RNAscope in situ hybridization reveals microvascular sequestration of Plasmodium relictum pSGS1 blood stages but absence of exo-erythrocytic dormant stages during latent infection of Serinus canaria.

BACKGROUND: Birds chronically infected with avian malaria parasites often show relapses of parasitaemia after latent stages marked by absence of parasites in the peripheral circulation. These relapses are assumed to result from the activation of dormant exo-erythrocytic stages produced during secondary (post-erythrocytic) merogony of avian Plasmodium spp. Yet, there is no morphological proof of persistent or dormant tissue stages in the avian host during latent infections. This study investigated persistence of Plasmodium relictum pSGS1 in birds with latent infections during winter, with the goal to detect presumed persisting tissue stages using a highly sensitive RNAscope® in situ hybridization technology. METHODS: Fourteen domestic canaries were infected with P. relictum pSGS1 by blood-inoculation in spring, and blood films examined during the first 4 months post infection, and during winter and spring of the following year. After parasitaemia was no longer detectable, half of the birds were dissected, and tissue samples investigated for persisting tissue stages using RNAscope ISH and histology. The remaining birds were blood-checked and dissected after re-appearance of parasitaemia, and their tissues equally examined. RESULTS: Systematic examination of tissues showed no exo-erythrocytic stages in birds exhibiting latent infections by blood-film microscopy, indicating absence of dormant tissue stages in P. relictum pSGS1-infected canaries. Instead, RNAscope ISH revealed rare P. relictum blood stages in capillaries of various tissues and organs, demonstrating persistence of the parasites in the microvasculature. Birds examined after re-appearance of parasitemia showed higher numbers of P. relictum blood stages in both capillaries and larger blood vessels, indicating replication during early spring and re-appearance in the peripheral circulation. CONCLUSIONS: The findings suggest that persistence of P. relictum pSGS1 during latent infection is mediated by continuous low-level erythrocytic merogony and possibly tissue sequestration of infected blood cells. Re-appearance of parasitaemia in spring seems to result from increased erythrocytic merogony, therefore representing recrudescence and not relapse in blood-inoculated canaries. Further, the study highlights strengths and limitations of the RNAscope ISH technology for the detection of rare parasite stages in tissues, providing directions for future research on persistence and tissue sequestration of avian malaria and related haemosporidian parasites.

Asymptomatic malaria parasitaemia and virological non-suppression among children living with HIV in Accra, Ghana: a cross-sectional study.

Background: Human Immunodeficiency Virus (HIV) and malaria are two major diseases in sub-Saharan Africa, with coinfections having an impact on the outcomes of both. We assessed the association between asymptomatic malaria parasitaemia and virological non-suppression among children living with HIV attending a clinic at the Korle Bu Teaching Hospital (KBTH) and the Princess Marie Louis Hospital (PML) in the city of Accra, Ghana. Methods: This was a cross-sectional study of asymptomatic malaria in children receiving care at paediatric HIV clinics at KBTH and PML conducted from September to November 2022. Patients who had been on ART for at least 6 months were eligible to participate. Structured questionnaires were used to collect socio-demographic, malaria prevention behaviors, and ART-related data using in-person interviews. Microscopy and PCR were used to screen for malaria and GeneXpert to determine viral load. To examine the determinants of malaria PCR positivity and virological non-suppression, Chi-square tests and logistic regression were utilized. Results: The participants' median age was 9 years with a range of 6 to 12 years. Males made up 57% of the population. We detected 3.6% (10 of 277) and 7.6% (21 of 277) cases of malaria using microscopy and PCR, respectively. Virological non-suppression (VL > 1000 copies/ml) was seen in 82 (29.6%) of the 277 participants. Among the suppressed individuals, 62 (22.4%) exhibited low-level viraemia (VL level 40-1000 copies/ml) and 133 (48%) had non-detectable viral load levels. There were no factors associated with malaria PCR positivity carriage. Poor adherence to antiretroviral therapy was associated with a fivefold increase in the risk of viral load non-suppression (AOR = 4.89 [CI = 2.00-11.98], p = 0.001). Conclusion: The study showed that the proportion of children living with HIV with asymptomatic malaria parasitaemia was low, with about one third of the study population having virological non suppression. The interaction between malaria parasitemia and viral replication may not be the main culprit for virological non suppression.

Haematological parameters and their correlation with the degree of malaria parasitaemia among outpatients attending a polyclinic.

BACKGROUND: Malaria is a parasitic disease caused by various species of the blood parasite Plasmodium; of all the parasitic diseases, malaria has the highest prevalence and mortality with an estimated 247 million cases and 619,000 deaths recorded worldwide as of 2021. Malaria causes febrile illness with several changes in blood cell parameters. Some of these changes include leucopenia, thrombocytopenia, and anaemia. If these changes could be correlated with the degree of parasitaemia, it can serve as a guide to physicians when treating malaria. This study was therefore aimed at correlating haematological parameters with levels of parasitaemia during malaria infection. METHODS: The study was a cross-sectional study involving 89 malaria positive patients. About 5 ml of blood was collected from each participant who gave his or her informed consent to partake in the study. A full blood count was performed on their samples to determine their haematological parameters using a haematology auto-analyzer. A parasite count was also performed via microscopy to determine the degree of parasitaemia. The data obtained from the study was entered into a database and statistically analysed using Statistical Package for Social Sciences (SPSS) version 23 and Microsoft Excel 2016. RESULTS: The study comprised of 89 participants out of which 35 were males and 54 were females with the mean age of 26.15 years. Secondary education participants were the highest with quaternary education the lowest. The highest parasite count recorded was 398,174 parasites/µl of blood, lowest count was 101 with the average being 32,942.32584. There was also a significant positive Pearson's correlation between total WBC and parasitaemia and with the WBC differentials, neutrophils, lymphocytes and monocytes had positive correlations while eosinophils and basophils had negative correlations. Furthermore, platelets, total RBC's, haemoglobin, MCH, MCHC and Hct all showed negative correlations. Linear regression also showed a linear relationship between parasite density and the various haematological parameters. CONCLUSION: The linear relationship (correlation) between WBC and MCH were the only significant ones at 95% and 99% confidence interval, respectively based on a two-tail t-test. Also, based on the regression analysis, the changes caused by WBC and PLT were the only significant changes at 95% confidence level in a two-tailed t-test.

Prophylactic effects of probiotic bacterium Latilactobacillus sakei on haematological parameters and cytokine profile of mice infected with Plasmodium berghei ANKA during early malaria infection.

Malaria is a deadly parasitic disease caused a by protozoan parasite of the genus plasmodium. The challenges facing by chemotherapy and vector control couple with the lack of vaccine against malaria necessitate an urgent need for the development of alternative treatment regimens to combat this disease. One possible antimalarial treatment regimen is the use of probiotic bacteria as dietary supplements. Traditionally fermented milk is a rich source of probiotic bacteria that up to date, very few studies have been carried out on their immunoprotective effects against early malaria infection in mice. This study sought to assess the prophylactic activities of a probiotic bacterium Latilactobacillus sakei on malaria and inflammation in Plasmodium berghei infected mice. The probiotic bacterium was isolated from the Fulani's traditionally fermented milk and identified using the sequencing of the 16S r RNA gene. The repository activity of L. sakei on malaria was assessed using the method described by Peters with slight modification. Eighty-four BALB/c mice were randomly divided into two sets of seven groups of six mice each. One set received orally different doses of L. sakei Chloroquine and Sulfadoxine/Pyrimethamine for seven days before infection while the other set received for fourteen days before infection with 0.1 mL of 107Plasmodium berghei. Parasitaemia density, haematological parameters and inflammatory cytokines profile were evaluated. Data were presented as Mean ± SEM and analysed using SPSS version 20.0. The results of this study revealed that L. sakei significantly (p < 0.05) reduced in dose dependent manner parasite load, body weight loss and reduction of body temperature in all the treated mice when compare to untreated mice. Leukocytopenia, thrombocytosis and inflammation were also found to be significantly (p < 0.05) prevented in treated mice as compared to untreated mice. This study suggested that L sakei possesses immunomodulation and protective effects on early malaria infection in Plasmodium berghei mice.

Avian Haemosporidians Infecting Short- and Long-Distance Migratory Old World Flycatcher Species and the Variation in Parasitaemia After Endurance Flights.

PURPOSE: Avian haemosporidians are widespread parasites, occurring in many bird families and causing pathologies ranging from rather benign infections to highly virulent diseases. The state of knowledge about lineage-specific intensities of haemosporidian infection (i.e., parasitaemia) is mainly based on infection experiments conducted under laboratory conditions. The levels and range of parasitaemia in natural host-parasite associations as well as their influencing factor remain largely unexplored. METHODS: Thus, we explored the parasitaemia of four songbird species (i.e., European Robins, Black and Common Redstarts and Whinchats) during migration by screening individuals upon landing on an insular passage site after extensive endurance flights to (1) describe their natural host-parasite associations, (2) quantify parasitaemia and (3) explore potential host- and parasite-related factors influencing parasitaemia. RESULTS: We found 68% of Whinchats to be infected with haemosporidians, which is more frequent than any other of the studied host species (30-34%). Furthermore, we confirmed that parasitaemia of Haemoproteus infections was higher than average Plasmodium infections. Median parasitaemia levels were rather low (parasite cells in 0.01% of hosts' red blood cells) and varied largely among the different parasite lineages. However, we found four individuals hosting infections with parasitaemia higher than typical chronic infections. CONCLUSIONS: Based on the known transmission areas of the respective lineages, we argue that these higher intensity infections might be relapses of consisting infections rather than acute phases of recent primary infections.

Unravelling factors associated with malaria parasitaemia among children 6-24 months to inform malaria interventions in Nigeria: evidence from 2021 Malaria Indicator Survey.

BACKGROUND: As an additional two million malaria cases were reported in 2021 compared to the previous year, concerted efforts toward achieving a steady decline in malaria cases are needed to achieve malaria elimination goals. This work aimed at determining the factors associated with malaria parasitaemia among children 6-24 months for better targeting of malaria interventions. METHODS: A cross-sectional study analysed 2021 Nigeria Malaria Indicator Survey dataset. Data from 3058 children 6-24 months were analyzed. The outcome variable was children 6-24 months whose parasitaemia was determined using a rapid diagnostic test (RDT). Independent variables include child age in months, mothers' age, mothers' education, region, place of residence, household ownership and child use of insecticide-treated net (ITN), exposure to malaria messages and knowledge of ways to prevent malaria. Logistic regression analysis was conducted to examine possible factors associated with malaria parasitaemia in children 6-24 months. RESULTS: Findings revealed that 28.7% of the 3058 children aged 6-24 months tested positive for malaria by RDT. About 63% of children 12-17 months (aOR = 1.63, 95% CI 1.31-2.03) and 91% of children 18 to 24 months (aOR = 1.91, 95% CI 1.51-2.42) were more likely to have a positive malaria test result. Positive malaria test result was also more likely in rural areas (aOR = 1.79, 95% CI 2.02-24.46), northeast (aOR = 1.54, 95% CI 1.02-2.31) and northwest (aOR = 1.63, 95% CI 1.10-2.40) region. In addition, about 39% of children who slept under ITN had a positive malaria test result (aOR = 1.39 95% CI 1.01-1.90). While children of mothers with secondary (aOR = 0.40, 95% CI 0.29-0.56) and higher (aOR = 0.26, 95% CI 0.16-0.43) levels of education and mothers who were aware of ways of avoiding malaria (aOR = 0.69, 95% CI 0.53-0.90) were less likely to have a malaria positive test result. CONCLUSION: As older children 12 to 24 months, children residing in the rural, northeast, and northwest region are more likely to have malaria, additional intervention should target them in an effort to end malaria.

Variability in white blood cell count during uncomplicated malaria and implications for parasite density estimation: a WorldWide Antimalarial Resistance Network individual patient data meta-analysis.

BACKGROUND: The World Health Organization (WHO) recommends that when peripheral malarial parasitaemia is quantified by thick film microscopy, an actual white blood cell (WBC) count from a concurrently collected blood sample is used in calculations. However, in resource-limited settings an assumed WBC count is often used instead. The aim of this study was to describe the variability in WBC count during acute uncomplicated malaria, and estimate the impact of using an assumed value of WBC on estimates of parasite density and clearance. METHODS: Uncomplicated malaria drug efficacy studies that measured WBC count were selected from the WorldWide Antimalarial Resistance Network data repository for an individual patient data meta-analysis of WBC counts. Regression models with random intercepts for study-site were used to assess WBC count variability at presentation and during follow-up. Inflation factors for parasitaemia density, and clearance estimates were calculated for methods using assumed WBC counts (8000 cells/µL and age-stratified values) using estimates derived from the measured WBC value as reference. RESULTS: Eighty-four studies enrolling 27,656 patients with clinically uncomplicated malaria were included. Geometric mean WBC counts (× 1000 cells/µL) in age groups < 1, 1-4, 5-14 and ≥ 15 years were 10.5, 8.3, 7.1, 5.7 and 7.5, 7.0, 6.5, 6.0 for individuals with falciparum (n = 24,978) and vivax (n = 2678) malaria, respectively. At presentation, higher WBC counts were seen among patients with higher parasitaemia, severe anaemia and, for individuals with vivax malaria, in regions with shorter regional relapse periodicity. Among falciparum malaria patients, using an assumed WBC count of 8000 cells/µL resulted in parasite density underestimation by a median (IQR) of 26% (4-41%) in infants < 1 year old but an overestimation by 50% (16-91%) in adults aged ≥ 15 years. Use of age-stratified assumed WBC values removed systematic bias but did not improve precision of parasitaemia estimation. Imprecision of parasite clearance estimates was only affected by the within-patient WBC variability over time, and remained < 10% for 79% of patients. CONCLUSIONS: Using an assumed WBC value for parasite density estimation from a thick smear may lead to underdiagnosis of hyperparasitaemia and could adversely affect clinical management; but does not result in clinically consequential inaccuracies in the estimation of the prevalence of prolonged parasite clearance and artemisinin resistance.

Performance of a novel melting curve-based qPCR assay for malaria parasites in routine clinical practice in non-endemic setting.

BACKGROUND: High-quality malaria diagnosis is essential for effective treatment and clinical disease management. Microscopy and rapid diagnostic tests are the conventional methods performed as first-line malaria diagnostics in non-endemic countries. However, these methods lack the characteristic to detect very low parasitaemia, and accurate identification of the Plasmodium species can be difficult. This study evaluated the performance of the MC004 melting curve-based qPCR for the diagnosis of malaria in routine clinical practice in non-endemic setting. METHODS AND RESULTS: Whole blood samples were collected from 304 patients with clinical suspicion of malaria and analysed by both the MC004 assay and conventional diagnostics. Two discrepancies were found between the MC004 assay and microscopy. Repeated microscopic analysis confirmed the qPCR results. Comparison of the parasitaemia of nineteen Plasmodium falciparum samples determined by both microscopy and qPCR showed the potential of the MC004 assay to estimate the parasite load of P. falciparum. Eight Plasmodium infected patients were followed after anti-malarial treatment by the MC004 assay and microscopy. The MC004 assay still detected Plasmodium DNA although no parasites were seen with microscopy in post-treatment samples. The rapid decline in Plasmodium DNA showed the potential for therapy-monitoring. CONCLUSION: Implementation of the MC004 assay in non-endemic clinical setting improved the diagnosis of malaria. The MC004 assay demonstrated superior Plasmodium species identification, the ability to indicate the Plasmodium parasite load, and can potentially detect submicroscopic Plasmodium infections.

Drug Resistance Molecular Markers of Plasmodium falciparum and Severity of Malaria in Febrile Children in the Sentinel Site for Malaria Surveillance of Melen in Gabon: Additional Data from the Plasmodium Diversity Network African Network.

The objective of this study was to analyze the relationship between the frequency of artemisinin-based combination (ACT) drug resistance molecular markers and clinical forms of P. falciparum malaria and parasitemia. A cross-sectional study was carried out between January and April 2014 at the Operational Clinical Research Unit of Melen in febrile children aged 12 to 240 months with a Plasmodium sp. infection. A total of 3 mL of peripheral blood collected from an EDTA tube was used for leukocyte depletion. DNA mutation detection was performed by next generation sequencing (NGS). A total of 1075 patients were screened for malaria. Among them, 384 had a Plasmodium infection. P. falciparum mono-infection was found in 98.9% of the patients. Pfcrt-326T mutation was found in all isolates, while 37.9% had Pfmdr2-484I mutant allele. The highest median parasite densities were found in patients infected by parasites carrying the CVIET haplotype of the Pfcrt gene. The different genetic profiles found here, and their variations according to clinical and biological signs of severe malaria, are additional arguments for the surveillance of P. falciparum strains.

PET-PCR reveals low parasitaemia and submicroscopic malarial infections in Honduran Moskitia.

BACKGROUND: Malaria remains a main parasitic disease of humans. Although the largest number of cases is reported in the African region, there are still endemic foci in the Americas. Central America reported 36,000 malaria cases in 2020, which represents 5.5% of cases in the Americas and 0.015% of cases globally. Most malaria infections in Central America are reported in La Moskitia, shared by Honduras and Nicaragua. In the Honduran Moskitia, less than 800 cases were registered in 2020, considering it an area of low endemicity. In low endemicity settings, the number of submicroscopic and asymptomatic infections tends to increase, leaving many cases undetected and untreated. These reservoirs challenge national malaria elimination programmes. This study aimed to assess the diagnostic performance of Light Microscopy (LM), a nested PCR test and a photoinduced electron transfer polymerase chain reaction (PET-PCR) in a population of febrile patients from La Moskitia. METHODS: A total of 309 febrile participants were recruited using a passive surveillance approach at the Puerto Lempira hospital. Blood samples were analysed by LM, nested PCR, and PET-PCR. Diagnostic performance including sensitivity, specificity, negative and positive predictive values, kappa index, accuracy, and ROC analysis was evaluated. The parasitaemia of the positive samples was quantified by both LM and PET-PCR. RESULTS: The overall prevalence of malaria was 19.1% by LM, 27.8% by nPCR, and 31.1% by PET-PCR. The sensitivity of LM was 67.4% compared to nPCR, and the sensitivity of LM and nPCR was 59.6% and 80.8%, respectively, compared to PET-PCR. LM showed a kappa index of 0.67, with a moderate level of agreement. Forty positive cases by PET-PCR were not detected by LM. CONCLUSIONS: This study demonstrated that LM is unable to detect parasitaemia at low levels and that there is a high degree of submicroscopic infections in the Honduran Moskitia.

Sub-microscopic Plasmodium falciparum parasitaemia, dihydropteroate synthase (dhps) resistance mutations to sulfadoxine-pyrimethamine, transmission intensity and risk of malaria infection in pregnancy in Mount Cameroon Region.

BACKGROUND: Plasmodium falciparum resistance to intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) continues to spread throughout sub-Saharan Africa. This study assessed the occurrence of microscopic and sub-microscopic P. falciparum parasitaemia, dihydropteroate synthase mutations associated with resistance to SP and maternal anaemia in the Mount Cameroon area. METHODS: Consenting pregnant women living in semi-rural and semi-urban/urbanized settings were enrolled in this cross-sectional study. Socio-demographic, antenatal and clinical data were documented. Microscopic and sub-microscopic parasitaemia were diagnosed using peripheral blood microscopy and nested polymerase chain reaction (PCR) respectively. The dhps mutations were genotyped by restriction fragment length polymorphism analysis. The presence of A437G, K540E, and A581G was considered a marker for high-level resistance. Haemoglobin levels and anaemia status were determined. RESULTS: Among the women, the prevalence of microscopic and sub-microscopic P. falciparum infection were 7.7% (67/874) and 18.6% (93/500) respectively. Predictors of microscopic infection were younger age (< 21 years) (AOR = 2.89; 95% CI 1.29-6.46) and semi-rural settings (AOR = 2.27; 95% CI 1.31-3.96). Determinants of sub-microscopic infection were the rainy season (AOR, 3.01; 95% CI 1.77-5.13), primigravidity (AOR = 0.45; 95% CI 0.21-0.94) and regular ITN usage (AOR = 0.49; 95% CI 0.27-0.90). Of the145 P. falciparum isolates genotyped, 66.9% (97) carried mutations associated with resistance to SP; 33.8% (49), 0%, 52.4% (76) and 19.3% (28) for A437G, K540E, A581G and A437G + A581G respectively. The A581G mutation was associated with ≥ 3 SP doses evident only among sub-microscopic parasitaemia (P = 0.027) and multigravidae (P = 0.009). Women with microscopic infection were more likely from semi-rural settings (AOR = 7.09; 95% CI 2.59-19.42), to report history of fever (AOR = 2.6; 95% CI 1.07-6.31), to harbour parasites with double resistant mutations (AOR = 6.65; 95% CI 1.85-23.96) and were less likely to have received 2 SP doses (AOR = 0.29; 95% CI 1.07-6.31). Microscopic infection decreased Hb levels more than sub-microscopic infection. CONCLUSION: The occurrence of sub-microscopic P. falciparum parasites resistant to SP and intense malaria transmission poses persistent risk of malaria infection during pregnancy in the area. ITN usage and monitoring spread of resistance are critical.

Effectiveness and compliance to the use of sulphadoxine-pyrimethamine as a prophylaxis for malaria among pregnant women in Port Harcourt, Rivers State, Nigeria.

Background: Malaria during pregnancy escalates the damaging consequence to the mother and neonate. The usage of intermittent preventive treatment of malaria (IPTp) with sulfadoxine-pyrimethamine (SP) is recommended for averting the deleterious consequences of malaria in pregnancy. This study evaluated the effectiveness of, and compliance with the use of SP for malaria among pregnant women in Port Harcourt Rivers State, Nigeria. Method: A total of 300 samples of maternal peripheral blood (MPB), 84 neonatal cord blood (NCB) and 84 placental blood (PLB) were collected from consenting mothers. Malaria parasitaemia were analysed using standard parasitological methods, and bio-data of consenting mothers were collected through questionnaires and from ANC records. Results: Out of the samples examined for MPB, 59(19.7%) tested positive to malaria. Those with only primary education (57.1%) and women of age ≤ 20yrs (25%) had higher prevalence. Women who took SP had significantly lower prevalence (17.6%) than those that took other drugs (36.4%) (p < 0.05). Malaria prevalence was highest among women who had 3 months interval between each dose (39.1%), followed by those of 2months (23.7%) and those of 1 month (7.0%) (p < 0.05). The primigravidaes (22.8%) had an insignificantly higher prevalence than secundigravidae (19.4%) and multigravidae (15.9%). Also, 30.5% of women who registered in their third trimester of pregnancy had a significantly higher malaria parasitaemia than those who registered during their first 8.10%, or second trimesters, 19.4%. Of the 84 MPB-NCB-PLB pairedamples examined, 16.7%, 8.3% and 25% respectively were infected with malaria parasitaemia. On frequency of compliance, mothers who took SP once (37.5%) had a significantly higher MPB parasitaemia than those who took it twice (7.84%) and those of thrice (6.25%). Neonatal cord blood parasitaemia prevalence revealed that those that took SP once, that is, 25%, had a higher prevalence than others like those of twice (5.88%) and thrice (0%) respectively. Conclusion: The use and compliance of SP reduced the prevalence of malaria among pregnant women and their new-borns.

Malaria Knowledge-Base and Prevalence of Parasitaemia in Asymptomatic Adults in the Forest Zone of Ghana.

PURPOSE: To determine the levels of knowledge, awareness and perception of malaria, and to determine the infection status among asymptomatic adults in selected districts. METHODS: This descriptive, cross-sectional study recruited 849 participants from seven districts in the malaria meso-endemic forest zone of Ghana. Questionnaires were administered to elicit responses from asymptomatic adults on malaria awareness, knowledge and insecticide-treated net (ITN) usage. Capillary blood samples were taken from study subjects for malaria Rapid Diagnostic Test (RDT) and microscopy. Descriptive statistics was used to analyse quantitative and qualitative data. RESULTS: Ninety-eight percent of participants were aware of malaria, 94.0% owned ITNs but only 35.5% consistently used them. Also, 56.7% correctly associated malaria with mosquitoes and 54.5% identified stagnant water as the breeding site. Twelve percent (12.2%) and 13.1% of the subjects tested positive for malaria via RDT and microscopy, respectively. Of the 111 confirmed malaria cases, 107 had Plasmodium falciparum infections, two had Plasmodium ovale infections and there were two Plasmodium falciparum-Plasmodium ovale mixed infections. CONCLUSION: Awareness and knowledge of malaria was satisfactory but this did not translate into mosquito avoidance behaviour due to deep-seated perceptions and myths. With the prevalence of asymptomatic parasitaemia observed, this reservoir of infection could be dislodged with appropriate health education targeted at women in the rural communities.

Effectiveness of antenatal intermittent preventive treatment for malaria with sulphadoxine-pyrimethamine on peripartum outcomes.

Background: Following the World Health Organization (WHO) recommendations for 4-weekly antenatal intermittent preventive treatment of malaria in pregnancy using sulphadoxine-pyrimethamine (IPTp-SP), there is a need to evaluate the drug performance in order to determine their effectiveness as tools in malaria control policy. Objectives: To determine prevalence of cord blood malaria, compliance gap and adverse pregnancy outcomes (anaemia, preterm delivery, spontaneous abortion, intra-uterine foetal death and low birth weight) among antenatal IPTp-SP users compared with non-users. Methods: A cross-sectional analytical study was conducted among consenting 390 participants who were administered a questionnaire, and paired blood samples were collected from the venous blood of participants and neonatal cord immediately after delivery. The participants were categorised as IPTp-SP users and non-users. Adverse pregnancy outcomes were assessed. Neonatal birth weights were also measured within 1 h after delivery. Malaria parasitaemia and anaemia were analysed using standard parasitological and haematological methods of examination. Data were analysed using SPSS version 25 for Windows and p-value of < 0.05 considered significant. Results: Of 390 women, 336 (86.2%) were IPTp-SP users, while 54 (13.8%) were non-users. The compliance gap was 13.8%. Malaria parasitemia in pregnant women (21.7% versus 53.7%; p < 0.001) and their babies (12.2% versus 25.4%; p = 0.002) were observed for IPTp-SP users and non-users, respectively. The prevalence of maternal anaemia was 27(8.0%) in IPTp-SP users and 5 (9.3%) in non-users (p = 0.789). Mean parasite density was reduced in IPTp-SP users than in non-users (p < 0.001). Correlation of birth weight according to their sex showed a weak correlation [correlation coefficient (r) = 0.027; p = 0.736]. Pregnant women with preterm delivery, spontaneous abortion, intra-uterine foetal death, and low birth weight were significantly lower (p < 0.001, for all) in IPTp-SP users compared with non-users. Conclusion: Although the compliance gap was low, IPTp-SP users had significantly better pregnancy and foetal outcomes compared with non-users. Efforts should be intensified towards achieving total compliance in IPTp-SP usage by pregnant women.

Vivax malaria in Duffy-negative patients shows invariably low asexual parasitaemia: implication towards malaria control in Ethiopia.

BACKGROUND: The increase in detections of Plasmodium vivax infection in Duffy-negative individuals in Africa has challenged the dogma establishing the unique P. vivax Duffy Binding Protein-Duffy antigen receptor for chemokines (PvDBP-DARC) pathway used by P. vivax merozoites to invade reticulocytes. Information on the impact of Duffy antigen polymorphisms on the epidemiology of P. vivax malaria remains elusive. The objective of this study was to determine the distribution of asexual parasitaemia of P. vivax according to the Duffy antigen polymorphisms in Ethiopia. METHODS: DNA was extracted from dried blood spots (DBS) collected from prospectively recruited 138 P. vivax-infected patients from health centres. The identification and estimation of P. vivax asexual parasitaemia were performed by microscopic examination and quantitative real-time polymerase chain reaction (PCR). Duffy genotyping was conducted by DNA sequencing in a total of 138 P.vivax infected samples. RESULTS: The proportion of Duffy-negatives (FY*BES/FY*BES) in P. vivax infected patients was 2.9% (4/138). Duffy genotype FY*B/FY*BES (48.6%) was the most common, followed by FY*A/FY*BES genotype (25.4%). In one patient, the FY*02 W.01/FY*02 N.01 genotype conferring a weak expression of the Fyb antigen was observed. All P.vivax infected Duffy-negative patients showed low asexual parasitaemia (≤ 110 parasites/µL). The median P. vivax parasitaemia in Duffy-negative patients (53 parasites/µL) was significantly lower than those found in homozygous and heterozygous individuals (P < 0.0001). CONCLUSION: Plasmodium vivax in Duffy-negative patients shows invariably low asexual parasitaemia. This finding suggests that the pathway used by P. vivax to invade Duffy-negative reticulocytes is much less efficient than that used in Duffy-positives. Moreover, the low asexual parasitaemia observed in Duffy-negative individuals could constitute an 'undetected silent reservoir', thus likely delaying the elimination of vivax malaria in Ethiopia.

Heavy Malaria Parasitaemia in Young Nigerian Infants: Prevalence, Determinants and Implication for the Health System.

BACKGROUND: Infants who are aged six months and below are often protected from malaria and usually present with light parasitaemia when infected. However, complications following heavy malaria parasitaemia in this age group are being increasingly reported. This study set out to determine the prevalence, determinants and the public health implications of heavy malaria parasitaemia in young infants (aged one to six months) at the Wesley Guild Hospital, Ilesa (a unit of the Obafemi Awolowo University Teaching Hospitals Complex). METHODS: Ill infants aged one to six months in out-patient and in-patient care were recruited over an 11-month period. Clinical examinations and blood film for malaria parasite were done for all the study participants. Heavy parasitaemia was defined as > 5000 parasites/µl. Clinical predictors of heavy parasitaemia were determined. RESULTS: Heavy parasitaemia was observed in 16(23.9%) of the sixty-seven participants with malaria infection. Presence of fever at presentation (p=0.007), excessive crying (p=0.003) and pallor (p=0.001) were associated with heavy malaria parasitaemia. However, pallor (OR = 20.653; 95%CI 2.091-203.958; p=0.010) was the only independent predictor of heavy parasitaemia among the young infants. CONCLUSION: About one-in-four ill young infants with malaria had heavy parasitaemia, which was predicted by pallor. Hence, the presence of pallor and factors related to low parental socio-economic status should increase the suspicion of heavy malaria parasitaemia in ill young infants in malaria endemic settings.

CONTEXTE: Nourrissons âgés de six mois et moins sont souvent protégés du paludisme et généralement présents avec de la lumière parasitémie lorsqu'il est infecté. Cependant, les complications qui suivent une parasitémie palustre lourde dans ce groupe d'âge est en cours de plus en plus signalés. Cette étude visait à déterminer la prévalence, les déterminants et les répercussions de l'action sur la santé publique parasitémie palustre sévère chez les jeunes nourrissons (âgés de un à six ans)mois) à l'hôpital Wesley Guild, Ilesa (une unité de l'Obafemi Complexe des hôpitaux universitaires d'Awolowo). MÉTHODES: Nourrissons malades âgés de un à six mois en ambulatoire et les soins aux patients hospitalisés ont été recrutés sur une période de 11 mois. Les examens cliniques et le film sanguin pour le parasite du paludisme ont été fait pour tous les participants à l'étude. La parasitémie lourde était défini comme > 5000 parasites/µl. Prédicteurs cliniques de lourd la parasitémie a été déterminée. RÉSULTATS: Une parasitémie sévère a été observée chez 16 (23,9%) des soixante-sept participants atteints d'une infection palustre. Présence de fièvre à la présentation (p = 0,007), pleurs excessifs (p = 0,003) et la pâleur (p = 0,001) était associée à un paludisme lourdparasitémie. Cependant, pâleur (OR = 20,653; IC à 95 % 2,091-203.958; p=0,010) était le seul prédicteur indépendant de parasitémie chez les jeunes nourrissons. CONCLUSION: Environ un jeune nourrisson malade sur quatre atteint de paludisme avait une parasitémie lourde, qui était prédite par pâleur. D'où la présence de pâleur et de facteurs liés à un faible niveau parental le statut socio-économique devrait accroître la suspicion de lourd parasitémie palustre chez les jeunes nourrissons malades dans le paludisme endémique Paramètres. Mots-clés: Jeunes nourrissons, Parasitémie palustre, Parasite lourddensité, prévalence.

Evaluation of Asymptomatic Malaria Antigenaemia and Parasitaemia in Human Immunodeficiency Virus-Infected Children in Benin City, Nigeria.

BACKGROUND: Malaria and HIV/AIDS are rampant in subSaharan Africa with prevalence of one reinforcing the other and control of one impactful on control of the other. Malaria parasitaemia (MP) prevalence is increased in HIV-infected individuals while certain drugs used in latter cause decline in MP but it is uncertain how they affect malaria antigenaemia (MA). How certain bio-social and disease characteristics affect MA and MP in this cohort is unknown. OBJECTIVES: To determine prevalence of asymptomatic MP and MA and their clinical and social determinants in HIV infected. METHODS: In a prospective cross-sectional study carried out at the University of Benin Teaching Hospital (April to June 2016), 221 HIV-infected children (aged 1-17years) asymptomatic for malaria and 221 apparently healthy HIV-negative controls were studied. MA was assessed using rapid diagnostic test while MP was evaluated using microscopy. Standard method was used to determine parasite count. RESULTS: Prevalence of asymptomatic MP was 24.4% in subjects and 17.6% in controls while MA prevalence in subjects and controls were comparable (20.8% vs 18.1%). Malaria parasitaemia rate (MPr) of 24.4% was higher than malaria antigenaemia rate (MAr) (20.8%). MP and MA rates were independent of socioeconomic status, access to anti-retroviral drugs, their duration of use and clinical disease stage. CONCLUSION: MA occurred frequently enough to warrant its use as malaria case definition surrogate in asymptomatic children with HIV/AIDS receiving trimethoprim-sulfamethoxazole prophylaxis and protease inhibitors.

CONTEXTE: Le paludisme et le VIH / SIDA sont endémiques en Afrique subsaharienne, la prévalence de l'un renforçant l'autre et le contrôle de l'un ayant un impact sur le contrôle de l'autre. La prévalence de la parasitémie du paludisme (MP) est augmentée chez les personnes infectées par le VIH, tandis que certains médicaments utilisés dans ces derniers entraînent une baisse de la MP, mais on ignore comment ils affectent l'antigénémie du paludisme (AM). On ne sait pas comment certaines caractéristiques biosociales et pathologiques affectent l'AMM et la MP dans cette cohorte. OBJECTIFS: Déterminer la prévalence de la MP et de l'AMM et leurs déterminants cliniques-sociaux chez les enfants infectés par le VIH. METHODES: Dans une étude transversale prospective menée à l'hôpital universitaire de l'Université du Bénin (avril et juin 2016), 221 enfants infectés par le VIH (âgés de 1 à 17 ans) asymptomatiques pour le paludisme et 221 témoins séronégatifs apparemment en bonne santé ont été étudiés. La MA a été évaluée à l'aide d'un test de diagnostic rapide tandis que la MP a été évaluée à l'aide de la microscopie à coloration de Giemsa. La méthode standard a été utilisée pour déterminer le nombre de parasites. RESULTATS: La prévalence de la MP asymptomatique était de 24,4% chez les sujets et de 17,6% chez les témoins, tandis que la prévalence de l'AM chez les sujets et les témoins était comparable (20,8% vs 18,1%). Le taux de parasitémie du paludisme (MPr) de 24,4% était plus élevé que le taux d'antigénémie du paludisme (MAr) (20,8%). Les taux de MP et d'AM étaient indépendants du statut socio-économique, de l'accès aux médicaments antirétroviraux, de leur durée d'utilisation et du stade clinique de la maladie. CONCLUSION: l'AMM est survenue suffisamment fréquemment pour justifier son utilisation comme substitut de la définition de cas dans la prise en charge de ces sujets, étant donné l'implication de la parasitémie dans la physiopathologie et la virulence du VIH. MOTS CLÉS: Paludisme, Antigénémie, Parasitémie, Enfants infectés par le VIH, Benin City.

Trends of malaria infection in pregnancy in Ghana over the past two decades: a review.

BACKGROUND: There has been a global decline in malaria transmission over the past decade. However, not much is known of the impact of this observation on the burden of malaria infection in pregnancy in endemic regions including Ghana. A narrative review was undertaken to help describe trends in malaria infection in pregnancy in Ghana. Among others, such information is important in showing any progress made in malaria in pregnancy control. METHODS: To describe trends in pregnancy-associated malaria infection in Ghana, a search and review of literature reporting data on the prevalence of asymptomatic Plasmodium falciparum infection in pregnancy was conducted. RESULTS: Thirty-six (36) studies, conducted over 1994-2019, were included in the review. In the northern savannah zone with largely seasonal malaria transmission, prevalence appeared to reduce from about 50-60% in 1994-2010 to 13-26% by 2019. In the middle transitional/forest zone, where transmission is perennial with peaks in the rainy season, prevalence apparently reduced from 60% in the late 1990 s to about 5-20% by 2018. In the coastal savannah area, there was apparent reduction from 28 to 35% in 2003-2010 to 5-11% by 2018-2019. The burden of malaria infection in pregnancy continues to be highest among teenagers and younger-aged pregnant women and paucigravidae. CONCLUSIONS: There appears to be a decline in asymptomatic parasite prevalence in pregnancy in Ghana though this has not been uniform across the different transmission zones. The greatest declines were noticeably in urban settings. Submicroscopic parasitaemia remains a challenge for control efforts. Further studies are needed to evaluate the impact of the reduced parasite prevalence on maternal anaemia and low birthweight and to assess the local burden of submicroscopic parasitaemia in relation to pregnancy outcomes.

In vitro Evaluation and Molecular Dynamics, DFT Guided Investigation of Antimalarial Activity of Ethnomedicinally used Coptis teeta Wall.

BACKGROUND: Malaria is caused by different species of Plasmodium; among which P. falciparum is the most severe. Coptis teeta is an ethnomedicinal plant of enormous importance for tribes of northeast India. OBJECTIVE: In this study, the antimalarial activity of the methanol extracts of Coptis teeta was evaluated in vitro and lead identification was carried out via in silico study. METHODS: On the basis of the in vitro results, in silico analysis by application of different modules of Discovery Studio 2018 was performed on multiple targets of P. falciparum taking into consideration some of the compounds reported from C. teeta. RESULTS: The IC50 of the methanol extract of Coptis teeta was reported to be 0.08 µg/ml in 3D7 strain and 0.7 µg/ml in Dd2 strain of P. falciparum. From the docking study, noroxyhydrastatine was observed to have better binding affinity in comparison to chloroquine. The binding of noroxyhydrastinine with dihydroorotate dehydrogenase was further validated by molecular dynamics simulation and was observed to be significantly stable in comparison to the co-crystal inhibitor. During simulations, it was observed that noroxyhydrastinine retained the interactions, giving strong indications of its effectiveness against the P. falciparum proteins and stability in the binding pocket. From the Density-functional theory analysis, the bandgap energy of noroxyhydrastinine was found to be 0.186 Ha, indicating a favorable interaction. CONCLUSION: The in silico analysis as an addition to the in vitro results provides strong evidence of noroxyhydrastinine as an antimalarial agent.

Comparative study of Trypanosoma brucei brucei infection in rabbits and guinea fowls.

Trypanosoma brucei is one of the most pathogenic species of the genus Trypanosoma, and T. brucei brucei is one of the subspecies that is of great economic concern to animals. A large range of labouratory animals are commonly used in Trypanosoma studies. This study is aimed at exploring the possibility of using guinea fowls as experimental models for future studies and preservation of T. b. brucei. In achieving our aim, we studied the infectivity and pathogenicity of T. b. brucei in guinea fowls in relation to rabbits. The level of parasitaemia, mean body weight, mean temperature, haematological and histopathological parameters were accessed. Ten each of rabbits (Oryctolagus cuniculus) (control model) and guinea fowls (Numidia meleagris) (study model) (5 in the uninfected groups and 5 in the infected groups) were used for this study. The infected rabbits were inoculated intraperitoneally, while the infected guinea fowls were inoculated through the wing veins. Both animals were inoculated with 0.20 ml of T. b. brucei-infected blood estimated to be 1× 106 parasites/ ml. The infected rabbits and guinea fowls were screened daily for the presence of T. b. brucei using the haematocrit centrifugation technique (HCT). The mean weight, mean temperature and haematological parameters were accessed weekly, while the histopathological parameters were accessed at the end of the study. Trypanosoma b. brucei was detected in the blood of infected rabbits about 8 days post-infection, while there was no parasitaemia in the infected guinea fowls. The haemoflagellate exerted a significant (p < 0.05) effect on the mean body weight, mean temperature and haematological parameters of rabbits compared to guinea fowls. The pathological effects of T. b. brucei infection was seen in the liver and kidney of infected rabbits, and in the spleen of infected guinea fowls. There appears to be no successful multiplication and proliferation of T. b. brucei in the guinea fowls, making it not to be a suitable animal model for experimental studies and preservation of T. b. brucei.