Giemsa-stained Thick Blood Films Research Articles

Evaluation of Malaria Microscopy Diagnostic Performance at 40 Public Health Facilities in Abidjan, Côte d'Ivoire in 2020.

Microscopic diagnosis of Giemsa-stained thick and thin blood films remained the gold standard laboratory method for the diagnosis of malaria. In this context, we felt it was important to conduct this evaluation with 40 public medical biology laboratories (MBLs) in the Abidjan 1 health region that perform blood parasitology tests to improve their implementation process. This descriptive and analytical study took place in July 2020 and involved participating laboratories (PLs) from the public sector in Abidjan. A set of 3 blood smear slides of variable parasite densities (PDs) with assigned values (AVs) of parasite densities and assigned Plasmodium species was used. The criterion for establishing the parasite density compliance interval was assigned values of ± 25%, and the performance rates were compared to the 80% recommended by the WHO for the African region. Nearly a quarter (11/40) of the participating laboratories had a compliance rate greater than 80%, including 10 with a performance of 100% for the ability to identify parasites. Regarding identifying plasmodial species, a concordance rate of 100% was obtained for slide 1 for Plasmodium falciparum, while this rate was 20% for slide 2 for Plasmodium ovale. For parasite densities < 200/µl, 87.5% of the participating laboratories (PLs) had a performance rate lower than 80%, while 95% of these PLs had a performance rate higher than 80% for parasitaemia > 2000/µl. There is a need to strengthen adapted to low parasitaemia, to improve the biological confirmation of malaria in Côte d'Ivoire.

Prevalence of Concomitant Bacteria among malaria Patients attending Government Hospitals in Ondo State, South-West Nigeria

Background:Patients suffering from severe malaria have an increased risk of co-occurring bacterial sepsis, which results in higher mortality rates than malaria alone. Concomitant bacterial infections can worsen malaria symptoms, leading to increased illness and death rates. This study aimed to investigate the relationship between malaria and concomitant bacteremia among patients in Ondo State, Nigeria.Aim: The study's objective was to determine the prevalence of bacterial concomitant among malaria patients and assess the relationship between malaria and bacteremia in the study population.Material and Methods: A cross-sectional study was conducted among feverish individuals in certain Ondo State government hospitals. One milliliter of blood was collected from malaria-positive patients, confirmed using microscopic examination of Giemsa-stained thick and thin blood films, and an Malaria rapid diagnostic tests (RDT) kit was cultured for bacterial enumeration. The collected data were statistically analyzed using Chi-square and correlation tests, with a 𝑃value &lt;0.05 considered significant.Result: The study found a concomitant bacteria prevalence of 19.95% (85/426), with a significant (P= &lt;0.001, r = 0.00334) positive correlation between malaria and bacterial concomitant.Age was significantly (p = 0.072, df= 18, χ2 = 27.389) associated with bacterial concomitant, and the mean bacterial count was 9.71±1.481 cfu/ml x 107. Furthermore, level of education, marital status and tribe also significantly (p&lt;0.05) contributed to the prevalence of concomitant bacteria.Conclusion: Our research concludes that malaria may increase the risk of bacteremia, and a significant association between malaria and concomitant bacterial infection exists. However, the reasons for bacteria's abilityto invade and thrive in the bloodstream vary. The study's findings suggest that interventions are needed to address the high prevalence of concomitant bacterial infections among malaria patients in the study area.

Prevalence of Malaria Parasitemia and Perceptions of the Use of Long-Lasting Insecticide Nets in a Sample of Pregnant Women in a Malaria-Endemic Nigerian Community

Objectives: The objectives of the study were to evaluate the prevalence of malaria and the perception on the use of long-lasting insecticide-treated nets (LLINs) among pregnant women attending antenatal care at Neni Community Health Center, Anaocha Local Government Area, Anambra State, Nigeria. Methods: A sample of 364 pregnant women were randomly selected for the study. Malaria parasitemia and the use of LLINs were critically evaluated among pregnant women in the study area. Two milliliters of venous blood samples was collected by a medical laboratory scientist from each pregnant woman; it was stored in an ethylenediaminetetraacetic acid container. This was done under sterile conditions and examined for malaria parasites using Giemsa-stained thin and thick blood films under a microscope. Interviews and observations were used to collect information from pregnant women regarding their sociodemographic characteristics and use of LLINs. The level of statistical significance was set at Ρ ≤0.05. Results: The prevalence of malaria in relation to parity indicated that primigravidae had the highest proportion (46.2%). In terms of gestational stage, malaria infection was highest among women in their first trimester (37.2%). Based on occupational status, farmers recorded the highest prevalence of 40.7%. There was a significantly higher proportion of pregnant women who were aware of LLINs (χ2 = 25.36, P &lt; 0.05), chose antenatal classes as a source of information on awareness of LLINs (χ2 = 27.33, P &lt; 0.05), and had reasons for noncompliance with LLINs (χ2 = 25.71, P &lt; 0.05). Conclusions: This study reveals a relatively high prevalence of malaria parasitemia and low compliance with the use of long-lasting insecticide nets among pregnant women attending antenatal care at Neni Community Health Center in Anambra State, Nigeria.

Effects of Malaria and HIV Infection on Anemia and T-cells Levels in Children in Douala City, Cameroon.

Introduction Human immunodeficiency virus (HIV) infection and malaria are priority health issues for sub-Saharan Africa. Both diseases worsen each other through their effect on the immune and hematological systems. This study aimed to determine the effects of HIV infection and asymptomatic malaria on anemia and T-cells counts in children in the city of Douala in the republic of Cameroon. Method From May to November 2016, 197 HIV infected and 98 HIV-free non-febrile children up to 19 years old(128 male and 167 female) participated in the study. All HIV-infected children were receiving antiretroviral treatment and co-trimoxazole. Malaria diagnosis was performed using Giemsa-stained thick blood film; immunological and hematological parameters were assessed through a flow cytometer and an automated analyzer respectively. Chi-squared or Fischer's exact tests was used to compare the proportions, Mann-Whitney and ANOVA tests were used for the means. Statistical significance was set at p˂0.05. Results The prevalence of malaria was 8.8%, and that of anemia was 40.7%. CD4+-T cells were higher in malaria-infected children, both in HIV positive and negative (p=0.049). No significant association was found between malaria parasitemia and CD8+-T cell levels, both in HIV-positive and negative children (p=0.41). Anemia was higher in HIV-positive children (p=0.019), especially in those with severe immunosuppression (p=0.001) and in younger children (p=0.0083).Children on HIV treatment presented lower malaria prevalence (8.6% versus 10.10%), though the difference was not significant (p=0.7068). Malaria infection was associated with lower hemoglobin levels (10.5±1.7 versus 11.2±1.4; p=0.016). Conclusion Malaria infection may enhance CD4+-T cells. Both malaria and HIV infection lead to a drop in hemoglobin levels. The HIV treatment protocol may reduce malaria prevalence.

Malaria among under-five children in rural communities of Al-Mahweet governorate, Yemen

BackgroundMalaria burden among under-five children living in endemic areas of Yemen is largely unknown due to the lack of community-based studies. Therefore, this study determined the prevalence and risk factors associated with falciparum malaria among under-five children in rural communities of Al-Mahweet governorate, Yemen.MethodsThis community-based, cross-sectional study recruited 400 under-five children from two rural districts of Al-Mahweet governorate in December 2019. Demographic characteristics (gender, age, education and occupation of the child’s parents, and household size) and risk factors associated with malaria were collected through interviews with children’s caregivers using a structured questionnaire. Finger-prick blood was screened for Plasmodium falciparum and non-falciparum species using rapid diagnostic tests (RDTs), and duplicate Giemsa-stained thick and thin blood films were examined for malaria parasites. The density of asexual P. falciparum stages was also estimated. Data were then analysed, and the agreement between the results of thick-film microscopy and RDTs for diagnosing falciparum malaria was assessed using the kappa index. Statistical significance was set at a P-value of < 0.05.ResultsPlasmodium falciparum was prevalent among 9.8% (95% CI 7.0–13.1) of under-five children in the rural communities of Al-Mahweet, with a median asexual parasite density of 763 ± 2606 parasites/μl of blood (range: 132–4280) and low-to-moderate parasitaemia levels. Approximately one-third of microscopy-confirmed cases were gametocyte carriers. Multivariable logistic regression analysis confirmed that age of three years or older (AOR = 5.6, 95% CI 1.6–19.8; P = 0.007), not sleeping under a mosquito net the previous night of the survey (AOR = 8.0, 95% CI 2.4–27.4; P = 0.001), sleeping outdoors at night (AOR = 4.4, 95% CI 2.0–10.0; P < 0.001), and absence of indoor residual spraying (IRS) during the last year (AOR = 4.2, 95% CI 1.9–9.4; P < 0.001) were the independent predictors of falciparum malaria among under-five children in the rural communities of Al-Mahweet. The observed percentage agreement between thick-film microscopy and RDTs was 98.5%, with a very good agreement (k-index = 0.9) between the two methods for falciparum malaria diagnosis that was statistically significant.ConclusionApproximately one in ten under-five children in rural communities of Al-Mahweet is infected with P. falciparum based on microscopy and RDTs. Age of three years or older, not sleeping under mosquito nets, sleeping outdoors at night and absence of IRS can independently predict falciparum malaria among them. The very good agreement between thick-film microscopy and RDTs for diagnosing falciparum malaria in children supports the usefulness of using RDTs in such resource-limited rural communities.

Malaria Prevalence among Pregnant Women in Relation to Parity, Gestation Period and Age in Gombe, North Eastern Nigeria

This study was conducted in order to determine malaria prevalence in relation to parity, gestational period and age of the pregnant women in Gombe, Nigeria. Three hundred and eighty four (384) pregnant women who registered for antenatal care in five randomly selected health care facilities (Tudun Wada Primary Health Care, Idi Health Clinic, Madaki Health Clinic, Pantami Primary Health Care And Gombe Town Maternity) residing within Gombe Local Government Area, Gombe State, Nigeria, constituted the study population. Five (5) ml of the maternal peripheral blood was obtained from each participant by the use of a sterile syringe and placed in a sterile Ethylene Diamine Tetraacetic Acid (EDTA) container for laboratory analysis. The malaria parasite was detected by microscopic examination of Giemsa-stained thick blood films. A high prevalence of 78.4% was observed among the studied population, with the primigravidae having higher prevalence (87.8%) than the multigravidae (73.6%). Women in second trimester recorded the highest prevalence (81.6%) followed by those in third trimester (76.4%), then the first trimester (68.4%). In relation to age, younger women (17 – 20 years) had the highest prevalence (88.4%) of malaria parasitaemia followed by 21-25 years category (79.1%), while those above 25years had the lowest prevalence (67.7%).significant association between age and malaria infection was established. The vulnerable age group need to be cautious of their exposure to mosquitoes’ bites so as to reduce the pressure on the already overstretched health facilities.

Serum cytokine profile of pregnant women with malaria, intestinal helminths and HIV infections in Ibadan, Nigeria.

Malaria, helminthiasis and HIV are widespread in developing countries taking a heavy toll on pregnant women. Due to similar environmental and human factors of transmission, they co-exist. The epidemiology and pathology of these diseases have been extensively studied but data on serum cytokine profile changes which is crucial in pregnancy is limited. The aim of this study was to evaluate the co-infections and their impact on peripheral blood cytokines. Blood and stool samples were collected from recruited 18-45-year-old pregnant women in different trimesters who were apparently healthy with no obvious complications in pregnancy. Pretested questionnaires were administered for personal and socio-demographic details. Malaria parasitemia in Giemsa-stained thick blood films was examined microscopically. Stool samples were screened for helminths using Kato-Katz method. Cytokine levels of TNF-α, IFN-γ, IL-1α, IL-2, IL-4, IL-6, IL-10, IL-12p70, IL-13 and IL-17 in 121 serum samples were determined using ELISA. Data were analysed using descriptive statistics and Mann-Whitney U test at α0.05. Relative to the single infections, there were significant reductions in IFN-γ and IL-13 in second and third trimesters respectively in those with Plasmodium and helminth co-infection. IFN-γ and IL-17 were elevated while IL-1α and IL-12p70 were reduced in co-infection of helminths and HIV. Co-infection of Plasmodium and HIV in second and third trimesters showed significant elevations in IL-1α, IL-10 and IL-17 while TNF-α, IL-4 and IL-12p70 were significantly reduced. HIV in pregnancy and its co-infection with Plasmodium resulted in significant distortions in the cytokine profile. However, helminth and its co-infection with Plasmodium or HIV produced less changes in the cytokine profile.

Rationalization of the Laboratory Diagnosis for Good Management of Malaria: Lessons from Transitional Methods

Introduction Malaria is an endemic disease in sub-Saharan Africa. In clinical practice, the main concern is the overdiagnosis of malaria leading to inappropriate drug prescription without laboratory confirmation. Objective This study aimed to evaluate clinical examination reliability compared with translational laboratory methods of malaria diagnosis. Methods The study was conducted in Goundi Hospital among hospitalized patients over a seven-month period. Patients were interviewed, and malaria tests done included the Giemsa-stained thick and thin blood smears. Diagnostic accuracy was analysed by calculating sensitivity, specificity, and predictive values. Results Among 1,874 participants, 674 (35.96%) patients had positive Giemsa-stained thick blood films. The rate of positivity is higher for patients under 5 years of age. The parasite densities were between 160 and 84.000 parasites/μL. The threshold pyrogen of the parasitic density was around 10.000 parasites/μL for patients between 0 and 11 months of age, between 1 and 4 years of age, and between 5 and 14 years of age. This threshold was lower for patients over 15 years of age. The study reported some issues in the findings: 60.88% (607/997) cases of fever without positivity of the blood thick smear and 40.13% (284/674) cases of positivity of the thick drop without fever. The positive predictive value of malaria was between 80 and 85% for patients under 5 years of age. This value is lower for patients between 5 and 14 years of age and patients over 15 years of age. Conclusion A presumptive diagnosis of malaria should be confirmed by the laboratory in all suspected cases in all possible scenarios. Every parasitemia should be followed by the calculation of parasitic density. However, for the children under 5 years of age in areas of high transmission, the presumptive diagnosis of malaria in certain circumstances could be considered.

Congenital cerebral malaria: a masquerader in a neonate

BackgroundCongenital malaria, which is caused by vertical transmission of malaria parasites, is a potentially fatal condition. Despite Africa’s high malaria burden, congenital malaria is not routinely screened for, and thus may go undiagnosed. Malaria, if not treated promptly, can quickly progress to severe forms and result in death. Severe congenital malaria is believed to be uncommon in neonates due to maternal antibodies, fetal haemoglobin, and the placenta’s sieving effect. The majority of reported cases were classified as having severe anaemia. Following a thorough review of the literature, only one case of congenital cerebral malaria (CCM) has been reported, and it was misdiagnosed.Case presentationA 5-day-old Nigerian neonate born to an apparently healthy mother initially displayed characteristics consistent with neonatal sepsis and severe neonatal hyperbilirubinaemia. He quickly developed characteristics consistent with meningitis. Surprisingly, the peripheral blood film revealed evidence of malaria parasites, which was immediately confirmed by Giemsa-stained thick and thin blood film microscopy for malaria. The patient was diagnosed with congenital cerebral malaria. The medication was modified to parenteral artesunate followed by oral artemisinin combination therapy. The neonate recovered fully and had no neurological deficits on follow up.ConclusionBecause CCM and infant meningitis have similar clinical presentations, CCM could be misdiagnosed and lead to death if there isn’t a high index of suspicion.

Assessment of genetic diversity of Plasmodium falciparum circumsporozoite protein in Sudan: the RTS,S leading malaria vaccine candidate

BackgroundThe currently used malaria vaccine, RTS,S, is designed based on the Plasmodium falciparum circumsporozoite protein (PfCSP). The pfcsp gene, besides having different polymorphic patterns, can vary between P. falciparum isolates due to geographical origin and host immune response. Such aspects are essential when considering the deployment of the RTS,S vaccine in a certain region. Therefore, this study assessed the genetic diversity of P. falciparum in Sudan based on the pfcsp gene by investigating the diversity at the N-terminal, central repeat, and the C-terminal regions.MethodsA cross-sectional molecular study was conducted; P. falciparum isolates were collected from different health centres in Khartoum State between January and December 2019. During the study period, a total of 261 febrile patients were recruited. Malaria diagnosis was made by expert microscopists using Giemsa-stained thick and thin blood films. DNA samples were examined by the semi-nested polymerase chain reaction (PCR). Single clonal infection of the confirmed P. falciparum cases, were used to amplify the pfcsp gene. The amplified amplicons of pfcsp have been sequenced using the Sanger dideoxy method. The obtained sequences of pfcsp nucleotide diversity parameters including the numbers of haplotypes (Hap), haplotypes diversity (Hapd), the average number of nucleotide differences between two sequences (p), and the numbers of segregating sites (S) were obtained. The haplotype networks were constructed using the online tcsBU software. Natural selection theory was also tested on pfcsp using Fuand Li’s D, Fuand Li’s F statistics, and Tajima’s D test using DnaSP.ResultsIn comparison with the different pfcsp reference strains, the Sudanese isolates showed high similarity with other African isolates. The results of the N-terminal region showed the presence of 2 different haplotypes with a Hapd of 0.425 ± 0.00727. The presence of the unique insertion of NNNGDNGREGKDEDKRDGNN was reported. The KLKQP motif was conserved in all the studied isolates. At the central repeat region, 11 haplotypes were seen with a Hapd of 0.779 ± 0.00097. The analysis of the genetic diversity in the C-terminal region showed the presence of 10 haplotypes with a Hapd of 0.457 ± 0.073. Several non-synonymous amino acids changes were also seen at the Th2R and the Th3R T-cell epitope regions including T317K, E317K, Q318E, K321N, I322K, T322K, R322K, K324Q, I327L, G352N, S354P, R355K, N356D, Q357E, and E361A.ConclusionsIn this study, the results indicated a high conservation at the pfcsp gene. This may further contribute in understanding the genetic polymorphisms of P. falciparum prior to the deployment of the RTS,S vaccine in Sudan.

Prevalence and risk factors associated with asymptomatic malaria among school children: repeated cross-sectional surveys of school children in two ecological zones in Ghana

BackgroundAsymptomatic Plasmodium infections significantly drive malaria transmission and impact control and elimination strategies, but are largely uncharacterized. We investigated the prevalence and risk factors of asymptomatic malaria infections to inform malaria control strategies in Ghana.MethodFive cross-sectional surveys were conducted at the end of the peak transmission season (August–September) on 4892 school children aged between 6 and 14 years in two distinct ecological settings in Ghana between 2013 and 2017. The study sites were Begoro (forest ecology) and Cape Coast (coastal ecology). The children were screened for malaria parasites by microscopic examination of Giemsa-stained thin and thick blood films. Hemoglobin levels were measured using the Hemocue HB analyzer. In addition, height was measured and the height-for-age z-scores estimated from the reference population defined by WHO to determine children who were stunted. Proportions of categorical and means of continuous variables were compared using Chi-square test and Student’s t-test respectively, and multivariable logistic regression was done to assess risk factors associated with asymptomatic infections.ResultsThe overall prevalence of asymptomatic malaria in the school children was higher in Begoro compared to Cape Coast (27% (95% CI: 17, 24%) vs. 24% (95% CI: 17, 24%), p value = 0.04). The study recorded three species of Plasmodium (Plasmodia falciparum, malariae, and ovale) in both sites. Plasmodium falciparum was the predominant species, accounting for about 85% of infections in both study sites. The asymptomatic school children were more likely to be anaemic (OR = 2.01, p value< 0.001) and stunted in growth (OR = 1.46, p value< 0.001). Males carried more asymptomatic infection than females (OR = 1.18, p value = 0.015). School children aged 12–14 years had more asymptomatic infections than those aged 6–8 years (OR = 1.28, p value = 0.005).ConclusionThere is a considerable burden of asymptomatic malaria in the two regions of Ghana, which is associated with males, older children, anaemia, and stunted growth in children, and may have implications for malaria control and elimination strategies in Ghana.

A review on lab-on-chip as a potential diagnostic tool for early detection of Plasmodium knowlesi

Massive elimination efforts have been done to control the malaria disease caused by the emergence of the fifth human malaria parasite known as Plasmodium knowlesi. Early detection of the parasite is important in treating malaria infection. Microscopic examination of Giemsa-stained thick and thin blood films is the gold standard for laboratory malaria diagnosis, while rapid diagnostic tests (RDTs), polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) are significant diagnostic techniques to detect acute infection. However, these methods have several limitations in which it could delay the treatment. The potential of lab-on-chip (LOC) as a point-of-care diagnostic tool for malaria fulfils the requirement of limitations where it is able to produce early detection of malaria infection. This review discusses advantages and disadvantages of malaria diagnostic methods as well as new approaches that could be used for high speed, sensitive and reliable malaria detection to prevent the disease from causing severe complications and even fatal if left untreated.

Genetic diversity and complexity of Plasmodium falciparum infections in the microenvironment among siblings of the same household in North-Central Nigeria

BackgroundPlasmodium falciparum parasites are known to exhibit extensive genetic diversity in areas of high transmission intensity and infected individuals in such communities often harbour several complex mixtures of parasite clones with different genetic characteristics. However, in the micro-environment, the extent of genetic diversity of P. falciparum parasites remain largely unknown. In this study therefore, the complexity of P. falciparum infections in households was investigated among symptomatic siblings, living under the same roof in north-central Nigeria.MethodsChildren were enrolled into the study if they were at least two from a household and presented with symptoms of uncomplicated malaria. Clinical malaria was confirmed by light microscopy of Giemsa-stained thick and thin blood films. Genomic DNA was isolated from blood spots on filter paper. Molecular characterization of P. falciparum isolates was done by allele-specific nested PCR of the highly polymorphic merozoite surface protein-2 (msp-2) gene.ResultsNinety-three children from 43 households were enrolled into this study. A total of 26 different msp-2 alleles were identified from 215 fragments (range: 180–480 bp). Majority of the isolates [65.6% (n = 61)] were polyclonal infections consisting of 2–6 clones and were significantly more common with the FC27 allelic family (p = 0.036). The multiplicity of infection (MOI) per household ranged from 1.0 to 4.5 while the overall MOI in the study population was 2.31. The pattern of distribution of msp-2 allele types among the households fell into two categories: households where both msp-2 allele types (FC27 and 3D7) were present; households where only one msp-2 allele type (FC27 or 3D7) was present. Majority of the households [88.4% (n = 38)], had both msp-2 allele types but they were disproportionately distributed among the children while in a few households [11.6% (n = 5)], all the children were infected with only one type of msp-2 allele.ConclusionThese findings showed that P. falciparum isolates exhibit remarkable degree of genetic diversity in the micro-environment and are composed mainly of multiclonal infections, which is an indication of a high ongoing parasite transmission. This suggests that the micro-environment is an important area of focus for malaria control interventions and for evaluating intervention programmes.

Quantitative Detection of Plasmodium falciparum Using, LUNA-FL, A Fluorescent Cell Counter.

The microscopic examination of Giemsa-stained thin and/or thick blood films (Giemsa microscopy) is the standard method of malaria diagnosis. However, the results of the diagnosis significantly depend on the skills of clinical technicians. Furthermore, sample preparation and analysis are laborious and time-consuming. Therefore, in this study, we investigated if a commercially available fluorescent cell counter, LUNA-FL, was useful for the detection of Plasmodium parasite and the estimation of parasitemia. Whole blood samples from uninfected persons, spiked with P. falciparum-infected erythrocytes, were analysed. Most of the leucocytes and platelets were removed from whole blood samples with SiO2-nanofiber filters set on spin columns. The filtered samples were stained with acridine orange, and automatic detection, as well as counting of erythrocytes and parasites, were performed using LUNA-FL. Whole blood, with various levels of parasites, was analysed by Giemsa microscopy or with LUNA-FL to estimate parasitemia, and a comparative analysis was performed. The coefficient determination value of the regression line was high (R2 = 0.98), indicating that accurate quantitative parasite detection could be performed using LUNA-FL. LUNA-FL has a low running cost; it is compact, fast, and easy to operate, and may therefore be useful for point-of-care testing in the endemic areas.

Impact of Insecticide Treated Nets and Intermittent Preventive Treatment in Reducing Malaria Morbidity among Pregnant Women in Gombe, Nigeria

Malaria in pregnancy is a major public health problem affecting women fetuses and new borns. Many studies highlight the critical importance of continuing the use of Insecticide Treated Nets (ITN) and Intermittent Preventive Treatment In Pregnancy (IPTp) among pregnant women to reduce the adverse consequences of malaria in pregnancy. This study was conducted in order to determine malaria prevalence in relation to the use ofITN and IPTp among the pregnant women in the study area. Five (5) ml of blood was obtained from each participant by the use of a sterile syringe and placed in a sterile EDTA container for laboratory analysis. The malaria parasite was detected by microscopic examination of Giemsa-stained thick blood films. Information on the use of ITN and IPTP was collected using administered questionnaire. A high prevalence of 78.4% was observed among the studied population. Although 74.4% of those that use ITN were positive for malaria parasite as against the 83.6% of those that reported not using the ITN, the difference was statistically not significant (p&lt;0.05). 70.0% of those reported using IPTp were positive however, higher percentage was observed for those reported not using IPTp (83.7.0%). The difference was statistically significant in this case. This study has shown the influence of malaria prevention method during pregnancy on malaria infection and the need for targeted preventive starategies when designing and implementing policies aimed at improving uptake of these measures during pregnancy in Gombe.&#x0D; Keywords: malaria, pregnant women, ITN, Gombe, IPTp&#x0D;

Plasma mEV levels in Ghanain malaria patients with low parasitaemia are higher than those of healthy controls, raising the potential for parasite markers in mEVs as diagnostic targets

ABSTRACT This study sought to measure medium-sized extracellular vesicles (mEVs) in plasma, when patients have low Plasmodium falciparum early in infection. We aimed to define the relationship between plasma mEVs and: (i) parasitaemia, (ii) period from onset of malaria symptoms until seeking medical care (patient delay, PD), (iii) age and (iv) gender. In this cross-sectional study, n = 434 patients were analysed and Nanosight Tracking Analysis (NTA) used to quantify mEVs (vesicles of 150–500 nm diameter, isolated at 15,000 × g, β-tubulin-positive and staining for annexin V, but weak or negative for CD81). Overall plasma mEV levels (1.69 × 1010 mEVs mL−1) were 2.3-fold higher than for uninfected controls (0.51 × 1010 mEVs mL−1). Divided into four age groups, we found a bimodal distribution with 2.5- and 2.1-fold higher mEVs in infected children (<11 years old [yo]) (median:2.11 × 1010 mEVs mL−1) and the elderly (>45 yo) (median:1.92 × 1010 mEVs mL−1), respectively, compared to uninfected controls; parasite density varied similarly with age groups. There was a positive association between mEVs and parasite density (r = 0.587, p < 0.0001) and mEVs were strongly associated with PD (r = 0.919, p < 0.0001), but gender had no effect on plasma mEV levels (p = 0.667). Parasite density was also exponentially related to patient delay. Gender (p = 0.667) had no effect on plasma mEV levels. During periods of low parasitaemia (PD = 72h), mEVs were 0.93-fold greater than in uninfected controls. As 75% (49/65) of patients had low parasitaemia levels (20–500 parasites µL−1), close to the detection limits of microscopy of Giemsa-stained thick blood films (5–150 parasites µL−1), mEV quantification by NTA could potentially have early diagnostic value, and raises the potential of Pf markers in mEVs as early diagnostic targets.

Morphological and genetic variation of Wuchereria bancrofti microfilariae in carriers in Thailand, Lao PDR and Myanmar: evaluation using Giemsa-stained thick blood films.

There is geographical variation in the morphology and genetics of Wuchereria bancrofti, the major cause of human lymphatic filariasis. This study aims to compare morphological and genetic variation of W. bancrofti microfilariae recovered from carriers in Lao PDR, Myanmar and Thailand. Six morphological parameters (body length, cephalic space length and width, length of head to nerve ring, body width at nerve ring, Innenkȍrper length and number of column nuclei between the cephalic space and nerve ring) were evaluated from microfilariae in Giemsa-stained thick blood films. A portion of the cytochrome c oxidase subunit 1 gene of mitochondrial DNA was sequenced and analysed. Wuchereria bancrofti microfilariae showed a wide variation in their morphology and morphometry among three countries. Phylogenetic analysis confirmed that all microfilariae belonged to W. bancrofti. Higher mutation frequencies were observed in samples from Myanmar, relative to Thailand and Lao PDR. This study highlights the morphological disparities of microfilariae and genetic variability within W. bancrofti among three geographical locations. We found that reported morphometric differences between localities were less clear-cut than previously thought. Further studies are needed to determine the microfilarial periodicity in Lao PDR.

PO 8571 CYTOKINE PROFILE IN ASYMPTOMATIC SCHOOL CHILDREN CO-INFECTED WITH HELMINTHS ANDPLASMODIUM FALCIPARUMIN IBADAN, SOUTH-WEST NIGERIA

BackgroundIntestinal helminths and malaria are among the most prevalent infectious diseases in the tropics. The effect of co-infections on immune response is not clearly understood. We therefore investigated the immune response profile in children with and without symptoms.MethodsA total of 78 afebrile school children (20 helminth/malaria-co-infected, 17 helminth-infected, 19 malaria-infected and 22 uninfected) and 75 febrile children (14 helminth/malaria-co-infected, 16 helminth-infected, 20 malaria-infected and 25 uninfected) were recruited into the study. Helminths were screened using Kato Katz method while malaria parasite screening was done using Giemsa-stained thick blood films. Circulating TNF-α, IFN-γ, IL-1, IL-10 and IL-6 concentrations were assessed by ELISA from serum samples. Data were analysed using analysis of variance.ResultsAmong the afebrile school children, IL-10 was significantly increased in helminth-infected children compared with helminth/malaria-co-infected, malaria-infected and uninfected groups (p&lt;0.05). IFN-γ was significantly elevated in malaria and malaria/helminth-co-infection relative to helminth alone (p&lt;0.05). IL-1 level was significantly higher in single infection of helminth and malaria relative to co-infection and the uninfected groups (p&lt;0.05). An insignificant difference was observed for IL-6 and TNF-α concentrations across all the four groups while among febrile children. IL-6 was significantly increased among helminth alone and helminth/malaria-co-infection relative to malaria-infected group (p&lt;0.05). IL-10 was significantly elevated in co-infected group compared with helminth- or malaria-infected group while TNF-α was significantly increased in helminth and helminth-malaria co-infection compared with uninfected or malaria-infected group (p&lt;0.05). IFN-γ level was insignificant in the infection groups relative to uninfected group (p&lt;0.05); IL-1 level similar across the groups.ConclusionHelminth infection seems to upregulate the Th2 immune response among children with symptomatic uncomplicated malaria while there were no significant changes in Th immune response among afebrile children.

Microscopic-Based Trend in Imported Malaria among Workers of Trenggalek District Returning from Kalimantan Island, Indonesia During 2012 – 2016

Malaria in Indonesia remains a significant health problem. Trenggalek District is one of the receptive malaria areas in East Java Province, Indonesia, with mainly imported malaria from outside Java Island. The people of this district accustomed to traveling to outside Java where malaria is endemic for temporary working purposes. Usually, they have acquired malaria infection in the areas where they worked and brought to their homeland during their return to the district. The number of imported malaria cases depend on the returning season of the workers. When no workers return from outside Java malaria case is zero. During the year of 2012-2016 microscopic examination of Microscopic examination of Giemsa-stained thick blood films of the workers have been done in the working activity of Pandean Primary Health Center on their arrival from Kalimantan Island either by active or passive case detection. Microscopically positive data were reported herein to describe the trend of imported malaria in the studied areas. A total number of malaria-infected workers were 118 cases. The trend towards increasing case number yearly between 2012 and 2013 being 1.35%, then decreasing between 2013 and 2016 to only 4 cases in 2016. Different patterns of imported malaria by month were seen in each year but no specific pattern throughout the year. The Plasmodium vivax infection was predominant every year and followed by Plasmodium falciparum and mixed infection of those two species. Trends of imported malaria cases in Trenggalek district were decreased and increased irregularly in each month yearly. However, the number of cases declined annually during 2013 – 2016. Antimalarial prophylaxis and insecticides prevent the workers from malaria infection.

&amp;lt;i&amp;gt;Mansonella perstans&amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;Plasmodium falciparum&amp;lt;/i&amp;gt; Co-infection in the Akonolinga Health District, Centre Region, Cameroon

Mansonella perstans and Plasmodium falciparum are among the most common human parasites in Sub-Saharan Africa. They pass through the bloodstream during their life in human host. This study aimed at determining the prevalence, determinants of co-infection with M. perstans and P. falciparum and their possible interaction mechanism. A cross-sectional study was conducted in the Akonolinga Health District among pupils. Each of them was screened for the presence of peripheral blood parasites stages using Giemsa-stained thick and thin blood films. Socio-demographic information was documented using a questionnaire forms. A total of 416 pupils aged 4-15 years (average: 9.17 ± 0.27) were recruited. The overall prevalence was 4.32% and 37.26% for M. perstans and P. falciparum respectively, and prevalence of co-infection was 1.92%. Mean parasite density was 508.7±310.3 (min: 430 - max: 1300) µF/ml for M. perstans and 5240.38±2037.42 (min: 857 – max: 10400) T/μl for P. falciparum . Risks of single infections (aOR = 0.46, P = 0.0264 for M. perstans and aOR = 0.64, P = 0.0432 for P. falciparum ) and co-infection (aOR = 0.10, P = 0.0371) were lower for pupils living in urban area than those living in rural area. Parasitemia of both parasite species were similar in single and co-infection situations ( P > 0.05). The interaction between these parasites could involve another mechanism than a competition for blood resources. This study outlined that M. perstans and P. falciparum are co-endemic in the Akonolinga health District. In order to guarantee future success in control and eradication of malaria, a bigger attention should be given to M. perstans or other filarial where it is co-endemic with P. falciparum .