Asymptomatic Malaria Parasitaemia Research Articles

Asymptomatic Malaria During Pregnancy: Prevalence, Influence on Anemia and Associated Factors in West Guji Zone, Ethiopia - A Community-Based Study.

Pregnant women with asymptomatic malaria parasitemia are at increased risk of anaemia, stillbirth, miscarriage, and preterm delivery. The asymptomatic nature of the population makes diagnosis difficult, and there is generally a lack of urgency to address this specific outcome. This study aimed to determine the prevalence of asymptomatic malaria and associated factors among pregnant women in West Guji Zone, Oromia, Ethiopia. A community-based cross-sectional study was conducted among randomly selected 557 asymptomatic pregnant women in the West Guji Zone from February to March 2022. A standardized questionnaire was used to collect information on socio-demographic and obstetric characteristics. Approximately 2 milliliters of peripheral blood was collected for microscopy to identify species and parasite density. Epi-Data and SPSS were used for data entry and analysis respectively. Binary logistic regression was used to identify risk factors. The prevalence of malaria among asymptomatic pregnant women was 24.10% (95% CI: 20.55%-27.65%). The prevalence of Plasmodium vivax and falciparum prevalence was 73 (54.5%) and 61 (45.5%), respectively. Of the study subjects, 105 (78.4%) had mild parasitemia and 29 (21.6%) had moderate parasitemia. Pregnant women with Plasmodium infection were anaemic in two-thirds (66.5%) of cases. Living near standing water (AOR=2.6, 95% CI: 1.74-3.96), having a history of Plasmodium species infection (AOR=2.12, 95% CI: 1.36-3.31), not using indoor residual spraying (AOR=2.0, 95% CI: 1.32-3.14), and not using insecticide-treated bed nets (AOR=1.62, 95% CI: 1.02-2.55) were all factors that were significantly associated with asymptomatic infection. Pregnant women with Plasmodium infection had a significantly higher rate of anaemia than those who were not infected (OR = 6.31, p = 0.000). Pregnant women had a significant prevalence of asymptomatic Plasmodium infection. Regular screening, appropriate treatment for those who test positive, and health education for pregnant women should be provided by the West Guji Zone Health Bureau.

Prevalence of Asymptomatic Malaria Parasitemia among Blood Donors in Cape Coast, Ghana: A Cross-Sectional Study.

Malaria is an important transfusion-associated infection in many parts of the world, particularly in sub-Saharan Africa, where it is endemic. We studied the prevalence of malaria parasites among blood donors in the Cape Coast Metropolitan Area. A malaria parasite examination was added to the blood donor screening protocol for 240 voluntary and replacement blood donors (224 males and 16 females) between December 2020 and July 2021. Overall, 2.5% (6/240) had Plasmodium falciparum trophozoites detected in their blood sample. The remaining had no parasites detected. Four of the 148 who passed the blood donor screening tests were infected. The remaining two with malaria parasites failed one screening test. These included one donor with "hepatitis B + P. falciparum" and another with "syphilis + P. falciparum" parasite coinfection. All blood donors who had malaria parasites detected in their blood were males. Most donors, 45.8% (110/240), were in the 26-35 age group, with the highest prevalence of 1.3% (3/240). Blood group O was predominant (75.0%, 180/240), followed by B (12.9%, 31/240), A (11.3%, 27/240), and AB (0.8%, 2/240). All malaria parasites detected were among individuals with blood group O. Moreover, 96.3% (231/240) were rhesus-positive and had the highest prevalence of 2.1% (5/240). Screening of blood donors in Ghana does not include malaria, although there is the potential for transmission through blood products. Malaria transmission via blood transfusion remains an issue of public health concern, as indicated in the results of this current study. We recommend studies on malaria prevention, pretransfusion and posttransfusion, and pathogen reduction technology.

Evaluation of an ultrasensitive HRP2–based rapid diagnostic test for detection of asymptomatic Plasmodium falciparum parasitaemia among children in western Kenya

BackgroundAccurate detection of asymptomatic malaria parasitaemia in children living in high transmission areas is important for malaria control and reduction programmes that employ screen-and-treat surveillance strategies. Relative to microscopy and conventional rapid diagnostic tests (RDTs), ultrasensitive RDTs (us-RDTs) have demonstrated reduced limits of detection with increased sensitivity to detect parasitaemia in symptomatic individuals. In this study, the performance of the NxTek™ Eliminate Malaria P.f test was compared with traditional microscopy and quantitative polymerase chain reaction (qPCR) testing methods of detection for P. falciparum parasitaemia among asymptomatic children aged 7–14 years living in an area of high malaria transmission intensity in western Kenya.MethodsIn October 2020, 240 healthy children without any reported malaria symptoms were screened for the presence of P. falciparum parasitaemia; 120 children were randomly selected to participate in a follow-up visit at 6–10 weeks. Malaria parasitaemia was assessed by blood-smear microscopy, us-RDT, and qPCR of a conserved var gene sequence from genomic DNA extracted from dried blood spots. Sensitivity, specificity, and predictive values were calculated for field diagnostic methods using qPCR as the gold standard. Comparison of detectable parasite density distributions and area under the curve were also calculated to determine the effectiveness of the us-RDT in detecting asymptomatic infections with low parasite densities.ResultsThe us-RDT detected significantly more asymptomatic P. falciparum infections than microscopy (42.5% vs. 32.2%, P = 0.002). The positive predictive value was higher for microscopy (92.2%) than for us-RDT (82.4%). However, false negative rates were high for microscopy and us-RDT, with negative predictive values of 53.7% and 54.6%, respectively. While us-RDT detected significantly more infections than microscopy overall, the density distribution of detectable infections did not differ (P = 0.21), and qPCR detected significantly more low-density infections than both field methods (P < 0.001, for both comparisons).ConclusionsUs-RDT is more sensitive than microscopy for detecting asymptomatic malaria parasitaemia in children. Though the detectable parasite density distributions by us-RDT in our specific study did not significantly differ from microscopy, the additional sensitivity of the us-RDT resulted in more identified asymptomatic infections in this important group of the population and makes the use of the us-RDT advisable compared to other currently available malaria field detection methods.

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.&#x0D; Objectives: To determine prevalence of asymptomatic MP and MA and their clinical and social determinants in HIV infected.&#x0D; 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.&#x0D; 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.&#x0D; 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.&#x0D; Authors&#x0D; M O Ibadin 1, N Eghafona 2

Attributable risk factors for asymptomatic malaria and anaemia and their association with cognitive and psychomotor functions in schoolchildren of north-eastern Tanzania.

In Africa, children aged 5 to 15 years (school age) comprises more than 50% (>339 million) of the under 19 years population, and are highly burdened by malaria and anaemia that impair cognitive development. For the prospects of improving health in African citizens, understanding malaria and its relation to anaemia in school-aged children, it is crucial to inform targeted interventions for malaria control and accelerate elimination efforts as part of improved school health policy. We conducted a study to determine the risk factors for asymptomatic malaria and their association to anaemia. We explored the prevalence of antimalarial drug resistance as well as the association of asymptomatic malaria infection and anaemia on cognitive and psychomotor functions in school-aged children living in high endemic areas. This study was a comprehensive baseline survey, within the scope of a randomised, controlled trial on the effectiveness and safety of antimalarial drugs in preventing malaria and its related morbidity in schoolchildren. We enrolled 1,587 schoolchildren from 7 primary schools located in Muheza, north-eastern Tanzania. Finger-pricked blood samples were collected for estimation of malaria parasitaemia using a microscope, haemoglobin concentration using a haemoglobinometer, and markers of drug resistance processed from dried blood spots (DBS). Psychomotor and Cognitive functions were assessed using a ‘20 metre Shuttle run’ and a test of everyday attention for children (TEA-Ch), respectively. The prevalence of asymptomatic malaria parasitaemia, anaemia and stunting was 26.4%, 49.8%, and 21.0%, respectively with marked variation across schools. In multivariate models, asymptomatic malaria parasitaemia attributed to 61% of anaemia with a respective population attribution fraction of 16%. Stunting, not sleeping under a bednet and illiterate parent or guardian were other factors attributing to 7%, 9%, and 5% of anaemia in the study population, respectively. Factors such as age group (10–15 years), not sleeping under a bednet, low socioeconomic status, parents’ or guardians’ with a low level of education, children overcrowding in a household, and fewer rooms in a household were significantly attributed to higher malaria infection. There was no significant association between malaria infection or anaemia and performance on tests of cognitive function (sustained attention) or psychomotor function (VO2 max). However, a history of malaria in the past one month was significantly associated with decreased cognitive scores (aOR = -4.1, 95% CI -7.7–0.6, p = 0.02). Furthermore, stunted children had significantly lower VO2max scores (aOR = -1.9, 95% CI -3.0–0.8, p = 0.001). Regarding the antimalarial drug resistance markers, the most prevalent Pfmdr1 86-184-1034-1042-1246 haplotypes were the NFSND in 47% (n = 88) and the NYSND in 52% (n = 98). The wild type Pfcrt haplotypes (codons 72–76, CVMNK) were found in 99.1% (n = 219) of the samples. Malaria, stunting and parents’ or guardians’ illiteracy were the key attributable factors for anaemia in schoolchildren. Given malaria infection in schoolchildren is mostly asymptomatic; an addition of interventional programmes such as intermittent preventive treatment of malaria in schoolchildren (IPTsc) would probably act as a potential solution while calling for an improvement in the current tools such as bednet use, school food programme, and community-based (customised) health education with an emphasis on nutrition and malaria control.

The Rate of Asymptomatic Plasmodium Parasitemia and Placental Parasitization in Urban and Rural Areas of Cross River State, Nigeria

Background: Malaria in pregnancy contributes to feto-maternal morbidity and mortality even in asymptomatic forms of the disease especially in malaria endemic regions such as Nigeria. Objective: To determine the rate of asymptomatic malaria parasitemia and placental parasitization among the rural and urban pregnant women and its feto-maternal effects in Cross River State, Nigeria. Methodology: This was a prospective study of 440 pregnant women in rural and urban settings. Participants completed structured questionnaire and also have their blood samples and placentas examined for presence of malaria parasites by microscopy and histology respectively. Maternal hemoglobin concentration, birth weight, neonatal length, Apgar score and other anthropometric measurements were obtained to assess feto-maternal effect of asymptomatic malaria parasitemia and placental parasitisation in pregnancy. Data were analyzed using SPSS version 21.0 and level of significance was set as 0.05. ResultsThe prevalence of asymptomatic malaria parasitemia was 40.2% while malaria placental parasitization was 70.2%. Based on residential status, 49.5% of rural residents had malaria parasitemia which is significantly higher than their urban resident counterparts 30.9% (p=0.000). The prevalence of placental parasitization was significantly higher among rural residents 80.9% than their urban resident counterparts 59.5% (p=0.000). Concerning obstetric outcome of patients with positive malaria placental parasitisation, preterm delivery, low 5th minutes Apgar score (&lt;7), low birth weight (&lt;2.5kg) and low neonatal length were significantly higher in pregnancy with positive placental parasitisation than in women with negative placental malaria parasitisation. Also, preterm delivery, anemia, low 5th minutes Apgar score (&lt;7) and low birth weight (&lt;2.5kg) were significantly higher in pregnancy with positive malaria parasitemia than women with negative malaria parasitemia. ConclusionAsymptomatic malaria parasitemia (40.2%) and malaria placental parasitization (70.2%) in this study is high and contributes to poor obstetric outcomes mostly in the rural areas. Rural pregnant women have the highest burden than the urban women. Promotion of the use of ITNs, IPT during pregnancy and other malaria preventive measures are necessary especially in rural areas where malaria burden is highest.

High Prevalence of Asymptomatic Malarial Anemia and Association with Early Conversion from Asymptomatic to Symptomatic Infection in a Plasmodium falciparum Hyperendemic Setting in Cameroon.

Asymptomatic malarial parasitemia is highly prevalent in Plasmodium falciparum endemic areas and often associated with increased prevalence of mild to moderate anemia. The aim of this study was to assess the prevalence of anemia during asymptomatic malaria parasitemia and its interplay with persistent infection in highly exposed individuals. A household-based longitudinal survey was undertaken in a malaria hyperendemic area in Cameroon using multiplex nested polymerase chain reaction to detect plasmodial infections. Residents with P. falciparum asymptomatic parasitemia were monitored over a 3-week period with the aid of structured questionnaires and weekly measurements of axillary temperatures. Of the 353 individuals included (median age: 26 years, range 2-86 years, male/female sex ratio 0.9), 328 (92.9%) were positive for malaria parasitemia of whom 266 (81.1%) were asymptomatic carriers. The prevalence of anemia in the study population was 38.6%, of which 69.2% were asymptomatic. Multivariate analyses identified high parasitemia (> 327 parasites/µL) and female gender as associated risk factors of asymptomatic malarial anemia in the population. Furthermore, risk analyses revealed female gender and anemia at the time of enrolment as key predictors of early development of febrile illness (< 3 weeks post enrolment) among the asymptomatic individuals. Together, the data reveal an extremely high prevalence of asymptomatic malaria parasitemia and anemia in the study area, unveiling for the first time the association of asymptomatic malarial anemia with early clinical conversion from asymptomatic to symptomatic infection. Furthermore, these findings underscore the negative impact of asymptomatic malaria parasitemia on individual health, necessitating the development of appropriate control and preventive measures.

Socio-Demographic Profile, Asymptomatic Malaria Parasitaemia and Glycemic Control among Midled-Aged and Elderly Type 2 Diabetes Mellitus Patients in Rural Southwestern Nigeria: A Cross Sectional Study

The main therapeutic goal for all type 2 diabetes mellitus (T2DM) patients is to maintain good control so as to prevent the risk of complications associated with poor control. This study determined the prevalence of poor control and its association with socio-demographics and malaria parasitaemia among middle aged and elderly T2DM patients at a tertiary hospital in rural Southwestern Nigeria. We conducted a retrospective observational study on 250 T2DM using semi-structured interviewer administered questionnaire. Venous blood samples were collected and processed for glycated hemoglobin sugar estimation and malaria parasite detection by microscopy. Data were analyzed using SPSS version 20.0. Multivariate logistic regression identified the association of socio-demographics and asymptomatic malaria parasitaemia with poor control. The prevalence of poor glycemic control was 31.6% (95%CI: 34.4%-45.8%). Old age, (AOR=4.868; 95% CI: 1.258-24.574), female genders (AOR=7.100; 95% CI: 1.875-34.655), no formal education (AOR=3.447; 95% CI: 1.098-21.478), presence of malaria parasitaemia (AOR=48.423; 95% CI: 4.987-411.366), and higher parasite density (AOR=7.102; 95% CI: 1.785-15.002), were significantly associated with poor control. Health facilities should integrate screening of malaria parasitaemia into the management of T2DM patients while also exploring other barriers of poor control.

Asymptomatic and sub-microscopic Plasmodium falciparum infection in children in the Mount Cameroon area: a cross-sectional study on altitudinal influence, haematological parameters and risk factors

BackgroundThe Mount Cameroon area has experienced a 57.2% decline in confirmed malaria cases between 2006 and 2013 with the implementation of different control measures but, the disease is still of public health concern. The objective of the study was to assess the burden of asymptomatic and sub-microscopic Plasmodium infection, altitudinal influence on it, their effect on haematological parameters as well as identify the risk factors of infection.MethodologyA cross-sectional community-based survey involving 1319 children of both sexes aged 6 months to 14 years was conducted between July 2017 and May 2018. Malaria parasitaemia was confirmed by Giemsa-stained microscopy, sub-microscopic Plasmodium infection by 18S mRNA using nested PCR and full blood count analysis was done using an auto haematology analyser.ResultsMalaria parasite, asymptomatic malaria parasitaemia and sub-microscopic Plasmodium infection and anaemia were prevalent in 36.4%, 34.0%, 43.8% and 62.3% of the children, respectively. The risk of having sub-microscopic Plasmodium infection was highest in children 5‒9 (OR = 3.13, P < 0.001) and 10‒14 years of age (OR = 8.18, P < 0.001), non-insecticide treated net users (OR = 1.69, P < 0.04) and those anaemic (OR = 9.01, P < 0.001). Children with sub-microscopic infection had a significantly lower mean haemoglobin (9.86 ± 1.7 g/dL, P < 0.001), red blood cell counts (4.48 ± 1.1 × 1012/L, P < 0.001), haematocrit (31.92%, P < 0.001), mean corpuscular haemoglobin concentration (313.25 ± 47.36, P = 0.035) and platelet counts (280.83 ± 112.62, P < 0.001) than their negative counterparts. Children < 5 years old (73.8%), having asymptomatic (69.8%) and sub-microscopic Plasmodium infection (78.3%) as well as resident in the middle belt (72.7%) had a higher prevalence of anaemia than their peers.ConclusionThe meaningful individual-level heterogeneity in the burden of asymptomatic and sub-microscopic Plasmodium infection in addition to its corollary on haematological variables among children in the different attitudinal sites of the Mount Cameroon Region accentuate the need for strategic context specific planning of malaria control and preventative measures.

Towards the use of a smartphone imaging-based tool for point-of-care detection of asymptomatic low-density malaria parasitaemia

BackgroundGlobally, there are over 200 million cases of malaria annually and over 400,000 deaths. Early and accurate detection of low-density parasitaemia and asymptomatic individuals is key to achieving the World Health Organization (WHO) 2030 sustainable development goals of reducing malaria-related deaths by 90% and eradication in 35 countries. Current rapid diagnostic tests are neither sensitive nor specific enough to detect the low parasite concentrations in the blood of asymptomatic individuals.MethodsHere, an imaging-based sensing technique, particle diffusometry (PD), is combined with loop mediated isothermal amplification (LAMP) on a smartphone-enabled device to detect low levels of parasitaemia often associated with asymptomatic malaria. After amplification, PD quantifies the Brownian motion of fluorescent nanoparticles in the solution during a 30 s video taken on the phone. The resulting diffusion coefficient is used to detect the presence of Plasmodium DNA amplicons. The coefficients of known negative samples are compared to positive samples using a one-way ANOVA post-hoc Dunnett’s test for confirmation of amplification.ResultsAs few as 3 parasite/µL of blood was detectable in 45 min without DNA extraction. Plasmodium falciparum parasites were detected from asymptomatic individuals’ whole blood samples with 89% sensitivity and 100% specificity when compared to quantitative polymerase chain reaction (qPCR).ConclusionsPD-LAMP is of value for the detection of low density parasitaemia especially in areas where trained personnel may be scarce. The demonstration of this smartphone biosensor paired with the sensitivity of LAMP provides a proof of concept to achieve widespread asymptomatic malaria testing at the point of care.

Epidemiological and clinical implications of asymptomatic malaria and schistosomiasis co-infections in a rural community in western Kenya

BackgroundMalaria and schistosomiasis present considerable disease burden in tropical and sub-tropical areas and severity is worsened by co-infections in areas where both diseases are endemic. Although pathogenesis of these infections separately is well studied, there is limited information on the pathogenic disease mechanisms and clinical disease outcomes in co-infections. In this study, we investigated the prevalence of malaria and schistosomiasis co-infections, and the hematologic and blood chemistry abnormalities in asymptomatic adults in a rural fishing community in western Kenya.MethodsThis sub-study used samples and data collected at enrollment from a prospective observational cohort study (RV393) conducted in Kisumu County, Kenya. The presence of malaria parasites was determined using microscopy and real-time-PCR, and schistosomiasis infection by urine antigen analysis (CCA). Hematological analysis and blood chemistries were performed using standard methods. Statistical analyses were performed to compare demographic and infection data distribution, and hematologic and blood chemistry parameters based on different groups of infection categories. Clinically relevant hematologic conditions were analyzed using general linear and multivariable Poisson regression models.ResultsFrom February 2017 to May 2018, we enrolled 671 participants. The prevalence of asymptomatic Plasmodium falciparum was 28.2% (157/556) and schistosomiasis 41.2% (229/562), with 18.0% (100/556) of participants co-infected. When we analyzed hematological parameters using Wilcoxon rank sum test to evaluate median (IQR) distribution based on malarial parasites and/or schistosomiasis infection status, there were significant differences in platelet counts (p = 0.0002), percent neutrophils, monocytes, eosinophils, and basophils (p < 0.0001 each). Amongst clinically relevant hematological abnormalities, eosinophilia was the most prevalent at 20.6% (116/562), whereas thrombocytopenia was the least prevalent at 4.3% (24/562). In univariate model, Chi-Square test performed for independence between participant distribution in different malaria parasitemia/schistosomiasis infection categories within each clinical hematological condition revealed significant differences for thrombocytopenia and eosinophilia (p = 0.006 and p < 0.0001, respectively), which was confirmed in multivariable models. Analysis of the pairwise mean differences of liver enzyme (ALT) and kidney function (Creatinine Clearance) indicated the presence of significant differences in ALT across the infection groups (parasite + /CCA + vs all other groups p < .003), but no differences in mean Creatinine Clearance across the infection groups.ConclusionsOur study demonstrates the high burden of asymptomatic malaria parasitemia and schistosomiasis infection in this rural population in Western Kenya. Asymptomatic infection with malaria or schistosomiasis was associated with laboratory abnormalities including neutropenia, leukopenia and thrombocytopenia. These abnormalities could be erroneously attributed to other diseases processes during evaluation of diseases processes. Therefore, evaluating for co-infections is key when assessing individuals with laboratory abnormalities. Additionally, asymptomatic infection needs to be considered in control and elimination programs given high prevalence documented here.

Altered Ex-Vivo Cytokine Responses in Children With Asymptomatic Plasmodium falciparum Infection in Burkina Faso: An Additional Argument to Treat Asymptomatic Malaria?

IntroductionPatients with clinical malaria have an increased risk for bacterial bloodstream infections. We hypothesized that asymptomatic malaria parasitemia increases susceptibility for bacterial infections through an effect on the innate immune system. We measured circulating cytokine levels and ex-vivo cytokine production capacity in asymptomatic malaria and compared with controls.MethodsData were collected from asymptomatic participants <5 years old with and without positive malaria microscopy, as well as from hospitalized patients <5 years old with clinical malaria, bacteremia, or malaria/bacteremia co-infections in a malaria endemic region of Burkina Faso. Circulating cytokines (TNF-α, IFN-γ, IL-6, IL-10) were measured using multiplex assays. Whole blood from asymptomatic participants with and without positive malaria microscopy were ex-vivo stimulated with S. aureus, E. coli LPS and Salmonella Typhimurium; cytokine concentrations (TNF-α, IFN-γ, IL-1β, IL-6, IL-10) were measured on supernatants using ELISA.ResultsIncluded were children with clinical malaria (n=118), bacteremia (n=22), malaria and bacteremia co-infection (n=9), asymptomatic malaria (n=125), and asymptomatic controls (n=237). Children with either clinical or asymptomatic malaria had higher plasma cytokine concentrations than controls. Cytokine concentrations correlated positively with malaria parasite density with the strongest correlation for IL-10 in both asymptomatic (r=0.63) and clinical malaria (r=0.53). Patients with bacteremia had lower circulating IL-10, TNF-α and IFN-γ and higher IL-6 concentrations, compared to clinical malaria. Ex-vivo whole blood cytokine production to LPS and S. aureus was significantly lower in asymptomatic malaria compared to controls. Whole blood IFN-γ and IL-10 production in response to Salmonella was also lower in asymptomatic malaria.InterpretationIn children with asymptomatic malaria, cytokine responses upon ex-vivo bacterial stimulation are downregulated. Further studies are needed to explore if the suggested impaired innate immune response to bacterial pathogens also translates into impaired control of pathogens such as Salmonella spp.

Haemoglobin phenotypes and the risk of asymptomatic malaria parasitemia among blood donors in northwest Nigeria: clinical implications in the practice of tropical transfusion medicine

Background: In malaria-endemic populations, sickle cell trait (SCT) protects against both severe and non-severe malaria, but inconsistencies exist about protective effect of SCT on asymptomatic malarial parasitemia (AMP). Surprisingly, the effect of Hb-phenotypes on AMP has not been explored among blood donors in Nigeria or other malaria-endemic countries, where risks of AMP and transfusion transmitted malaria (TTM) are high. The objective of this study is to determine risk of AMP with respect to donor Hb-phenotypes (SCT versus HbAA), and elucidate clinical implications of AMP with respect to risk of TTM vis-à-vis the practice of transfusion medicine in Nigeria, and by implication other malaria-endemic tropical countries.Methodology: Analysis of 100 blood donors with AMP (cases) and 100 donors without AMP (controls) was performed. Frequencies of SCT and HbAA (determined by Hb electrophoresis) among cases and controls were compared by X2 -test. Risks of AMP (detected by microscopy) with respect to Hb-phenotypes were expressed as Odds ratios (OR) by case-control logistic regression.Results: In comparison with blood donor without AMP (controls), donors with AMP had lower frequencies of SCT (12% vs 28%, p&lt;0.05) with corresponding higher frequencies of HbAA (88% vs 72%, p&lt;0.05). HbAA is associated with high risk of AMP (OR=2.91, 95%CI: 2.10-3.48, p=0.021), while SCT is associated low risk of AMP (OR=0.49, 95%CI: 0.27-0.73, p=0.032).Conclusion: This finding shows that donor SCT is a surreptitious mitigator of the risk of AMP and TTM in the tropics. Therefore, patients who are selectively transfused with HbAA blood (e. g. neonates and sickle cell disease patients) could be at greater risks of TTM, and such patients need closer post transfusion monitoring. The risk of TTM calls for diligent post transfusion haemovigilance in Nigeria and other malaria endemic tropical countries in Africa&#x0D; Keywords: blood donors, sickle cell trait, asymptomatic malaria parasitemia, transfusion transmitted malaria

Asymptomatic malaria parasitaemia among HIV infected children and adolescents

Background: Malaria manifests with life-threatening manifestations resulting in hospital admissions and sometimes death may ensue. This is more devastating among children due to high susceptibility resulting from impaired immune system following severe malaria. Human immunodeficiency virus (HIV) coinfection with malaria further compromises the immune system and increases the vulnerability. The effect of co-trimoxazole prophylaxis in curtailing malaria has not being well evaluated in our environment where both malaria and HIV are endemic. This study sets out to determine the magnitude of asymptomatic malaria among HIV-infected children and adolescents receiving care at our facility. Study Design: This was a descriptive cross-sectional study. Materials and Methods: A prospective study among HIV-infected children aged 2–18 years was enrolled in our care. Nonprobability convenience sampling was used to recruit individuals who fulfilled the criteria. Questionnaire and patients' medical records were used to gather some data. A sample was taken for malaria parasite microscopy. The analysis was done using the Statistical Package for the Social Sciences version 20. Categorical variables were presented as percentages and association assessed using Chi-square test, whereas continuous variables were presented as mean and standard deviation, and the association between two means was checked using Student's t-test. Results: The mean age of the study population is 7.02 ± 2.97 years. Of the 420 participants in this study, 92 (45.7%) had confirmed malaria. There was no significant difference in the gender, age groups, and viral loads of patients with malaria. Conclusion: There is a high prevalence of malaria coinfection with HIV in this study.

Prevalence of Asymptomatic Malaria Parasitemia in Odisha, India: A Challenge to Malaria Elimination.

The prevalence of malaria in India is decreasing, but it remains a major concern for public health administration. The role of submicroscopic malaria and asymptomatic malaria parasitemia and their persistence is being explored. A cross-sectional survey was conducted in the Kandhamal district of Odisha (India) during May-June 2017. Blood samples were collected from 1897 individuals for screening of asymptomatic parasitemia. Samples were screened using rapid diagnostic tests (RDTs) and examined microscopically for Plasmodium species. Approximately 30% of randomly selected samples (n = 586) were analyzed using real-time PCR (qPCR), and the genetic diversity of Plasmodium falciparum was analyzed. The prevalence of Plasmodium species among asymptomatic individuals detected using qPCR was 18%, which was significantly higher than that detected by microscopy examination (5.5%) or RDT (7.3%). Of these, 37% had submicroscopic malaria. The species-specific prevalence among asymptomatic malaria-positive cases for P. falciparum, Plasmodium vivax, and mixed infection (P. falciparum and P. vivax) by qPCR was 57%, 29%, and 14%, respectively. The multiplicity of infection was 1.6 and 1.2 for the merozoite surface protein-1 gene (msp1) and (msp2), respectively. Expected heterozygosity was 0.64 and 0.47 for msp1 and msp2, respectively. A significant proportion of the study population, 105/586 (18%), was found to be a reservoir for malaria infection, and identification of this group will help in the development of elimination strategies.

Haematological Parameters and Spleen Rate of Asymptomatic and Malaria Negative Children in Edo South District, Nigeria.

Background:Malaria is commonly associated with alteration in haematologic cells of infected individuals in both the acute uncomplicated and severe phases. Whether this alteration occurs in the asymptomatic phase of the disease is still being investigated.Objectives:To examine the haematocrit, thrombocytes, and monocytes levels of children with asymptomatic malaria compared with age/sex-matched controls who are malaria parasite negative and living in a stable malaria endemic region. It also set out to identify spleen rate of the children and to compare it with that observed in malaria negative controls.Methods:One hundred well-nourished children 2–9 years old with asymptomatic malaria parasitaemia and 100 age- and sex-matched malaria negative controls were recruited by multi-stage sampling from schools in a malaria endemic region of Nigeria. Malaria diagnosis was by microscopy, and each haematologic parameter was analysed following standard protocols.Results:Mean (±) monocyte count of 2.25 ± 0.9 × 109 cells/L observed in asymptomatic malaria children was significantly higher than 1.34 ± 0.5 × 109 cells/L observed in those with no malaria (p = 0.00). Mean (±) thrombocyte count was significantly lower (asymptomatic 203.64 ± 45.90 × 109 cells/L Vs no malaria 230.91 ± 57.40 × 109 cells/L) (p = 0.00). Spleen rate in the children was 15.5%. Presence of splenomegaly was not statistically significantly fewer in children with asymptomatic malaria parasitaemia (ASMP) (14/31) when compared to those who were malaria parasite negative (17/31) (χ2 = 0.34, p = 0.57). Similarly, there was no significant difference in the mean [±] spleen length of children with ASMP (n = 14; 2.86 ± 0.9 cm) and those who were malaria negative (n = 17; 2.53 ± 0.6 cm) (t = 1.22, p = 0.23).Conclusion:Thrombocytopaenia and monocytosis could be pointers to malaria parasitaemia in asymptomatic phase in a stable malaria region.

Associations among Soil-Transmitted Helminths, G6PD Deficiency and Asymptomatic Malaria Parasitemia, and Anemia in Schoolchildren from a Conflict Zone of Northeast Myanmar.

In tropical areas of developing countries, the interactions among parasitic diseases such as soil-transmitted helminths (STHs) and malaria, and glucose-6-phosphate dehydrogenase deficiency (G6PDd), are complex. Here, we investigated their interactions and impact on anemia in school students residing in a conflict zone of northeast Myanmar. A cross-sectional survey was conducted between July and December 2015 in two schools located along the China-Myanmar border. Stool samples from the schoolchildren were analyzed for STH infections, whereas finger-prick blood samples were analyzed for G6PDd, hemoglobin concentrations, and Plasmodium infections. Among 988 enrolled children, Plasmodium vivax, Plasmodium falciparum, hookworm, Ascaris lumbricoides, and Trichuris trichiura infections occurred in 3.3%, 0.8%, 31.5%, 1.2%, and 0.3%, respectively. Glucose-6-phosphate dehydrogenase deficiency was present in 16.9% of the children, and there was a very high prevalence of anemia (73%). Anthropometric measures performed on all children showed that 50% of the children were stunted and 25% wasted. Moderate to severe anemia was associated with STH infections, stunting, and wasting. In addition, children had increasing odds of anemia with increasing burden of infections. This study revealed a high prevalence of G6PDd, STHs, and anemia in schools located in a conflict zone. In areas where malnutrition and STH infections are rampant, testing for both glucose-6-phosphate dehydrogenase and anemia should be considered before treating vivax malaria with 8-aminoquinolines.

Asymptomatic Malaria Parasitemia Amongst Patients with Steady-State Sickle Cell Anaemia and The Influence of Proguanil Prophylaxis

Asymptomatic Malaria Parasitemia Amongst Patients with Steady-State Sickle Cell Anaemia and The Influence of Proguanil Prophylaxis

Prevalence of asymptomatic malaria parasitaemia following mass testing and treatment in Pakro sub-district of Ghana

BackgroundGlobal efforts to scale-up malaria control interventions are gaining steam. These include the use of Long-Lasting Insecticide Nets, Indoor Residual Spraying, Intermittent Preventive Treatment and Test, Treat and Track. Despite these, the drive for malaria elimination is far from being realistic in endemic communities in Africa. This is partly due to the fact that asymptomatic parasite carriage, not specifically targeted by most interventions, remains the bedrock that fuels transmission. This has led to mass testing, treatment and tracking (MTTT) as an alternative strategy to target asymptomatic individuals. We report the impact of MTTT on the prevalence of asymptomatic malaria parasitaemia over a one-year period in Ghana, hypothesizing that implementing MTTT could reduce the rate of asymptomatic parasitaemia.MethodsA population of about 5000 individuals in seven communities in the Pakro sub-district of Ghana participated in this study. A register was developed for each community following a census. MTTT engaged trained community-based health volunteers who conducted house-to-house testing using RDTs every 4 months and treated positive cases with Artemisinin–based Combination Therapy. Between interventions, community-based management of malaria was implemented for symptomatic cases.ResultsMTTT Coverage was 98.8% in July 2017 and 79.3% in July 2018. Of those tested, asymptomatic infection with malaria parasites reduced from 36.3% (1795/4941) in July 2017 to 32.9% (1303/3966) in July 2018 (p = 0.001). Prevalence of asymptomatic parasitaemia among children under 15 years declined from 52.6% (1043/1984) in July 2017 to 47.5% (820/1728) in July 2018 (p = 0.002). Implementing MTTT significantly reduced asymptomatic parasitaemia by 24% from July 2017 to July 2018 after adjusting for age, ITN use and axillary temperature (OR = 0.76, CI = 0.67, 0.85 p ≤ 0.001).ConclusionThis study has demonstrated that implementing MTTT is feasible and could reduce the prevalence of asymptomatic malaria parasitaemia in children under 15 years of age. Furthermore, the use of community-based health volunteers could ensure high coverage at lower cost of implementation.Trial registrationNCT04167566, Date 14/11/2019. Retrospective registration.

Challenges and perceptions of implementing mass testing, treatment and tracking in malaria control: a qualitative study in Pakro sub-district of Ghana

BackgroundMalaria remains endemic in Ghana despite several interventions. Studies have demonstrated very high levels of asymptomatic malaria parasitaemia in both under-five and school-age children. Mass testing, treatment and tracking (MTTT) of malaria in communities is being proposed for implementation with the argument that it can reduce parasite load, amplify gains from the other control interventions and consequently lead to elimination. However, challenges associated with implementing MTTT such as feasibility, levels of coverage to be achieved for effectiveness, community perceptions and cost implications need to be clearly understood. This qualitative study was therefore conducted in an area with on-going MTTT to assess community and health workers’ perceptions about feasibility of scale-up and effectiveness to guide scale-up decisions.MethodsThis qualitative study employed purposive sampling to select the study participants. Ten focus group discussions (FGDs) were conducted in seven communities; eight with community members (n = 80) and two with health workers (n = 14). In addition, two in-depth interviews (IDI) were conducted, one with a Physician Assistant and another with a Laboratory Technician at the health facility. All interviews were recorded, transcribed, translated and analyzed using QSR NVivo 12.ResultsBoth health workers and community members expressed positive perceptions about the feasibility of implementation and effectiveness of MTTT as an intervention that could reduce the burden of malaria in the community. MTTT implementation was perceived to have increased sensitisation about malaria, reduced the incidence of malaria, reduced household expenditure on malaria and alleviated the need to travel long distances for healthcare. Key challenges to implementation were doubts about the expertise of trained Community-Based Health Volunteers (CBHVs) to diagnose and treat malaria appropriately, side effects of Artemisinin-based Combination Therapies (ACTs) and misconceptions that CBHVs could infect children with epilepsy.ConclusionThe study demonstrated that MTTT was perceived to be effective in reducing malaria incidence and related hospital visits in participating communities. MTTT was deemed useful in breaking financial and geographical barriers to accessing healthcare. The interventions were feasible and acceptable to community members, despite observed challenges to implementation such as concerns about CBHVs’ knowledge and skills and reduced revenue from internally generated funds (IGF) of the health facility.