[Prevalence of child and teenage obesity in schools in Dakar]

Obesity is currently viewed as a serious worldwide public health issue. In this survey, we aim to determine its prevalence among schoolchildren and teenagers in Dakar. The sample of our survey consisted of 2,356 students aged 11-17, including 1,110 boys and 1,246 girls. For each of them, we have calculated their body mass index. Based on the higher value of the norm of that index, referred to the 97th percentile of Rolland-Cachera MF's curves, we have identified obese students according to their age and sex. The prevalence of obesity within our sample is 9.34%, with 2.88% for boys and 6.46% for girls. It is at its peak in the age of 11, though there is no significance (p > 0.05) in its decrease (from age 12 to 17). There are significantly (p < 0.05) more obese students in "catholic private" schools than in "public" schools where schooling is free. Child and teenage obesity is a reality in Dakar schools. Consequently, it is advisable to determine its nationwide prevalence to take on its prevention as well as its cure.

[Two cases of Crimean-Congo haemorrhagic fever (CCHF) in two tourists in Senegal in 2004]

Two cases of Crimean-Congo haemorrhagic fever (CCHF) occurred in two French tourists during their visit in Senegal in November 2004. Febrile and hemorrhagic syndrome with ulorrhagia, petechiae, haematemesis, haematomas associated with biological signs of disseminated intramuscular coagulation were observed. For the first case who had a medical evacuation to France before diagnosis, Crimean-Congo virus infection was revealed by laboratory tests performed by the National Reference Center for Hemorrhagic Fevers (NRCHF, Institut Pasteur, Lyon) and secondly by the Centre de Référence OMS sur la Recherche des Arbovirus et des virus des Fièvres Hémorragiques (CRORA) in the Dakar Pasteur Institute (DPI). The second case diagnosed by the CRORA died after clinical deterioration with liver failure and severe haemorrhages. Healthcare workers and family members who had contact with tissue or blood from patients were followed up after the putative exposure either in France or in Senegal.

[Supervision of body composition and cardiovascular parameters in long sprint running athletes (400 m)]

INTRODUCTION

The follow-up of performances and the prevention about possible incidents at the athletes make necessary the medical supervision in physical training. The aims of this study are to estimate the effect of a precompetition training program in athletes' body composition, and cardiovascular modifications (in clinical examination and electrocardiogram)

MATERIALS AND METHODS

Ten athletes (3 men and 7 women; mean age of 23.6 +/- 3.16 years) of Dakar international Athletics' Center are subjected to a training on a period of 2 months in aerobic dominant followed by a period of 3 months in anaerobic dominant. At the beginning and the end of training program, an electrocardiogram is recorded after blood pressure (BP) measure in lying and standing posture and heart rate (HR) take. The weight, height and cutaneous folds are measured to calculate the body fat percentage, fat body mass, fat-free mass and body mass index. Every athlete has performed the Ruffier test Comparisons are realized by the paired t-test, statistically significant for a p value < 0,05 RESULTS: Significant declines after training interest HR (79.2 +/- 14.7 vs 63.2 +/- 10.25 beat min(-1); p< 0.001), systolic BP in standing posture (11.8 +/- 0.44 vs 10.6 +/- 0.96 mmHg; p= 0.02), and Ruffier index (4.4 +/- 3.28 vs 2.23 +/- 1.62; p= 0.048) whereas the fat-free mass increased (53.14 +/- 8.41 vs 54.16 +/- 9.67 kg; p= 0.046). At the electrocardiogram, the number of athletes having sinusal bradycardia is crossed from 1 to 4; there is no modification as for the two cases of uncomplete right bundle-branch block and the pre-existent left ventricular hypertrophy. Negative T waves in V1 and V2 leads are present in one athlete before training and in two others after.

CONCLUSION

The impact of the specific training on body is real, interesting more the cardiovascular system.

[Effects of Ramadan fast on weight, performance and glycemia during training for resistance]

INTRODUCTION

Pysical activity and sports training can be proved exhausted for the organism during normal alimentation period. These sensations may go on more pronounced during Ramadan, period of complete fast marked by an absence of energetic and hydroelectrolytic supply. Our propose was to evaluate the impact of Ramadan on weight, performance and glycaemia during a training for resistance.

MATERIALS AND METHODS

Ten Senegalese males 200 and 400 meters runners aged 24.4 +/- 6 years old had two training sessions, one during the Ramadan and the other during normal non fast time. The 200 meters runners had executed each one two series of 3 x 150 m, and the 400 meters runners executed one serie of 3 x 250 m. These parameters have been measured respectively by a SECA scales, a PC 70 A chronometer, and a capillary glycaemia reader.

RESULTS

During Ramadan the weights a nd performances of our athletes decreased significantly (0.01 > p > 0.001) with race intensities equal to or slightly higher than those of competition, requiring anaerobic glycolysis. We found severe hypoglycaemia mainly before the training session, 10 hours after the last meal. We found no severe hypoglycaemia in normal non-fast time. Therefore all differences in average glycaemia rates in each testing case (except between the morning and after training in time of complete fast) a nd between them, a re significant. The performance fall is the conjugation of the blood sugar rate collapse a nd recovery.

CONCLUSION

A balance diet with high content of carbon hydrates is a dvisable to prevent h ypoglycaemia that c an a dversely affect the health of fasting sportsman training for resistance.

[High and long jumps: limiting criteria of performance]

It is absolutely essential to acquire the basic techniques of high and long jumps in the initial stage of training when relevant global gestures are learned, as well as during further training for the improvement of such techniques. Our purpose is to identify a number of gestures which are not in keeping with elements of the required techniques. It concerns execution mistakes, which we call "limiting criteria". because they are more or less likely to have an adverse effect on performances. In order to identify them, we used pictures, filming and recording, by category of jump, 4 to 5 successive attempts of each one of 48 subjects selected for our study. The best attempt was viewed 5 times either in normal or slow motion, or picture by picture. For each criterium at the end of the impulse, we compared the average of performances of students who did not make mistakes to those of the critenum concerned. Our results show that, except for two criteria. all the averages differencies are significant to P Probabilities between either .05 and .01 or less than .001. This attest that some criteria have a less adverse effect than others, but that all criteria constitute hindrances to good performance. Therefore, they must be taken into account by anyone intervening in sports and/or physical education who is anxious of the output of his athletes or students.

[Cohorts and bio-libraries for studying malaria in tropical areas]

The relationship between Plasmodii transmission, infection, morbidity, genetic susceptibility and acquisition of natural immunity is studied among two cohorts in the Senegalese villages of Dielmo (300 inhabitants) and Ndiop (350 inhabitants) where malaria is holoendemic (about 200 P. falciparum infective bites/person/year) and mesoendemic (about 20 P. falciparum infective bites/person/year), respectively. The populations are under a daily active clinical survey. Blood samples are collected at least once per month. Plasma and red blood cells are stored in bio-libraries that allow longitudinal studies of the immune responses against plasmodial antigens and the investigation of the natural history of P. falciparum infections by molecular genotyping methods.

[Transverse study comparing certain physical characteristics of Senegalese children and adolescents from 7 to 13 years of age]

350 boys and 350 girls 7 to 13 years of age that are equally divided into 7 age groups according to sex, have been submitted to action speed tests (pure speed), co-ordination-speed, pure-power, co-ordination-power, flexibility and balance. The objective of our study was to compare the average evolution of each of these qualities according sex and age. From 7 to 13 boys were more performing than the girls in the first four tests; it's the opposite when il comes to the last two ones. Yet, the differences shown on both sides were not altogether significant but in action--speed (except at 9) and in flexibility. The two sexes were significantly different at the age of 7 and from 9 to 10 in balance, from 10 to 13 in pure-power, from 11 to 13 in co-ordination-power and from 12 to 13 in co-ordination-speed. It is often from the age of 7 to 9 or 10 that the average yearly gains of the performances are significant. Among the girls, they undergo more noticeable reductions from 9 or 10 until 12, before to decrease between 12 and 13 (in pure speed, co-ordination-speed and pure power), whereas the boys', for all the above mentioned physical qualities, remain unchanged or increase in a more significant way (except in flexibility). These significant results suggest a diversification of motor learning contents for boys and girls of the same age, or of different age according to sex.

[Bicycle test: measure of anaerobic power, heart rate and blood lactic acid]

Seven sportsmen, 100 meters and 400 meters runners are submitted to an effort test of 30 seconds. The subjects are on average 23.7 +/-2 years old. The purpose of our work is to study on the one hand the evlution of the anaerobic power. the heart rate and the lactic acid in blood during and after a bicycle test. and their relation, and on the other hand. to know the suitable pratical importance of the heart rate and the lactic acid in blood in connection with the intermittent efforts recovery aiming the anaerobic power developpement. These physiological parameters have been measured by a Monark bicycle 864, a sport-tester PE 3000 and a spectrophotometer JASCO 7800 UV/VIS. The power and the heart rate increase quickly in the 5 first seconds. Our subjects reach their average maximal anaerobic power at the 10th second, and then this power decreases progressively, while the heart rate continues to increase, without being maximal at the end of te test. Five minutes later it decreases in a half, while the lactic acid level calculated at the 30th second is continuing significantly. We have not found a significant relation between the measured parameters at the test stopping and during the recovery period (except between the lactic acid and the recovery index of the heart rate at the 25th minute). The lactic acid in blood would inform better about a good recovery during an interval training effort.

A survival analysis of trypanosomosis diagnostic-test performance under natural infection challenge

Little is known about the time-to-first detection and the time difference (TD) between first parasitological and first serological diagnosis of Trypanosoma spp. infections under natural infection challenge in cattle. The objective of our study was to estimate these measures of "longitudinal aspects" of diagnostic performance and to investigate potential biological factors. Emphasis was on diagnosis at the genus level (Trypanosoma spp.). Twelve N'Dama, 12 Gobra zebu and 12N'DamaxGobra (F1) crossbred cattle (all animals non-infected at the start of the experiment, six male and six female animals in each cohort) were exposed to natural high tsetse challenge in the Niamina East area in The Gambia [Acta Trop. 71 (1998) 57]. The animals were investigated parasitologically (detection of trypanosomes by buffy-coat technique), serologically (detection of T. brucei, T. congolense and T. vivax antigen by enzyme-linked immunosorbent assay (ELISA)) and clinically (packed-cell volume, PCV) over a period of 180 days. The time-to-first detection of trypanosomes, trypanosomal antigen (cut-off as suggested by test supplier) and drop in PCV (subject-based cut-off values) were recorded as outcomes of interest. Thus, incidence was both parasitologically (I(p)), serologically (I(s)) and clinically (I(c)). Recurrent events were not considered. The TD between first parasitological and first serological detection was established as I(s) time minus I(p) time. The effect of breed and sex on the time-to-first detection and on TD was investigated using Cox (proportional hazard) regression and ANOVA, respectively. We found that time-to-first parasitological detection of trypanosomosis in N'Dama animals was significantly longer than in the two other breeds (Cox regression, P=0.002). A similar but less-strong (P=0.063) effect of breed on time-to-first detection of trypanosomal antigen was found, whereas no breed effect was observed for clinical detection (P=0.432). Sex had no effect in all detection systems. The TD varied between -56 and 115 (mean 28). Marked differences among breeds and between sexes were not observed (ANOVA, P=0.8). We suggest that incidence studies are more suitable for detecting risk factors for animal trypanosomosis than prevalence-based (cross-sectional) studies because the latter often result in misinterpretation of factors that increase the survival time with infection as risk factors.

Bayesian analysis of an epidemiologic model of Plasmodium falciparum malaria infection in Ndiop, Senegal

Plasmodium falciparum has a complex transmission cycle. Public health planning and research would benefit from the ability of a calibrated model to predict the epidemiologic characteristics of populations living in areas of malaria endemicity. This paper describes the application of Bayesian calibration to a malaria transmission model using longitudinal data gathered from 176 subjects in Ndiop, Senegal, from July 1, 1993, to July 31, 1994. The model was able to adequately predict P. falciparum parasitemia prevalence in the study population. Further insight into the dynamics of malaria in Ndiop was provided. During the dry season, the estimated fraction of nonimmune subjects goes down to 20% and then increases up to 80%. The model-predicted time-weighted average incidences contributed by nonimmune and immune individuals are 0.52 cases per day and 0.47 cases per day, respectively. The median times needed to acquire infection (conversion delay) for nonimmune and immune individuals are estimated at 39 days and 285 days, respectively.

[Method for recovering and concentrating lactic acid during interval training]

Sixteen athletes were divided into 2 equal groups, A and B. Then, they were put through a series of repetitive trial exercises consisting in a sequence of 400 m races run to a sub-maximum speed (75% of maximum speed) and with pauses of a length of time equal to race time, and repeated to exhaustion, i.e., inability to keep up required speed. Recuperation in between races varied: Group A was completely passive, motionless; Group B was still going, albeit rather slowly. The parameters measured included blood concentration of lactic acid at rest and on completion of exercise and overall distance covered. At rest, there was a significant difference of lactatemia between the two groups. During the exercise, the distance run by Group B was longer (by 187.5 m) that that covered by Group A, though the difference was not significant (0.05 < P < 0.10), but his lactatemia was significantly much lower (P < 0.05). On average, the race speed and the time for recuperation which were alternatively measured were just the same for the two groups.

Estrogens modulate bovine vascular endothelial cell permeability and HSP 25 expression concomitantly

The atheroprotective properties of estrogens are supported by clinical data from postmenopausal women who use estrogen replacement therapy. However, the mechanisms mediating activity remain unknown, and it has been suggested that estrogens may help to modulate endothelial permeability to atherogenic lipoproteins. In these studies we used bovine vascular endothelial cells as an in vitro model to show that estrogens were able to regulate low-density lipoprotein transport and permeability of the endothelial monolayer. Macromolecular transport was observed to be a second-order polynomial function of estrogen concentration. Moreover, this regulation was correlated with expression of heat shock protein (HSP) 25, which is known to influence fluid phase pinocytosis and cytoskeleton remodeling, thus suggesting a role for HSP 25 in the estrogenic control of transcellular permeability of the endothelium monolayer.

A comparison of field tick infestation on N'Dama, Zebu and N'Dama x Zebu crossbred cattle

Tick burdens, estimated from cumulative tick counts, were determined on N'Dama, Zebu and F1 N'Dama x Zebu crossbred cattle. N'Dama showed significantly fewer ticks than the Zebu and F1 cattle (P < 0.001). A previous trypanosomosis infection did not affect tick burdens on the three genotypes. Amblyomma variegatum had a prevalence of 84.8% and Hyalomma spp. 15.2%, with the ratio similar on all cattle breeds. Trypanosomosis infection increased the serological prevalence of Anaplasma marginale in Zebu and F1 cattle but not in N'Dama cattle. These observations supported the view that N'Dama cattle are less susceptible to tick attachment than Zebu cattle.

[Effect of water fasting on sport performances in the laboratory]

15 sport men heart rate and central temperature were measured at rest and at the end of a progressive maximal exercise. Maximum consumption of oxygen (VO2 max) was estimated after the effort. The experience began in the morning from 9 to 11 a.m. and the afternoon from 4 to 6 p.m. In the first time subjects had a normal alimentation and in the second they observed a rigorous fast. The comparison of the results doesn't show difference induced by fast on VO2 max and maximal heart rate. However heart rate at rest and capacity of work decrease during fast and permit to think that a more intensive and long exercise in more strenuous climates than this one should give significative modifications.

[Aerobic capacity training in heterozygote sickle cell athletes]

Two sport groups, all training physical educational and sports teachers at the H.N.I.P.S.S. of Dakar have been tested by measure of maximum consumption of oxygen (VO2max) before and after a three month aerobic training. The first group contained 10 abnormal hemoglobin (AS) subjects. The second group 11 normal hemoglobin (AA) subjects. The results do not show any difference in the reaction of adaptation between the two groups.

Isolation and cultivation in vitro to the infective, metacyclic stage of Trypanosoma (Nannomonas) simiae from Glossina morsitans submorsitans

Two separate trypanosome isolations were made from a single Nannomonas-infected Glossina morsitans submorsitans from The Gambia. Inoculation of a piglet with the infected hypopharynx produced an infection with Trypanosoma simiae. DNA was isolated from the bloodstream forms to prepare a probe specific for this species. Trypanosomes isolated from the fly midgut were frozen in liquid nitrogen and then cultivated in vitro. Amplification of this population and elimination of a yeast contaminant were achieved by two passages through laboratory G. m. morsitans. Further cultivation in vitro resulted in the production of epimastigotes and, later, metacyclic forms. Two pigs inoculated with cultivated metacyclic forms developed infections with atypical, relapsing parasitaemias and extended survival time. Neither the metacyclic forms, nor bloodstream forms derived from them, infected calves. The identity of various stages of the in vitro cultivated, procyclic-derived stock was confirmed morphologically and with the T. simiae-specific DNA probe.