The comparative efficacies of malartin, with and without amodiaquine, in the treatment of Plasmodium falciparum malaria in the Buea district of Cameroon.

The in-vivo efficacies of the artesunate malartin, alone and in combination with amodiaquine, have been assessed against uncomplicated cases of Plasmodium falciparum malaria attending two treatment centres in Cameroon (the WHO/University of Buea malaria health post in Bolifamba and the University of Buea's health centre in Molyko). The 213 participants were treated for 3 days (malartin-amodiaquine) or 5 days (malartin alone) and then followed-up on days 3, 7 and 14. Only 86 of the patients given malartin alone and 80 of those given malartin-amodiaquine completed follow-up. Most patients given malartin alone showed an adequate clinical and parasitological response (91.9%), the rest showing late parasitological failure (7.0%) or early treatment failure (1.2%). The corresponding values for the malartin-amodiaquine combination were slightly better, at 93.8%, 5.0% and 1.2%, respectively. No late clinical failures were recorded in either treatment arm. In both treatment arms, the prevalence of anaemia in the treated adults (aged>15 years) and children decreased significantly during follow-up (P<0.05). Both regimens were well tolerated and neither gave rise to any serious adverse effects. The most common side-effects were dizziness and fatigue in those given malartin alone and fatigue, itching and nausea in those given malartin-amodiaquine. Three days of treatment with the malartin-amodiaquine combination appears to be slightly more effective and a slightly better choice than 5 days of treatment with malartin alone.

Influence of urbanisation on asymptomatic malaria in school children in Molyko, South West Cameroon.

OBJECTIVE: To determine the impact of urbanisation on the prevalence of asymptomatic malaria in Molyko, a rapidly urbanising area of South West Cameroon. DESIGN: A cross-sectional study. SETTING: Molyko, South West Province Cameroon. SUBJECTS: One hundred and sixty six and two hundred and forty four randomly selected children in Molyko in the rainy seasons of 2000 and 2004 respectively. MAIN OUTCOME MEASURES: Prevalence and geometric mean parasite density of asymptomatic malaria, measurement of axillary temperatures and haematocrit (PCV) values in 2000 and 2004. RESULTS: There was a significant association between axillary temperature and malaria parasitaemia in both years (p<0.05). Overall, the prevalence of asymptomatic malaria and parasite density values in all age groups in 2004 were lower than in 2000 while the reverse was the case with PCV values. CONCLUSION: Urbanisation in Molyko has likely reduced the level of malaria endemicity in the area. It is advisable to repeat this study over a period of time in order to assess the long-term effects of urbanisation in the study area.

Traditional use of indigenous mosquito-repellents to protect humans against mosquitoes and other insect bites in a rural community of Cameroon.

OBJECTIVE: To document and test the efficacy of indigenous traditional personal protection methods against mosquito bites and general nuisance. DESIGN: A prospective study based on a survey and field evaluation of selected plant-based personal protection methods against mosquito bites. SETTING: Bolifamba, a rural setting of the Mount Cameroon region. SUBJECTS: A structured questionnaire was administered to 179 respondents and two anti-mosquito measures were tested under field conditions. MAIN OUTCOME MEASURES: Identified traditional anti-mosquito methods used by indigenes of Bolifamba. Two plants tested under field conditions were found to be effective. RESULTS: Of the 179 respondents, 88 (49.16%) used traditional anti-mosquito methods; 57 (64.77%) used plant-based methods while 31 (35.2%) used various petroleum oils. The rest of the respondents, 91 (50.8%) used conventional personal protection methods. Reasons for using traditional methods were because they were available, affordable and lack of known more effective alternatives. The demerits of these methods were: labourious to implement, stain dresses, produce a lot of smoke/ repulsive odours when used; those of conventional methods were lack of adequate information about them, high cost and non-availability. When the two most frequently used plants, Saccharum officinarium and Ocimum basilicum were evaluated under field conditions, each gave a better protection than the control. CONCLUSION: Most plants used against mosquitoes in the area are known potent mosquito repellents but others identified in the study warrant further research. The two tested under field conditions were effective though less than the commonly used commercial diethyltoluamide.

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

In vivo efficacy study of quinine sulphate in the treatment of uncomplicated P. falciparum malaria in patients from Southwestern Cameroon.

OBJECTIVE: To evaluate clinical, parasitological and haematological responses to quinine sulphate therapy in patients with uncomplicated malaria using the 14-day WHO protocol. DESIGN: Longitudinal study. SETTING: The Buea Provincial hospital annex located in South Western Cameroon. SUBJECTS: The study participants consisted of children (> or = 8 months) and adults (< or = 550 years) with acute malaria attending the outpatient division of health institutions within Fako Division. RESULTS: Quinine sulphate failure was found in 42% of the patients. Of these 10% were resistant at the RI while 32% were at the RII level. Clinically, the overall success rate (ACR) was 94.2% while therapeutic failures (ETF and LTF) were observed in four patients (5.8%). 27.4% and 17.4% of the patients were anaemic at enrolment and day 14 respectively. The mean PCV levels of the patients increased during the follow-up period except on day three when mean PCV levels dropped. The difference in the mean PCV levels during the follow-up was significant (F = 60.29; P = 0.0001). CONCLUSION: The relatively high resistance of quinine sulphate observed in this study suggests the need to monitor the spread of resistance to this drug in the study region.

Malaria infection and its consequences in school children.

OBJECTIVES: To evaluate the prevalence and consequences of malaria infection in school children in the Muea area and its environment. DESIGN: A cross-sectional study. SETTING: Muea area, South West Cameroon. SUBJECTS: Two hundred and fourty six randomly selected school children aged three to sixteen years. MAIN OUTCOME MEASURES: Prevalence of malaria in the Muea area. Determination of parasitaemia. Measurement of haematocrit (PCV) values. Species identification. Consequences of malaria infection in terms of school days lost. RESULTS: Prevalence of malaria was 98% and highest prevalence rate (100%) and geometric mean parasite density (1520 parasites/microl of blood) occurred in the < or = 5 years age group. Prevalence of anaemia was generally low (10.8%) and there were no cases of severe anaemia (PCV < 20%). P. vivax-like parasites were detected for the first time in this area. Plasmodium falciparum was the predominant species (93%) followed by P. malariae (52%), P. ovale (42.7%) and P. vivax-like parasites (33.3%). Mixed infections also occurred. Fifty three out of 144 (36.8%) children lost a number of school days ranging from 0.5-14 days, with each child losing an average of 1.53 school days in a month. CONCLUSION: The prevalence of asymptomatic malaria in the Muea area is very high. P. vivax parasites were observed for the first time in the area, but this needs to be confirmed by molecular methods in future studies. Children lost school days as a consequence of malaria infection.

The epidemiology of malaria in Bolifamba, a rural community on the eastern slopes of Mount Cameroon: seasonal variation in the parasitological indices of transmission.

The prevalences of malarial parasitaemia, fever, splenomegaly and anaemia and the levels of parasitaemia were investigated, through part of one wet season (in 2001) and the following dry season (in 2002), in 2157 subjects in the village of Bolifamba, in south-western Cameroon. Overall, 55.9% of the villagers checked in the wet season but only 49.5% of those examined in the dry season were found smear-positive for malaria (P<0.0001). Rainfall was found to be significantly associated with the mean level of parasitaemia (P=0.001). The prevalences of fever (40.3% v. 19.6%), splenomegaly (37.4% v. 4.0%) and marked splenomegaly (i.e. a Hackett's score of 2 or higher; 25.8% v. 2.4%) were all significantly higher in the wet season than in the dry (P<0.0001 for each). No seasonal difference was observed, however, in the prevalence of anaemia. Parasitaemia, fever, splenomegaly and anaemia were all significantly more common in the young children investigated (i.e. those aged < 5 years) than in the older subjects. When the data were subjected to a multiple logistic regression, age-group, anaemia, fever, and month of examination were all found to be significantly associated with the presence of malarial parasitaemia. The results of this large-scale study, the first of its kind in the Buea district of Cameroon, indicate the intense transmission of malarial parasites in rural Bolifamba, with young children at greatest risk. The data collected provide a useful 'base line' for an ongoing study to assess the immune status of the residents of Bolifamba.

Evaluating a malaria intervention strategy using knowledge, practices and coverage surveys in rural Bolifamba, southwest Cameroon.

We evaluated the impact of a malaria intervention in Bolifamba in rural Cameroon. The intervention consisted of educating the community on management of malaria and provision of a dispensary for early diagnosis and treatment. In July 2001, prior to the intervention, a questionnaire was used to obtain information on knowledge of and practices toward childhood malaria of 185 mothers of children aged 0-5 years. The same questionnaire was administered to 120 of the 185 mothers, one-year post-intervention. Clinical and laboratory investigations were carried out on children whose mothers were interviewed. A comparison of pre- and post-intervention data indicated significant changes in (i) the use of appropriate malaria treatment (from 50% to 81.7%); (ii) recognition of splenomegaly as a feature of malaria (from 18.4% to 80.8%); (iii) prevalence of splenomegaly (from 26.5% to 13.3%); (iv) prevalence of fever (from 27.8% to 13.3%); (v) parasite prevalence (from 60.5% to 44.2%) and (vi) severe malaria anaemia (from 2.6% to 0.0%). These findings revealed that proper education of villagers, particularly mothers, on malaria and the presence of health facilities, where treatment is readily available at affordable cost, close to villages, are important strategies that would reduce malaria morbidity and mortality significantly.

Prevalence of asymptomatic malaria among school children in an urban and rural area in the Mount Cameroon region.

OBJECTIVE: To assess the prevalence of asymptomatic malaria among school children in an urban and a rural area during different seasons. SETTING: Molyko (urban area) and Bova (rural area), South West Province, Cameroon. SUBJECTS: 166 and 158 randomly selected children in Molyko during the dry and rainy seasons respectively and 122 and 117 children in Bova during the respective seasons. DESIGN: A cross sectional study. MAIN OUTCOME MEASURES: Prevalence and parasite density of asymptomatic malaria in the urban and rural areas in the dry and rainy seasons. Prevalence of anaemia in infected and uninfected children during both seasons in the two areas. RESULTS: There was a significant association between axillary temperature and malaria parasitaemia in both seasons (p<0.05). Overall, the prevalence of asymptomatic malaria in the urban area (Molyko) was higher than that in the rural area (Bova) during both seasons, although the differences were not statistically significant (p>0.05). During the dry season, the prevalence of asymptomatic malaria in the urban area was 42.17% while that of the rural area was 40.16%. During the rainy season, the prevalence value in the urban area was 46.20% and that in the rural area was 43.59%. Malaria infection rates decreased with age during both seasons in both areas and the difference between age groups was statistically significant in Molyko during the rainy season (p<0.05), and Bova during the dry season (p<0.05). Mean packed cell volume (PCV) levels were lower in infected than in uninfected children in all age groups and the difference was significant in Molyko during the rainy season and Bova during the dry season. CONCLUSION: The lack of a significant difference between the two seasons implies perennial transmission of the disease in the areas. Control measures are, therefore, urgently needed in this region to reduce the burden of the disease.

In vivo efficacy study of quinine sulphate in the treatment of uncomplicated P. Falciparum malaria in patients from southwestern Cameroon

Objective: To evaluate clinical, parasitological and haematological responses to quinine sulphate therapy in patients with uncomplicated malaria using the 14-day WHO protocol. Design: Longitudinal study.Setting: The Buea Provincial hospital annex located in South Western Cameroon. Subjects: The study participants consisted of children (≥8 months) and adults (≤50 years) with acute malaria attending the outpatient division of health institutions within Fako Division.Results: Quinine sulphate failure was found in 42% of the patients. Of these 10% were resistant at the RI while 32% were at the RII level. Clinically, the overall success rate (ACR) was 94.2% while therapeutic failures (ETF and LTF) were observed in four patients (5.8%). 27.4% and 17.4% of the patients were anaemic at enrolment and day 14 respectively. The mean PCV levels of the patients increased during the follow-up period except on day three when mean PCV levels dropped. The difference in the mean PCV levels during the follow-up was significant (F=60.29; P=0.0001).Conclusion: The relatively high resistance of quinine sulphate observed in this study suggests the need to monitor the spread of resistance to this drug in the study region

Malaria and intestinal helminthiasis in school children of Kumba Urban Area, Cameroon.

BACKGROUND: Malaria and intestinal helminthiasis are parasitic diseases causing high morbidity and mortality in most tropical parts of the world, where climatic conditions and sanitation practices favour their prevalence. These infections do co-exist and have different effects on infected individuals. OBJECTIVES: To assess the level of endemicity of malaria and helminth infections in school children of the Kumba Urban Area of Cameroon, and to determine how these infections relate to each other. DESIGN: Cross sectional study. SETTING: Four primary schools in the Kumba urban area. SUBJECTS: Two hundred and forty three randomly selected pupils aged four and fifteen years of both sexes. RESULTS: All two hundred and forty three pupils had malaria parasites in their blood. The geometric mean parasite load was 1282 parasites per microl of blood. Only 17 pupils were anaemic (PCV<30%), The helminth infections showed a 38.3% prevalence, with a geometric mean parasite load of 687 eggs per gram of faeces. Co-infections were recorded in 38.3% of the pupils. There was no significant correlation between the helminth and malaria parasite densities (r=0.04, P=0.7337). CONCLUSION: Both malaria and helminth parasites do co-exist without clinical symptoms of infection in school children of the Kumbi Urban Area.

Adoptive transfer of immunity induced with chloroquine attenuated Plasmodium yoelii nigeriensis from immune to immunologically naive mice.

Immunity was induced in albino mice using Chloroquine-attenuated Plasmodium yoelii nigeriensis which had been maintained under drug pressure in 4 passages. Attempts were made to adoptively transfer immunity from the immune to immunologically naive mice by means of serum, spleen and thoracic duct extracts. None of them conferred complete immunity on the recipients but some protection was gained. This was evident from the prolongation of both the pre-patent periods of the infection and the survival periods of the host mice. The best protection conferred by the different extracts was seen in groups that received 0.4 ml serum, 0.9 ml spleen and 1.2 ml thoracic duct extracts whose survival periods lasted 23, 21 and 15 days respectively as compared to 9 days for the controls.

Induction of chloroquine resistance in Plasmodium yoelii nigeriensis.

Chloroquine resistance was induced in Plasmodium yoelii nigeriensis by the method of drug pressure. Twenty five albino mice were used at each passage and each of them was inoculated intra-peritoneally with approximately 10(5) erythrocytes infected with the parasite. The first fifteen mice divided into three groups of five mice each were treated with different sub-curative doses of chloroquine which usually cleared the infection for a few days before recrudescence. Inocula for passages to the next set of mice was made from the recrudesced infection. The sub-curative dose was progressively increased as rapidly as the build-up of parasitaemia permitted. The last ten mice divided into two groups of five mice each were used in the 'two percent test' to assess the level of resistance in the parasite. Full resistance to the maximum tolerated dose of chloroquine to the host mouse (80 mg/kg body weight) was reached at passage 20.

Efficacy of Cymbopogon giganteus and Enantia chrantha against chloroquine resistant Plasmodium yoelii nigeriensis.

The antimalarial activity of boiled water extracts of two medicinal plants (Cymbopogon giganteus and Enantia chlorantha) against chloroquine resistant Plasmodium yoelii nigeriensis in albino mice was assessed. Twenty-five mice were used for each extract. Each mouse was inoculated with approximately 10(5) erythrocytes infected with chloroquine-resistant P.y. nigeriensis. At five to seven percent parasitaemia, the mice were randomly divided into five groups of five mice each. The first four groups were treated intraperitoneally for three consecutive days with different doses of the stock solution per mouse. The two extracts cleared the infection in a dose-dependent manner.

Immunization of albino mice using chloroquine attenuated Plasmodium yoelli nigeriensis.

In an attempt to induce chloroquine resistance in Plasmodium yoelii nigeriensis by the method of drug pressure, it was found that the mice continued to be infected until the fourth passage when they became refractory or immune to the infection. When the immune mice were challenged at four weekly intervals, they remained refractory to the infection until week 12 when one of them became infected. However, by the sixteenth week, the rest of the mice became susceptible to the infection. Four of the mice which received a booster dose of the parasite which had been exposed to chloroquine in three passages, that is, chloroquine-attenuated at the sixteenth week, did not pick up a challenge infection two weeks later while the controls did.