Physicochemical factors affecting the diversity and abundance of Afrotropical Culicoides species in larval habitats in Senegal.

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are the biological vectors of arboviruses of global importance in animal health. We characterized the physicochemical parameters that determine the density and composition of the main Culicoides species of veterinary interest in larval habitats of the Niayes region of Senegal. For this purpose, we combined larval and substrate sampling in the field in different habitat types with adult emergence and physicochemical analyses in the laboratory. Three major habitat types were identified, conditioning the predominant species of Culicoides and pH and the amount of organic matter were positively correlated with the abundance of larvae and emerging Culicoides, as opposed to salinity. The diversity of emerging Culicoides was positively correlated with pH while it was negatively correlated with salinity. Culicoides distinctipennis was the predominant species in the larval habitat group of freshwater lake edges. In the larval habitat group of pond and puddle edges, C. oxystoma and C. nivosus were predominant; both species were again most abundant in the larval habitat group of saltwater lake edges. These variabilities in physicochemical parameters support the distribution of different Culicoides species in different habitat groups. These results make it possible to implement effective, selective and environmental-friendly control measures but also to improve current models for estimating the abundance of adult vector populations at a local scale.

[Toxicological study of emissions resulting from a diesel and a gazoline engine using an organotypic culture of lung slice]. / Etude toxicologique des gaz d'échappement issus de moteurs diesel et essence sur une culture organotypique de tissu pulmonaire.

INTRODUCTION: Many studies were carried out in vivo and/or in vitro for better understanding toxic effects of exhausts or particles emitted by Diesel vehicles. Few studies were interested in Gazoline engines when progress of metrology made it possible to highlight the presence of small particles with a strong capacity of penetration within pulmonary tissue. The aim of this study is to compare the toxic impact of the emissions of Diesel and Gasoline engines of recent technology. MATERIALS AND METHODS: Biological material was constituted by an organotypic rat lung precision slice. It was exposed to a continuous flow exhausts thanks to a preparation and dilutions system of these emissions placed on the line of exhaust. A measurement of the biological markers involved in the process of the lung tissue reaction to the air-contaminants was carried out. RESULTS: With Diesel exhausts, the results showed a stability of the rate of ATP and an increase in enzymatic activities of the antioxydant system (GPx and catalase). Gazoline emissions, as for them, were responsible for a cytotoxic attack of the pulmonary tissue defined by a reduction in the rate of ATP as well as a deterioration of the system of detoxication with reduction in the antioxydant enzymatic activities. CONCLUSION: These results show that toxicological profiles obtained with this system of exposure depends on the engine technology used, highlighting thus the specific response of the model in relation with the type of atmospheres which it is exposed.

[Illicit drug trade on the markets of Yaounde (Cameroon) and Niamey (Niger): characteristics of salesmen and quality of drugs]. / Le circuit informel des médicaments à Yaoundé et à Niamey: étude de la population des vendeurs et de la qualité des médicaments distribués.

This study characterizes salesmen and evaluates the drugs offer and quality of the drugs in the illicit selling network in Yaoundé (Cameroon) and Niamey (Niger). A sample of 75 and 124 drug salesmen working in these cities was questioned using a standardized questionnaire. The prescription of drugs and the advices provided by these poorly trained salesmen could have an important impact in term of public health: 32% and 67% of the salesmen in Yaoundé give systematically or occasionally advices regarding the prescription. The active substances are always present in the 153 drugs of our analysed sample, except for chloroquine-based drugs, among which 5/30 samples did not contain active substance. However, the rate of nonconformity is approximately 50% in the two cities. Complementary studies are needed to explore the origin of these nonconformities, between counterfeiting, low quality of the products provided by the factories, defects of conservation or instability of the formulations.

[Comparative study of the effect of fasting during Ramadan on the glycaemia at rest in sportsmen and sedentaries]. / Etude comparative de l'effet du jeûne du ramadan sur la glycémie au repos chez des sportifs et des sédentaires.

The fast of Ramadan submits body to transient metabolic modifications; and decrease of glycaemia can be one of results. Physical exercise modifies rate of plasmatic hormones responsible for its regulation. The purpose of this study is to appreciate the influence of the fast on this biologic parameter in sportsmen and sedentaries. Thirty (30) healthy subjects (15 sportsmen of stamina and 15 sedentaries), with 25 years of average age were recruited. They have all a comparable diet. We excluded subjects having practised a physical exercise the day of the test. Capillary glycaemia was measured after weighed and physical exam, in 2 periods: in second Ramadan's fortnight, 15 minutes before food intake, two (2) months after Ramadan at least 4 hours at distance of the last meal. Comparisons were remitted in the test of Student, significant for p value lower than 0.05. During Ramadan, the glycaemia of the sportsmen at rest, is at one exception always superior or equal to that of the sedentaries. However, there is non significant difference as much during the fast as in normal food intake. Respective averages are 4.6 mmol/l, 0.15 and 4.5 mmol/l, 0.01 during Ramadan. They cross then in 4.8 mmol/l, 0.2 and 4.8 mmol/l, 0.4 in normal food intake. Landmark, the comparison of the averages from period to the other one in every group shows a significant difference only for the sedentaries. The return to normal food intake was expressed by an important gain in weight for all subjects. The fast of Ramadan has no notorious influence on sportsman's glycaemia contrary to that of sedentary. In other words, the sportsman administers better his stocks of glucose. Previous works however strongly advised against sports practice during Ramadan and more particularly the competitions, because, exercises of strong intensity can induce dehydration.

[Prescription of morphinics in the management of pain in Dakar teaching hospitals]. / La prescription des morphiniques dans la prise en charge de la douleur dans les centres hospitalo-universitaires de Dakar.

The correct management of pain is one of the most frequent problems in a daily medical practice. To achieve this goal physicians have to use many drugs. Among these drugs morphinics represent a special category with specific rules of administration. To assess the use of morphinics in the management of pain in Dakar teaching hospitals and to determine the reasons of under or over prescription, we carried out this study A questionnaire was sent to 200 medical doctors in two teaching hospitals in Dakar between February and April 1999. The response rate was 89.5% (179). According to 73.2% of medical doctors who answered the questionnaire, pain frequently leads to consultation but surprisingly only 14 physicians (7.8%) recognize a regular use of morphinics while 70.1% of them prescribe morphinics exceptionally Morphinics are mainly used to control pain in cancerology (37.2%) and post-operative pain (21.3%). The main reasons to explain the under-use of morphinics were: the fear of respiratory side-effects of morphinics (35.3%), the ignorance of prescription rules (23.5%). The training regarding prescription of morphinics was provided during medical studies and only 10 out of the medical doctors had an adequate postgraduate training in this domain. As expected 51.4% of physicians thought that their training during medical studies was inadequate. To improve the management of pain in our country we recommend a better training of medical doctors during medical studies and the promotion of postgraduate seminars on the use of these molecules. The legislation and rules of administration must be cleared and these drugs should be more available in drugstores and hospital pharmacies. All of these modifications are necessary to help medical doctors to overcome the fear of morphinics for a better management of pain in our country.

[Quality of butter sold in Dakar (Sénégal)]. / Etude de la qualité des beurres vendus a Dakar (Sénégal).

Among foods that are introduced in Senegal, butter takes a significant place particularly at home where it is frequently eaten. Nevertheless, Senegalese authorities don't carry out any quality control under those different types (mark) of butter. In consequence, to find butter without quality or characteristics of authentic butter may be high. The aim of this work is to analyse quality of main varieties of butter in Dakar market. Chemical methods were used to determine the characteristic of butter samples and gas chromatography was made to authentify their fatty acid profile. Our results have shown that most of analysed sample respected the standards of quality. In fact the composition of fatty acid and characteristic factors of authentic butter were certified by this study.

[Ammonia-gas poisoning: respiratory troubles evaluated by functional exploration]. / Evaluation par l'exploration fonctionnelle des troubles respiratoires dans l'intoxication à l'ammoniac.

The objective of our research is first to evaluate the defects in the respiratory function which have been noticed among patients suffering from ammonia poisoning during the accident at the SONACOS factory of Dakar in 1992. Secondly it is to set precisely the seriousness of the problem. This retrospective study is carried out on 50 patients examined at the Physiology and Functional Exploration Laboratory of the faculty of Medicine of Dakar University from March 1993 to October 1995. These patients have been submitted to at least two respiratory functional explorations. Ten of them have been treated for two years, thus benefiting from a spirographic control of these respiratory troubles already noticed. 58 % of the patients have developed an obstruction syndrome with the following specifities : fourteen patients out of 29 revealed a serious stoppage of the bronchi, twelve had a moderate bronchial obstruction, and three showed a minor bronchial obstruction. Besides, 34 % of the patients have developed a mixed syndrome with a minor restrictive component and a severe obstructive component. 8 % of the poisoned have presented a normal lung function testing. About the localisation of the respiration disorders at the level of the bronchial system, 61 % of the patients have shown an obstruction of the proximal, medial and distal bronchi. 26 % have presented obstruction of the distal bronchi, 13 % have shown an attack at their medial and distal bronchi. 5 patients out of 10 have shown any modification in their respiratory troubles while 3 of 10 have shown significant improvement. Then 2 out of 10 have shown degradation in their respiratory problems with an extension of bronchial obstruction. The ammonia poisoning has caused serious respiratory disorders related to the general and local toxic action of ammonia on the respiratory tract, its retention at their level and its effects on the respiratory function. The severity of the patent injuries incites to issue recommendations concerning the prevention of ammonia poisoning and the quick and efficient taking charge of the casualties in case of any accidental intoxication.

[Complications of colpohysterectomy with lymph node dissection in the cervix carcinoma at the Cancer Institute of Dakar: report of 412 cases]. / Les complications des colpohystérectomies élargies avec lymphadénectomie pour cancer du col utérin à l'Institut du Cancer de Dakar: à propos de 412 cas.

The wertheim complications are dominated by the urinary dysfonction and the lymphocele which are linked at this procedure. This study reported 412 Wertheim associated to the radiotherapy. The purpose was to evaluate the complications among patients who underwent the Wertheim and to analyse the differents factors promotions the complications. The diagnosis was always late and the disease stage was advanced. The stages II, III and IV represented more than 80%. We found 86 complications (20.87%) distributed as follow: 17 urinary (19.76%), 30 secondary infections (34.88%), 8 colonic fistula (9.30%), 7 hemorrage (8.13%), 6 lymphedema (6.97%), 3 occlusions (3.48%), 1 phlebitis (1.16%), 1 lymphocele (1.16%). among all patients, 17 died, the mortality rate was 4.12%. A very good dissection preceded by radiotherapy may reduce the complications rate.

[Mango leaves (Manguifera indica, Anacardiacea) used as biomarker of pollution by pp'Dichlorodiphenyltrichloroethane (pp'DDT)]. / Utilisation des feuilles de manguier (Manguifera indica, Anacardiacea) comme bioindicateur de pollution par le pp'Dichlorodiphényltri-Chloroéthane (pp'DDT).

Dichlorodiphenyltrichloroethane (DDT), organochlorine pesticide, byanother way cumulative pesticide is banned in mostdeveloped countries. Whatever, it is still used in many countries in the Third World. This work consist to check whether this chemical compound is still used in Senegal. The biomarker of pollution by this pesticide for this research was mango leaves (mango tree is widespread in Senegal) open to accumulate halogenated hydrocarbons. Leaves sample were taken in many sites in the centerline of Dakar-Thiès (Senegal), then analysed by gas chromatography. The results allowed to note the presence of DDT and its metabolites [(dichlorodiphenyltrichloroethylen (DDE), (dichlorodiphenyltrichloroethane (DDD)] in most of samples. The comparison of DDT content in relation to those of the principal metabolite allowed to make the difference according to sample sites, an old contamination of an utilisation more or less recent of this pesticide. From those results, we can conclude that DDT, typical pesticide by its big persistence is still used in some spherical zones in this country, in particular in farming gardening zones.

[Aflatoxin contamination level in artisanal and industrial peanut butter food in Dakar (Senegal)]. / Niveaux de contamination par les aflatoxines des pâtes d'arachide alimentaires de préparation artisanale et industrielle de Dakar (Senegal).

Aflatoxins are mycotoxins produced by some strains of fungus (Aspergillus) which develop in peanut seeds. Peanut oil and past are very used up in Senegal, then the aflatoxin poisoning risk is very actual. The aim of this study was to determinate the aflatoxin level in artisanal and industrial peanut pastry food from Dakar (Sénégal). High Performance Liquid Chromatography (HPLC) analysis of the different samples showed that the most contaminated by aflatoxins are artisanal pastry sold in different market of Dakar (Sénégal). Indeed, 40% of these samples contained mean values of aflatoxin B1 (the most dangerous) widely over allowable EEC specifications (5ppb). Furthermore, most of industrial and domestic peanut pastry were cleaned and could be consumed without risk.

[Contamination by aflatoxins of local peanut oils prepared in Senegal]. / Contamination par les aflatoxines des huiles d'arachide artisanales préparées au Sénégal.

Aflatoxins are mycotoxins produced by certain strains of fungus (Aspergillus) which develop in peanut seeds. Peanut oil and peanut meal are widely used in Senegal. The risk of intoxication is quite real. We determined aflatoxin contamination levels in peanut oil and food prepared by small scale production plants in the Kaolack and Diourbel regions of Senegal. High performance liquid chromatography (HPLC) of the different samples showed that 80% of them were contaminated. Aflatoxin B(1), B(2), G(1) and G(2) were detected. The pattern of contamination was similar for the two regions. Aflatoxin B(1) was prevalent and found in over 85% of the samples. The mean content of this mycotoxin (the most dangerous toxin) was about 40 ppb, a value which largely exceeds specifications for allowable levels.

[Aflatoxins in food: tests of decontamination of peanut cakes by ionizing treatment]. / Aflatoxines dans les aliments: essais de décontamination des tourteaux d'arachide par traitement ionisant.

The efficacy of ionising treatment for decontaminating peanut cakes was tested. The influence of cakes water content and the effect of ionisation dose rate were studied. The results obtained after a reverse phase liquid chromatographic determination of B1, B2, G1 and G2 aflatoxins have revealed an important contamination of the peanut cakes (up to 1000 ppb of total aflatoxin's contents). After ionising treatment at 25 kGy, the aflatoxins degradation in peanut cake's was less important in dried samples (about 5-10% at 0.55 water activity: aw) than in the humid ones (40-60% degradation at 0.95 water activity). At this dose, any indicative difference of the degradation rate of aflatoxins, with regard to the ionising process was observed. The efficacy of ionising treatment for decontaminating peanut cakes could probably be improved, however the economic interest of such process as alternative of the treatment with ammonia is questionable.

[Pesticide bioaccumulation: measurement and levels of organochlorine residues in products of vegetable origin]. / Bioaccumulation des pesticides: recherche et dosage de résidus d'organochlorés dans les produits d'origine végétale.

Because of their lipophilic properties and their persistence, organochlorine pesticides residues can be accumulated in human body by consuming regularly plants products. This study consisted of the monitoring of the contamination level of pesticides residues from various plants products, in order to assess the long- term intoxication risk to which Senegalese consumer is exposed ant identify throughout these plants some indicators of atmospheric pollution. The chromatographic analysis of medicinal plants, fruits and vegetables extracts showed that they could be contaminated by organochlorine residues. About ten of these pesticides residues were found confirming that the analysed plants were really contaminated. The residues level in medicinal plants (from 0.1 to 45 micrograms/kg) were widely below the maximum allowed concentrations and were also lower than those in fruits and vegetables (from 0.1 microgram/kg to 460 micrograms/kg). Heptachlorine residues contents of tomatoes and citrus fruits were higher than FAO/WHO norms, so that, a regular monitoring of the plants products is recommended for better protection of consumers.

[Measurement and levels of aflatoxins in small-scale pressed peanut oil prepared in the Diourbel and Kaolack regions of Senegal]. / Recherche et dosage des aflatoxines dans l'huile de pression artisanale préparée dans les regions de Diourbel et Kaolack (Sénégal).

Aflatoxins are mycotoxins produced by some strains of fungus (Aspergillus) which develops in peanuts seeds. Peanuts oil and past are very used up in Senegal, then the aflatoxins poisoning risk are very actual. This study relates to the determination of contamination levels by aflatoxins from peanut oil food prepared by small scale production in areas of Kaolack and Diourbel. High Performance Liquid Chromatography (HPLC) analysis of the different samples showed that 80% of them were contaminated in the areas of Kaolack and Diourbel. Aflatoxin B1, B2, G1 and G2 has been detected with a profile of contamination almost identical in the both areas. Aflatoxin B1 was prevalent and has been found in over 85% of samples. Mean contents of this mycotoxin (the most dangerous toxin) is about 40 ppb, value widely superior to allowable specifications.

[Well water pollution in the Khombole district: research on the contamination by organochlorine pesticide residues and organic substances (feces)]. / Etude du niveau de pollution de l'eau de puits du district de Khombole: recherches de contamination par les résidus de pesticides organochlorés et par les matières organiques (fécès).

The study realized in the district of Khombole (SENEGAL) has permit to estimate the contamination levels of wells waters used by the populations. The research and the dosage of the organichlorine pesticide residues, nitrites and nitrates and microbiologic analysis have been done on 19 wells chosen after a drawning of lots. The organochlorine pesticide residues which have been found prove that the wells are permanently exposed to these chemical substances which don't constitute nevertheless a major risk for the populations health. The results of our research proved also that there is a real risk of intoxication with the nitrogen oxides. In effects more than 50% of the wells have revealed nitrates contents up to the indicative value (25 mg/l). As for the nitrates, with a few exceptions (5/18), the contents are superior to the authorized norm (0.1 mg/l). By another way the bacteriologic analysis has revealed in the one hand a DBT (Total Bacterian Count) up to 10,000 germs/l for all the wells, and in the other hand the presence of Escherichia coli, Enterococcus faecalis that confirm a faecal contamination.

[Air pollution by lead emitted from vehichles in the Dakar region]. / Etude de la pollution atmosphérique par le plomb émis par les véhicules dans la région de Dakar.

The use of super carburant involves a lot of lead particles by the vehicles. This type of pollution specially affects the urban populations and the environment. This phenomenon is emphasized in the big cities like Dakar where more than 60% of the national car park move. This study shows that the trees can be used as indicator of lead pollution level. Unfortunately, the estimation of the pollution level isn't always easy whereas numerous factors can play a role in the mechanism. In this study, we have shown that the atmospheric pollution of Dakar by the muffler gases is a real fact.

[Artificial depigmentation practice of the skin in women of Dakar and analytical study of the cosmetic products used]. / Pratique de la depigmentation artificielle de la peau chez les femmes a Dakar et etude analytique des produits dits cosmetiques utilises.

This survey which involved 6 salesman and 159 women, allowed us to carry out a study on the different cosmetic products used by women in Dakar to artificially bleach their skin. An analytical study has been conducted on those skin bleaching products through colorimetric identifications of hydroquinone, corticoids and mercurial derivates and the dosage of hydroquinone by High Performance Liquid Chromatography (HPLC). It was established that those products were essentially corticoids and hydroquinone based products and could induce serious dermatological troubles to users. This phenomenon, known in Wolof "xessal", and motivated by various factors, is facilitated by easy access to skin bleaching products available in the town market places. It affects an important part of the female population of all ages (educated, illiterate, married and single). In view of the importance of the phenomenon, emergency actions must be taken to eradicate it.

[ Dietary intake of fluorine through of tea prepared by the traditional method in Senegal]. / L'apport de fluor dans l'alimentation par le thé préparé selon la méthode traditionnelle au Sénégal.

The consumption of tea in Senegal is known and called "trois normaux". The use of Thea sinensis as drink many times per day with a lot of sugar, may cause some public health problems. In the aim to face that situation, we have analysed the fluor level in the available tea samples in the senegalese market in respect of the ways of the preparation. The fluor level has been analysed by ionometric specific electrode. The concentrations were from 3.8 to 6.1 mg/l in the infusion and from 11.1 mg/l in the decoction. These results showed that the tea plant contain a high concentration of fluoride. In addition, the level of fluoride may be higher, when the water drink itself is rich in fluoride.