Helen Kuokuo Kimbi

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 higher (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.

Performance and usefulness of the Hexagon rapid diagnostic test in children with asymptomatic malaria living in the Mount Cameroon region

BackgroundRapid and correct diagnosis of malaria is considered an important strategy in the control of the disease. However, it remains to be determined how well these tests can perform in those who harbour the parasite, but are asymptomatic, so that rapid diagnostic tests (RDTs) could be used in rapid mass surveillance in malaria control programmes.MethodsMicroscopic and immunochromatographic diagnosis of malaria were performed on blood samples from the hyperendemic Mount Cameroon region. Thin and thick blood films were stained with Giemsa and examined under light microscopy for malaria parasites. The RDT was performed on the blood samples for the detection of Plasmodium species. In addition, the performance characteristics of the test were determined using microscopy as gold standard.ResultsResults revealed 40.32% to be positive for microscopy and 34.41% to be positive for the RDT. Parasites were detected in a greater proportion of samples as the parasite density increase. Plasmodium falciparum was the predominant Plasmodium species detected in the study population either by microscopy or by the RDT. Overall, the test recorded a sensitivity and specificity of 85.33% and 95.05% respectively, and an accuracy of 91.40%. The sensitivity and specificity of the RDT increased as parasite densities increased.ConclusionThe Hexagon Malaria Combi™ test showed a high sensitivity and specificity in diagnosing malaria in asymptomatic subjects and so could be suitable for use in mass surveillance programmes for the management and control of malaria.

Knowledge and perceptions towards malaria prevention among vulnerable groups in the Buea Health District, Cameroon

BackgroundMalaria is a public health problem especially in vulnerable groups such as pregnant women and children under five years in Cameroon including the Buea Health District (BHD). Misconceptions concerning it exist. This study assessed the level of knowledge and perceptions towards malaria control among pregnant women and mothers/caretakers of under-fives in the BHD.MethodsA community-based cross-sectional study was conducted in the BHD in August, 2011 in five health areas. A questionnaire was used to collect data on demographic variables, knowledge and perceptions towards malaria control from 443 respondents aged 15–73 years.ResultsOf the 443 respondents interviewed, 99% had heard about malaria. Awareness of malaria was similar in rural (98.04%) and urban (98.97%) areas. The health facility was the most popular source of information (74%). The radio, television, tracts/posters and the community relay agents (CRAs) all informed significantly higher proportions of respondents in the urban than rural communities (P <0.05). Overall, 92% of respondents had the right perception of malaria and 88% knew at least one correct sign/symptom of malaria. The most recognised sign of malaria was fever. When all aspects of malaria were considered, majority (88%) of respondents had good levels of knowledge on malaria. The level of good knowledge in respondents with ≥ secondary school education (91%) was significantly higher (P = 0.01) than in those with ≤ primary school level (83%). Overall, 99% had heard about insecticide treated nets (ITNs); 99% perceived ITNs as a good means to prevent malaria; most respondents (57%) used ITNs mainly for protection against mosquito bites while 48% used them for protection against malaria.ConclusionRespondents with no formal education had a poor level of knowledge on malaria. Hence, new strategies for sensitization messages involving their active participation need to be developed.

Genetic Diversity of Plasmodium falciparum Merozoite Surface Protein-1 Block 2 in Sites of Contrasting Altitudes and Malaria Endemicities in the Mount Cameroon Region

The present study analyzed the relationship between the genetic diversity of Plasmodium falciparum and parasitologic/entomologic indices in the Mount Cameroon region by using merozoite surface protein 1 as a genetic marker. Blood samples were collected from asymptomatic children from three altitude zones (high, intermediate, and low). Parasitologic and entomologic indices were determined by microscopy and landing catch mosquito collection/circumsporozoite protein-enzyme-linked immunosorbent assay, respectively. A total of 142 randomly selected P. falciparum-positive blood samples were genotyped by using a nested polymerase chain reaction-based technique. K-1 polymerase chain reaction products were also sequenced. As opposed to high altitude, the highest malaria prevalence (70.65%) and entomologic inoculation rate (2.43 infective/bites/night) were recorded at a low altitude site. Seven (18.91%), 22 (36.66%), and 19 (42.22%) samples from high, intermediate, and low altitudes, respectively, contained multiclonal infections. A new K-1 polymorphism was identified. This study shows a positive non-linear association between low/intermediate altitude (high malaria transmission) and an increase in P. falciparum merozoite surface protein 1 block 2 polymorphisms.

Cross-sectional study of specific antibodies to a polymorphic Plasmodium falciparum antigen and of parasite antigen genotypes in school children on the slope of Mount Cameroon

To investigate relationships between Plasmodium falciparum parasitaemia, parasite genotypes, and specific anti-parasite antibodies, 244 school children (aged 4 to 16 years) were studied in April/May 2002, the peak malaria transmission season in Buea, Cameroon. Antibody reactivities were analysed by ELISA using an array of recombinant antigens representing different sequences from the polymorphic block 2 region of the merozoite surface protein 1 (MSP1), and the blood samples that were slide-positive for P. falciparum were genotyped for msp1 block 2 alleles. The prevalence of antibodies to the specific MSP1 block 2 antigens was significantly higher in children at one particular school (situated at the lowest altitude) compared to the others, although the prevalence of infection or particular parasite genotypes did not differ. Thus, at a population level, the prevalence of these antibodies does not simply reflect prevalence of parasites, but rather may be due to differences in the incidence of past infections. However, there were weak positive associations between specific antibody reactivity and the presence of the corresponding allele in the blood of individuals (statistically significant for the MAD20-type allele of block 2), indicating that antibody specificities are to some extent determined by current parasite infections.

Malaria Risk Factors in Women on Intermittent Preventive Treatment at Delivery and Their Effects on Pregnancy Outcome in Sanaga-Maritime, Cameroon

Malaria is known to have a negative impact on pregnant women and their foetuses. The efficacy of Sulfadoxine-Pyrimethamine (SP) used for intermittent preventive treatment (IPT) is being threatened by increasing levels of resistance. This study assessed malaria risk factors in women on intermittent preventive treatment with SP (IPTp-SP) at delivery and their effects on pregnancy outcome in Sanaga-Maritime Division, Cameroon. Socio-economic and obstetrical data of mothers and neonate birth weights were documented. Peripheral blood from 201 mothers and newborns as well as placental and cord blood were used to prepare thick and thin blood films. Maternal haemoglobin concentration was measured. The overall malaria parasite prevalence was 22.9% and 6.0% in mothers and newborns respectively. Monthly income lower than 28000 FCFA and young age were significantly associated with higher prevalence of placental malaria infection (p = 0.0048 and p = 0.019 respectively). Maternal infection significantly increased the risk of infection in newborns (OR = 48.4; p<0.0001). Haemoglobin concentration and birth weight were lower in infected mothers, although not significant. HIV infection was recorded in 6.0% of mothers and increased by 5-folds the risk of malaria parasite infection (OR = 5.38, p = 0.007). Attendance at antenatal clinic and level of education significantly influenced the utilisation of IPTp-SP (p<0.0001 and p = 0.018 respectively). Use of SP and mosquito net resulted in improved pregnancy outcome especially in primiparous, though the difference was not significant. Malaria infection in pregnancy is common and increases the risk of neonatal malaria infection. Preventive strategies are poorly implemented and their utilization has overall reasonable effect on malaria infection and pregnancy outcome.

An Update of Asymptomatic Falciparum Malaria in School Children in Muea, Southwest Cameroon

Despite efforts put in by the international community to reduce malaria burden in Africa, the disease especially that is caused by Plasmodium falciparum, still remains a major health problem in sub-Saharan Africa. A cross-sectional study involving 366 pupils was conducted in Muea, Southwest Cameroon to assess an update of the burden of falciparum malaria in school children. Capillary blood samples were collected and Giemsa-stained blood films were observed microscopically for the identification and quantification of malaria parasites. Capillary tubes were filled with blood and spun at 10,000 rpm for 5 minutes, for the determination of packed cell volume (PCV). The overall prevalence of asexual parasites and anaemia were compared with the values, previously reported in a similar study at the same site in 2005. The overall prevalence of P. falciparum asexual parasites was 44.26%, as opposed to a value of 98% reported in 2005. The prevalence of asexual parasites significantly decreased with age (X 2 =20.86, p<0.0001). The values were similar in the sexes. The overall geometric mean parasite density (GMPD) of asexual P. falciparum was 1490.00 ± 1674.92 and the value was similar in the sexes and age groups. P. falciparum gametocyte prevalence was 17.49% and the value decreased significantly with age (X 2 =22.88, p< 0.0001). The overall GMPD of gametocytes was 23.48 ± 6.96 parasites/ µl. Gametocytaemia decreased with age and the difference was significant (F=62.61, p<0001). The overall prevalence of anaemia was 3.83%, as opposed to 10.6% in 2005. Generally, there was a significant drop in prevalence of asexual malarial parasites and anaemia in school children, compared to the previously reported values in 2005, and this is ascribed to the use of intervention strategies in recent years in the area.

Malarial anaemia and anaemia severity in apparently healthy primary school children in urban and rural settings in the Mount Cameroon area: cross sectional survey.

Background This study examines the relative importance of living in an urban versus rural setting and malaria in contributing to the public health problem of malarial anaemia (MA) and anaemia respectively in apparently healthy primary school children. Methods A cross-sectional study was conducted among 727 school children aged between four and 15 years living in an urban (302) and rural (425) settings in the Mount Cameroon area. 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. Based on haemoglobin (Hb) measurements, children with malaria parasitaemia were stratified into MA (Hb<11g/dL); mild MA (Hb of 8–10.9g/dL); moderate MA (Hb of 6.1–7.9g/dL) and severe MA (Hb≤6g/dL). Evaluation of potential determinants of MA and anaemia was performed by multinomial logistic-regression analysis and odds ratios used to evaluate risk factors. Results Out of the 727 children examined, 72 (9.9%) had MA. The prevalence of MA and anaemia were significantly higher (χ2 = 36.5, P <0.001; χ2 = 16.19, P <0.001 respectively) in children in the urban (17.9%; 26.8% respectively) than in the rural area (4.2%; 14.8% respectively). Majority of the MA cases were mild (88.9%), with moderate (5.6%) and severe MA (5.6%) occurring in the urban area only. The age group ≤6years was significantly (P <0.05) associated with both MA and anaemia. In addition, low parasite density was associated with MA while malaria parasite negative and microcytosis were associated with anaemia. Conclusions Malarial anaemia and anaemia display heterogeneity and complexity that differ with the type of settlement. The presence of severe MA and the contributions of the age group ≤6 years, low parasite density and microcytosis to the public health problem of MA and anaemia are noteworthy.

Co-Infections of Asymptomatic Malaria and Soil-Transmitted Helminths in School Children in Localities with Different Levels of Urbanization in the Mount Cameroon Region

Malaria and Soil-Transmitted Helminths (STHs) do co-infect hosts and it has been speculated that urbanization alters the frequency and transmission dynamics of both infections. This study was aimed at finding out the influence of urbanization on the prevalence and intensity of co-infections of asymptomatic malaria and STHs in schoolchildren in the Mount Cameroon Region. A total of 235 and 208 children from Ekona (rural) and Great Soppo (urban) respectively aged 4-14 years were enrolled into a cross-sectional study. Blood films were Giemsa-stained for the determination of malaria parasite density and speciation. Capillary blood was spun for the determination of packed cell volume. Stool samples were examined by the Kato-Katz technique for the presence and intensity of STHs. The prevalences of malaria in Ekona and Great Soppo were, 92.34 % and 82.70 % respectively (X2 = 9.60, p = 0.002). Malaria Geometric Mean Parasite Density (GMPD) in Ekona (277 ± 1988) was higher than that in Great Soppo (251±2400 parasites/ µl). Prevalence of helminths was higher in Ekona (43.82%) than Great Soppo (11.54%) (X2 = 60.12, p < 0.001). Coinfections were higher in Ekona (41.70 %) than Great Soppo (10.58%) (X2 = 45.83, p < 0.001). Ascaris lumbricoides was the most prevalent helminth and also had the highest Geometric Mean Egg Density (GMED) in Ekona, followed by Trichuris trichiura and hookworm. A similar pattern was observed in Great Soppo except for T. trichiura which was the most prevalent helminth. Prevalences of anemia in Ekona and Great Soppo were 6.00% and 1.00% respectively. The highest prevalence of anemia, GMPD and GMED occurred in co-infected participants when compared to those infected only with malaria or STHs. The prevalence of the infeections decreased with increase in level of urbanization. Schoolbased control of these infections especially in rural areas will reduce their related morbidities.

Malaria in HIV/AIDS Patients at Different CD4+ T Cell Levels in Limbe, Cameroon

HIV infection has resulted in an increased risk of severe malaria and death, because the odds of parasitaemia and risk of malaria fever increase with decreasing CD4+ T cell count and increasing viral load. A cross-sectional study was conducted on 203 HIV/AIDS patients to determine the pattern of malaria infection, anaemic status and the outcome of ARV therapy vis-a-vis malaria treatment at different CD4+ T cell levels of the patient. Participants were HIV patients aged ≥ 20 years attending the HIV treatment centre of Limbe Regional Hospital, Cameroon. Clinical manifestations of malaria in patients were determined using a structured questionnaire. Their CD4+ T cell count and haemoglobin level were determined using the FACS count method. Malaria prevalence and density were determined from Giemsa-stained blood films. Clinical manifestations of malaria increased with decreasing CD4+ T cell counts. There was a negative correlation between malaria severity and decreasing CD4+ T cell counts. A significantly greater proportion (p<0.01) of patients had moderate anaemia. Cases of anaemia increased significantly (p<0.001) with decreasing CD4+ T cell counts. Declining immunity increases vulnerability to malaria infection and highly active ARV combination therapy has great potential to reduce HIV-related malaria.