[Obstacles to laboratory diagnosis of malaria in Mali--perspectives]. / Problématique du diagnostic biologique du paludisme au Mali--perspectives.

Rapid accurate laboratory diagnosis is necessary for effective malaria management. In Mali, meeting this prerequisite is impeded by underuse of laboratory diagnosis by clinicians, absence of qualified laboratory facilities in some locations, and poor continuous professional education of laboratory technicians. The twofold aim of this investigation was to perform quality control of thick smear readings made by laboratory technicians in 1998 and 1999 and to study the feasibility and diagnostic value of two rapid diagnostic tests (RDT), i.e., ParaSight and OptiMAL, in comparison with the thick smear technique in the period from 1998 to 2003. Quality control of thick smear readings indicated a 56% false positive rate with 49.3% concordance between laboratory technician readings and the reference centre. Trials using RDT showed that the OptiMAL test was more efficient with 97.2% sensibility, 95.4% specificity and 93% concordance in comparison with thick smear. A program of training, refresher courses, and regular didactic supervision (quality control) for laboratory technicians has been set up in Mali under the sponsorship of the "Fondation Mérieux" (ACTION BIOMALI) and the President's Malaria Initiative (PMI). These institutions provide funding for training as well as equipment and consumables in all public medical laboratories in Mali. The thick smear method is still being used as the reference technique, but use of RDT is to be implemented at all levels of the health care pyramid.

Effectiveness of a community intervention on malaria in rural Tanzania - a randomised controlled trial.

BACKGROUND: Malaria infections are a major public health problem in Africa and prompt treatment is one way of controlling the disease and saving lives. METHODS: This cluster-randomised controlled community intervention conducted in 2003-2005 aimed at improving early malaria case management in under five children. Health workers were trained to train community-based women groups in recognizing malaria symptoms, providing first-line treatment for uncomplicated malaria and referring severe cases. Evaluation was through a pre- (2004) and a post-intervention survey (2005). Anaemia prevalence was the primary outcome. RESULTS: 1715 children aged 6-59 months were included in the pre-intervention survey and 2169 in the post-intervention survey. The prevalence of anaemia decreased significantly from 37% [95% CI 34.7-39.3] to 0.5% [95% CI 0.2-0.7] after the intervention (p<0.001); slightly more in the intervention (from 43.9% to 0.8%) than in the control (30.8% to 0.17%) group (p=0.038). Fever and reported fever decreased significantly and the mean body weight of the children increased significantly over the study period in both control and intervention groups. CONCLUSION: The decrease in anaemia was significantly associated with the intervention, whereas the fever and body weight trends might be explained by other malaria control activities or seasonal/climate effects in the area. The community intervention was shown to be feasible in the study context.

Clinical diagnosis of malaria and the risk of chloroquine self-medication in rural health centres in Burkina Faso.

OBJECTIVE: To assess the quality of healthcare workers' performance with regard to malaria diagnosis and treatment and to assess patients' self-medication with chloroquine (CQ) before and after presentation at a health centre. METHODS: In the rainy season 2004, in five rural dispensaries in Burkina Faso, we observed 1101 general outpatient consultations and re-examined all these patients. CQ whole blood concentrations of confirmed malaria cases were measured before and after treatment. RESULTS: The clinical diagnosis based on fever and/or a history of fever had a sensitivity of 75% and a specificity of 41% when compared to confirmed malaria (defined as an axillary temperature of >/=37.5 degrees C and/or a history of fever and parasites of any density in the blood smear). Few febrile children under 5 years of age were assessed for other diseases than malaria such as pneumonia. No antimalarial was prescribed for 1.3% of patients with the clinical diagnosis malaria and for 24% of confirmed cases, while 2% received an antimalarial drug prescription without the corresponding clinical diagnosis. CQ was overdosed in 22% of the prescriptions. Before and 2 weeks after consultation, 25% and 46% respectively of the patients with confirmed malaria had potentially toxic CQ concentrations. CONCLUSION: As long as artemisinin-based combination therapy remains unavailable or unaffordable for most people in rural areas of Burkina Faso, self-medication with and prescription of CQ are likely to continue despite increasing resistance. Apart from considering more pragmatic first-line regimens for malaria treatment such as the combination of sulfadoxine-pyrimethamine with amodiaquine, more and better training on careful clinical management of febrile children including an appropriate consideration of other illnesses than malaria should be made available in the frame of the IMCI initiative in sub-Saharan Africa.

Immunohematological reference values for healthy adults in Burkina Faso.

Reference ranges for peripheral blood lymphocyte subsets were generated for 186 healthy adults in Burkina Faso using single-platform flow cytometry. CD4(+) T-cell counts ranged from 631 to 1,696 cells microl(-1); they were lower in males (n = 97) than in females (n = 89), whereas natural killer cell counts were higher.

A simple method to estimate tobacco-related lung cancer deaths based on smoking prevalence data.

OBJECTIVE: Tobacco is the major cause of cancer and a relevant risk factor for several other chronic diseases. Due to the epidemiological transition in developing countries with overall increasing life expectancy there is an increasing relevance of chronic diseases to the total burden of diseases. Furthermore, there are indications for a rise in the consumption of tobacco products in developing countries. Since in Africa data on smoking prevalence are scarce and cancer diagnosis is often imprecise or missing, it is difficult to estimate the current and future number of cancer cases attributable to tobacco smoking. In this paper, we present an approach to estimate the effects of smoking on lung cancer in selected developing countries in Africa. METHODS: We combined data on smoking prevalence from different African countries with estimates on age-specific lung cancer rates in smokers and non-smokers from industrialized countries and data on age and sex distribution in African countries. We perform a sensitivity analysis to evaluate the effect of the assumptions necessary for the procedure. RESULTS: If the smoking prevalence in African countries will remain on the current level, we estimate age-specific lung cancer rates lower than those in Germany. Despite the relatively small proportion of adults aged 50 and more which is the age when most cancer cases occur, there is an appreciable number of deaths from lung cancer that could be prevented when smoking prevalence could be reduced. Depending on assumptions we estimate up about 50,000 lung cancer deaths per year in Africa, most of which could be prevented. CONCLUSIONS: Efforts for smoking prevalence reduction are much more needed in the developing world. Better and more comprehensive data on smoking are needed for more precise estimates.

Comparison of different PCR protocols for the detection and diagnosis of Plasmodium falciparum.

An assessment of differing PCR protocols for the diagnosis of Plasmodium falciparum infection was performed on samples from an area of holoendemic malaria transmission in western Burkina Faso. The PCR protocols had generally high sensitivities (>92%) and specificities (>69%), but the negative predictive values (NPV) were moderate and differed widely among the PCR protocols tested. These PCR protocols that amplified either the P. falciparum pfcrt gene or the small subunit ribosomal DNA were the most reliable diagnostic tools. However, the moderate NPV imply that more than one PCR protocol should be used for diagnosis in holoendemic areas.

Effect of zinc supplementation on growth in West African children: a randomized double-blind placebo-controlled trial in rural Burkina Faso.

OBJECTIVE: To analyse the effects of zinc supplementation on growth parameters in a representative sample of young children in rural Burkina Faso. Design Randomized, double-blind, placebo-controlled efficacy trial. Setting Eighteen villages in rural northwestern Burkina Faso. Subjects In all, 709 children aged 6-31 months were enrolled; 685 completed the trial. Intervention Supplementation with zinc (12.5 mg zinc sulphate) or placebo daily for 6 days a week for 6 months. Outcomes Weight, length/height, mid-arm circumference, and serum zinc. RESULTS: In a representative subsample of study children, 72% were zinc-deficient at baseline. After supplementation, serum zinc increased in zinc-supplemented but not in control children of the subsample. No significant differences between groups were observed during follow-up regarding length/height, weight, mid-arm circumference, and z scores for height-for-age, weight-for-age, and weight-for-height. CONCLUSIONS: We conclude that zinc supplementation does not have an effect of public health importance on growth in West African populations of young children with a high prevalence of malnutrition. Multinutrient interventions are likely to be more effective.

Mortality patterns, 1993-98, in a rural area of Burkina Faso, West Africa, based on the Nouna demographic surveillance system.

The Nouna demographic surveillance system database was analysed for the period 1993-98. Basic demographic parameters, age-specific and age-standardized mortality rates were calculated and a seasonal variation in mortality was analysed. Poisson regression was used to model the calculated mortality rates and to investigate the seasonal mortality pattern. Both the population distribution by age and the mortality rates reflect a typical pattern of population structures and total mortality in rural Africa as a whole: high childhood mortality and a young population (about 60% are up to age 25; about 10% above age 64). We identified a significant seasonal pattern with highest mortality rates in February. Demographic surveillance systems in Africa provide a viable method for the collection of reliable data on vital events in rural Africa and should therefore be established and supported.

Effect of zinc supplementation on malaria and other causes of morbidity in west African children: randomised double blind placebo controlled trial.

OBJECTIVE: To study the effects of zinc supplementation on malaria and other causes of morbidity in young children living in an area holoendemic for malaria in west Africa. DESIGN: Randomised, double blind, placebo controlled efficacy trial. SETTING: 18 villages in rural northwestern Burkina Faso. PARTICIPANTS: 709 children were enrolled; 685 completed the trial. INTERVENTION: Supplementation with zinc (12.5 mg zinc sulphate) or placebo daily for six days a week for six months. MAIN OUTCOME MEASURES: The primary outcome was the incidence of symptomatic falciparum malaria. Secondary outcomes were the severity of malaria episodes, prevalence of malaria parasite, mean parasite densities, mean packed cell volume, prevalence of other morbidity, and all cause mortality. RESULTS: The mean number of malaria episodes per child (defined as a temperature >/=37.5 degrees C with >/=5000 parasites/microliter) was 1.7, 99.7% due to infection with Plasmodium falciparum. No difference was found between the zinc and placebo groups in the incidence of falciparum malaria (relative risk 0.98, 95% confidence interval 0.86 to 1.11), mean temperature, and mean parasite densities during malaria episodes, nor in malaria parasite rates, mean parasite densities, and mean packed cell volume during cross sectional surveys. Zinc supplementation was significantly associated with a reduced prevalence of diarrhoea (0.87, 0.79 to 0.95). All cause mortality was non-significantly lower in children given zinc compared with those given placebo (5 v 12, P=0.1). CONCLUSIONS: Zinc supplementation has no effect on morbidity from falciparum malaria in children in rural west Africa, but it does reduce morbidity associated with diarrhoea.

[Evaluation of a direct serologic card agglutination test for the diagnosis of camel trypanosomiasis caused by Trypanosoma evansi]. / Evaluation d'un test sérologique d'agglutination directe sur carte dans le diagnostic de la trypanosomose caméline à Trypanosoma evansi.

The results of a novel direct serological card agglutination test for the diagnosis of camel trypanosomosis due to Trypanosoma evansi (CATT/T. evansi) were compared with those obtained by direct detection of parasites in a study using 1,093 sera from camels raised in northern Mali. A good correlation was revealed between the percentage of positive results obtained by CATT and the presence of trypanosomes (89%), as well as a good coincidence between the percentage of positive results obtained by CATT and low haematocrit values (packed cell volume). CATT revealed a global serological prevalence of 30.6%, whereas trypanosomes were found in only 5.85% of the corresponding animals. CATT/T. evansi is a quick and easy-to-read test, which merits further evaluation in camel-rearing countries.

Evaluation of mono- and polyclonal antibody-based antigen detection immunoassays for diagnosis of Trypanosoma evansi infection in the dromedary camel.

Two enzyme-linked immunosorbent assays (ELISA), one based on a mouse anti-Trypanosoma brucei group-specific monoclonal antibody and the other on rabbit anti-Trypanosoma evansi polyclonal antibodies, have been evaluated for their ability to detect circulating trypanosome antigens in camel sera as a means for the diagnosis of T. evansi infections. All 91 sera from a negative control camel herd from Kenya gave negative antigen-ELISA results in the monoclonal antibody-based ELISA and only 2 of them (2.2%) gave false positive results in the polyclonal antibody-based ELISA. In subsequent analyses of sera from infected camels (as determined by mouse inoculation), the monoclonal antibody-based ELISA detected antigens in 90 (83.3%) out of the 108 sera tested. This percentage was lower for the polyclonal antibody-based ELISA which was able to detect antigens in 67 (60.9%) out of the 110 sera tested. The two tests detected probably different antigens and when the results were combined, 99 out of 107 (92.5%) sera were shown to be ELISA positive. In a survey involving 316 camels from the Gao and Nara areas, in Mali, a high proportion of animals tested were antigen positive (43.5 and 42.9%, respectively for the mono- and polyclonal antibody-based ELISA) compared to only 22 (7.0%) diagnosed by the parasite detection techniques. Thus, these immunoassays were at least six times more sensitive than the haematocrit centrifugation technique. As a large proportion of cases may be antigen positive but parasite negative, these two of "surra" immunoassays should be used in routine diagnosis in addition to the parasite detection techniques in the dromedary camel.

Chromosomes of six species of Onchocerca (Nematoda: Filarioidea).

Examination of ovaries and testes from adult Onchocerca ochengi, O. gutturosa, O. armillata and O. lienalis revealed five pairs of chromosomes, but in contrast O. volvulus and O. gibsoni had only four pairs.

Cloning and characterization of a species-specific repetitive DNA sequence from Onchocerca armillata.

Two clones, pOA1 and pOA5, have been isolated from a genomic DNA library prepared from pools of Onchocerca armillata adults in the plasmid vector pUC12. In dot-blot hybridisations, these two clones do not cross-hybridise significantly with total genomic DNA from O. volvulus, O. gutturosa, O. ochengi, O. gibsoni, O. lienalis, bovine, human, Culicoides nubeculosus, Simulium species or Brugia pahangi, but do hybridise with as little as 100 pg of DNA from two separate geographic isolates of O. armillata. The sequence of pOA1 and pOA5 has been determined and found to contain a repetitive DNA sequence 147 bp in length. These clones can be used as specific and sensitive DNA probes for the identification of O. armillata capable of identifying a single L3 larva.

[Edesonfilaria cynocephali n. sp., a filarial parasite of Dermoptera in Malaysia]. / Edesonfilaria cynocephali n. sp., filaire parasite de Dermoptère en Malaisie.

Edesonfilaria cynocephali n. sp., a parasite of Cynocephalus variegatus taylori (Thomas) in Malaysia, is described. Makifilaria Krishnasamy et coll., 1981 is placed in synonymy with Edesonfilaria and the new combination E. inderi (Krishnasamy et coll., 1981) n. comb. is proposed. Edesonfilaria and the closely related genus Macacanema constitute a small evolutionary line of Filariae with a hyperspecialized oesophagus (the glandular portion lacks lumen); the line is restricted to the Indo-Malaysian region and occurs in arboreal Dermopterans, Chiropterans and Primates.