried out to bridge this gap.

Methods

PubMed, Web of Science, Scopus, Embase, and ProQuest were systematically searched for relevant studies published until 4 August 2020, and also the expansion of the search was performed by October 24, 2020. We assessed heterogeneity among included studies using I-squared statistics (I²). Publication bias was assessed by visual inspection of the funnel plot and further quantitatively validated by Egger’s and Begg’s tests. The pooled prevalence and pooled odds ratio (OR) and their corresponding 95% Confidence Interval (CI) were estimated using the random-effects model in Stata 15 software.

Results

For this meta-analysis, we included 35 eligible studies. The overall prevalence estimate of asymptomatic Plasmodium infection prevalence was 26.1%% (95%CI: 21–31.2%, I² = 99.0%). According to species-specific pooled prevalence estimate, Plasmodium falciparum was dominant species (22.1%, 95%CI: 17.1–27.2%, I² = 98.6%), followed by Plasmodium vivax, Plasmodium malariae and Plasmodium ovale, respectively, found to be 3% (95%CI: 0–5%, I² = 88.3%), 0.8% (95%CI: 0.3–0.13%, I² = 60.5%), and 0.2% (95%CI: -0.01–0.5%, I² = 31.5%). Asymptomatic malaria-infected pregnant women were 2.28 times more likely anemic (OR = 2.28, 95%CI: 1.66–3.13, I² = 56.3%) than in non-infected pregnant women. Asymptomatic malaria infection was 1.54 times higher (OR = 1.54, 95%CI: 1.28–1.85, I² = 11.5%) in primigravida women compared to multigravida women.

Conclusion

In SSA, asymptomatic malaria infection in pregnant women is prevalent, and it is associated with an increased likelihood of anemia compared to non-infected pregnant women. Thus, screening of asymptomatic pregnant women for malaria and anemia should be included as part of antenatal care.

Towards the elimination of Plasmodium vivax malaria: Implementing the radical cure

In this review for the Vivax malaria collection, Kamala Thriemer and colleagues explore efforts to eliminate P. vivax malaria.

Glucose-6-phosphate dehydrogenase activity in individuals with and without malaria: Analysis of clinical trial, cross-sectional and case-control data from Bangladesh

BACKGROUND

Glucose-6-phosphate dehydrogenase (G6PD) activity is dependent upon G6PD genotype and age of the red blood cell (RBC) population, with younger RBCs having higher activity. Peripheral parasitemia with Plasmodium spp. induces hemolysis, replacing older RBCs with younger cells with higher G6PD activity. This study aimed to assess whether G6PD activity varies between individuals with and without malaria or a history of malaria.

METHODS AND FINDINGS

Individuals living in the Chittagong Hill Tracts of Bangladesh were enrolled into 3 complementary studies: (i) a prospective, single-arm clinical efficacy trial of patients (n = 175) with uncomplicated malaria done between 2014 and 2015, (ii) a cross-sectional survey done between 2015 and 2016 (n = 999), and (iii) a matched case-control study of aparasitemic individuals with and without a history of malaria done in 2020 (n = 506). G6PD activity was compared between individuals with and without malaria diagnosed by microscopy, rapid diagnostic test (RDT), or polymerase chain reaction (PCR), and in aparasitemic participants with and without a history of malaria. In the cross-sectional survey and clinical trial, 15.5% (182/1,174) of participants had peripheral parasitemia detected by microscopy or RDT, 3.1% (36/1,174) were positive by PCR only, and 81.4% (956/1,174) were aparasitemic. Aparasitemic individuals had significantly lower G6PD activity (median 6.9 U/g Hb, IQR 5.2-8.6) than those with peripheral parasitemia detected by microscopy or RDT (7.9 U/g Hb, IQR 6.6-9.8, p < 0.001), but G6PD activity similar to those with parasitemia detected by PCR alone (submicroscopic parasitemia) (6.1 U/g Hb, IQR 4.8-8.6, p = 0.312). In total, 7.7% (14/182) of patients with malaria had G6PD activity < 70% compared to 25.0% (248/992) of participants with submicroscopic or no parasitemia (odds ratio [OR] 0.25, 95% CI 0.14-0.44, p < 0.001). In the case-control study, the median G6PD activity was 10.3 U/g Hb (IQR 8.8-12.2) in 253 patients with a history of malaria and 10.2 U/g Hb (IQR 8.7-11.8) in 253 individuals without a history of malaria (p = 0.323). The proportion of individuals with G6PD activity < 70% was 11.5% (29/253) in the cases and 15.4% (39/253) in the controls (OR 0.7, 95% CI 0.41-1.23, p = 0.192). Limitations of the study included the non-contemporaneous nature of the clinical trial and cross-sectional survey.

CONCLUSIONS

Patients with acute malaria had significantly higher G6PD activity than individuals without malaria, and this could not be accounted for by a protective effect of G6PD deficiency. G6PD-deficient patients with malaria may have higher than expected G6PD enzyme activity and an attenuated risk of primaquine-induced hemolysis compared to the risk when not infected.

Phytol suppresses parasitemia and ameliorates anaemia and oxidative brain damage in mice infected with Plasmodium berghei

The quest for the development of a novel antimalarial drug informed the decision to subject phytol to in vivo trials following a demonstration of therapeutic potential against chloroquine sensitive strain of Plasmodium falciparum under in vitro condition. On this basis, the in vivo anti-Plasmodium berghei activity of phytol including the ameliorative effects of the compound on P. berghei-associated anaemia and organ damage were investigated. Mice were infected with chloroquine-sensitive strain of P. berghei and were treated with phytol at a dose of 10 and 20 mg/kg body weight (BW) for four days. The levels of parasitemia, packed cell volume and redox sensitive biomarkers of liver, brain and spleen tissues were determined. Our result revealed that phytol significantly (p < 0.05) suppressed the multiplication of P. berghei in a dose-dependent manner. Additionally, the phytol significantly (p < 0.05) ameliorated the P. berghei-induced anaemia and brain damage. Data from the present study demonstrated that phytol has suppressive effect on P. berghei and could ameliorate some P. berghei-induced pathological changes.

Dual Anti-Malarial and GSK3β-Mediated Cytokine-Modulating Activities of Quercetin Are Requisite of Its Potential as a Plant-Derived Therapeutic in Malaria

Although death in malaria is attributed to cerebrovascular blockage and anaemia, overwhelming cytokine production can contribute to the severity of the disease. Therefore, mitigation of dysregulated inflammatory signalling may provide further benefit for malaria treatment. Quercetin (3,3′,4′,5,7-pentahydroxyflavone) is known to inhibit glycogen synthase kinase-3β (GSK3β), a potent regulator of both pro- and anti-inflammatory effects. Quercetin is therefore a potential therapeutic to modulate the imbalanced cytokine production during malarial infection. Anti-malarial effects of quercetin were evaluated in murine models of severe and cerebral malaria using Plasmodium berghei NK65 and ANKA strains, respectively. Western blotting and analysis of cytokines were carried out to determine the GSK3β-mediated cytokine-modulating effects of quercetin in infected animals. Quercetin (25 mg/kg BW) treatment in P. berghei NK65-infected animals resulted in 60.7 ± 2.4% suppression of parasitaemia and significantly decreased serum levels of TNF-α and IFN-γ, whilst levels of IL-10 and IL-4 were elevated significantly. Western analysis revealed that pGSK3β (Ser9) increased 2.7-fold in the liver of quercetin-treated NK65-infected animals. Treatment of P. berghei ANKA-infected mice with quercetin (15 mg/kg BW) increased (2.3-fold) pGSK3β (Ser9) in the brains of infected animals. Quercetin is a potential plant-derived therapeutic for malaria on the basis that it can elicit anti-malarial and GSK3β-mediated cytokine-modulating effects.

Malaria and helminth co-infections in children living in endemic countries: A systematic review with meta-analysis

Background

Current knowledge on the burden of, and interactions between malaria and helminth co-infections, as well as the impact of the dual infections on anaemia, remains inconclusive. We have conducted a systematic review with meta-analysis to update current knowledge as a first step towards developing and deploying coordinated approaches to the control and, ultimately, elimination of malaria-helminth co-infections among children living in endemic countries.

Methodology/Principal findings

We searched Medline, Embase, Global Health and Web of Science from each database inception until 16 March 2020, for peer-reviewed articles reporting malaria-helminth co-infections in children living in endemic countries. No language restriction was applied. Following removal of duplicates, two reviewers independently screened the studies for eligibility. We used the summary odds ratio (OR) and 95% confidence intervals (CI) as a measure of association (random-effects model). We also performed Chi-square heterogeneity test based on Cochrane’s Q and evaluated the severity of heterogeneity using I² statistics. The included studies were examined for publication bias using a funnel plot and statistical significance was assessed using Egger’s test (bias if p<0.1).

Fifty-five of the 3,507 citations screened were eligible, 28 of which had sufficient data for meta-analysis. The 28 studies enrolled 22, 114 children in 13 countries across sub-Saharan Africa, Southeast Asia and South America. Overall, the pooled estimates showed a prevalence of Plasmodium-helminth co-infections of 17.7% (95% CI 12.7–23.2%). Summary estimates from 14 studies showed a lower odds of P. falciparum infection in children co-infected with Schistosoma spp (OR: 0.65; 95%CI: 0.37–1.16). Similar lower odds of P. falciparum infection were observed from the summary estimates of 24 studies in children co-infected with soil transmitted helminths (STH) (OR: 0.42; 95%CI: 0.28–0.64).

When adjusted for age, gender, socio-economic status, nutritional status and geographic location of the children, the risk of P. falciparum infection in children co-infected with STH was higher compared with children who did not have STH infection (OR = 1.3; 95% CI 1.03–1.65).

A subset of 16 studies showed that the odds of anaemia were higher in children co-infected with Plasmodium and STH than in children with Plasmodium infection alone (OR = 1.20; 95% CI: 0.59–2.45), and were almost equal in children co-infected with Plasmodium-Schistosoma spp or Plasmodium infection alone (OR = 0.97, 95% CI: 0.30–3.14).

Conclusions/Significance

The current review suggests that prevalence of malaria-helminth co-infection is high in children living in endemic countries. The nature of the interactions between malaria and helminth infection and the impact of the co-infection on anaemia remain inconclusive and may be modulated by the immune responses of the affected children.

Updated evidence is needed to guide the planning and implementation of appropriate interventions for control of mixed infections involving malaria and worms affecting children living in endemic countries. We performed a systematic review and meta-analysis to update current knowledge on the magnitude of the burden of dual infections with malaria and worms in children in the developing world. We searched all published articles available in Medline, Embase, Global Health and Web of Science from the database inception until 16 March 2020, without any language restriction. We found 55 eligible studies, and 28 of these studies were included in the meta-analysis. A summary of the evidence synthesis showed that the burden of dual infections involving malaria and worm parasites is high in children and varies significantly across endemic countries. There was a lower risk of P. falciparum infection in children infected with soil transmitted helminths (STH) or S. haematobium or S.mansoni. Conversely, the odds of anaemia were higher in children who had dual infections with Plasmodium and STH parasites than in children with a Plasmodium infection alone while the odds of anaemia were almost equal in children who were co-infected with Plasmodium-Schistosoma compared to those with a Plasmodium infection alone. These findings underscore the need to further understand the epidemiology of malaria-helminth co-infections in order to support implementation of appropriate interventions for control and, ultimately, elimination of the dual infections in children living in endemic countries, especially low and middle-income countries (LMIC).

Erythroblastic Island Macrophages Shape Normal Erythropoiesis and Drive Associated Disorders in Erythroid Hematopoietic Diseases

Erythroblastic islands (EBIs), discovered more than 60 years ago, are specialized microenvironments for erythropoiesis. This island consists of a central macrophage with surrounding developing erythroid cells. EBI macrophages have received intense interest in the verifications of the supporting erythropoiesis hypothesis. Most of these investigations have focused on the identification and functional analyses of EBI macrophages, yielding significant progresses in identifying and isolating EBI macrophages, as well as verifying the potential roles of EBI macrophages in erythropoiesis. EBI macrophages express erythropoietin receptor (Epor) both in mouse and human, and Epo acts on both erythroid cells and EBI macrophages simultaneously in the niche, thereby promoting erythropoiesis. Impaired Epor signaling in splenic niche macrophages significantly inhibit the differentiation of stress erythroid progenitors. Moreover, accumulating evidence suggests that EBI macrophage dysfunction may lead to certain erythroid hematological disorders. In this review, the heterogeneity, identification, and functions of EBI macrophages during erythropoiesis under both steady-state and stress conditions are outlined. By reviewing the historical data, we discuss the influence of EBI macrophages on erythroid hematopoietic disorders and propose a new hypothesis that erythroid hematopoietic disorders are driven by EBI macrophages.

Mesenchymal Stem Cells: A Novel Therapeutic Approach to Enhance Protective Immunomodulation and Erythropoietic Recovery in Malaria

Mesenchymal stem cells (MSCs) are self-renewing, multi-potent heterogeneous stem cells that display strong tissue protective and restorative properties by differentiating into cells of the mesodermal lineages. In addition to multi-lineage differentiation capacity, MSCs play important roles in regulating immune responses, inflammation, and tissue regeneration. MSCs play a role in the outcome of the pathogenesis of several infectious diseases. A unique subset of MSCs accumulates in secondary lymphoid organs during malaria disease progression. These MSCs counteract the capacity of malaria parasites to subvert activating co-stimulatory molecules and to regulate expression of negative co-stimulatory molecules on T lymphocytes. Consequently, MSCs have the capacity to restore the functions of CD34⁺ haematopoietic cells and CD4⁺ and CD8⁺ T cells during malaria infection. These observations suggest that cell-based therapeutics for intervention in malaria may be useful in achieving sterile clearance and preventing disease reactivation. In addition, MSCs provide host protection against malaria by reprogramming erythropoiesis through accelerated formation of colony-forming-units-erythroid (CFU-E) cells in the bone marrow. These findings suggest that MSCs are positive regulators of erythropoiesis, making them attractive targets for treatment of malarial anemia. MSC-based therapies, unlike anti-malarial drugs, display therapeutic effects by targeting a large variety of cellular processes rather than a single pathway. In the present review we focus on these recent research findings and discuss clinical applications of MSC-based therapies for malaria.

Preoperative anemia and surgical outcomes following laparotomy in a resource-limited setting

INTRODUCTION

Anemia is a common and potentially modifiable condition in sub-Saharan Africa. We sought to determine the role of preoperative anemia on post laparotomy abdominal complications.

METHODS

We conducted a six-month prospective, observational study of patients age >12 years following laparotomy at a tertiary hospital in Malawi. The outcome was the occurrence of abdominal complications. Poisson regression analyses estimated the risk of abdominal complications in patients with moderate/severe anemia.

RESULTS

Of 280 patients, most were male (76.4%) with median age of 35 years (IQR 24-50). Abdominal complications developed in 34 patients (15.2%). Of the 224 patients with known preoperative hemoglobin 54 (20.7%) were moderately or severely anemic at the time of surgery. Patients with moderate-to-severe anemia had an increased risk of abdominal complications (RR 4.44, 95% CI 2.0-9.6).

CONCLUSION

Anemia is a common but modifiable comorbidity among laparotomy patients and independently increases the risk of abdominal complications.

Predictors of outcome in childhood Plasmodium falciparum malaria

Plasmodium falciparum malaria is classified as either uncomplicated or severe, determining clinical management and providing a framework for understanding pathogenesis. Severe malaria in children is defined by the presence of one or more features associated with adverse outcome, but there is wide variation in the predictive value of these features. Here we review the evidence for the usefulness of these features, alone and in combination, to predict death and other adverse outcomes, and we consider the role that molecular biomarkers may play in augmenting this prediction. We also examine whether a more personalized approach to predicting outcome for specific presenting syndromes of severe malaria, particularly cerebral malaria, has the potential to be more accurate. We note a general need for better external validation in studies of outcome predictors and for the demonstration that predictors can be used to guide clinical management in a way that improves survival and long-term health.

Correlates and spatial distribution of the co-occurrence of childhood anaemia and stunting in Ghana

Childhood anaemia and stunting are major public health concerns in Ghana. Using the 2014 Ghana Demographic and Health Survey, we evaluated whether childhood anaemia (Haemoglobin concentration < 110 g/L) and stunting (height-for-age z score < -2) co-occur beyond what is expected in Ghana, and employed spatial analysis techniques to determine if their co-occurrence is spatially correlated. There was no statistically significant difference between the observed and expected frequency of co-occurrence. Among 24-35 month and 36-59-month-old children, belonging to a high wealth household compared to low wealth household was associated with lower odds of the co-occurrence of childhood anaemia and stunting (OR, 95% CI: 0.3[0.1, 0.8] and 0.2[0.1, 0.5], respectively). Children aged 6-23 months with caregivers who had formerly been in union compared to their counterparts with caregivers who have never been in union had higher odds of co-occurrence of anaemia and stunting (5.1, [1.1, 24.3]). Overall, households with high wealth and having a mother with secondary or more education were associated with lower odds of the co-occurrence of childhood anaemia and stunting (OR, 95% CI: 0.4[0.2, 0.8] and 0.5[0.3, 0.9], respectively). There was substantial spatial clustering of co-occurrence, particularly in the northern region of the country. Interventions purposed to improve linear growth and anaemia must identify the specific factors or context which contribute to childhood anaemia and stunting.

Mesenchymal stem cells protect against malaria pathogenesis by reprogramming erythropoiesis in the bone marrow

Malaria remains a major public health problem worldwide. The immune mechanisms that mediate protection against malaria are still unclear. Previously, we reported that mesenchymal stem cells (MSCs) play a critical role in host protection against malaria by altering the dynamic balance of T regulatory cells and effector T cells producing inflammatory cytokines. Here, we report that MSCs reprogram haematopoiesis in primary (bone marrow) and secondary (spleen) lymphoid organs to provide host protection against malaria. Adoptive transfer of MSCs from malaria-infected mice to naïve recipient mice that were subsequently infected with malaria parasites dramatically accelerated the formation of colony-forming units-erythroid cells in the bone marrow. Adoptively transferred MSCs also induced expression of the key erythroid cell differentiation factor GATA-1 in the spleen of recipient animals. Interestingly, we further observed a subtle increase in the CD34⁺ hematopoietic stem and progenitor cells in lymphoid organs, including spleen and lymph nodes. Infusion of MSCs also enhanced T cell proliferation, resulting in increased numbers of both CD4⁺ and CD8⁺ T cells in the spleen. MSCs also inhibited the induction of the negative co-stimulatory receptor programmed death-1 by T cells in recipient animals upon infection with malaria parasites. Taken together, our findings suggest that MSCs play a critical role in host protection against malaria infection by modulating erythropoiesis and lymphopoiesis.

The immunoglobulin G antibody response to malaria merozoite antigens in asymptomatic children co-infected with malaria and intestinal parasites

Background

Co-infection with malaria and intestinal parasites is common in children in Africa and may affect their immune response to a malaria parasite infection. Prior studies suggest that co-infections may lead to increased susceptibility to malaria infection and disease severity; however, other studies have shown the reverse. Knowledge on how co-morbidities specifically affect the immune response to malaria antigens is limited. Therefore, this study sought to determine the prevalence of co-infection of malaria and intestinal parasites and its association with antibody levels to malaria merozoite antigens.

Methods

A cross sectional study was carried out in two villages with high transmission of malaria in Cameroon (Ngali II and Mfou) where mass drug administration (MDA) had been administered at ~6-month intervals (generally with albendazole or mebendazole). Children aged 1–15 years were enrolled after obtaining parental consent. A malaria rapid diagnostic test was used on site. Four (4) ml of peripheral blood was collected from each participant to determine Plasmodium falciparum infections by microscopy, haemoglobin levels and serology. Fresh stool samples were collected and examined by wet mount, Kato-Katz method and modified Ritchie concentration techniques. A Multiplex Analyte Platform assay was used to measure antibody levels.

Results

A total of 320 children were enrolled. The prevalence of malaria by blood smear was 76.3% (244/320) and prevalence of malaria and intestinal parasites was 16.9% (54/320). Malaria prevalence was highest in young children; whereas, intestinal parasites (IP+) were not present until after 3 years of age. All children positive for malaria had antibodies to MSP1₄₂, MSP2, MSP3 and EBA175. No difference in antibody levels in children with malaria-co infections compared to malaria alone were found, except for antibody levels to EBA-175 were higher in children co-infected with intestinal protozoa (p = 0.018), especially those with Entamoeba histolytica infections (p = 0.0026).

Conclusion

Antibody levels to EBA175 were significantly higher in children co-infected with malaria and E. histolytica compared to children infected with malaria alone. It is important to further investigate why and how the presence of these protozoans might modulate the immune response to malaria antigens.

Antimalarial properties and preventive effects on mitochondrial dysfunction by extract and fractions of Phyllanthus amarus (Schum. and Thonn) in Plasmodium berghei-infected mice

OBJECTIVES

Broad spectrum antimalarial drugs without deleterious effects on mitochondria are scarce. It is in this regard that we investigated the potency of methanol extract and solvent fractions of Phyllanthus amarus on chloroquine-susceptible and resistant strains of Plasmodium berghei, toxicity and its consequential effects on mitochondrial permeability transition (mPT) pore opening.

METHODS

Malaria was induced in male Swiss mice with susceptible (NK 65) strain, divided into groups (n=5) and treated with 100, 200 and 400 mg/kg of methanol extract, n-hexane, dichloromethane, ethylacetate and methanol fractions daily for seven days. Percentage parasitemia and parasite clearance were determined microscopically. The two most potent fractions were tested on resistant (ANKA) strains. Heme and hemozoin contents were determined spectrophotometrically. The mPT, mitochondrial ATPase (mATPase) and lipid peroxidation (mLPO) were determined spectrophotometrically. Similar groups of animals were used for toxicity studies.

RESULTS

Dichloromethane fraction (400 mg/kg) had the highest antimalarial curative effect via least parasitemia (0.49) and high clearance (96.63) compared with the negative control (10.08, 0.00, respectively), had the highest heme and least hemozoin contents (16.23; 0.03) compared with the negative control (8.2, 0.126, respectively). Malaria infection opened the mPT, caused significant increase in mLPO and enhanced mATPase; while dichloromethane fraction reversed these conditions. Serum ALT, AST, ALP, GGT, urea and creatinine of dichloromethane fraction-treated mice decreased relative to control. No significant lesion was noticed in liver and kidney tissue sections.

CONCLUSIONS

Dichloromethane fraction of Phyllanthus amarus had the highest antimalarial activity with the highest mito-protective effect and it was well tolerated without toxic effects.

Teratogen update: Malaria in pregnancy and the use of antimalarial drugs in the first trimester

Malaria is a particular problem in pregnancy because of enhanced sensitivity, the possibility of placental malaria, and adverse effects on pregnancy outcome. Artemisinin-containing combination therapies (ACTs) are the most effective antimalarials known. WHO recommends 7-day quinine therapy for uncomplicated Plasmodium falciparum malaria in the first trimester despite the superior tolerability and efficacy of 3-day ACT regimens because artemisinins caused embryolethality and/or cardiovascular malformations at relatively low doses in rats, rabbits, and monkeys. The developmental toxicity of artesunate, artemether, and DHA were similar in rats but artesunate was embryotoxic at lower doses in rabbits (5 mg/kg/day) than artemether (no effect level = 25 mg/kg/day). In clinical studies in Africa, treatment with artemether-lumefantrine in the first trimester was observed to be highly efficacious and the miscarriage rate (≤3.1%) was similar to no antimalarial treatment (2.6%). When data from the first-trimester use of largely artesunate-based therapies in Thailand were pooled together, there was no difference in miscarriage rate compared to quinine. However, individually, artesunate-mefloquine was associated with a higher miscarriage rate (15/71 = 21%) compared to other artemisinin-based therapies including 7-day artesunate + clindamycin (2/50 = 4%) and quinine (92/842 = 11%). Thus, appropriate statistical comparisons of individual ACT groups are needed prior to assuming that they all have the same risk for developmental toxicity. Current limitations in the assessment of the safety of ACTs in the first trimester are a lack of exposures early in gestation (gestational weeks 6-7), limited postnatal evaluation for cardiovascular malformations, and the pooling of all ACTs for the assessment of risk.