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The aims of this study were to determine the place of malaria at the Infectious Disease Clinic in Dakar, Senegal, to identify diseases associated with malaria, and to assess malaria mortality with or without co-morbidity. The files of all patients hospitalized from 2001 to 2003 in whom at least one test for malaria (thick films/spears) was performed to detect malaria parasites were reviewed. Malaria was diagnosed in patients presenting fever and positive thick films demonstrating asexual blood stages of Plasmodium. Data were collected from hospital charts. A total of 416 patients presented malaria (prevalence rate, 25.9%). The male-to-female sex ratio was 1:7 and mean age was 33 +/- 18 years. Of the 416 patients diagnosed with malaria, 273 (65.6%) presented severe forms. The overall mortality rate of malaria with or without co-morbidity was 25.7% (107/416). There was not a statistically significant difference between mortality due to isolated malaria and malaria associated with tuberculosis (23.4% versus 18.5%) (p = 0.7) or tetanus (23.4% versus 17.6%) (p = 0.34). Conversely mortality of malaria in HIV-positive patients was higher (58% versus 19%) (p = 10(-6)). Thus, malaria is of major concern in our department.

Artesunate is a highly effective antimalarial and there is some evidence that it is also active against schistosome infections. We therefore investigated whether treatment with artesunate of acute malaria in Senegalese children had an impact on their level of infection with Schistosoma haematobium. Twenty-seven children who were entered into a clinical trial of antimalaria treatment were excreting S. haematobium eggs in their urine on the day of treatment. Fifteen children received a combination of a single dose of sulfadoxine/pyrimethamine together with three daily doses of artesunate (4 mg/kg); the remaining 12 children received three daily doses of amodiaquine and artesunate. The overall cure rate and reduction in the mean number of excreted eggs at 28 days post treatment were 92.6% and 94.5%, respectively. Our findings indicate that artesunate, in addition to being a very effective treatment for uncomplicated malaria, can also sharply reduce the S. haematobium loads harboured by pre-school African children.

We previously investigated malaria in the southern health district of the city of Dakar, which includes the oldest neighborhoods. In this study, we investigated malaria in the central health district, corresponding to the central area of the conurbation. The study was carried out at 12 sites, from March 1996 to February 1997. The sites were selected such that the entire district was covered and included 2 sites in the shanty town and three in an old village that has been absorbed into the city. We carried out prospective monthly entomological analyses with a view to identifying the vectors and the mode of transmission of malaria. We also carried out clinical and parasitological follow up to determine the incidence of parasitemia and of bouts of malaria. Insects were collected overnight from humans and the insects remaining the next morning in 10 bedrooms in the health district were collected. For clinical and parasitological follow up, families were visited at home once per week and their clinical state was assessed. Blood smears were taken to facilitate the detection of bouts of malaria. Body temperature was measured and we checked for the presence of organisms in the blood systematically during the last weekly visit of each month. For a total of 308 collections at night from human volunteers and 1,395 bedroom collections of residual fauna, we obtained 12,879 Culicidae females, 199 (1.5%) of which were anopheles mosquitoes, with Culex quinquefasciatus accounting for 98% of the remaining mosquitoes. As in the southern district, A. arabiensis was the only species of the A. gambiae complex collected. Anopheles mosquitoes accounted for only 0.3 bites per man per night and 0.07 females per room. They were therefore poorly represented in this district and were not detected at all at five sites. They were found in large numbers only during the rainy season, especially in September, when they accounted for 2.25 bites per man per night and 0.3 females per room at 3 sites in an undeveloped zone in which 81.4% of all the anopheles mosquitoes were collected. The parturition frequency of the biting females was 32.6% and that of the females collected in houses was 50.0%. None of the A. arabiensis females dissected (98.5% of those collected) carried Plasmodium sporozoites. The clinical and parasitological follow up concerned 2,583 individuals, aged from 1 month to 80 years, from 285 families resident in Dakar who volunteered for the study; 41.9% of these individuals were less than 15 years old and 92.2% had been living in Dakar for more than 2 years. Thick and thin blood smears taken monthly showed the frequency of the parasite to be 1.0% and that of gametocytes to be 0.1%. P. falciparum was the only parasite detected in the subjects. Plasmodium infections were observed in all age groups, with a frequency of 0.4% (adults over the age of 20 years) to 1.6% (children under two years of age). Parasitized subjects were detected in every month of the study, with a frequency of 0.4% (in January) to 1.9% (in December). The largest number of cases detected in a three-month period (38.8% of all cases) was that for October to December, the three-month period immediately after the rainy season (July to September). Parasite frequency, which was no higher than 1. 2% at 10 sites, was clearly higher at two sites in the shanty town (3.8 and 6.8%), mostly inhabited by immigrants from rural areas. At the end of the study year, satisfactory weekly follow up was considered to have been achieved for 1,067 of the participants. The annual incidence of parasitemia in this cohort was 5.1% and that of malaria was 2.4%. Incidence did not vary significantly with age and was between 1.8% and 7.6% for parasitemia and between 0.8% and 3.5% for malaria. However, significant differences in incidence were observed between areas. Incidence was higher at the two sites in the shanty town, with rates of 12.1% and 36.5% for parasitemia and 6.1% and 15.9% for malaria. (ABSTRACT TR

A survey of endemic malaria in Dakar was carried out in the southern sanitary district covering the city centre and neighbouring areas. The survey was scheduled from June 1994 to May 1995 in 12 sites distant from each other by 1000 to 1500 meters. Clinical and parasitological data were collected during weekly medical follow-ups at the patients' home with the systematic research of Plasmodium once a month. The study included 2,337 persons aged between 1 month and 88 years and belonging to 284 volunteer resident families. Through monthly parasitological examinations, a parasite rate (P.R.) of 0.3% and a gametocyte rate (G.R.) of 0.005% were recorded. Only Plasmodium falciparum was observed. The P.R. varied according to age: from 0.1% in the children under 2 years to 0.7% in the young adults (15-20 years) who appeared significantly more affected than the other age groups, including that of children from 2 to 9 years, of whom only 0.3% were infected by the parasite. The P.R. varied also according to the site surveyed: from 0% in the city centre to 1.3% at the periphery of the sanitary district and according to the time of year, reaching its height of 0.8%, between October and December, that is just after the rainy season. At the end of the year of survey, 929 among those surveyed were considered to have been satisfactorily followed. Their annual incidence rate was 2.4% for the parasitemia and of 1.5% for the malaria attacks. None of the participants aged under 2 years had the parasite. Among the others, the annual incidence rate varied according to the age--although not significantly--passing from 1.1% to 5.3% for parasitemia and from 0.4% to 3.0% for malaria attacks. Theses rates did not differ significantly according to site; the cases registered varied between 1% and 8% for parasitemia and 1% and 5.8% for malaria attacks. Only 10.6% of febrile subjects suffered from malaria attacks, but this rate seemed to go up between October to December, rising to 26.6% which corresponds to 1 case of malaria attacks for 4 cases of hyperthermia in that period. Weak density of Anopheline population and satisfactory medical surveillance explain the recorded results.

In order to assess the parasitic risks related to Ferlo's valley water launching, a study has been carried out from september 15 to october 10, 1996 in 12 villages. Four villages surrounding the Guiers lake, four lower within lower Ferlo already water launched 7 years ago, and four villages within upper Ferlo not water launched. Malaria strikes at hypoendemic level in the villages surrounding the Guiers lake (p.i = 6.2%) and at mesoendemic level in the area stretching along lower (P.I = 37.6%) and upper Ferlo (P.I = 34.3%) The prevalence rate of urinary bilharziosis is 0.002% in the first area, 1.3% in the second one and 14.5% in the third area. In these areas, intestinal parasitosis were prevailing respectively at rates of 38.2%, 36.4% and 22.2%. Although, there is no reason to fear immediately a worsening of the epidemiological situation due to Ferlo's valley revitalisation project, nevertheless, appropriate steps should be taken right now aiming at tacking the extension of conditions related to hydric medium.

To determine risk factors for fatal malaria in Senegalese children, a 3-year case-control study was carried out between October 1992 and November 1995 at the Albert Royer Hospital in Dakar. The case group included 52 children who died from documented malaria in the hospital. The matched control group consisted of children who responded favorably to hospital treatment. Exposure to risk was measured with regard to age, nutritional status, educational level of parents, self-medication prior to hospitalization, socioeconomic level, degree of fever, and blood parasite levels. Cases and controls were compared using statistical tests for matched groups. Age lower than 5 years, poor educational level of parents, delay of treatment more than 24 hours, nutritional status, and blood parasite levels greater than 5% were associated with a significantly higher risk of fatal outcome. Conversely, low socio-economic level, recent self-medication, and fever over 41 degrees C were not associated with higher fatality. These findings emphasize the need for more information campaigns to encourage people to seek institutionalized care when fever appears. Our results also suggest that prophylactic treatment may be advisable in children under 5 years of age and in some high risk groups.

The authors carried out an epidemiological survey from october 12 to december 4, 1995, at Medina's mother and Child care centre (MCC) in Dakar in order to assess chemoprophylaxis among pregnant women in Dakar. The midwife/pregnant women ratio is 0.08 The mentioned diagnosis criteria were relevant regards to the references established for most of the answers because since the latter base malaria diagnosis on the following signs: fever, chills, headaches and vomiting. 64.6% of them assume compliance to antimalarial chemoporphylaxis. Education level seems to be the main determining factor in this trend. Although chloroquine is the most widely used drug, nevertheless 11.9% of pregnant women assuming compliance use it at inappropriate posology. Besides, pyrimethamine is used by 12.3% of them. 34% of pregnant women do show chloroquine in urine. The plasmodial index is 1.4%. Only 8.1% of these women are supplied by health centres where shortages are noted.

Evaluating knowledge about the diagnosis and treatment of malaria is a prerequisite for both understanding the development of chemoresistance and improving ongoing programs of chemotherapy and chemoprophylaxis. To gain such knowledge we distributed a questionnaire to 900 household heads in twelve villages in the M'Backe district of Senegal. Awareness of the main symptoms of malaria was satisfactory in comparison with previous references. Public health care facilities such as dispensaries were cited as the first resort for treatment by 72.6% of respondents. Chloroquine was mentioned as the first line antimalarial by 23% of respondents who practiced self-medication. Improper dosages were stated by 60% of the respondents. A total of 52.3% of respondents practiced chemoprophylaxis mainly using chloroquine. In 65.8% of cases antimalarial drugs were obtained from public health care units but drugs were purchased on the market in 15.7% of cases. These findings indicate the threefold Bamako initiative should be reinforced and that a campaign should be undertaken to educate people living in rural areas about malaria.

The practices of health care workers and the population with regard to diagnosis of malaria and use of antimalarial drugs were studied in the city of Dakar from September 1991 to March 1992. Study included 847 heads of family, 191 treatment prescribers including 77 physicians, 53 nurses and 61 midwives, and 60 pharmacists. Three separate questionnaires were used: one for the population, one for physicians and paramedical staff, and one for pharmacists. The data collected showed that the 4 main symptoms used by both health care workers and the general population for diagnosis of malaria were fever, chills, vomiting, and headache. Treatment was administered upon suspicion of infection by 72% of treatment prescribers. Chloroquine was the drug most widely used by prescribers and for self-treatment of malaria. Prophylactic drug treatment was practised by all groups studied except treatment prescribers but was unappropriate for the target groups. Chloroquine is the drug most widely used to protect against the disease. Pharmacists have adequate supplies but distribution is poor. Despite promising results in the fight against malaria, further effort is needed to train health care workers and provide information to the population.

The distribution of T-cell subsets in acute and cerebral malaria have been studied using two monoclonal antibodies. In the course of the disease both in acute and cerebral malaria in persons living in senegalese hypoendemic area occurred important alterations of circulating T-cell subsets. A significant loss of OKT4 positive cells is observed; OKT8 positive lymphocytes are also affected but to a lesser extent. The reversal of the OKT4/OKT8 ratio found in this disease is associated with decrease responsiveness of lymphocytes to PHA. The considerable loss seen in OKT4 cells fonction could be of great importance in reducing cell mediated immune mechanisms and humoral response needed to eradicate the malaria parasite.