Prevalence Of Asymptomatic Malaria Research Articles

Utilization of malaria preventive strategies among pregnant women at Adeoyo Maternity Teaching Hospital, Ibadan, Nigeria

INTRODUCTION: Malaria in pregnancy is associated with a high rate of maternal and perinatal morbidity and mortality. Utilization of preventive strategies during pregnancy is an integral part of controlling the burden of malaria in pregnancy. This study evaluated the malaria preventive strategies utilized and the prevalence of asymptomatic malaria among pregnant women at Adeoyo Maternity Teaching Hospital (AMTH), Ibadan, Nigeria.
 METHODS: A facility-based descriptive cross-sectional study among 223 pregnant women in Adeoyo Maternity Teaching Hospital, Ibadan, Nigeria. Information on socio-demographic and obstetric characteristics, malaria symptoms, and the preventive strategies utilized were obtained using a structured questionnaire. Descriptive and bivariate analysis using chi-square test and multivariate analysis at 95% confidence interval and p< 0.05 was used to determine the predictors of asymptomatic malaria infection in relation to socio-demographic characteristics and malaria preventive strategies utilized.
 RESULTS: The mean age was 30±5 years. More than half (53.4%) of them used insecticide-treated nets consistently, 49.3% sprayed the room regularly with insecticides, while the majority (88.3%) reported they maintained a clean environment. However, 11.7% tested positive for the malaria parasite. Consistency in the use of insecticide-treated net (ITN) and participants age were factors associated with malaria occurrence (p=0.01). The use of ITN and being >30 years of age are protective factors against having malaria infection among pregnant women (AOR= 0.34; 95%, CI=0.14-0.84) and (AOR=0.31; 95% CI=0.13-0.76) respectively.
 CONCLUSION: Irrespective of all other malaria preventive strategies adopted by pregnant women, consistent use of ITN was independently a protective factor against developing malaria in pregnancy.

Symptomatic and asymptomatic malaria prevalence and its determinant factors in pastoral communities of Waghemira Zone, Northeast Ethiopia: A community-based cross-sectional study.

Malaria elimination programs have also encountered numerous challenges, such as widespread asymptomatic carriers in endemic areas, which should be taken into account in malaria-control programs for effective transmission interruption. The purpose of this research was to determine the prevalence of symptomatic and asymptomatic malaria infections and associated factors, in pastoral communities. A community-based cross-sectional study was conducted among selected districts in the Waghemra Zone, Northeast Ethiopia, from September to December 2022. A structured questionnaire was employed to collect sociodemographic data and associated risk factors. Plasmodium species were detected using light microscopy and a rapid diagnostic test. Data entry and analysis were carried out using SPSS version 26 software. The association between dependent and independent variables was explored by using multivariable logistic regression analyses. A statistically significant association was declared at a p-value of <0.05. The overall prevalence of malaria was 21.2% (134/633), with the predominant Plasmodium falciparum infections accounting for 67.8% (87/134). Among asymptomatic participants, 7.5% (34/451) and 10.2% (46/451) were diagnosed by rapid diagnostic test and light microscopy, respectively. On the other hand, the prevalence of symptomatic malaria was 44.5% (81/182) and 48.4% (88/182) as diagnosed by rapid diagnostic test and light microscopy, respectively. The presence of stagnant water near the houses, the utilization of insecticide-treated mosquito nets, the number of insecticide-treated mosquito nets, and outdoor stays at night were all positively linked with the prevalence of malaria. The overall prevalence estimate for symptomatic and asymptomatic malaria was high. Malaria is still a public health problem in the study area. Malaria infection was associated with the presence of stagnant water near the houses, the utilization of insecticide-treated mosquito nets, the number of insecticide-treated mosquito nets, and outdoor stays at night. Improved access to all malaria interventions is needed to interrupt the transmission at the community level.

A Comparative Study of the Risk Factors of Malaria within Urban and Rural Settings in the Sahelian Region of Cameroon and the Role of Insecticide Resistance in Mosquitoes

Background: Cameroon is among the 11 countries that account for 92 % of malaria infection in sub-Saharan-Africa in 2018, and Maroua III Health District and her environs witnessed a malaria outbreak in 2013 with hundredths of deaths.&#x0D; Aim: To determine the risk factors of malaria in the urban and rural population and to investigate the level of mosquito’s resistance to Deltamethrin and Permethrin.&#x0D; Methods: It was a cross-sectional community-based study carried out in August, September and October 2019, in which questionnaires were administered to 500 participants, to obtain information on demographics, socioeconomics, behavioral, and environmental factors thought to be associated with malaria infection in both rural and urban settings. Blood samples were collected for diagnosis of malaria and bivariate and multivariate regression analysis were used to identify risk factors of malaria. Mosquito resistance to Deltamethrin and Permethrin were determined using the CDC Bottle Bioassay test. &#x0D; Results: Malaria prevalence was 52.2 % which was significantly higher (P = 0.016) in rural areas (57.6%) than urban areas (46.8%). The prevalence of asymptomatic malaria was 43.4% and the geometric mean parasite density was 6333.60 parasites/µL of blood. Malaria infection was significantly (P&lt;0.001) associated with children (64.1%) and teenagers (58.1%). Likewise, the infection was significantly associated with the presence of crops around homes (P=0.031), usage of old LLINs for more than three years and in urban settings, with primary education level (P=0.023). The overall mortality of Anopheles species was 93.57% (91.19% in rural and 95.83% in urban areas) for deltamethrin which was more sensitive than 83.85% (85.24% in rural and 82.46% in urban areas) for permethrin.&#x0D; Conclusion: Relevant data for malaria control in Maroua III health district, a typical Sahelian environment has been generated, and indicates that most of the burden of malaria is borne by children and teenagers.

Malaria prevalence in Mauritania: a systematic review and meta-analysis

BackgroundUnderstanding malaria epidemiology is a critical step toward efficient malaria control and elimination. The objective of this meta-analysis was to derive robust estimates of malaria prevalence and Plasmodium species from studies conducted in Mauritania and published since 2000.MethodsThe present review followed the PRISMA guidelines. Searches were conducted in various electronic databases such as PubMed, Web of Science, and Scopus. To obtain pooled prevalence of malaria, meta-analysis was performed using the DerSimonian-Laird random-effects model. Methodological quality of eligible prevalence studies was assessed using Joanna Briggs Institute tool. Inconsistency and heterogeneity between studies were quantified by the I2 index and Cochran’s Q test. Publication bias was assessed with funnel plots and Egger’s regression tests.ResultsA total of 16 studies with a good individual methodological quality were included and analysed in this study. The overall random effects pooled prevalence of malaria infection (symptomatic and asymptomatic) across all included studies was 14.9% (95% confidence interval [95% CI]: 6.64, 25.80, I2 = 99.8%, P < 0.0001) by microscopy, 25.6% (95% CI: 8.74, 47.62, I2 = 99.6%, P < 0.0001) by PCR and 24.3% (95% CI: 12.05 to 39.14, I2 = 99.7%, P < 0.0001) by rapid diagnostic test. Using microscopy, the prevalence of asymptomatic malaria was 1.0% (95% CI: 0.00, 3.48) against 21.46% (95% CI: 11.03, 34.21) in symptomatic malaria. The overall prevalence of Plasmodium falciparum and Plasmodium vivax was 51.14% and 37.55%, respectively. Subgroup analysis showed significant variation (P = 0.039) in the prevalence of malaria between asymptomatic and symptomatic cases.ConclusionPlasmodium falciparum and P. vivax are widespread in Mauritania. Results of this meta-analysis implies that distinct intervention measures including accurate parasite-based diagnosis and appropriate treatment of confirmed malaria cases are critical for a successful malaria control and elimination programme in Mauritania.

Impact of long lasting insecticidal nets on asymptomatic malaria during pregnancy, in a rural and urban setting in Cameroon

According to the world malaria report more malaria cases were reported in 2020 than in 2019, due to disruptions in the distribution of insecticide treated nets, caused by the COVID-19 pandemic. Consequently a projected 34.32% (11.6 million out of 33.8 million) pregnancies were exposed to malaria in the WHO African Region in 2020. This study was therefore designed to assess the impact of long lasting insecticidal nets (LLINs) on asymptomatic malaria in the pregnant women attending the Foumbot District Hospital (rural setting) and the Bamenda Regional Hospital (urban setting). This was a hospital based cross-sectional study done within three months from February to April 2021. A structured questionnaire and the CareStart™ Pf Malaria HRP2 qualitative rapid diagnostic test were used for data collection. Data were analysed using descriptive statistics, and Chi-square test. The relative risk, attributable risk, odds ratio, and likelihood ratio of malaria occurrence in exposed patients were determined by Chi-square (and Fisher's exact) test. The prevalence of asymptomatic malaria was 10.14% (63/621), with a higher prevalence among the pregnant women in the rural setting (12.21%; 37/303), than the urban setting (8.18%; 26/318). As indicated by the attributable risk, 21% of malaria incidence was attributed to absence of LLINs distribution in neighborhoods of the rural setting meanwhile 10% of malaria incidence is attributed to absence of LLINs distribution in neighborhoods of the urban setting. Regular screening for asymptomatic malaria in pregnancy and consistent free distribution of LLINs are recommended in endemic areas, especially in the rural settings.

Prevalence of Asymptomatic Malaria in Urban and Semi-Urban Areas in 2016 and 2019, to Gabon

Malaria remains a major cause of mortality and morbidity in sub saharian Africa. Asymptomatic carriers of the parasite contribute to the parasite reservoir and allow the maintenance of malaria transmission. The aim of this study was to assess the evolution of the prevalence of asymptomatic malaria in 2016 and 2019 in Libreville and surrounding areas in Gabon. Thick- and thin-blood smears for malaria diagnosis were performed inpeople, showing no signs suggestive of malaria and having completed a questionnaire during the prospective, cross-sectional studies carried out in July 2016 and April 2019 in urban (Libreville) and semi-urban (Owendo ) in Gabon. A total of 724 participants were included over the two study years; 337 in 2016 and 384 in 2019. The prevalence of asymptomatic malaria was less frequent in 2019: 5.9% vs 12.8% in 2016 (p&lt;0.01). Asymptomatic carriage was more frequent in men regardless of the study period In 2016, under 5 years old, was the most infected population compared to other age groups and in 2018, it was higher among individuals aged 5-15 years old of 7.4%. These populations may contribute to the reservoirs for Plasmodium and thus may strongly contribute to the anchoring of malaria in favorable eco-epidemiological zones. These data highlight the need use of molecular tools to detect submicroscopic infections in asymptomatic individuals.

Detection of IgG Antibodies to Glycosylphosphatidylinositol (GPI) as a Biomarker of Immune Status to Plasmodium species

Finding new ways to eliminate malaria is critical and this would greatly be influenced by developing indicators of exposure as well as distribution of effective vaccines against Plasmodium. This study was aimed at detecting Immunoglobulin G(IgG) antibodies, to glycosylphosphatidylinositol (GPI) as a biomarker of immune status to Plasmodium species. In this study, blood samples were gotten from apparently healthy individuals and patients having symptoms of malaria attending Ahmadu Bello University Teaching Hospital, Zaria. Thick and thin blood smears were prepared and stained with Giemsa stain. The smears were observed microscopically. Parasite densities were estimated on positive slides. Samples positive and some negative for Plasmodium were further tested to detect IgG antibodies to GPI among both the Asymptomatic and Symptomatic participants using ELISA. The prevalence of Plasmodium infection among both asymptomatic and symptomatic participants in this study was 18.9% and the prevalence of asymptomatic malaria was 15.6%. There was a significant association between the level of parasitemia and concentration of IgG antibodies to GPI among the asymptomatic participants and a no significant association among symptomatic participants. Type of housing amongst other risk factors was the only factor significantly associated with malaria in this study. This study suggests PGPI as a biomarker of immunity to Plasmodium and may be a vaccine candidate for programs of malaria control.

Prevalence of asymptomatic malaria, submicroscopic parasitaemia and anaemia in Korogwe District, north-eastern Tanzania

BackgroundAsymptomatic malaria infections largely remain undetected and act as a reservoir for continuous transmission. The study assessed the prevalence of submicroscopic asymptomatic malaria infections and anaemia in two rural low (300 m above sea level) and highland (700 m asl) settings of Korogwe District north-eastern Tanzania.MethodsA cross-sectional malariometric survey involving individuals aged 0–19 years was conducted in June 2018 in the two rural villages. Venous blood was collected from eligible study participants for estimation of haemoglobin level, detection of malaria by rapid diagnostic test (RDT), quantification of malaria parasitaemia by microscopy, as well as dried blood spot (DBS) for determining submicroscopic infections by PCR targeting the small subunit of the ribosomal ribonucleic acid (ssrRNA) of human Plasmodium.ResultsOut of 565 individuals tested, 211 (37.3%) were malaria positive based on RDT, whereas only 81 (14.3%) were positive by microscopy. There was no significant difference in the prevalence between the highland and the lowland village, p = 0.19 and p = 0.78 microscopy and RDT, respectively. Three out of 206 (1.5%) RDT/microscopy negative samples were P. falciparum positive by PCR. Of the 211 RDT and 81 microscopy positive, 130 (61.6%) and 33 (40.7%), respectively, were defined as being asymptomatic. Of the 565 individuals, 135 (23.9%) were anaemic (haemoglobin < 11 g/dL) out of which 5.2% were severely anaemic. The risk of being anaemic was significantly higher among individuals with asymptomatic malaria as compared to those without malaria as confirmed by RDT (AOR = 2.06 (95% CI 1.32–3.20) while based on microscopic results there was no significant differences observed (AOR = 2.09, 95% CI 0.98–4.47). Age and altitude had no effect on the risk of anaemia even after adjusting for asymptomatic malaria.ConclusionsAsymptomatic malaria is associated with an increased risk of having anaemia in the study communities. The findings highlight the need for targeted interventions focusing on asymptomatic infections which is an important risks factor for anaemia in the community and act as a source of continued transmission of malaria in the study area.

Cross-sectional survey of asymptomatic malaria in Dak Nong province in the Central Highlands of Vietnam for the malaria elimination roadmap.

Asymptomatic parasite carriers represent a “silent” infective reservoir for malaria transmission and contributes to malaria persistence. However, limited data are available on asymptomatic malaria in Vietnam. Between November 2018 and March 2019, we conducted a malaria epidemiological survey of asymptomatic people (children ≥ 10 years old and adults ≥18 years old, n = 2,809) residing in three communes in Tuy Duc district, Dak Nong province in the Central Highlands of Vietnam. Based on the national stratification of malaria risk, Dak Buk So, Dak Ngo and Quang Truc communes were classified by the National Malaria Control Programme as low, moderate and high malaria endemic areas, respectively. Using participants’ finger prick blood samples, malaria parasites were detected by one-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The median age (Interquartile Range) for adults and children were 35 years (26–50) and 12 years (11–14), respectively. The prevalence of asymptomatic malaria was 1.7% (22/1,328), 3.5% (31/890) and 12.2% (72/591) for participants from Dak Buk So, Dak Ngo and Quang Truc, respectively. The prevalence of asymptomatic malaria was lower in children compared to adults: 2.6% (9/352) versus 4.7% (116/2,457) (Odds Ratio 0.53, 95% Confidence Interval 0.28 to1.02). Ownership of long-lasting insecticide-treated bed nets and hammocks was 97.1%, 99.0% and 94.7% for participants in Dak Buk So, Dak Ngo and Quang Truc, respectively, however, only 66.0%, 57.3% and 42.8% of the participants reported using bed nets every night. Of the several risk factors examined, going to the forest two weeks prior to enrolment into the study and sleeping in the forest had a significant association with participants being infected with asymptomatic malaria in Quang Truc, but not in the other two communes. Knowledge of the prevalence and distribution of asymptomatic malaria will help design and evaluate future intervention strategies for malaria elimination in Vietnam.

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.

High prevalence of Plasmodium malariae and Plasmodium ovale in co-infections with Plasmodium falciparum in asymptomatic malaria parasite carriers in southwestern Nigeria

Asymptomatic malaria parasite carriers do not seek anti-malarial treatment and may constitute a silent infectious reservoir. In order to assess the level of asymptomatic and symptomatic carriage amongst adolescents in a highly endemic area, and to identify the risk factors associated with such carriage, we conducted a cross-sectional survey of 1032 adolescents (ages 10–19 years) from eight schools located in Ibadan, southwestern Nigeria in 2016. Blood films and blood spot filter paper samples were prepared for microscopy and DNA analysis. The prevalence of asymptomatic malaria was determined using microscopy, rapid diagnostic tests and PCR for 658 randomly selected samples. Of these, we found that 80% of asymptomatic schoolchildren were positive for malaria parasites by PCR, compared with 47% and 9%, determined by rapid diagnostic tests and microscopy, respectively. Malaria parasite species typing was performed using PCR targeting the mitochondrial CoxIII gene, and revealed high rates of carriage of Plasmodium malariae (53%) and Plasmodium ovale (24%). Most asymptomatic infections were co-infections of two or more species (62%), with Plasmodium falciparum + P. malariae the most common (35%), followed by P. falciparum + P. malariae + P. ovale (21%) and P. falciparum + P. ovale (6%). Single infections of P. falciparum, P. malariae and P. ovale accounted for 24%, 10% and 4% of all asymptomatic infections, respectively. To compare the species composition of asymptomatic and symptomatic infections, further sample collection was carried out in 2017 at one of the previously sampled schools, and at a nearby hospital. Whilst the species composition of the asymptomatic infections was similar to that observed in 2016, the symptomatic infections were markedly different, with single infections of P. falciparum observed in 91% of patients, P. falciparum + P. malariae in 5% and P. falciparum + P. ovale in 4%.

Assessment of effectiveness of DAMaN: A malaria intervention program initiated by Government of Odisha, India.

India, a persistently significant contributor to the global malaria burden, rolled out several anti-malaria interventions at the national and state level to control and recently, to eliminate the disease. Odisha, the eastern Indian state with the highest malaria burden experienced substantial gains shown by various anti-malaria initiatives implemented under the National Vector-borne Disease Control Programme (NVBDCP). However, recalcitrant high-transmission "pockets" of malaria persist in hard-to-reach stretches of the state, characterised by limited access to routine malaria surveillance and the forested hilly topography favouring unbridled vector breeding. The prevalence of asymptomatic malaria in such pockets serves as perpetual malaria reservoir, thus hindering its elimination. Therefore, a project with the acronym DAMaN was initiated since 2017 by state NVBDCP, targeting locally identified high endemic 'pockets' in 23 districts. DAMaN comprised biennial mass screening and treatment, provisioning of long-lasting insecticidal net (LLIN) and behavioural change communication. Subsequently, to inform policy, assessment of DAMaN was conceived that aims to estimate the coverage of the various components of the project; the prevalence of malaria, even at sub-patent level especially among pregnant/lactating women and children; and its impact on malaria incidence. A survey of DAMaN beneficiaries will measure coverage; and knowledge and practices related to LLIN; along with collection of blood specimens from a probability sample. A multi-stage stratified clustered sample of 2228 households (~33% having pregnant/lactating women) will be selected from 6 DAMaN districts. Routine DAMaN project data (2017-2018) and NVBDCP data (2013-2018) will be extracted. Rapid Diagnostic Test, Polymerase Chain Reaction and blood smear microscopy will be conducted to detect malarial parasitemia. In addition to measuring DAMaN's coverage and malarial prevalence in DAMaN pockets, its impact will be estimated using pre-post differences and Interrupted Time Series analysis using 2017 as the "inflection" point. The assessment may help to validate the unique strategies employed by DAMaN.

Evaluation of Asymptomatic Malaria Status in Eastern of Afghanistan Using High Resolution Melting Analysis

Malaria is threatening more than half of Afghanistan population. Asymptomatic malaria is notable problem against malaria controlling strategies. In this study we evaluated the asymptomatic malaria status in Nangarhar Province, Afghanistan in 2017. Overall, 296 finger blood samples were taken on DNA Banking Cards and microscopic slides from asymptomatic individuals in Jalalabad city. We used a novel post real time PCR high resolution melting analysis beside microscopy and semi-nested multiplex PCR to evaluate status of asymptomatic malaria in this city. The prevalence of asymptomatic malaria in Jalalabad city was determined 1.7% (5/296), 7.43% (22/296) and 7.78% (26/296) by microscopy, Seminested multiplex PCR and qRT-PCR-HRM, respectively. Out of 26 positive cases were detected by qRT-PCR-HRM, 21, 1 and 4 cases were detected P. falciparum, P. vivax and mixed infection of P. falciparum and P. vivax, respectively. Our data indicating on existence of significant number of asymptomatic reservoirs that assists in prolonged endemicity of the disease. On the other hand, the molecular methods are better alternatives for microscopy especially for monitoring of asymptomatic cases of malaria.

Prevalence and Correlates of Asymptomatic Malaria and Anemia on First Antenatal Care Visit among Pregnant Women in Southeast, Tanzania.

Asymptomatic malaria and anemia during pregnancy increase the risk of negative birth outcomes. This cross-sectional study investigated the prevalence and correlates of asymptomatic malaria and anemia during first antenatal care (ANC) visit among pregnant women in a rural district, Tanzania. HIV-uninfected pregnant women without symptoms of malaria (n = 819) attending their first ANC at Kibiti Health Centre were enrolled from February 2017 to February 2018. Asymptomatic malaria was detected by malaria rapid-diagnostic tests (mRDT) and real-time PCR. Hemoglobin concentration was determined by HemoCue Hemoglobin 201+. The study outcomes were the prevalence of asymptomatic malaria and anemia (Hemoglobin level <11 g/dL). The overall prevalence of asymptomatic malaria was 36.4% (95% CI: 33.1, 39.8). The monthly prevalence of asymptomatic malaria remained >25% throughout the year, and the highest prevalence (40%) was recorded during the rainy season. Asymptomatic malaria was significantly associated with primigravida, younger maternal age, and anemia. The prevalence of anemia was 68.5% (95% CI: 65.2, 71.6). Asymptomatic malaria, primigravida, younger maternal age and low Body Mass Index were significant predictors of low hemoglobin concentration. We report high prevalence of asymptomatic malaria and anemia among pregnant women on the first ANC visit. Screening of malaria and anemia during the first ANC visit is recommended for targeted interventions.

Prevalence of asymptomatic malaria in HIV-infected subjects on cotrimoxazole antimalarial prophylaxis attending a tertiary health care center in southern Nigeria: a cross-sectional study.

Co-infection has become a major contributor to increased burden of morbidity and mortality in HIV infection. The aim of this study was to assess the prevalence of asymptomatic malaria in the HIV-infected subjects on antimalarial prophylaxis and provide information to improve management of HIV subjects. This was a cross-sectional study with a purposive sampling. Microscopy method was used for the confirmation of malaria parasitemia status. The study was performed in University of Calabar Teaching Hospital, Calabar, Cross River State, Nigeria, a major tertiary health institution within the period of January to June 2016 involving 100 participants. The majority (65%) of the study participants were females. The majority of the studied population belonged to the age range 33-38 years old. Most (45%) of the patients had CD4 count ≥500 cells/µL. The prevalence of asymptomatic malaria was found to be 13% (13/100). The distribution of asymptomatic malaria based on gender and age were found not to be statistically significant (P>0.05). Subjects with CD4 count in the range of 200-499 cells/µL had the highest prevalence (24.39%) of asymptomatic malaria. Considering that all the studied participants were on antimalarial prophylaxis, it signals a public health concern to employ more intensive preventive methods in addition to antimalaria prophylaxis.

Prevalence of Asymptomatic Malaria among Children in the Tamale Metropolis: How Does the PfHRP2 CareStart™ RDT Perform against Microscopy?

Background Asymptomatic carriage of the malaria parasites, likewise its misdiagnosis, especially false negatives, due to the use of substandard rapid diagnosis tests (RDTs) has been shown to hinder the progress of the fight against malaria. Method The study assessed the prevalence of asymptomatic malaria as well as the performance of Plasmodium falciparum-specific protein and histidine-rich protein 2 (PfHRP2) CareStart™ RDT against standard microscopy in the detection of malaria infection among 345 children (1–15 yrs) from two (2) basic schools in Tamale Metropolis. Results From the microscopy (considered as gold standard), prevalence of malaria among the asymptomatic children was found to be 2.6%, with sensitivity and specificity of CareStart™ RDT in detecting P. falciparum infections found to be 55.6% and 93.8%, respectively. The positive predictive value (PPV) and negative predictive value (NPV) of CareStart™ RDT were found to be 19.23% and 98.45%, respectively. There was an evidence showing a significant relation between CareStart™ RDT and microscopy in determining malaria infection (χ2 = 30.579, p < 0.001). Conclusion Prevalence of asymptomatic malaria among children was found to be 2.6%. The study reported low sensitivity and PPV for PfHRP2 CareStart™ RDT in an asymptomatic population at instances of low parasitaemia.

High cases of submicroscopic Plasmodium falciparum infections in a suburban population of Lagos, Nigeria

BackgroundAsymptomatic malaria parasites are significant sources of infections for onward malaria transmission. Conventional tools for malaria diagnosis such as microscopy and rapid diagnostic test kits (RDT) have relatively low sensitivity, hence the need for alternative tools for active screening of such low-density infections.MethodsThis study tested var acidic terminal sequence-based (varATS) quantitative polymerase chain reaction (qPCR) for screening asymptomatic Plasmodium falciparum infections among dwellers of a sub-urban community in Lagos, Nigeria. Clinically healthy participants were screened for malaria using microscopy, RDT and varATS qPCR techniques. Participants were stratified into three age groups: 1–5, 6–14 and > 14 years old.ResultsOf the 316 participants screened for asymptomatic malaria infection, 78 (24.68%) were positive by microscopy, 99 (31.33%) were positive by RDT and 112 (35.44%) by varATS qPCR. Participants aged 6–14 years had the highest prevalence of asymptomatic malaria, with geometric means of ~ 116 parasites/µL and ~ 6689 parasites/µL as detected by microscopy and varATS, respectively.ConclusionThis study has revealed high prevalence of asymptomatic malaria in the study population, with varATS detecting additional sub-microscopic infections. The highest concentration of asymptomatic malaria was observed among school-age children between 6 and 14 years old. A large-scale screening to identify other potential hotspots of asymptomatic parasites in the country is recommended.

Prevalence of Asymptomatic Malaria in Relation to Haematological Parameters among Children Attending General Hospital, Minna, Nigeria

Asymptomatic Plasmodium falciparum parasitaemia (APFP) has been reported to be highly prevalent in Sub-Saharan Africa, a region heavily burdened by malaria; yet, the impact of APFP on the haematological reference values have not yet been established in Minna. This study was therefore designed to evaluate the prevalence of asymptomatic malaria in relation to haematological parameters among children attending General Hospital, Minna, Nigeria. After informed consent and clinical examination, blood samples were obtained from the participants for malaria diagnosis and a full blood count. The diagnosis of malaria was confirmed by thick and thin films stained with Giemsa's for malaria parasite and Complete Blood Counts (CBCs) were performed using an automated Abacus Junior machine. Of the 201 subjects sampled, the Age group 1-5years showed the highest prevalence of 24 (13.82%) for the symptomatic patients, followed by the age group 6-10years 3 (2.32%).The least prevalence of 1(2.86%) for the symptomatic patient was in the age group above 11years. The male symptomatic and asymptomatic subjects have higher gender prevalence characteristics of malaria parasite 20 (14.49%) than the female 8 (12.70%), though this difference was not significant (P&gt;0.05). The Chi-square analysis between the groups showed association among the gender with a value of 0.4919 at 5% level of significance. Patients with symptomatic parasitaemia tended to have significantly (P&lt;0.05) lower lymphocyte percentage (25.15±2.45), Red blood cell count (RBC) (4.14±0.21), Haemoglobin (HB)(8.81±0.44), Corpuscular Haemoglobin (MCH) (23.97±1.57) compared to that of asymptomatic and non-infected subjects. Corpuscular haemoglobin concentration (MCHC), Red Cell Distribution Width (RDWC), Platelet Volume (MPV) and Platelet Distribution Width showed no significant difference (P&gt;0.05). Platelet Count was, however, higher (269.57±6.93) significantly (P&lt;0.05) in non-infected control group compared to that of symptomatic and asymptomatic subjects with reduced platelet counts (140.36±13.09 and 123.63±6.99), respectively. Gender prevalence characteristics showed significance (P&lt;0.05) in platelet count (276.03±8.21, 255.88±12.72) in normal male and female subjects, respectively, compared to other groups. Among the malaria parasite density groups, least lymphocyte count (1.34±0.21) was found in 5001-10000mp/μl, symptomatic subjects. The mean Platelet Count was significantly lower in the asymptomatic density group compared to that of symptomatic malaria density group. This study confirms that haematological changes are frequent in asymptomatic plasmodial infection. Special attention should be applied when interpreting haematological parameters and evaluating immune responses in children living in malaria endemic area

Prevalence and Epidemiological Characteristics of Asymptomatic Malaria Based on Ultrasensitive Diagnostics: A Cross-sectional Study.

As the global public-health objectives for malaria evolve from malaria control towards malaria elimination, there is increasing interest in the significance of asymptomatic infections and the optimal diagnostic test to identify them. We conducted a cross-sectional study of asymptomatic individuals (N = 562) to determine the epidemiological characteristics associated with asymptomatic malaria. Participants were tested by rapid diagnostic tests (CareStart, Standard Diagnostics [SD] Bioline, and Alere ultrasensitive RDT [uRDT]), loop-mediated isothermal amplification (LAMP), and quantitative reverse transcription polymerase chain reaction (qRT-PCR) to determine malaria positivity. Hemoglobin values were recorded, and anemia was defined as a binary variable, according to World Health Organization guidelines. Compared to reference qRT-PCR, LAMP had the highest sensitivity (92.6%, 95% confidence interval [CI] 86.4-96.5), followed by uRDT Alere Malaria (33.9%, 95% CI 25.5-43.1), CareStart Malaria (14.1%, 95% CI 8.4-21.5), microscopy (5.0%, 95% CI 1.8-10.5), and SD Bioline (5.0%, 95% CI 1.8-10.5). For Plasmodium falciparum specimens only, the sensitivity for uRDT Alere Malaria was 50.0% (95% CI 38.8-61.3) and SD Bioline was 7.3% (95% CI 2.7-15.3). Based on multivariate regression analysis with qRT-PCR as the gold standard, for every 3.2% increase in the prevalence of asymptomatic malaria, hemoglobin decreased by 1 gram per deciliter (prevalence ratio 0.968, 95% CI 0.940-0.997; P = .032). Deletions (4.8%) in hrp2 were noted. While uRDT Alere Malaria has superior sensitivity to rapid diagnostic tests and microscopy in detecting asymptomatic malaria, LAMP is superior still. Ultrasensitive diagnostics provide the accurate prevalence estimates of asymptomatic malaria required for elimination.

Prevalence of asymptomatic malaria and anaemia among elderly population in Osun state Southwestern, Nigeria

Background: Malaria has remained a global burden for many centuries. It remains a major public health disease particularly in the tropic despite several interventional efforts targeted at its elimination. Malaria if not treated early enough could result in patients becoming anaemic. In Nigeria, elderly (60 years and above) represent a vulnerable group of individuals, they enjoy very little attention in terms of specific health related interventions and facilities. This study aimed to assess the prevalence and proportion of asymptomatic malaria infections and anaemia among the geriatric population in Osun state, Southwestern Nigeria.Methods: A community-based cross-sectional study was conducted among 396 elderly with average age of 69.14±7.27 years. Blood samples were collected for the preparation of Giemsa stained blood films for the detection and quantification of malaria parasites microscopically. Packed cell volume (PCV) was assessed using hematocrit.Results: Malaria parasites were present in the peripheral blood of 16.2% of the population and only 9.3% of the elderly were found to be anaemic. The ‘Very old’ age group of &gt;85 years years had highest prevalence of malaria (33.3%) but this was not statistically significant (p=0.17). Male respondents (24.4%) were more infected than females (13.7%) and this was found statistically significant (p=0.015). Having malaria parasite and living in the rural areas were significantly associated with being anaemic, p&lt;0.05 in each case.Conclusions: Considerable proportion of asymptomatic elderly individuals with parasitaemia were found anaemic. This group also represents a silent reservoir for malaria transmission in the country, if not addressed.