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Biomedical subjects

O Faye

Publications and source records attributed to O Faye.

At least 55 records · Page 3Linked to original sources

Evolution of malaria in Africa for the past 40 years: impact of climatic and human factors.

Different malarial situations in Africa within the past 40 years are discussed in order to evaluate the impact of climatic and human factors on the disease. North of the equator, more droughts and lower rainfall have been recorded since 1972; and in eastern and southern Africa, there have been alternating dry and wet periods in relation to El Niño. Since 1955, the increase in human population from 125 to 450 million has resulted in both expansion of land cultivation and urbanization. In stable malaria areas of West and Central Africa and on the Madagascar coasts, the endemic situation has not changed since 1955. However, in unstable malaria areas such as the highlands and Sahel significant changes have occurred. In Madagascar, cessation of malaria control programs resulted in the deadly epidemic of 1987-88. The same situation was observed in Swaziland in 1984-85. In Uganda, malaria incidence has increased more than 30 times in the highlands (1,500-1,800 m), but its altitudinal limit has not overcome that of the beginning of the century. Cultivation of valley bottoms and extension of settlements are in large part responsible for this increase, along with abnormally heavy rainfall that favored the severe epidemic of 1994. A similar increase in malaria was observed in neighboring highlands of Rwanda and Burundi, and epidemics have been recorded in Ethiopia since 1958. In contrast, in the Sahel (Niayes region, Senegal), stricken by droughts since 1972, endemic malaria decreased drastically after the disappearance of the main vector, Anopheles funestus, due to the destruction of its larval sites by cultivation. Even during the very wet year of 1995. An funestus did not reinvade the region and malaria did not increase. The same situation was observed in the Sahelian zone of Niger. Therefore, the temperature increase of 0.5 degree C during the last 2 decades cannot be incriminated as a major cause for these malaria changes, which are mainly due to the combination of climatic, human, and operational factors.

Africa South of the Sahara↗

[Malaria in the southern sanitary district of Dakar (Senegal). 1. Parasitemia and malarial attacks].

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.

Adolescent↗

[Toxoplasmosis in Dakar. Seroepidemiologic sampling of 353 women of reproductive age].

Thanks to a serological survey carried out in Dakar from January to November 1993 among 353 procreative women, immune cover regarding toxoplasmosis was assessed using ELISA methodology: 40.2% of the surveyed population had antibodies of toxoplasmosis. No evidence of age, pregnancy, number of previous pregnancies was noted in antitoxoplasmosis antibodies prevalence. The seroconversion risk seems to be low even when it has existed during pregnancy. Contamination occurred during childhood. Some sanitary education should be provided to the procreative population in order to achieve a better compliance with basic hygiene regulations during pregnancy.

Adolescent↗

[Malaria in the southern sanitary district of Dakar (Senegal). 2. Entomologic data].

To complete a parasitological survey, entomological prospections were carried out in the southern sanitary District of Dakar, the most urbanized of the city and which includes the city centre and the oldest administrative districts. The prospections took place between June 1994 and May 1995 in sites 1.5 km apart, and distributed in such a manner that they covered the entire area. On a monthly basis, female Culicidae were collected in each site at night on human volunteers, followed the next day by the collection of early morning residual fauna in 10 bedrooms located in district concessions. For a total of 308 collections at night on human volunteers and from 1,510 rooms for the residual fauna, 22,901 female Culicidae were caught of which 167 anopheles, corresponding to 0.7%, the remaining 98.5% being Culex quinquefasciatus. This was the species that thus explained the mosquito-nuisance of which the inhabitants of the southern District complained during the period of survey. The female anopheles collected belonged to 2 species, An. arabiensis for 97.6% of those caught and An. pharoensis for 2.4%. An. arabiensis were very slightly represented in the southern District with a density of aggressive females of 0.26 bite/man/night (B/M/N) and a density per room of 0.05 female. The aggressive populations appeared to be relatively important only at the end of the rainy season (September-October) with an average of 0.65 B/M/N in sites located at the periphery of the district with a maximum of 1.33 B/M/N. The highest density of endophilic females registered at the end of the rainy season was 0.1 and its highest value in a given site was 0.36 female/room. The parturity rate of aggressive females was 43.5% and those collected in houses of 84% with an anthropophilic index of 0.98. None of the dissected An. arabiensis females (77.3% of those collected) was a carrier of Plasmodium sporozoites and the circum-sporozoite antigen was not found. A very weak density of An. arabiensis and absence of plasmodial infection among dissected females favoured the absence of malarial transmission in the southern District for the period considered. However malaria transmission could not be absolutely ruled out given the presence of hematozoa carriers, as was revealed by the longitudinal follow-up of a cohort carried out concurrently with the entomological prospections of whom some were residents having declared permanent residence in the city for over two years. This entomological data explain the results of the afore mentioned parasitological survey which, with a registered plasmodic index of 0.3%, means that the southern District can be considered as non endemic. The area is however exposed to the risk of epidemic malaria following an important proliferation of anopheles, which is always possible after heavy rains and flooding and/or an important immigration of persons coming from regions of high malarial endemicity.

Animals↗

[Evaluation of parasitic risks for the population bordering on the Mbeubeuss public waste disposal, Dakar].

The authors carried out a parasitologic survey on 367 inhabitants of Malika, a village located in the immediate surroundings of M'Beubeuss disposal, as well as on 433 other residents of Keur Massar, a location 2 km farther, in order to assess parasitic hazards encountered by people neighbouring this disposal. As far as intestinal parasitosis are concerned, the prevalence rate was significantly higher in Malika (61.3%) than in Keur Massar (48.5%) The sex, social and economic status, level of education as well as the time of dwelling in the neighbouring area were identified as the risk factors of intestinal parasitism. Only the last one can be considered as significantly and independently related to a risk of intestinal parasitism. As for malaria, the plasmodial index in Malika was 6% versus 7.6% in Keur Massar (no significant difference). Thus, if it does exist for neighbouring people, an infestation risk by intestinal parasites related to exposure duration, contrarily, it does not exist for malaria. Appropriate steps should be taken to prevent the hazards encountered by inhabitants of surrounding villages.

Adolescent↗

[Endemic parasitoses in the villages surrounding the Saloum fossil valley, Senegal].

In order to determine the prevalence rates of malaria, urinary schistosomiasis and intestinal parasitosis in Saloum's valley, the authors carried out a study which took place from november 16 to november 24, 1996. For malaria, the global parasites index was 22% (146/662). Malaria prevails at a hypoendemic level in N'Diobène and N'Guent-paté villages and at a medium-endemic level in Ribo-Escale and N'Dodj. The infestation index for urinary schistosomiasis was 8.9% (137/154) About intestinal parasite, among 868 persons screened, 124 showed one or several parasites, that is an infestation index of 14.3%. Appropriate steps should be taken to prevent an extension of these conditions along the fossil Saloum's valley.

Adolescent↗

[Establishing a strain of Anopheles arabiensis (Diptera:Culicidae) in an insectarium].

For the first time in Dakar (Senegal), we managed to establish a local colony of Anopheles arabiensis (Diptera: Culicidae) in insectarium. The observations on the productivity of the colony showed a gradual adaptation of the preimaginal stages to insectarium conditions. The estimated duration of the development of the various preimaginal stages showed an interval of 24 hours for egg hatching, 48 h for stage I, 24 h for stage II, 24 h for stage III and 36 h for the pupal stage. Stage IV which makes the difference in the duration of the adult-egg cycle, varied from 1 to 13 days. Pupal moulting occurred mainly between 11 h and 19 h, with a peak between 14 h and 15 h. The duration of the preimaginal cycle in insectarium was from 8 to 11 days. This fits with the duration shown in natural breeding places during the rainy season (the best period for the development) which was from 9.5 to 13.3 days. Emergence, faster in males, occurred in the evening around 6.30-7 p.m. The emergence rate was higher in insectarium (92.9%) compared with that shown in the field (6 to 20%) (the natural breeding places are subject to biological and biochemical variations and to predators's action). The sex-ratio is equal to 1. The studies in insectarium showed that the gonotrophic cycle is 3 days in neonate blood fed after day 2 and also in parous ones. This cycle is 5 days in nulliparous with pregravid stage. The average longevity is 16 days with a maximum of 26 days in females and 43 days in males.

Animals↗

[Obstetric complications of the first trimester in Western Africa].

The obstetrical complications affecting women in Benin, Senegal and Ivory Coast during the first trimester of pregnancy were studied. Information about the 345 women included in the study was collected from registers maintained by the eight participating maternity units. The most frequent complications observed were spontaneous abortions (50% of admissions), complications of induced abortions (34%), and ectopic pregnancy (8%). Overall, the patients appear to have gained rapid access to care: two thirds of the women underwent interventions on the day of admission. Nevertheless, there were three maternal deaths, two of which followed induced abortion complications.

Abortion, Induced↗

Indoor resting by outdoor biting females of Anopheles gambiae complex (Diptera:Culicidae) in the Sahel of northern Senegal.

Three villages in the Senegal River basin were selected to study the biting and resting behavior of Anopheles gambiae s.l. in relation to human habits, rainfalls, and rice culture irrigation. All inhabitants sleep outside throughout the year, mainly under poor quality bednets. Mosquitoes were collected host-seeking during the night on human bait outside and resting during the day inside and outside in pit shelters. An. gambiae s.s. and An. arabiensis fed mainly outside, the only place where hosts are available; fed and gravid females resting indoors fed outside. The proportions of An. gambiae s.s. and An. arabiensis in outdoor biting catches and in indoor spray catches were not significantly different, but they differed from year to year with the latter sampling method, An. gambiae s.s. predominated in 1990, a more wet and humid year, whereas An. arabiensis was more common in 1991, which was an arid year. Both species are highly endophilic in this arid area where outdoor-resting places are limited.

Animals↗

[The role of Hühner's direct post-coital test in the evaluation of conjugal sterility in the African environment in Senegal. (Apropos of 2593 post-coital tests performed by the clinical cytology, cytogenetic and reproduction biology laboratory at the University Hospital Center in Dakar, Senegal) 1983-1993].

About 2593 post-coïtal tests (PCT) or Hühner direct tests were realised in the laboratory of clinical cytology, cytogenetics and reproductive biology of the University medical Centre of Dakar, Senegal from 1983 to 1993. Analysing the results, the authors showed the importance of the infectious factor in women and also the role of male deficiency in conjugal sterility in black African environment. These realities have been confirmed cytospermiologic test deficient results. These sperm exams have shown among other things, the prevailing number of azoospermia (25%) and of oligo-asthénotératozoospermia (44%) in husbands of sterile women in the black African environment of Senegal. Pap's Tests have been jointly realised at the same time as 1902 PCT. The results have enabled us to track down 120 cervix with precancerous and cancerous cell alterations; 81 condylomas (HPV), 25 CIN1, 11 CIN2 and 3 CIN3 (CIN: cervical intra-epithelial Neoplasia). These facts suggest a cautious technics, and a prudent interpretation of the results and taking into account the competence and the subjectivity of the practitioner. We have learnt from the study that we must give as much as possible to biologists of Reproduction in southern countries, where conjugal sterility and cervix precancerous and cancerous cell alterations are high, a polyvalent training so that they can practise jointly the post-coïtal or Hühner direct test (PCT) and the Papanicolaou Colpocytologic Test (TP), provided that one owes a microscope.

Adolescent↗

[Evaluation of the treatment of malaria using a 3-day regimen of quinine in Dakar].

The efficacy of quinine treatment for Plasmodium falciparum strains remains sound. However reports of decreased sensitivity and resistance of some strains in Asia and East Africa indicate that current treatment regimens should be re-adjusted. The purpose for the present study carried out in Dakar, Senegal, was to evaluate the local regimen for acute Plasmodium falciparum malaria using quinine at a dose of 20 mg/kg per day in two daily injections on 3 consecutive days. Thirty-seven patients with acute Plasmodium falciparum malaria including 10 severe cases were treated using the standard regimen and followed up clinically and parasitologically from Day 0 to Day 7. On Day 7 parasites were still detectable in the blood of four patients for a failure rate of 10.8%. Persistence of parasites despite disappearance of clinical symptoms suggests that the regimen should be increased to 25 mg/kg per day for at least for 3 days or longer if symptoms persist. Due to its adverse effects and cost (10 times higher than chloroquine treatment), quinine treatment should be prescribed only for patients with severe malaria forms.

Acute Disease↗

[Knowledge and treatment of malaria in rural Senegal].

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.

Antimalarials↗

[Impact of antimalarial drug accessibility on malarial morbidity and chloroquine resistance. A study carried out in Touba (Senegal)].

In Touba, more important accessibility to antimalarial drugs and their uncontrolled use let to assure that the rate of malarial morbidity would be lower there than in other place in Senegal whereas the rate of chloroquine resistance would be higher. A checking survey of these assumptions has been carried out from october 15 to november 10, 1995 in Touba's health center. Among 227 feverish subjects investigated, 111 were Plasmodium falciparum carriers. Malarial bouts accounted for 48.9% of the feverish fits observed and for the major cause of consultation during the rainy season. These figures are higher than those usually observed in urban environment. Conversely, the rate of chloroquine resistance is lower than those observed in urban zones, since the therapeutic efficacy of chloroquine on Plasmodium falciparum was 100% in that survey.

Adolescent↗

[Malaria in an urban environment: the case of the city of Rufisque in Senegal].

From April to November 1994, we carried out a study in Rufisque, an urban area located in Dakar Region. During dry season, 5.32% of febrile outpatients were infected with Plasmodium falciparum with a mean parasitic density evaluated at 12,471 p/microliter. One case of cerebral malaria was noted. During raining season, malaria represented 58.75% of the fevers. Ten presented neurological signs; the mean parasitic density was high, 131,140 p/microliter. Two children died. Good efficiency of quinine was noted but chloroquine treatment failures was present: 50%. Generally malaria is less prevalent in urban areas. But in Rufisque ecological conditions are main factors which permit spreading of the disease. Prior measures of control such correct treatment of cases and good management of environment must be done.

Adolescent↗

[Prevalence of malaria in the Senegal river basin in 1991].

In order to determine the prevalence of malaria and its epidemiological characteristics, a survey was carried out in 11 villages situated in all the Basin of River Senegal (B.R.S.). 3306 (0-14 years) children are examined. The results show that malaria is hypo-endemic in the B.R.S. with a plasmodic index of 8.6% and a splenic index of 9.9%. But these malariametric indexes change according to the areas visited. Thus, malaria prevails at a hypo-endemic level in Dagana and Podor districts while at a medium if not hyperendemic level in Matam and Bakel districts. The plasmodial index also change according to age reaching a maximum within children from 10 to 14 years. As for the spleen index, it is low among children from 10-14 years. As for the spleen index, it is low among children from 0 to 4 years old, then increases among those aging from 5 to 9 years, before decreasing within children ranging from 10 to 14 years. P.falciparum is the most prevalent species, representing 96% of the cases; it is followed by P.malarioe (3%) and P.ovale (1%). If our results are compared with those obtained before by other authors, we can conclude that the recent hydro-agricultural plannings carried out in the area, have not yet provoked an increase of the cases of malaria. But, in order to avoid this risk, it is necessary to take from now some preventive measures.

Adolescent↗

[Evaluation of malaria chemoprevention among 359 pregnant women attending a health center in Dakar].

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.

Adolescent↗