Le paludisme reste encore la maladie la plus meurtriere du monde et particulierement dans les pays tropicaux. Dans le but de preciser les modalites evolutives des formes graves de paludisme, nous avons mene une etude prospective durant la periode de haute transmission du paludisme (aout a novembre) des annees 1993 et 1994. L'etude a concerne 719 enfants de 6 mois a 15 ans presentant a l'admission dans le service de Pediatrie de l'Hopital Central de Ouagadougou, au moins un des signes de gravite du paludisme repondant aux criteres de l'OMS. Le schema therapeutique propose par l'OMS sur les formes graves de paludisme a ete applique a tous les patients. La letalite specifique a ete determinee pour chaque forme clinique. Nous avons note 530 guerisons (74,5 %) et 92 deces (12,9 %). La duree moyenne de sejour hospitalier etait de 3,8 jours et 88,1 % des deces ont ete observes avant le deuxieme jour d'hospitalisation. Les formes les plus letales ont ete celles ou l'on observait une hypoglycemie, (letalite de 52,1 %), une detresse respiratoire (letalite de 34,4 %), et une prostration (letalite de 33,3 %). Nous preconisons le traitement presomptif des acces febriles par la chloroquine pour limiter l'evolution des acces palustres simples vers des formes graves.

Malaria remains the leading cause of mortality throughout the world and imposes an especially heavy burden on tropical countries. The outcome of severe malaria was evaluated prospectively at the pediatric department of the Central Ouagadougou Hospital during the periods of intense Plasmodium transmission (August to November) in 1993 and 1994. The study identified 719 patients aged 6 months to 15 years with at least one of the WHO criteria for severe and complicated malaria. All patients were treated as recommended by the WHO. Patients were divided into subgroups based on clinical symptoms, and the case-fatality rate was determined for each subgroup. Five hundred thirty patients (74.5%) achieved a full recovery, and 92 (12.9%) died. Mean hospital stay duration was 3.8 days, and 88.1% of deaths occurred before the second hospital day. Case-fatality rates were highest in patients with hypoglycemia (52.1%), respiratory distress (34.4%), or prostration (33.3%). Routine chloroquine therapy in children with fever may reduce the risk of progression of uncomplicated malaria to severe and complicated malaria.

During the period of transmission of malaria, from August to November of 1993 and 1994, we conducted a study to determine the frequency of the clinical forms of severe and complicated malaria. The study involved children, from 6 months through 15 years old, admitted to the pediatric ward of the hospital in Ouagadougou, Burkina Faso. The criteria for inclusion followed the definition of severe malaria stated by the World Health Organization. We carefully noted the symptoms and signs on admission. Of the total of 719 children enrolled in the study, there was a prevalence of children under 5 years old. The most frequent clinical forms were those of coma (377 cases, 52.4%), prostration (268 cases, 37.3%), convulsion (152 cases, 21.4%), anemia (115 cases, 15.9%), and hypoglycemia (55 cases, 10.3%). No renal failure form was observed. We also observed the respiratory distress form (35 cases, 4.9%) and the hemorrhagic form (11 cases, 1.5%). Malaria remains a major cause of childhood morbidity and mortality in the developing world. Early therapeutic management of febrile attacks with chloroquine would reduce the incidence of severe and complicated malaria.

To evaluate whether insecticide‐treated netting (ITN) reduces child mortality in different epidemiological settings, 4 large, randomized, controlled trials were conducted in Africa. Here we report the findings from the trial in Burkina Faso, in an area of hyperendemic and markedly seasonal malaria transmission. The trial involved 158 villages, with a total population of some 90,000, grouped into 16 geographical clusters. Ascertainment of mortality among children aged 6–59 months began in early 1993. In June/July 1994, 8 of the clusters, randomly selected, received permethrin‐treated curtains. Follow‐up of children and ascertainment of mortality continued until May 1996. A 15% reduction in all‐cause mortality among children aged 6–59 months was observed over the 2‐year period following the installation of the curtains (95% c.i. ‐ 4% to 30%). In the first year, post‐intervention mortality was substantially lower in the clusters receiving curtains compared with the control clusters (rate ratio = 0.74; 95% c.i. 0.57, 0.95) but in the second year, there was no difference between mortality in the two groups (rate ratio = 0.99). The overall two‐year impact of the intervention is consistent with the impacts observed in other trials which have demonstrated reductions in child mortality of from 17% to 33%. However, the year‐by‐year analysis raises some concerns about the long‐term effect of ITN. Further follow‐up of this population is warranted.

Plasmodium falciparum parasite rate, parasite density and anti-CS antibodies were assessed in 196 subjects (age > 10 yrs) belonging to three sympatric West African ethnic groups, namely Mossi, Rimaibé and Fulani, all exposed to very high seasonal malaria transmission in the same rural village near Ouagadougou, Burkina Faso. No interethnic differences were noted in the use of antimalaria measures nor in the exposure to malaria vectors. However, interethnic differences were found in each of the three malariological indices. The Fulani appeared markedly less parasitized and more responsive to the CS-antigen than the Mossi and the Rimaibé who had very similar indices, except in the case of parasite density. These findings suggest a higher resistance to malaria of the Fulani ethnic group, possibly involving human genetic factors and/or the influence of extrinsic variables (e.g., socio-cultural) among which diet differences should be considered.

Plasmodium falciparum susceptibility to chloroquine in vivo and to chloroquine, mefloquine, quinine, amodiaquine and sulfadoxine/pyrimethamine in vitro was investigated in children living in Goundry village, Oubritenga Province (Burkina Faso) in November 1992. An extended WHO in vivo field test was used, with follow-up on days 2, 4, 7, 14, 21 and 28 after treatment with 25 mg chloroquine per kg body weight given over 3 days, in children from 2 to 8 years old with P. falciparum monospecific infection, asexual parasitaemia > 800 parasites/microliter of blood and negative Bergqvist urine tests. At the same time, the in vitro response was assessed using WHO standard test kits. Out of the 71 in vivo responses examined, 50 (70.4%) were classified as resistant to chloroquine at RI (43.6%) or RII (26.8%) levels. There were no RIII responses. Out of the 43 isolates tested for chloroquine susceptibility in vitro, 32 (74.4%) were resistant to the drug with mean EC50 and EC99 values of 1.41 mumol and 10.96 mumol/l of blood, respectively. Resistance to sulfadoxine/pyrimethamine in vitro was observed in one out of 19 tested cases, with mean EC50 and EC99 values of 0.00002 mumol and 35.05 mumol/l of blood, respectively. All isolates were inhibited by mefloquine at 12.8 mumol/l of blood, quinine at 51.2 mumol/l of blood and amodiaquine at 0.4 mumol/l of blood, indicating full sensitivity to these 3 drugs. The present study demonstrates the high prevalence of chloroquine-resistant strains of P. falciparum in the study area of Burkina Faso and indicates that isolates resistant to sulfadoxine/pyrimethamine may also be present.

To understand the evolution of drug-resistant forms of malaria in time and in space, we carried out an analysis of the results of a series of passive and active surveys conducted in Burkina Faso between 1982 and 1991. A total of 607 tests for resistance to chloroquine and mefloquine were carried out in vitro and 3,679 tests for resistance to chloroquine, quinine, and sulfadoxine-pyrimethamine were performed in vivo. The surveys principally involved the two main cities of Burkina Faso, Ouagadougou and Bobo-Dioulasso. However, another 10 locations representing the three different zones of malaria transmission were also studied. The first cases of Plasmodium falciparum resistant to chloroquine in vitro were reported in 1983, but it was only in 1988 that in vivo resistance appeared. The first cases of in vitro resistance to mefloquine were noted in 1987 while chloroquine sensitivity at a high rate (15.8%), which decreased during the following years. The prevalence of resistance to chloroquine increased in parallel to this decrease in sensitivity to an overall peak of 41% in vitro and 16% in vivo in 1990. These rates then decreased to 3% and 6%, respectively, in 1991. This pattern of decreasing resistance was broadly similar in all sites except for the town of Bobo-Dioulasso, where the level of resistance remained stable at approximately 14% from 1988 to 1991. Only two cases of resistance in vivo to sulfadoxine-pyrimethamine were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasmodium falciparum susceptibility to halofantrine hydrochloride was investigated in a small village near Ouagadougou, Burkina Faso, where the parasite was known to be chloroquine resistant. An in vivo test was carried out in July 1992 at the beginning of the rainy season in children ranging in age from two to eight years with P. falciparum monospecific infections, asexual parasitemia greater than 800/microliters of blood, and a negative result on a Bergqvist urine test for 4-aminoquinolines. Among 206 children screened, 74 were selected for study. Blood samples were collected on days 0, 2, 4, 7 and 14, and 100 microscopic fields of thick and thin blood smears were examined for parasite density and species identification. Halofantrine hydrochloride was administered under supervision at the standard dose of 24 mg/kg as 8 mg/kg given three times at 6-hr intervals with an observation period of 1 hr after each 8-mg/kg dose. Parasitemias cleared in all 74 cases by day 7, but there was a recurrence of parasitemia in six subjects (8.1%) on day 14. A second course of therapy with halofantrine resulted in prompt clearance of parasitemias in all of these children. The drug was well-tolerated and the hematologic and biochemical indices were not adversely affected by treatment.

Plasmodium falciparum susceptibility to chloroquine in vivo and to chloroquine and mefloquine in vitro was investigated in children living in Ouagadougou area (Burkina Faso) in October 1991. The 7-day WHO in vivo field test was used, with follow-up on days 2, 4, 7 after treatment with 25 mg base of chloroquine per kg body weight given over 3 days, on children aged 2-8 years with monospecific P. falciparum infection (parasite density higher than 800 asexual parasites/microliters of blood), and negative Bergqvist urine tests. At the same time, the in vitro response was assessed using WHO standard test kits. Chloroquine treatment in vivo resulted in parasite clearance in 47 subjects (92.2%) within 7 days (S/RI responses). Parasitaemia did not clear in 4 cases (7.8% of RII responses). There were no RIII responses. The sensitivity study in vitro showed a low degree of chloroquine resistance in 2 out of 12 isolates tested and a mean 50% effective dose (EC50) and EC99 of 0.12 mumol and 1.47 mumol/litre of blood, respectively. All isolates tested were inhibited by mefloquine at 1.6 mumol/litre of blood, indicating full sensitivity. The present study demonstrates that first-line treatment with chloroquine is still satisfactorily effective in the study area of Burkina Faso.

Plasmodium falciparum susceptibility to chloroquine was investigated in 10 areas of Burkina Faso in the rainy seasons in 1990-1991. The 7-days in-vivo test was carried out from August to November on children aged 2-8 years with monospecific P. falciparum infection (asexual parasitaemia > 800 microliters-1 of blood), axillary temperature < 37.5 degrees C, and a negative Bergqvist urine test for 4-aminoquinolines. Among 2190 children screened, 366 were selected. Blood samples were collected on days 0, 2, 4 and 7 by finger-prick, and 100 microscopic fields of thick and thin smears were examined for parasite density and species identification. Chloroquine was given under supervision at the standard dose of 25 mg kg-1 over three days (days 0, 1 and 2) with an observation period of one hour after treatment. Parasitaemia did not clear in 63 cases (17.2%) with a 13.4% RII response and 3.8% RIII response. The results do not seem to indicate a decline in the sensitivity of P. falciparum to chloroquine in Burkina Faso during the past two years.

The impact of duration and intensity of sporozoite challenge on the in vitro cell immune response to synthetic peptides of the circumsporozoite (CS) protein of Plasmodium falciparum was investigated in residents of a malaria endemic area in Burkina Faso (West Africa). Lymphocyte proliferation and interferon-gamma (IFN-gamma) production were used to assess immune recognition of synthetic peptides corresponding to the polymorphic Th2R and Th3R regions, to the conserved CS.T3 sequence and to NANP and degenerate NVDP repeats. Immune responses were measured in adults and children from a village where they received more than 100 sporozoite inoculations per year and in adults living in a town, exposed to a 10-100 times lower challenge. A lifetime intense exposure apparently increased the ability to proliferate in response to most peptides in the rural adults, who all produced antibodies to NANP repeats. Surprisingly, cell cultures from these subjects seldom contained appreciable levels of IFN-gamma. In the urban adults, possibly due to the moderate challenge they are exposed to, significant differences in the proliferative potentials of the peptides could be detected. The highest stimulation indices were obtained with the genetically unrestricted CS.T3 peptide. Remarkably, proliferative responses to Th2R and Th3R appeared to be correlated with the humoral response to the CS protein, indicating a T helper significance of the epitopes.The differing proliferative potential of the polymorphic epitopes in the urban adults suggests that polymorphism might delay the development of immune responsiveness under conditions of sporadic transmission.The children from the highly malarious village displayed the lowest proliferative scores, accompanied by a high prevalence of antibodies to NANP repeats. On the basis of these findings, the hypothesis is proposed that a pure B cell reactivity to NANP repeats could ontogenetically, precede the mounting of a conventional T-B cooperative immune response.

A study of Plasmodium falciparum sensitivity to chloroquine was carried out in 1988 and 1990 in 5 localities, representatives of different climatic areas of Burkina Faso. The 7-day in vivo standard test performed in 1988 showed a total clearance failure of 25%. No significant difference with 1990 data was found, except for an increase of the resistance in the area of Fada N'Gourma, close to the border with Benin, Niger and Togo.

We studied from January to December 1988 the part played by malaria in the etiology of febrile diseases observed in three community clinics of Ouagadougou city (Burkina Faso, West Africa). The diagnosis of malaria attacks was based on the association of a body temperature equal or above 38 degrees C and a parasite density equal or above 10,000 parasitized red blood cells per mm3. We observed that fever attacks were primarily caused by malaria. Among the 5-14 years age group, malaria attacks were responsible for more than 50% of febrile cases and occurred mainly during the rainy season and at the beginning of the dry season (July to October). Ear, nose, throat and lung infections were the other dominant causes of fever attacks and were found during the whole year but especially during the dry season (February, March, September). They were followed by urinary and gastrointestinal infections and other tropical febrile diseases. Clinical diagnosis only of malaria attacks and even more so of fever attacks is poorly reliable.

2 - MATERIEL ET METHODES2.1 - Zones d'etudeDeux zones d'etude ont ete selectionnees :. une zone rurale composee de 3 villages, proches de Ouagadougou, capitale du Burkina Faso. Le premier village, Tanlarghin, de 1965 habitants est situe a 25 km a l'Est de Ouagadougou et le second village, Saaba, avec ses 2029 habitants est situe a 15 km sur la route Ouaga-dougou-Tanlarghin. Un quartier, Moinmin, du troisieme village, Koubri, peuple de 6 145 habitants situe a envi-ron 30 km au Sud de Ouagadougou a ete egalement choisi.. une zone urbaine qui est la ville de Bobo-Dioulasso situeea 365 km au Sud-Ouest sur l'axe bitume Ouagadougou-Abidjan. Cette ville compte 250 000 habitants environ.Le climat est de type soudano-sahelien caracterise parl'alternance d'une saison des pluies (Mai-Octobre) et d'unesaison seche (Novembre-Avril). La duree de la saison despluies ainsi que la moyenne des precipitations annuellesaugmentent considerablement, de la region de Ouagadou-gou a la region de Bobo-Dioulasso.Le paludisme est une endemie dans ces zones avec unerecrudescence pendant la saison des pluies, plus courte aOuagadougou qu'a Bobo-Dioulasso.2.2 - Selection des casLe recrutement des cas a ete fait d'une part massivementpour la ville de Bobo-Dioulasso et de facon active auniveau des 3 villages de la region de Ouagadougou.2.2.1 - Selection activeSeuls les enfants âges de 8 mois a 9 ans ont ete examinesdans les 3 villages au mois de juillet et de septembre 1988.Pour etre retenu dans l'etude les cas devaient satisfaire auxconditions d'etude in vivo et in vitro preconisees parl'O.M.S. (18). In vivo, nous avons utilise l'epreuve pratiquede 7 jours. Chaque sujet retenu a ete traite per os avec la

We studied from January to December 1988 the part played by malaria in the etiology of febrile diseases observed in three community clinics of Ouagadougou city (Burkina Faso, West Africa). The diagnosis of malaria attacks was based on the association of a body temperature equal or above 38-degrees-C and a parasite density equal or above 10,000 parasitized red blood cells per mm3. We observed that fever attacks were primarily caused by malaria. Among the 5-14 years age group, malaria attacks were responsible for more than 50 % of febrile cases and occurred mainly during the rainy season and at the beginning of the dry season (July to October). Ear, nose, throat and lung infections were the other dominant causes of fever attacks and were found during the whole year but especially during the dry season (February, March, September). They were followed by urinary and gastrointestinal infections and other tropical febrile diseases. Clinical diagnosis only of malaria attacks and even more so of fever attacks is poorly reliable.

Within the context of the monitoring of malaria drug resistance in the countries of the OCCGE, a workshop has been organized in order to sum up the surveys carried out by the national teams. For active or passive monitoring mainly the in vivo tests have been used. The native population, mainly school children, was studied. Chloroquine resistance was detected in 1987 in Benin, and in the same year in Togo and Côte d'Ivoire. During 1988 it appeared in Senegal and Burkina Faso, in 1989 in Niger and in 1990 in Mali. Only Mauritania is as yet free of resistance. The main features of this resistance are described. It is above all parasitological and on average its rate is less than 30%.

The efficacy of permethrin impregnated curtains as a malaria control measure was evaluated in a rice field are nearby Ouagadougou (BF). Two groups of children aged 1-5 years matched for age, sex and malaria exposure, were followed through the rainy season of 1987 for illness and febrile episodes. One group of 118 children lived in houses protected with impregnated curtains, the other in houses without curtains. All children were examined for parasitaemia spleen index packed cell volume (PCV) and antisporozoites antibodies at the beginning and the end of the rainy season. During rainy season no difference could be found in the number of clinical episode between the two groups. A reduction in the prevalence of splenomegaly and parasitaemia and an increase in the PCV was observed during the dry season. It is suggested that curtains may have a protective effect during the period of moderate transmission.

The impact of permethrin-impregnated curtains on the incidence of malaria episodes, parasitaemia and splenomegaly was assessed during a 22 month period in 2 groups of children aged 0.5-6 years. One group lived in houses where permethrin-impregnated curtains had been installed, the other group lived in houses without curtains. A significant reduction of incidence of malaria episodes, mean parasite density, parasite prevalence and splenomegaly was consistently observed in the intervention group towards the end of the period of moderate transmission, whereas no clear-cut impact could be demonstrated during the high transmission period. The influence of malaria pressure and community utilization on the protective efficiency of curtains is discussed. Because of their acceptability and the ease of reimpregnation, curtains proved to be a suitable technique for integration into primary health care.

The efficacy of permethrin impregnated curtains as a malaria control measure was evaluated in a rice field area nearby Ouagadougou (BF). Two groups of children aged 1-5 years matched for age, sex and malaria exposure, were followed through the rainy season of 1987 for illness and febrile episodes. One group of 118 children lived in houses protected with impregnated curtains, the other in houses without curtains. All children were examined for parasitaemia spleen index packed cell volume (PCV) and antisporozoites antibodies at the beginning and the end of the rainy season. During rainy season no difference could be found in the number of clinical episode between the two groups. A reduction in the prevalence of splenomegaly and parasitaemia and an increase in the PCV was observed during the dry season.