Mean Parasite Density Research Articles

Association of placental Plasmodium falciparum parasitaemia with maternal and newborn outcomes in the periurban area of Bobo-Dioulasso, Burkina Faso

SUMMARYThe prevalence of placental malaria and its impact on maternal and newborn outcomes have been poorly documented in periurban settings of Burkina Faso. Peripheral and placental blood from 320 mothers, and cord blood from their newborns were collected through a cross-sectional study and used to prepare thick and thin blood films. Maternal haemoglobin concentration and birthweight were also measured. The overall malaria parasitaemia prevalence in peripheral, placental and cord blood was of 17·2, 9·1 and 0·9%, respectively.Plasmodium falciparumwas the sole species found in all cases and the mean parasite density in placental blood was 4·5 ± 0·8 parasitesµL−1. Primigravida (aOR: 3·5; 95% CI (1·1–11·2)) and women who did not use a bed net (aOR: 2·6; 95% CI (1·1–6·3)), were at higher odds of placental malaria infection. Women with placental parasitaemia were at increased odds of maternal anaemia (aOR: 3·1; 95% CI (1·3–7·4)). There was no odds difference for LBW between mothers with placental parasitaemia and those without. Placental malaria parasitaemia resulted in a significant mean birthweight reduction of 200 g. Placental malaria infection is higher in primigravida. Use of insecticide-treated bed nets should be therefore emphasized for primigravida during the first antenatal care visit.

Malaria and Hepatitis B co-infection in patients with febrile illnesses attending general outpatient unit of the Murtala Muhammed Specialist Hospital, Kano, Northwest Nigeria

Malaria and Hepatitis B Virus (HBV) infections are co-endemic throughout much of the tropical and sub-Saharan Africa and both present major threat to public health. A study on the prevalence of HBV and Malaria co-infection was carried out on 200 patients presenting with fever at the General Outpatient Department (GOPD) of the Murtala Muhammed Specialist Hospital (MMSH), Kano using Gold Standard microscopy and rapid diagnostic test (RDT). The effect of mono and co-infection on hematological parameters was also investigated. Fifty one (25.5%) out of the 200 patients studied were Malaria positive. Females had higher prevalence rate(18%) of Malaria infection than males with 7.5%. Age group 15-24 had the highest Malaria prevalence (11%) followed by age group 25-34 with 6.5%. Higher mean parasite density (1,200/il) was recorded among subjects with monoinfection of Malaria than mean parasite density (518/il) obtained among the co-infected. Mean parasite density was higher in female than male subjects. Thirteen (6.5%) subjects were HBV positive. Males had higher rate of infection with 4.5% prevalence than females with 2.0%. Nine individuals representing 4.5% of the total population had co-infection with higher prevalence (3%) among the males. Age groups 25-34 were observed to have high co-infection rate of 1.5% and the least prevalence was observed among the age group 15-24 with 0.5% prevalence for both males and females. Hematological evaluation carried out on all the categories of subjects shows significant difference in mean values of PCV (P=0.041), Hb (P=0.018) between the co-infection group and those with malaria infection and control groups. However, no significant difference (P>0.05) was observed in the values of WBC, PLT and Red cell indices among the co-infected and other test group. It was concluded that co-infection with the two ailments had no profound effect on hematologic parameters. Keywords : Co-Infection, Hepatitis B, Kano, Malaria, MMSH, Prevalence

Plasmodium falciparum parasitaemia and malaria among pregnant women at first clinic visit in the mount Cameroon Area.

BackgroundPregnant women in malaria endemic areas are at high risk of P. falciparum infection and its complications. This study investigated the prevalence and risk factors for P. falciparum infection and malaria among pregnant women reporting for first antenatal care (ANC) clinic visit in the mount Cameroon area.MethodsVenous blood samples from consented pregnant women were screened for malaria parasitaemia by light microscopy. Haemoglobin levels, white blood cell (WBC) counts, lymphocyte counts and percentage were determined using an automated haematology analyser. Socio-demographic/economic data, environmental factors and use of malaria control measures were documented. Univariate and multivariate statistical analyses were used.ResultsSixty-eight (22.4 %; N = 303) of the women enrolled were positive for P. falciparum parasitaemia. Malaria parasitaemia was significantly (P < 0.001) associated with febrile illness. The overall prevalence of malaria and asymptomatic infection was 16.0 % (95 % CI = 11-20 %) and 10.5 % (95 % CI = 7.3-15 %) respectively. A greater proportion of the malaria cases (61 %) reported at the clinic during unscheduled days meanwhile women with asymptomatic parasitaemia mostly (92.8 %) seek for ANC during scheduled clinic days. Lower lymphocyte percentage was significantly associated with increase parasite density (r = − 0.34; P = 0.011) and febrile status (MU = 2.46; P = 0.014). While age and gravidity were significant factors associated with P. falciparum infection and/or malaria, the presence of bush and/or standing water around human residence was an independent risk factor of P. falciparum parasitaemia (OR = 3.3: 95 % CI = 1.6 – 7.0; P = 0.002) and malaria ( OR = 5.2: 95 % CI = 2.0 – 14; P = 0.001). Being unmarried was significantly associated with increase risk (OR = 2.6:95 % CI = 1.1 – 6.0; P = 0.032) of P. falciparum parasitaemia. Similarly, single women (938) had a significantly higher (t = 2.70; P = 0.009) geometric mean parasite density (GMPD) compared with married women (338).ConclusionMarital status and human residence in areas with bushes and/or standing water modify risk of P. falciparum infection and malaria. Education on early ANC attendance and environmental sanitation are important public health targets for malaria control in pregnancy in this setting.

Clinical and laboratory features of congenital malaria in Nigeria

Since congenital malaria had previously been thought to be rare, blood film examination for malaria parasites is still sometimes not routinely performed in ill neonates in malaria-endemic regions. Because of increasing published reports of congenital malaria in Nigeria, there is a need to characterize the clinical and laboratory manifestations associated with malaria parasitemia within the first few hours of life. In a 12-month (April 2003-March 2004), multicenter study in Nigeria, thin and thick blood smears made from maternal (finger prick), placental aspirates, cord blood and neonate (heel prick taken within 4 hours of life) were Giemsa-stained and examined by light microscopy for asexual stages of Plasmodium. Parasitemic neonates were closely monitored for clinical and laboratory features of symptomatic malaria. Plasmodium falciparum was found in 5.1% (95/1875) of neonatal heel pricks; mean parasite density was low (mean = 48/μL, range 8–200/μL). Antepartum maternal and placental parasitemia were the most important risk factors for congenital parasitemia ( P P P 37.5°;) within the first 24 hours of life (100%) and refusal to suck (10.8%). Anemia at birth (hematocrit P = 0.03, OR = 1.84). The mean hematocrit of parasitemic neonates within 4 hours of life was 49.5 ± 6.4 as compared to 52.6 ± 8.2 in non-parasitemic babies ( P = 0.001). Furthermore, the mean hematocrit was 44.0 ± 5.5% in the symptomatic parasitemic babies. All symptomatic babies were treated with oral chloroquine with a cure rate of 89.1%. Treatment failures subsequently received oral sulfadoxine-pyrimethamine with good outcome. The febrile newborn should be evaluated for malaria especially if there is a history of prolonged labor or in the presence of maternal malaria infection. Efforts should be intensified to reduce the burden of maternal, placental malaria and therefore congenital malaria.

Malaria Prevalence among Young Infants in Different Transmission Settings, Africa.

The prevalence and consequences of malaria among infants are not well characterized and may be underestimated. A better understanding of the risk for malaria in early infancy is critical for drug development and informed decision making. In a cross-sectional survey in Guinea, The Gambia, and Benin, countries with different malaria transmission intensities, the overall prevalence of malaria among infants <6 months of age was 11.8% (Guinea, 21.7%; The Gambia, 3.7%; and Benin, 10.2%). Seroprevalence ranged from 5.7% in The Gambia to 41.6% in Guinea. Mean parasite densities in infants were significantly lower than those in children 1-9 years of age in The Gambia (p<0.0001) and Benin (p = 0.0021). Malaria in infants was significantly associated with fever or recent history of fever (p = 0.007) and anemia (p = 0.001). Targeted preventive interventions, adequate drug formulations, and treatment guidelines are needed to address the sizeable prevalence of malaria among young infants in malaria-endemic countries.

Prevalence and risk factors associated with malaria infection among pregnant women in a semi-urban community of north-western Nigeria.

BackgroundMalaria during pregnancy remains a serious public health problem, with substantial risks for the mother, her foetus and the newborn. The aim of this study was to determine the prevalence of malaria and possible risk factors for malaria infection among pregnant women in a semi-urban area in north-western Nigeria. Pregnant women are among the most susceptible to malaria infection. Knowledge of their malaria infection status is an important yardstick to measure the effectiveness of any malaria control programme.MethodsWe conducted a cross sectional study in the semi-urban area of Argungu, Kebbi State Nigeria. Two hundred and fifty five pregnant women were included in the study after informed verbal consent was obtained. For each participant, the socio-demographic profile, stage of pregnancy and attitude to the use of insecticide- treated nets (ITNs) were investigated using a questionnaire. Peripheral blood samples were collected and thick blood smears were prepared and stained with Giemsa stains to check for malaria parasitaemia. The associations between age, education level and use of ITNs with occurrence of malaria infection during pregnancy were analysed using the chi-square test.ResultsOne hundred and six (41.6%) out of 255 pregnant women were infected with malaria parasites, with a mean parasite density of 800 parasitesμl−1. It was found that prevalence and parasite density decreased as age increased. The chi-square test indicated that a lack of education and non-usage of ITNs were significantly associated with malaria infection.ConclusionMalaria is still a major public health issue among pregnant women mainly due to illiteracy and non -compliance to using ITNs. Increasing awareness about malaria preventive measures and early attendance of antenatal care services will help to reduce malaria and, consequently, its associated morbidities and mortalities.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-015-0054-0) contains supplementary material, which is available to authorized users.

Malaria parasite density estimated with white blood cells count reference value agrees with density estimated with absolute in children less than 5 years in central ghana.

Introduction. The estimation of malaria parasite density using a microscope heavily relies on White Blood Cells (WBCs) counts. An assumed WBCs count of 8000/µL has been accepted as reasonably accurate in estimating malaria parasite densities due to the challenge to accurately determine WBCs count. Method. The study used 4944 pieces of laboratory data of consented participants of age group less than 5 years. The study compared parasite densities of absolute WBCs, assumed WBCs, and the WBCs reference values in Central Ghana. Ethical approvals were given by three ethics committees. Results. The mean (±SD) WBCs and geometric mean parasite density (GMPD) were 10500/µL (±4.1) and 10644/µL (95% CI 9986/µL to 11346/µL), respectively. The difference in the GMPD compared using absolute WBCs and densities of assumed WBCs was significantly lower. The difference in GMPD obtained with an assumed WBCs count and that of the WBCs reference values for the study area, 10400/µL and 9200/µL for children in different age groups, were not significant. Discussion. Significant errors could result when assumed WBCs count is used to estimate malaria parasite density in children. GMPD generated with WBCs reference values statistically agreed with density from the absolute WBCs. When obtaining absolute WBC is not possible, the reference value can be used to estimate parasite density.

Prevalence of Malaria in Patients Attending the General Hospital Makarfi, Makarfi Kaduna – State, North-Western Nigeria

Nigeria is a high endemic country for malaria. Its large population, diverse weather conditions and cultures make it a bit difficult implementing the same malaria control measures throughout the country. Prevalence studies are therefore essential for better understanding and implementation of intervention programs. This study determined some malariometric parameters such as malaria prevalence, transmission based on age and gender, parasite density, fever and anaemia in patients attending General Hospital Makarfi, during the malaria transmission season. All participants were screened microscopically for malaria and classified into 3 groups: under 5 years, 5 – 15 years and above 15. A total of 1173 participants were screened out of which 419 (35.7%) were positive. The geometric mean parasite density was 15,108 parasite/µL of blood. Children aged 5 – 15 years had a statistically significant higher infection rate compared to the other groups. Males were more prone to malaria than females. Presence of parasitaemia, fever or anaemia did not correlate with the presence of malaria. Some of the positive patients had high parasite densities and yet asymptomatic. More malariometric surveys are needed in Nigeria in order to adopt control efforts that best suit rural areas and smaller communities especially during peak malaria transmission season.

Therapeutic efficacy of chloroquine for the treatment of uncomplicated Plasmodium falciparum in Haiti after many decades of its use.

Chloroquine (CQ) has been used for malaria treatment in Haiti for several decades, but reports of CQ resistance are scarce. The efficacy of CQ in patients with uncomplicated Plasmodium falciparum undergoing treatment in Haiti was evaluated. Malaria patients were enrolled, treated with CQ, and monitored over a 42-day period. The treatment outcomes were evaluated on day 28 by microscopy. The P. falciparum slide-confirmed rate was 9.5% (121 of 1,277). Malaria infection was seasonal, with peak observations between October and January; 88% (107 of 121) of patients consented to participate. Sixty patients successfully completed the 42-day follow-up, whereas 47 patients withdrew consent or were lost to follow-up. The mean parasite density declined rapidly within the first few days after treatment. Seven patients did not clear their malaria infections and were clinically asymptomatic; therefore, they were considered late parasitological failures. About 90% (95% confidence interval = 84.20-97.90) of patients had no detectable parasitemia by day 28 and remained malaria-free to day 42. Testing for recrudescence, reinfection, and CQ serum levels was not done in the seven patients, and therefore, their CQ resistance status is unresolved. CQ resistance surveillance by patient follow-up, in vitro drug sensitivity studies, and molecular markers is urgently needed in Haiti.

Therapeutic efficacy of artemether-lumefantrine on treatment of uncomplicated Plasmodium falciparum mono-infection in an area of high malaria transmission in Zambia.

BackgroundAnti-malarial drug resistance continues to be a leading threat to ongoing malaria control efforts and calls for continued monitoring of the efficacy of these drugs in order to inform national anti-malarial drug policy decision-making. This study assessed the therapeutic efficacy and safety of artemether-lumefantrine (AL)(Coartem®) for the treatment of uncomplicated Plasmodium falciparum malaria in two sentinel high malaria transmission districts in the Eastern Province of Zambia in persons aged six months and above, excluding women aged 12 to 18 years.MethodsThis was an observational cohort of 176 symptomatic patients diagnosed with uncomplicated Plasmodium falciparum mono-infection. A World Health Organization (WHO)-standardized 28-day assessment protocol was used to assess clinical and parasitological responses to directly observed AL treatment of uncomplicated malaria. DNA polymerase chain reaction (PCR) analysis for molecular markers of AL resistance was conducted on positive blood samples and differentiated recrudescence from re-infections of the malaria parasites.ResultsAll patients (CI 97.6-100) had adequate clinical and parasitological responses to treatment with AL. At the time of enrolment, mean slide positivity among study participants was 71.8% and 55.2% in Katete and Chipata, respectively. From a mean parasite density of 55,087, 98% of the study participants presented with zero parasitaemia by day 3 of the study. Fever clearance occurred within 24 hours of treatment with AL. However mean parasite density declines were most dramatic in participants in the older age. No adverse reactions to AL treatment were observed during the study.ConclusionAL remains a safe and efficacious drug for the treatment of uncomplicated Plasmodium falciparum malaria in Zambia, endemic for malaria, with some provinces experiencing high transmission intensity. However, the delayed parasite clearance in younger patients calls for further sentinel and periodical monitoring of AL efficacy in different areas of the country.

Co-infections of malaria and geohelminthiasis in two rural communities of Nkassomo and Vian in the Mfou health district, Cameroon.

BackgroundHuman co-infection with malaria and helmimths is ubiquitous throughout Africa. Nevertheless, its public health significance on malaria severity remains poorly understood.Methodology/Principal FindingsTo contribute to a better understanding of epidemiology and control of this co-infection in Cameroon, a cross-sectional study was carried out to assess the prevalence of concomitant intestinal geohelminthiasis and malaria, and to evaluate its association with malaria and anaemia in Nkassomo and Vian. Finger prick blood specimens from a total of 263 participants aged 1–95 years were collected for malaria microscopy, assessment of haemoglobin levels, and molecular identification of Plasmodium species by PCR. Fresh stool specimens were also collected for the identification and quantification of geohelminths by the Kato-Katz method. The prevalence of malaria, geohelminths, and co-infections were 77.2%, 28.6%, and 22.1%, respectively. Plasmodium falciparum was the only malaria parasite species identified with mean parasite density of 111 (40; 18,800) parasites/µl of blood. The geohelminths found were Ascaris lumbricoides (21.6%) and Trichuris trichiura (10.8%), with mean parasite densities of 243 (24; 3,552) and 36 (24; 96) eggs/gram of faeces, respectively. Co-infections of A. lumbricoides and P. falciparum were the most frequent and correlated positively. While no significant difference was observed on the prevalences of single and co-infections between the two localities, there was a significant difference in the density of A. lumbricoides infection between the two localities. The overall prevalence of anaemia was 42%, with individuals co-infected with T. trichiura and P. falciparum (60%) being the most at risk. While the prevalence of malaria and anaemia were inversely related to age, children aged 5–14 years were more susceptible to geohelminthiasis and their co-infections with malaria.Conclusion/SignificanceCo-existence of geohelminths and malaria parasites in Nkassomo and Vian enhances the occurrence of co-infections, and consequently, increases the risk for anaemia.

Therapeutic enhancement of newly derived bacteriocins against Giardia lamblia

Trials for identifying efficient anti-giardial agents are still ongoing. Nowadays, bacteriocins have attracted the attention as potential antimicrobial compounds. For the first time, the current study evaluated the therapeutic efficacy of bacteriocins derived from newly isolated Egyptian strains of probiotics Lactobacilli; L. acidophilus (P106) and L. plantarum (P164) against Giardia lamblia. Bacteriocins' efficacy was evaluated both in vitro; by growth inhibition and adherence assays, and in vivo; through estimation of parasite density, intestinal histopathological examination and ultrastructural analysis of Giardia trophozoites. In vivo bacteriocins' clinical safety was assessed. In vitro results proved that 50 µg of L. acidophilus bacteriocin induced reduction of the mean Giardia lamblia trophozoites by 58.3 ± 4.04%, while at lower concentrations of 10 and 20 µg of both L. acidophilus and L. plantarum, non significant reduction of the mean parasite density was achieved. In vitro trophozoites adherence was susceptible to the tested bacteriocins at all studied concentrations with variable degrees, while the highest adherence reduction was demonstrated using 50 µg of L acidophilus bacteriocin. In vivo, oral inoculation of 50 µg/mouse L. acidophilus bacteriocin for 5 successive days resulted in a noteworthy decline of the intestinal parasite density, along with amelioration of intestinal pathology of infected mice. Ultrastructural examination proved thatfive doses of L. acidophilus bacteriocin showed marked changes in cellular architecture of the trophozoites with evident disorganization of the cell membrane, adhesive disc and cytoplasmic components. This is the first reported study of the safe anti-giardial efficacy of L. acidophilus (P106) derived bacteriocin, hence highlighting its great promise as a potential therapeutic safe alternative to existing commercial drugs.

The Pattern of Parasite Density, Plasma Total Bile Acids and Lactate Dehydrogenase in Plasmodium Infected Patients in Rural Community

<b>Background to the study: </b>Pathophysiology of Plasmodium (vivax, ovale, falciparum and malariae) infection involves liver. Liver dysfunction and destruction of tissues could be indicated by the plasma level of Total Bile Acid (TBA) and Lactate Dehydrogenase (LDH). <b>Aim and Objective:</b> This work was designed to evaluate the pattern of parasite density, plasma total bile acids, and Lactate dehydrogenase in Plasmodium infected patients in rural community. <b>Materials and Methods:</b> The study was carried out in Kishi, the Headquarter of Irepo Local government area of Oyo state - Nigeria. Seven hundred and nine (709) subjects (Female: n=403: male: n=306) aged 5 to 68 years were tested for Plasmodium infection using Giemsa- thick film technique. The overall prevalence of Plasmodium infection among the seven hundred and nine subjects screened was found to be 29.1% (206) including 12.97% (92) HIV, HBsAg and anti-HCV seronagative patients and 16.1% (114) HIV, HBsAg or anti-HCV seropositive patients. Ninety two (92 (12.97%)) that were HIV, HBsAg and anti-HCV seronagative(female-58 (63.0%); male-34 (37%)) were recruited out of 206 (29.1%) that were found to be infected with plasmodium spp for the study. None of the subject was jaundiced as at the time of sample collection. Hepatitis B surface antigen (HBsAg) and anti-HCV tests were carried out by Enzyme Linked Immunozorbent Assay (ELIZA). HIV screening and confirmation were carried out by immuno-chromatographic and Immunobloting (Western blot) assays respectively. Fasting Plasma Total Bile Acids (TBA) and Lactate Dehydrogenase (LDH) were analyzed in the patients biochemically by spectrophotometry. <b>Result:</b> The result obtained showed an overall prevalence of Plasmodium infection as 29.1% (206) (female: 107 (52%); male: 99 (48%)) including 12.97% (92) (Female: 58 (63.0%) Male: 34 (37%)) that were HIV, HBsAg and anti-HCV seronagative and 16.1% (114) (Female: 61 (53.5%); Male: 53 (46.5%)) were co-infected with at least one of HIV, HBV or HCV. The plasmodium infected subjects were grouped into three based on the parasite density such as: patients with parasite density of 50-499; 500-999 and ≥1000. The mean value of the parasite density of each group was correlated with the plasma level of LDH and TBA. In all groups there was a strong positive correlation(R=1; R2 =1) between the plasma TBA, LDH and plasmodium parasite density. The pattern of parasite density obtained in the rural community studied include 45.7% had a mean parasite density of 282±12.0; 43.5% (853±31.0) and 10.9% (1130±61.0). There was also a statistical significant increase in the mean value of LDH and TBA with increase in parasite density with p<0.05. <b>Conclusion:</b> This work showed an overall prevalence of 29.1% (206) plasmodium infection including 16.1% (114) of the patients co-infected with at least one of HIV, HBV or HCV. The plasma level of LDH and TBA was also found to be positively correlated and directly proportional to the parasite density. Evaluation of these parameters is therefore recommended for effective control and management.

Pre-amplification methods for tracking low-grade Plasmodium falciparum populations during scaled-up interventions in Southern Zambia

BackgroundMalaria is receding in many endemic countries with intervention scale -up against the disease. However, this resilient scourge may persist in low-grade submicroscopic infections among semi-immune members of the population, and be poised for possible resurgence, creating challenges for detection and assessment of intervention impact. Parasite genotyping methods, such as the molecular barcode, can identify specific malaria parasite types being transmitted and allow tracking and evaluation of parasite population structure changes as interventions are applied. This current study demonstrates application of pre-amplification methods for successful detection and genotyping of residual Plasmodium falciparum infections during a dramatic malarial decline.MethodsThe study was a prospective cross-sectional design and based on a 2,000 sq km vicinity of Macha Mission Hospital in southern Zambia. Willing and predominantly asymptomatic residents of all ages were screened for malaria by microscopy during the 2005 and 2008 transmission seasons, with simultaneous collection of dried blood spots (DBS) on filter paper, and extraction of Plasmodium falciparum DNA was performed. Plasmodium falciparum infections were genotyped using a 24 SNP-based molecular barcode assay using real-time PCR. Submicroscopic parasitaemia samples were subjected to pre-amplification using TaqMan PreAmp Master Mix following the manufacturer’s instructions before SNP barcode analysis.ResultsThere was a dramatic decline of malaria between 2005 and 2008, and the geometric mean parasite density (95% CI) fell from 704/μL (390–1,271) in 2005 to 39/μL (23–68) in 2008, culminating in a large proportion of submicroscopic infections of which 90% failed to yield ample DNA for standard molecular characterization among 2008 samples. Pre-amplification enabled successful detection and genotyping of 74% of these low-grade reservoir infections, overall, compared to 54% that were detectable before pre-amplification (p <0.0005, n = 84). Furthermore, nine samples negative for parasites by microscopy and standard quantitative PCR amplification were positive after pre-amplification.ConclusionsPre-amplification allows analysis of an otherwise undetectable parasite population and may be instrumental for parasites identification, tracking and assessing the impact of interventions on parasite populations during malaria control and elimination programmes when parasitaemia is expected to decline to submicroscopic levels.

Influence of Malaria Prevention on Malaria Parasitaemia during Pregnancy

Malaria infection control remains a challenge in Africa. According to the World Health Organization, an estimated 660,000 deaths occurred from malaria infection in 2010, with Sub-Saharan Africa accounting for 90% of the mortality. The aim of this study is to assess the prevalence of peripheral malaria parasitaemia and the methods of malaria prevention commonly used among pregnant women. The study is a cross sectional survey of pregnant women attending an antenatal booking clinic in a secondary health care center in Southwest Nigeria. In addition to obtaining information about patients' knowledge of malaria infection and protection, obstetric history, general and obstetric examinations were completed, and blood film and capillary tube samples were obtained through a finger prick. Thick and thin blood films were stained and examined for identification and quantification of malaria parasite, and the capillary tube blood sample was processed for haematocritestimation. Results of 502 participants were used in the analysis; 38 (7.6%) women were positive for malaria parasite on microscopy. Peripheral malaria parasitaemia was more common among primigravidae25 (65.8%) compared with multigravidae 13(34.2%) (p-value< 0.001). The mean parasite density was higher among primigravidae, 6824.39parasites/µl compared to multigravidae, 606.69 parasites/µl. A total of 337 (67.1%) of the participants had haematocrits less than 11g/dl. Malaria prevention methods used by the participants included untreated nets 204 (40.7%), insecticide sprays and coils 211 (42.0%), and insecticide treated nets (ITNs) 87 (17.3%). Among the participants with peripheral malaria parasitaemia, one (2.6%) used ITNs compared with 21 (55.3%) and 16 (42.1%) who used insecticides and untreated nets respectively (p-value 0.032). Further analysis showed higher odds of peripheral malaria parasitaemia among those who used insecticides, and untreated nets relative to ITNs (odds ratio8.763, 95% CI 1.136 - 67.592, and odds ratio 6.993, 95% CI 0.899 - 54.411). Fewer pregnant women use ITN compared with other methods such as insecti- cides and untreated nets despite the protective benefits against malaria infection in pregnancy. Therefore, further exploration regarding improved accessibility and increased effectiveness of utilization is necessary to decrease malaria infection rates, es- pecially among pregnant women.

Delayed Hemolysis After Treatment With Parenteral Artesunate in African Children With Severe Malaria—A Double-center Prospective Study

Parenteral artesunate is recommended as first-line therapy for severe malaria. While its efficacy is firmly established, data on safety are still incomplete. Delayed hemolysis has been described in hyperparasitemic nonimmune travelers, but it is unknown if African children are equally at risk. Children aged 6 to 120 months with severe malaria were followed up after treatment with parenteral artesunate in Lambaréné, Gabon, and Kumasi, Ghana. The primary outcome was incidence of delayed hemolysis on day 14. In total, 72 children contributed complete data sets necessary for primary outcome assessment. Delayed hemolysis was detected in 5 children (7%), with 1 child reaching a nadir in hemoglobin of 2.8 g/dL. Patients with delayed hemolysis had higher parasite counts on admission (geometric mean parasite densities (GMPD) 306 968/µL vs 92 642/µL, P = .028) and were younger (median age: 24 months vs 43 months, P = .046) than the rest of the cohort. No correlation with sickle cell trait or glucose-6-phosphate-dehydrogenase deficiency was observed. Delayed hemolysis is a frequent and relevant complication in hyperparasitemic African children treated with parenteral artesunate for severe malaria. Physicians should be aware of this complication and consider prolonged follow-up. Pan-African Clinical Trials Registry: PACTR201102000277177 (www.pactr.org).

Inland valley rice production systems and malaria infection and disease in the forest region of western Côte d’Ivoire

BackgroundThis study aimed to determine the epidemiological impact of rice cultivation in inland valleys on malaria in the forest region of western Côte d’Ivoire. The importance of malaria was compared in terms of prevalence and parasite density of infections and also in terms of clinical malaria incidence between three agro-ecosystems: (i) uncultivated inland valleys, (R0), (ii) inland valleys with one annual rice cultivation in the rainy season, (R1) and (iii) developed inland valleys with two annual rice cultivation cycles, (R2).MethodsBetween May 1998 and March 1999, seven villages of each agro-ecosystem (R0, R1 and R2) were randomly selected among villages pooled by farming system. In these 21 villages, a total of 1,900 people of all age groups were randomly selected and clinically monitored during one year. Clinical and parasitological information was obtained by active case detection of malaria episodes carried out during eight periods of five consecutive days scheduled at six weekly intervals and by cross-sectional surveys.ResultsPlasmodium falciparum was the principal parasite observed in the three agro-ecosystems. A level of holoendemicity of malaria was observed in the three agro-ecosystems with more than 75% of children less than 12 months old infected. Geometric mean parasite density in asymptomatic persons varied between 180 and 206 P. falciparum asexual forms per μL of blood and was associated with season and with age, but not with farming system. The mean annual malaria incidence rate reached 0.7 (95% IC 0.5-0.9) malaria episodes per person in R0, 0.7 (95% IC 0.6-0.9) in R1 and 0.6 (95% IC 0.5-0.7) in R2. The burden of malaria was the highest among children under two years of age, with at least four attacks by person-year. Then malaria incidence decreased by half in the two to four-year age group. From the age of five years, the incidence was lower than one attack by person-year. Malaria incidence varied with season with more cases in the rainy season than in the dry season but not with farming system.ConclusionIn the forest area of western Côte d’Ivoire, inland valley rice cultivation was not significantly associated with malaria burden.

Malaria and haematologic parameters of pupils at different altitudes along the slope of Mount Cameroon: a cross-sectional study

BackgroundHaematologic abnormalities are features in Plasmodium falciparum infection, and anaemia is an inevitable outcome. This study examines the influence of malaria status and altitude on haematologic parameters in school-aged pupils.MethodsA cross-sectional study was conducted among 728 school pupils aged between four and 15 years at three different altitudinal ranges along the slope of the Mount Cameroon region. The investigative methods included the use of questionnaire, clinical evaluation and laboratory investigations. Blood sample collected from each child was used for the preparation of blood films for detection of malaria parasites and assessment of malaria parasite density as well as full blood count determination using an automated haematology analyzer.ResultsThe prevalence of malaria in the study population was 33.8% and 64.2% (158/246) of these were asymptomatic (AM). Pupils in lowlands had a significantly (P <0.05) prevalence (95% confidence interval, CI) of malaria (60.6%, CI = 54.6–65.9%) than those in middle belt (29.1%, CI = 23.9–34.8%) and highlands (7.7%, CI = 6.1–9.8%), while those in middle belt had significantly higher geometric mean parasite density (475) than those in lowlands (233) and highlands (388). The prevalence of malaria was significantly higher in children that presented with fever (40.4%, CI = 33.8–47.2%) when compared with afebrile subjects (31%, CI = 27–35.2%). Pupils with AM had a higher prevalence of leucopaenia (43.7%, CI = 35.8–51.8%), microcytosis (27.2%, CI = 20.5–34.9%), hypochromasia (27.8%, CI = 21–35.5%) and thrombocytopaenia (14.9%, CI = 8.9–22.8%) when compared with those with clinical malaria (CM). All mean haematological parameters were comparable in pupils with CM and AM, except for the mean white blood cell (WBC) counts. Pupils with AM had significantly lower (P = 0.02) mean WBC counts (5.1 ± 2.5 × 109/L) than those with CM (5.9 ± 2.3 × 109/L). Age, altitude and malaria parasitaemia was of significant influence on several haematological parameters.ConclusionAltitude influenced the distribution and density of malaria parasites and was of confounding influence on the haematologic profiles. These results highlight the insidious effects of AM on the haematologic components.

Evaluation of Paracheck-PfTM rapid malaria diagnostic test for the diagnosis of malaria among HIV-positive patients in Ibadan, south-western Nigeria

Febrile illnesses occur frequently among HIV positive patients and these are often treated presumptively as malaria in endemic areas. Parasite-based diagnosis of malaria will eliminate unnecessary treatment, reduce drug–drug interactions and the chances for the emergence of drug resistant Plasmodium.We evaluated finger prick blood samples from 387 people living with HIV (PLWHIV) and suspected of having malaria by expert microscopy and Paracheck-PfTM – a histidine-rich protein-II based malaria rapid diagnostic test. The study was conducted at the PEPFAR supported AIDS Prevention Initiative in Nigeria (APIN) Clinic of the University College Hospital Ibadan, southwest Nigeria. Outcome parameters were prevalence of malaria parasitemia, sensitivity and specificity of Paracheck-Pf as well as the positive and negative predictive values for Paracheck-Pf using microscopy of Giemsa-stained blood film as gold standard.Malaria parasites were detected in 19·1% (74/387) of enrollees by microscopy and 19·3% (74/383) by Paracheck-Pf. Geometric mean parasite density was 501/μl (range 39–749 202/μl). Sensitivity and specificity of Paracheck-Pf at all parasite densities were 55·4% and 89·3% while corresponding figures at parasite densities ≧200/μl were 90·9% and 90·3%. Sensitivity and specificity at parasite densities ≧500/μl was 97·6% and 90·3%. Positive and negative predictive values for parasite density ≧200/μl were 55·4% and 98·7%, respectively.Paracheck-pf was found to be a useful malaria diagnostic tool at parasite densities ≧200/μl facilitating appropriate clinical management.

Prevalence, pattern, and determinants of placental malaria in a population of southeastern Nigerian parturients

Placental malaria is a complication of malaria in pregnancy and is associated with adverse outcomes. Its burden is highest in Sub-Saharan Africa, but despite this, data based on histological analysis are scarce from this region. Questionnaires administered by the researchers were used to obtain information from parturients at a university teaching hospital in southeastern Nigeria between April and November 2010. Maternal blood and placental blood were collected for analysis. Placental blocks were taken for histological analysis. Statistical analyses were done using SPSS v. 17. Three hundred and sixty-five placentas were analyzed, out of which 254 showed histological evidence of malaria parasitization, giving a prevalence of 69.6%. Of the 254 placentas, 23 (9.0%) showed active infection and 196 (77.2%) showed active-on-past infection, while 35 (13.8%) showed past infection. Rural residence, hemoglobin genotype AA, not receiving intermittent preventive treatment in pregnancy (IPTp), and not sleeping under insecticide-treated bed nets (ITN) were significantly associated with placental malaria. Placental parasite density was inversely related to parity. This study showed that the prevalence of placental malaria in southeastern Nigeria is high, and demonstrated that the mean parasite density was inversely related to parity. Significant factors associated with placental malaria were also identified. Appreciation of these significant factors will assist program managers in implementing the strategies for the prevention of malaria in pregnancy.