Malaria vectors and transmission dynamics in coastal south-western Cameroon

Background: Malaria is a major public health problem in Cameroon. Unlike in the southern forested areas where the epidemiology of malaria has been better studied prior to the implementation of control activities; little is known about the distribution and role of anophelines in malaria transmission in the coastal areas. Methods: A 12-month longitudinal entomological survey was conducted in Tiko; Limbe and Idenau from August 2001 to July 2002. Mosquitoes captured indoors on human volunteers were identified morphologically. Species of the Anopheles gambiae complex were identified using the polymerase chain reaction (PCR). Mosquito infectivity was detected by the enzyme-linked immunosorbent assay and PCR. Malariometric indices (plasmodic index; gametocytic index; parasite species prevalence) were determined in three age groups (5yrs; 5-15yrs; 15yrs) and followed-up once every three months. Results: In all; 2;773 malaria vectors comprising Anopheles gambiae (78.2); Anopheles funestus (17.4) and Anopheles nili (7.4) were captured. Anopheles melas was not anthropophagic. Anopheles gambiae had the highest infection rates. There were 287; 160 and 149 infective bites/person/year in Tiko; Limbe and Idenau; respectively. Anopheles gambiae accounted for 72.7; An. funestus for 23and An. nili for 4.3of the transmission. The prevalence of malaria parasitaemia was 41.5in children 5 years of age; 31.5in those 5-15years and 10.5in those 15years; and Plasmodium falciparum was the predominant parasite species.Conclusions: Malaria transmission is perennial; rainfall dependent and An. melas does not contribute to transmission. These findings are important in the planning and implementation of malaria control activities in coastal Cameroon and West Africa

Environmental Factors Affecting Malaria Parasite Prevalence in Rural Bolifamba; South-West Cameroon

The impact of some environmental factors on malaria parasite prevalence was investigated in rural Bolifamba; Cameroon. The study population comprised 1454 subjects aged 0 - 65 years. Malaria parasite prevalence was higher in the rainy (50.1) than in the dry season (44.2) with a significant difference (P=0.001) in mean parasite density between seasons. Individuals 15 years old; had significantly higher malaria parasite prevalence (55.5) than those 15 years (37.4). Malaria parasite prevalence (P=0.001) and parasite density (P=0.03) were higher in the individuals of wooden plank houses than those of cement brick houses. Inhabitants of houses surrounded by bushes or garbage heaps and swamps or stagnant water showed higher malaria parasite prevalence and densities compared with those from cleaner surroundings. Anopheles gambiae (63.8) and A. funestus (32.8) were associated with perennial transmission of malaria. Our data indicates that poor environmental sanitation and housing conditions may be significant risk factors for malaria parasite burden in Bolifamba

The Pattern of Soil Transmitted Nematode Infections in Primary School Children of the Kumba Health District; South-West Cameroon

Biomedical studies accompanied by a questionnaire survey were carried out on 803 pupils of classes 3; 5 an 7 attending 17 primary schools in the Kumba Health District to determine the prevalence of soil - transmitted nematodes and infection-associated morbidity. The prevalence rate of worms in the sample population from the questionnaire survey was 42.3which correlates closely with 44.2recorded for abdominal pains. The biomedical studies gave a worm infection rate of 67.1. Ascaris lumbricoides; Trichuris trichiura and hookworm had prevalence rates of 54.9; 33.8and 20.3respectively. Mixed infections were recorded in 34.4of the sample population compared to 32.8for single infections. Hookworm infection rate was significantly higher in the rural areas than in the urban areas (27.5versus 14.8; P 0.001). A similar trend was observed for T. trichiura (38.4versus 30.3; P 0.02). Prevalence of A. lumbricoides was similar in the urban and rural areas (56.5versus 52.6). Males carried heavier burdens of Ascaris and Trichuris than females. The worm burden for all 3 species decreased as children moved to higher classes and with age after the first decade of life. There was a significant correlation between the intensities of infection of A. lumbricoides and T. trichiura

Infection Pattern of Schistoma Haematobium in Primary School Children of the Kumba Health District; South-West Cameroon

"Studies were carried out on 855 pupils of classes 3; 5 and 7 (age range 5-16 years) attending 17 primary schools in the Kumba Health District; Cameroon; to determine the infection pattern of Schistosoma haematobium in its different communities. The results reveal prevalence rates of 9.7for urinary schistosomiasis and 11.6for haemuturia. The focal area for Schistosomiasis was Barombi kotto with a prevalence rate of 75.9; a finding not significantly different from 78.2for haematuria. Low prevalence rates were recorded in the villages at the periphery of Barombi Kotto and also in the vicinity of Kumba town. Lake Barombi Kotto and ""Kumba Water"" were the main sources of infection in these areas. No significant differences in prevalence were observed between males and females or between children in the different classes surveyed. Age-specific evaluation revealed that peak infection was attained at /and 83.8respectively."