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Biomedical subjects

O Gaye

Publications and source records attributed to O Gaye.

68 records · Page 4Linked to original sources

[Factors of humoral and cellular immunity in onchocercosis (results of studies conducted in Senegal)].

In the course of Onchocerca volvulus infection in subjects with from light to heavy microfilarial count in skin snips occurred important alterations concerning both humoral and cell-mediated immunity. Serum examination for immunoglobulins showed high synthesis of IgG, IgM and IgE. The level of IgM was found to be correlated to the intensity of the infection, an important reduction of T4 cells was observed and is associated with hyporeactivity to in vitro stimulation to phytohemagglutinin A (PHA). The considerable loss seen in T4 cells function could lead to a reducing of cell-mediated immune mechanisms and humoral response needed in the acquisition of resistance.

Adult↗

[T-cell subpopulations during acute attacks of pernicious malaria].

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.

Acute Disease↗

[Intestinal parasitosis in the inhabitants of a suburban zone in which the groundwater is polluted by nitrates of fecal origin (Yeumbeul, Senegal)].

This study was carried out in 1997 to 1998, to determine the prevalence of intestinal parasite infestations due to groundwater pollution at Yeumbeul, Senegal, and to follow the progression of parasite infestations following anti-parasite treatment. The study included 705 people living in a suburban zone in which the water table was polluted with nitrates of fecal origin. These individuals consumed either well water or water from springs. The overall prevalence of parasite infestation was 42.26%, but varied significantly with age (p < 0.001). Individuals who consumed well water were more frequently infested than those who consumed spring water, but the difference was not significant (p > 0.3). Giardia and Entamoeba coli were the most frequently isolated parasites, with Giardia predominating in the 0 to 9 year age-group. There was no significant correlation between the prevalence of the various parasites and indicators of water pollution (R2 = 0.0566 for nitrates and 0.1086 for fecal coliform bacteria). Similarly, no correlation was found with water pollution factors such as the depth of the water table (R2 = 0.027) and the distance between the wells and the latrines (R2 = 0.00007). Following specific treatment, the prevalence of parasite infestation fell to 30.81%. This indicates the limitations of drug treatment, which is always used alone to combat intestinal parasites, in the face of possible reinfestation.

Adolescent↗

[Malaria in the central health district of Dakar (Senegal). Entomological, parasitological and clinical data].

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

Adolescent↗

[Malaria morbidity in the urban environment. Study of 353 fever attacks].

The authors make a study of malaria morbidity in Dakar during October and November 1988 in Dakar where malaria is endemic but with a pick in pathophoresis during the rainy season. Out of 353 surveyed cases of malaria, 110 were carriers of Plasmodium falciparum, i.e., 31%. Mean parasitic density was 7462 red cells/mm3 and more than an half of patients got an higher density. Parasitic density was higher in children (0-14 years old) than in adults, but with no significant indication. Malaria fever represents 20.4% of all types of fever observed and was the first cause to consult during the rainy season. Whatever threshold of parasitic density selected parasitologic criterion may be in order to identify a malaria fever, percentage of diagnosis misinterpretation linked up to clinical examination was always higher than 30%.

Adolescent↗

[Malaria morbidity in rural and urban areas in Senegal].

During September and November 1987, the authors surveyed the incidence of malaria fever in populations of a rural zone in Casamance and in adults as outpatients in an urban area. In these regions, the malaria is endemic with a recrudescence during the rainy season from July to October. In rural zone, 169 persons were examined. The malaria fevers represented 7.1% of the consultations and 23.3% of fevers. Differences were significantly observed between the parasitic densities of febrile and afebrile patients.

Adolescent↗

[Malaria morbidity and therapeutic efficacy of antimalarials. Study conducted in the Dakar region].

During November and December 1992, the authors surveyed the malaria morbidity and the drugs efficiency in an urban area of Dakar region. Malaria represented 13.68% of the fevers in Dakar district and 12.4% in Pikine. The mean parasitic density was evaluated at 5000/mm3. Good efficiency of antimalarial drugs were noted but chloroquine-resistance is present with 24% of prevalence.

Adolescent↗

[Seroprevalence of toxoplasmosis in Dakar (Senegal) in 1993: study of women in their reproductive years].

To establish the seroprevalence of toxoplasmosis in women during their reproductive years, we examined 720 women, of whom 404 were pregnant and 306 were not, all residing in and around Dakar. Of the serum tested by indirect immunofluorescence, 40.3% contained antibodies recognizing toxoplasmosis. The seroprevalence did not vary significantly with the age of the women, the number of previous pregnancies, the place of residence or the length of residence in Dakar. It was higher in the pregnant women (44.4%) than in the nonpregnant women (37.2%), but this difference is not statistically different. The titers of antibodies were generally weak, varying between 10 and 320 IU/ml of serum. Also, IgM specific antibodies were absent. These results indicate that the seroconversion had occurred previously, probably at a young age. We observed seroprevalences higher than those obtained by authors using comparable techniques twenty years ago. This indicates an increase of the transmission of toxoplasmosis in the population. Few women during their reproductive years had antibodies against toxoplasmosis. Thus, they are at risk of developing a primary infection during a pregnancy. This undergoes the necessity of promoting measures to prevent toxoplasmosis infection in pregnant women.

Adolescent↗

[Drought and malaria decrease in the Niayes area of Senegal].

The Niayes is geographically characterized by an alternating succession of sand dunes and wet depressions, 20 km wide, which are behind the offshore bars from Saint-Louis to Dakar. Since 1970, the area has been affected by drought. The rainfall which was around 700 mm per year before 1960 has fallen below 500 mm during the last 30 years. In 1991 it was only 350 mm and in 1992, 260 mm. The vegetation has become impoverished in the depressions which are now more and more cultivated for vegetables. Entomological, parasitological and clinical studies on malaria were carried out in 1991 and 1992 in three villages and the results were compared with data gathered from 1967 to 1968 with comparable methods. The main points concerning the evolution of malaria are listed as follows. An. funestus, which was previously the predominant malaria vector, has almost disappeared. An. gambiae has regressed ahead of its sibling species An. arabiensis, a less competent vector. These changes in vector populations have led to lower malaria transmission and consequently a decrease of the endemicity. The children parasitic index, which was between 40 to 80% according to the localities in 1967, fell to 10% or less in 1991 and 1992. Finally, the incidence of clinical cases, calculated on a cohort of 100 children was only 4% in 1992, which is very low for an African endemic country. We conclude that drought and human activities have modified the environment such that malaria endemicity has seriously decreased. However, the risk of epidemic remains with the eventual occurrence of heavy rains. Therefore a surveillance of the area is needed to prevent a future epidemic.

Animals↗

[Care charges and direct costs related to hospitalization of Senegalese children with cerebral malaria. Study of 76 cases in the Albert-Royer Hospital in Dakar in 1991-1992].

To optimize the funds devoted to health care, and to objectively assess the tools used in monitoring patients with cerebral malaria, we determined two parameters, care charges and direct costs due to hospitalization. During this longitudinal study conducted at the Albert Royer Pediatric Hospital in Dakar from October 15, 1991 to October 15, 1992 with 76 cases, malaria represented 5.2% of the febrile cases and 3.4% of the hospitalized cases. The lethality rate was 3.4%. Clinical features were not correlated with care charges and thus were not good indicators of worker's labor. The average cost of a cerebral malaria hospitalization was estimated at 35,710 F CFA (In October 1992, 1 F CFA = 0.02 FF). This cost is very high depending the limited resources of the region. Rapid and proper treatment of malaria cases may lead to a significant reduction of costs.

Adolescent↗

[Prediction and prevention of malaria epidemics in the valley of the Senegal River].

The Sahel region has been suffering from severe drought for the last thirty years, with large deficits and a high degree of variability in the amount of annual rainfall. Agricultural production in the Sahelian zone of the Senegal River valley depends on the flooding of the river. The management of this flooding affects malaria transmission. The area is prone to malaria epidemics because the immunity level of the population is low. We studied epidemiological, meteorological and river level data to identify epidemic risk factors. We propose an epidemiological and managerial system for the early detection of risks and early intervention. This system is based mainly on the water level of the Senegal River and the early detection of unusual increases in the number of cases.

Disasters↗