Leopold Gustave Lehman

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.

High mosquito burden and malaria transmission in a district of the city of Douala, Cameroon

BackgroundRapid demographic growth in Douala city, Cameroon, has resulted in profound ecological and environmental changes. Although demographic changes can affect anopheline mosquito breeding sites, there is a lack of understanding about the epidemiological impact that such changes might have on vector ecology and malaria transmission.MethodsA 12-month entomological study was conducted in a highly populated district of Douala called Ndogpassi. Adult mosquitoes were collected using two methods: 1) human landing catches (HLC); and 2) Centers for Disease Control and Prevention (CDC) light traps; these methods were used twice monthly from January to December 2011. Mosquito genus and species were identified with morphological and molecular diagnostic tools. The sampling efficiency of the CDC light trap and HLC were compared. Anopheles gambiae infection with Plasmodium falciparum was detected using ELISA. Susceptibility to DDT, permethrin, and deltamethrin insecticides were also determined.ResultsA total of 6923 mosquitoes were collected by HLC (5198) and CDC light traps (1725). There was no equivalence in the sampling efficiency between light traps and human landing catches (P > 0.01). With 51% of the total, Culex was the most common, followed by Anopheles (26.14%), Mansonia (22.7%) and Aedes (0.1%). An. gambiae ss (M form) comprised ~98% of the total anophelines collected. An. gambiae had a biting rate of 0.25 to 49.25 bites per human per night, and was the only species found to be infected with P. falciparum. A P. falciparum infection rate of 0.5% was calculated (based on enzyme-linked immunosorbent assays using the circumsporozoite surface protein). The entomological inoculation rate was estimated at 31 infective bites per annum. Insecticide susceptibility tests on An. gambiae females revealed a mortality rate of 33%, 76% and 98% for DDT, permethrin and deltamethrin, respectively. The West African kdr allele (L1014F) was detected in 38 of the 61 An. gambiae analyzed (62.3%).ConclusionsThe present study revealed seasonal malaria transmission in Douala. High levels of An. gambiae were detected along with a high prevalence of insecticide resistance in this vector population. These findings highlight the need to promote use of insecticide-impregnated bed nets in Douala.

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.

HIV, HBV, HCV and T. pallidum infections among blood donors and Transfusion-related complications among recipients at the Laquintinie hospital in Douala, Cameroon.

BackgroundTransfusion-transmissible infections (TTIs) pose a major health risk in Cameroon given the high prevalence of such pathogens and increased demands for blood donations in the local communities. This study aims at establishing the prevalence of commonly encountered TTIs among blood donors and transfusion-related complications among recipients in an urban center of Cameroon.MethodsA total of 477 blood donors and 83 blood recipients were recruited by consecutive sampling at the Laquintinie Hospital in Douala (LHD), Cameroon. Serum samples from blood donors were tested by quantitative enzyme-linked immunosorbent assays (ELISA) and/or using various Rapid diagnostic test (RDT) for presence of Hepatits B (HBV) viral antigens, and antibodies to human immunodeficiency (HIV-1/2), Hepatits B (HCV) and Treponema pallidum. Recipient’s medical records were also analyzed for possible transfusion-associated complications.ResultsThe male/female sex ratio of the blood donors was 4/1 with a mean age of 30.2 (Sd = 8.3) years. Of all blood donors, 64/467 (13.7%) were infected by at least one of the four TTIs. Infected volunteer donors represented 8.3% while infected family donors comprised 14.3% of the donor population. The prevalence of HCV, HIV, HBV and T. pallidum were 1.3%, 1.8%, 3.5%, and 8.1%, respectively. More than half of the blood recipients were female (78.3%) and the mean age was 20.6 (SD = 16.1) years. The causes of severe anemia indicative of transfusion in recipients varied with wards (postpartum hemorrhage, caesarean section, uterine or cervical lacerations, abortions, urinary tract infections, severe malaria, vaso-occlusive attacks, wounds and gastrointestinal bleeding). The most frequent complications were chills and hematuria, which represented 46.1% of all observed complications. Other complications such as nausea, vomiting, jaundice, sudden diarrhea, anxiety, tachycardia, or hyperthermia were also found in recipients. Three cases of deaths occurred during the study, including a girl of less than one year.ConclusionThis study confirms the presence of blood-borne infectious diseases in blood donors at the LHD, identifying T. pallidum as the greatest threat to blood safety in the region, and hematuria as the most common immunological complications in blood recipients.

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.

Environmental Factors and Preventive Methods against Malaria Parasite Prevalence in Rural Bomaka and Urban Molyko, Southwest Cameroon

Malaria remains a major public health problem in Cameroon. This work was aimed at determining the influence of environmental factors and control measures on malaria parasite prevalence, and anaemia in pupils in rural Bomaka and urban Molyko, Southwest Cameroon. A total of 303 pupils (174 and 129 from Bomaka and Molyko, respectively), aged 4-15 years were studied. Information on demographic data, environmental and anti-malarial measures was recorded. Malaria was diagnosed from Giemsa-stained blood smears. Packed Cell Volume (PCV) was determined. The overall malaria parasite prevalence was 33.0%, and children from Bomaka had a significantly higher value (38.51%) than those from Molyko (25.58%). Malaria parasite prevalence was significantly higher in males and highest in children aged ≤ 6 years. Overall location, age and stagnant water were associated with malaria parasite prevalence. Although malaria parasite prevalence was higher in pupils who had bushes around their homes, lived in plank houses, and did not use Insecticide Residual Spraying (IRS), the differences were, however, not significant. The overall prevalence of anaemia was 14.0%, with the ≤ 6 years old pupils having the highest anaemia prevalence. Parasite density was significantly higher in anaemic ((1369, CI=504.25-2511.89) than non-anaemic children ((507, CI=313.74-603.32). A combination of environmental and preventive measures (especially in rural areas) as well as community participation will reduce malaria transmission.

Anopheles gambiae, vecteur majeur du paludisme à Logbessou, zone péri-urbaine de Douala (Cameroun)

An entomological survey was carried out from August to November 2013, in order to determine the vector system of a building site for social housing in a coastal periurban district of Douala (Cameroon). Mosquito larvae were collected and adult endophilic mosquitoes captured on volunteers, for a total sample of 4897 mosquitoes. Morpho-taxonomic techniques alongside molecular techniques enabled the identification of 4 species, all aggressive to humans: Cx. pipiens (22.3%), Ae. albopictus (0.3%), An. coluzzii and An. gambiae (77.4%). The overall average biting rate recorded was 41.73 bites/person/night (b/p/n). An. gambiae s.l. represents 90.82% of this aggressive fauna, followed by Cx. pipiens (8.58%) and Ae. albopictus (0.6%). The detection of CSP showed that An. gambiae was responsible for 100% of P. falciparum transmission. The overall mean Entomological Inoculation Rate (EIR) was 3.94 ib/p/n. Female An. gambiae mortality rates were 14.47%, 82.5% and 100% respectively with DDT, permethrin and deltamethrin. The proliferation of An. gambiae in this area during raining season, at the detriment of An. coluzzii Coetze & Wilkerson and An. melas Theobald known to be major malaria vectors in island and coastal areas of Africa, may owe to the forest that still colonises this coastal peri-urban locality. Residents should therefore make use of deltamethrin based protective measures.

Mosquito Species Diversity and Malaria Transmission in Ayos, an Area of Degraded Forest Targeted for Universal Long-Lasting Insecticidal Net Distribution in Southern Cameroon

This study was conducted from January to December 2010 to evaluate the anopheline diversity and transmission of malaria in Ayos, a degraded forest area in the south of Cameroon, targeted for the distribution of long-lasting insecticidal nets (LLINs). Mosquito larvae were collected by the dipping method and endophilic female adult mosquitoes were captured on volunteers. Molecular techniques were used alongside morphological techniques for mosquito identification; ELISA was used for the detection of plasmodium circumsporozoite antigens. Ten mosquito species, including four Anopheles species (Anopheles gambiae s.s., An. funestus s.s., An. moucheti s.s. and An. hancocki), were identified. The mean biting rate of these Anopheles species was 12.7 bites per person per night (b/p/n). An. gambiae s.s. (6.9 b/p/n) appeared to be the most aggressive species. Malaria transmission is mainly ensured by An. gambiae s.s., An. funestus ss. and An. moucheti s.s. Plasmodium falciparum was the only malaria parasite transmitted. The mean entomological inoculation rate (EIR) for these vectors was 0.7 infecting b/p/n. An. gambiae s.s. (65.6 %) is the major vector, with an annual EIR of 167.9 infectious b/p/n/year. The utilization of LLINs alongside other methods would highly contribute to effective malaria control in Ayos.

Active Case Detection and Prevalence of Urinary Schistosomiasis and Malaria in Pupils of Kotto Barombi, Southwest Cameroon using the CyScope® Fluorescence Microscope

This work was carried out in collaboration between all authors. Author HKK designed the study and wrote the protocol, carried out field and laboratory work and wrote the first draft of the manuscript. Author GBW designed the study, wrote the protocol, carried out field work, read and corrected the manuscript. Author JAK designed the study, read and corrected the manuscript. Author CT performed the statistical analysis, read and corrected the manuscript. Authors BA, CN, LKN and HNN participated in the data collection and literature searches. Author LGL designed the study wrote the protocol, carried out field work and supervised the work at all stages. All authors read and approved the final manuscript.