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M Diallo

Publications and source records attributed to M Diallo.

At least 19 recordsLinked to original sources
PubMed2006

Differences in circulating dendritic cell subtypes in peripheral, placental and cord blood in African pregnant women.

Dendritic cells (DC) are important for induction of primary immune responses and immunological tolerance. Changes in the frequency of DC subsets were analyzed in peripheral blood from pregnant women (mPB) and compared to placental blood (PB) and cord blood (CB). DCs were identified by flow cytometry in whole blood as lineage negative and HLA-DR-positive cells. Different DC subtypes were identified with CD123 and CD11c markers. In these data, the percentage of DC was significantly lower in mPB, PB and CB than in control women, but the absolute number of DC was higher in CB, suggesting that numbers of DC in CB do not explain the decrease of the immune response in newborn infants. Myeloid DCs (MDC) decreased in all compartments of pregnant women compared to control women, especially in mPB where MDC became lower than lymphoid DCs. An increase of less differentiated DC was observed in mPB and CB from pregnant women. DCs in pregnant women were mainly immature DC with a proportion of CD83-positive DC, identical as control women. The levels of IFNgamma, TNFalpha, IL-2, IL-4, IL-5 and IL-10 were not different in the three compartments (mPB, PB, CB). In conclusion, the phenotype and subset of DCs were different in pregnant women than in control women, suggesting a role in maintenance of immune tolerance against the fetus. The distribution of DC subsets was different in mPB, PB and CB. Their role in the regulation of immune response remains to be elicited.

Adult↗
PubMed2006

[Feeding pattern of Rift Valley Fever virus vectors in Senegal. Implications in the disease epidemiology].

During the rainy season 2003, an entomological survey was undertaken in the Sahelian bioclimatic zone of the Ferlo area in northern Senegal, in order to evaluate the degree of interaction between Rift valley fever (RVF) virus vectors and domestic animals and to determine the role of natural vertebrate hosts in the transmission and maintenance cycle. The study of vector-host contact was carried out under bed net traps using man, cow, sheep, chicken as bait whereas the RVFV vectors-vertebrate host interactions were studied through the analysis by an ELISA technique of the origin of the blood meals from naturally engorged females collected by aspiration. Blood meals sources were determined using a set of eight antibodies. Overall, the different known RVFV vectors (Culex poicilipes, Aedes vexans and Aedes ochraceus) were opportunistic although the bovine-baited net was, as far the more effective trap with 53.6% of collected mosquitoes. It was followed by the sheep-baited net (16.7%), man-baited net (12.6%) and chicken-baited net (11.6%). The more effectiveness of the bovine-baited net confirms the degree of implication of this host in RVF epidemiology. The study of vector-hosts interactions in nature showed that among the 1,112 mosquito blood meals tested, 701 were identified of which 693 were from Aedes vexans. The percentage of non-reacting blood meal was 36.7% whereas 16.9 % of the blood meals were taken at least on two vertebrate hosts. Overall, 53.2% of the blood meals from Ae. vexans were taken on equine, 18.6% on bovines, 7.1% on sheep and 0.6% on human. No blood meal was taken on rodent. The greatest diversity was observed in August. These host feedings patterns show that although equine is known to play a minor role in RVF epidemiology a thorough attention should be made to this host with regard to the percentage of blood meals taken in this host. The low percentage of blood meals taken on human could probably explain the low human infection rate observed up to now in Senegal. With the high percentage of non-reacting blood meals, our results also underline the necessity of an improvement of ELISA techniques and the use of more reliable tools as molecular markers for an exhaustive identification of vertebrates hosts involved in RVF epidemiological cycle.

Animals↗
PubMed2005

Gamma interferon-producing CD4 T-cells correlate with resistance to Mycoplasma mycoides subsp. mycoides S.C. infection in cattle.

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC), is one of the most significant cattle disease in Africa. The control measures, which led to eradication from numerous countries are not feasible in Africa where the only prophylaxis relies on vaccination. However, the attenuated vaccines, used up to now in Africa, are of low efficiency. The development of an improved vaccine is, therefore, a necessity. The purpose of this study was to compare some immunological parameters in MmmSC-infected cattle (endobronchial versus natural in-contact infection) and assess the response in correlation with the clinical outcome (death versus recovery). Characterization of the immune parameters elicited in recovered animals, known to be refractory to new infection, will be an important step towards development of new vaccines against CBPP. A significant outcome of this study was the demonstration that all MmmSC-infected cattle developed a MmmSC-specific cell-mediated immune response. A kinetic analysis of the MmmSC responsiveness showed that the main difference between endobronchially- and in-contact infected animals was the delay before the onset of the MmmSC-specific immune response. The first MmmSC-responding PBMC sample was selected from each animal for cell phenotyping. The phenotypic analysis of this early MmmSC-induced response revealed the predominant contribution of the CD4 T-cells in all animals whereas IFNgamma was only constantly produced in recovered animals. Evolution of this early MmmSC-specific immune response was then followed by a kinetic analysis of the MmmSC-induced CD4 T-cell response and IFNgamma released. The results demonstrated that in recovered animals, the MmmSC-specific CD4 Th1-like T-cell response was maintained until slaughtering whereas in animals with acute disease, progression of CBPP was associated with a decreased ability of the PBMC to produce IFNgamma. The results led to the identification of immune parameters, which correlate with protection against CBPP and to a relevant strategy for the development of improved vaccines against this disease.

Animals↗
PubMed2005

[Sickle cell beta-thalassemia leading to serious ischemic retinopathy: a study of 18 patients in Abidjan].

The authors in this study intended to demonstrate that S-beta thalassemia can lead to severe ocular hemorrhagic risks, as is true of the sickle cell form. Both forms are also comparable in terms of the risk of aseptic necrosis of the femoral head. Out of the 18 patients studied, 13 (72.2%) had sickle cell retinopathy. Three of 13 patients had already developed new vessels and risked intravitreous hemorrhage. The authors recommend that more vigilance be mounted for the detection of S-beta thalassemia so as to benefit from rigorous and systematic follow-up and early treatment. Retinal argon laser photocoagulation is only effective if a clear diagnosis is made early.

Anemia, Sickle Cell↗
PubMed2005

Mosquito vectors of the 1998-1999 outbreak of Rift Valley Fever and other arboviruses (Bagaza, Sanar, Wesselsbron and West Nile) in Mauritania and Senegal.

Following an outbreak of Rift Valley fever (RVF) in south-eastern Mauritania during 1998, entomological investigations were conducted for 2 years in the affected parts of Senegal and Mauritania, spanning the Sénégal River basin. A total of 92 787 mosquitoes (Diptera: Culicidae), belonging to 10 genera and 41 species, were captured in light traps. In Senegal, Culex poicilipes (41%) and Mansonia uniformis (39%) were the most abundant species caught, whereas Aedes vexans (77%) and Cx. poicilipes (15%) predominated in Mauritania. RVF virus was isolated from 63 pools of Cx. poicilipes: 36 from Senegal in 1998 and 27 from Mauritania in 1999. These results are the first field evidence of Cx. poicilipes naturally infected with RVFV, and the first isolations of this virus from mosquitoes in Mauritania - the main West African epidemic and epizootic area. Additional arbovirus isolates comprised 25 strains of Bagaza (BAG) from Aedes fowleri, Culex neavei and Cx. poicilipes; 67 Sanar (ArD 66707) from Cx. poicilipes; 51 Wesselsbron (WSL) from Ae. vexans and 30 strains of West Nile (WN) from Ma. uniformis, showing differential specific virus-vector associations in the circulation activity of these five arboviruses.

Animals↗
PubMed2005

[Pyoderma gangrenosum in dakar: about 14 cases].

From January 1990 to December 2001, we undertook a retrospective study in the dermatology department of Aristide le Dantec hospital in order to assess the epidemiologic, clinical and evolutionary profiles of pyoderma gangrenosum (P.G). All files of patients diagnosed with PG were reviewed. The diagnosis was based on clinical and histological aspects. Fourteen files of patients with PG were reviewed. They were constituted of 8 males and 6 females, with a median age of 24.5 (extreme 4 and 54 years). Paediatric forms represented 30 % of the cases. The typical aspect with an ulceration with elevated edge comprising of purulent hutchs was observed in all the cases. The localization on the level of the lower limbs was noted among 12 patients (85.7 %). The PG was associated to chronic ulcerative colitis (1 case), rheumatoid spondylitis (1 case) and rheumatoid arthritis in all cases. After 11 weeks treatment by oral corticothérapy at the daily posology of 1 mg/kg/, cicatrization of cutaneous lesions were noted in all the cases. Five reccurences were observed. P.G remains a rare pathology with no difference on races and regions . this is particularly true on children. Our serie, is remarkable by the high frequency of its paediatric forms. As for clinical and evolutive aspects as well as associated pathologies, findings are comparable with those described other series

Adrenal Cortex Hormones↗
PubMed2004

Comparison of schistosome transmission in a single- and a double-cropped area in the rice irrigation scheme, 'Office du Niger', Mali.

Rice is becoming increasingly important as a staple food in West Africa and there is a need to increase production to meet the demand and one way to achieve this is to harvest two annual crops. It is possible that such intensified irrigation could affect transmission of schistosomes and this study attempts to compare schistosome transmission in single and double-cropped areas of an irrigation scheme, 'Office du Niger', in Mali. Double cropping has been practised for some years in the Niono area while in the Kolongotomo area still only a single crop is grown. Parasitological surveys conducted in 10 villages (5 from each of these 2 areas) showed that Schistosoma haematobium was less prevalent in the area with single cropping than in the area with double cropping. In order to compare transmission patterns between the two areas, all human-water contact sites around four villages (two from each area) were identified and included in transmission studies. From August 1996 to June 1997, eight surveys were conducted, at intervals of approximately 45 days, in each of these sites to record density of the intermediate hosts, density of infected snails, environmental factors (especially density of aquatic macrophytes), and frequency of human-water contacts. Although the data provide useful information on transmission patterns in Niono and Kolongotomo areas, they fail to demonstrate clear-cut differences in snail population dynamics and transmission patterns between the two areas. A key element in snail habitats in both areas is the abundance of aquatic macrophytes, especially the submerged species. Snail control using environmental modification should focus on controlling these plants in human-water contact sites.

Adolescent↗
PubMed2004

[A new case of rhinoscleroma with skin extension].

Scleroma is a chronic and specific granulomatous disease of bacterial origin. Klebsialla rhinoscleromatis, a gram-negative bacillus. The majority of cases affect the upper airways, particularly the nose, thus justifying the term of rhinoscleroma. Extension to the palate, the upper lip and the skin is possible. A new case of rhinoscleroma with skin extension is reported. To us, this is the second case in Senegal (Casamance). Epidemiological, clinical, bacteriological and histological aspects of the disease are reviewed. Under suitable antibiotic, evolution is currently favorable.

Adult↗
PubMed2004

[Assessment of chloroquine resistance two years after stopping chemoprophylaxis in 0 to 9-year-old children living in a malaria-endemic village of Mali].

This study was carried out in the village of Faladié, Mali located in the malaria-endemic Kati region, two years after routine use of chloroquine prophylaxis was discontinued in children 0 to 9 years old. The main purpose of this study was to assess changes in chloroquine resistance. Two cross-sectional surveys in association with WHO in vivo chloroquine sensitivity testing were conducted, i.e., one in September 2000 and one in December 2002. Findings in 2000 showed that 77.5% of mothers administered chloroquine prophylaxis to their children in compliance with physician orders. The plasmodic index was 62%. The overall level of parasitologic resistance (based on the 1996 WHO in vivo tests) was 80%. The overall therapeutic failure rate was 17.5%. Findings in 2002 demonstrated a plasmodic index of 28%, an overall parasitologic resistance rate of 45% (based on WHO in vivo tests), and an overall therapeutic failure rate of 15%. The diminution of resistance in 2002 may be due to the decrease of drugs pressure and to low exposure of individuals to mosquitoes at the end of transmission season. Althougt these data indicate a 44% drop in chloroquine resistance (P=0.0001), no increase in the clinical efficacy of chloroquine was observed (P=0.05). In view of these results we propose more emphasis on information campaigns to increase public awareness of the need for chemoprophylaxis only for pregnant women, on the promotion of the use of bednets and insecticide-impregnated materials, and on environmental management.

Animals↗
PubMed2004

[Control of tuberculosis as seen "in the field": popular perceptions of the disease and access to care in Conakry, Guinea].

Tuberculosis is a public health priority especially in developing countries. A variety of control programs have been implemented. The purpose of this survey was to study the perceptions and practices of the victims of this disease "in the field". The findings of this survey carried out in a cohort of 65 patients and their families in Conakry, Guinea underline the importance of popular perceptions of the disease in care-seeking behavior. This survey also shows that health care workers share the same perceptions as the general population, which constitutes a major impediment for screening and treatment.

Adult↗
PubMed2003

Long endogenous dsRNAs can induce complete gene silencing in mammalian cells and primary cultures.

Recently, double-stranded RNA (dsRNA)-mediated RNA interference (RNAi) has rapidly developed to a powerful instrument for specific silencing of gene expression in several organisms, including Caenorhabditis elegans, Drosophila melanogaster, and plants. The finding that synthetic small interfering RNAs (siRNAs) of 21 nt as well as stable, endogenously expressed, large dsRNA are suited to specifically induce gene silencing in mammalian cells offered the possibility of expanding this technique to mammalian systems. In this work, we engineered stably transfected human cells that express large dsRNAs mediating specific posttranscriptional silencing of genes. We used this technique to specifically silence genes coding for glucosylceramide synthase (GCS), the sphingolipid activator protein precursor (SAP), and glucocerebrosidase (GBA), all implicated in glycosphingolipid metabolism. From a 1600-bp inverted repeat DNA template, a dsRNA of 800 bp is expressed and predicted to mediate the specific suppression of the corresponding gene by RNAi. Remarkably, we were able to use this method to achieve complete inhibition of those genes we targeted in different cultured human cell lists. These findings testify to the generality of RNAi application in suppressing gene expression in mammalian cells.

Animals↗
PubMed2003

[Epidemiology of malaria in a village of Sudanese savannah in Mali (Bancoumana). Anti-TRAP and anti-CS humoral immunity response].

Vaccine development research is an important component of malaria control strategies. Thrombospondin related anonymous protein (TRAP) and the circumsporozoite (CS) protein are two antigens of sporozoite surface. Immune response to these two antigens may contribute to the development of anti-sporozoite vaccine. Recent studies suggest that antibodies anti-TRAP may partially block sporozoites penetration in hepatocyte, and thereby reducing malaria morbidity. We carried out a study to assess the seroprevalence of anti-TRAP and anti-CS antibodies and to identify a possible role of these antibodies on malaria morbidity in children 1-9 years old living in a rural hyperendemic village. We performed 5 cross sectional surveys and a longitudinal follow up in 1993 and 1994. During each cross sectional study, children were examined for fever and splenomegaly; all febrile children received thick film examination, and serologic analysis was performed in one third of these, randomly selected. The results show that the seroprevalence of anti-TRAP and anti-CS varied with age and season (p < 0.05). Association between the prevalence of anti-TRAP and splenomegaly was observed during two cross sectional surveys (June and October 1993). The presence of anti-TRAP antibody was associated with Plasmodium falciparum infection at the beginning of the transmission season (June 1993 and July 1994). A negative association between the level of anti-TRAP title and parasitemia was observed (March and October 1994). These findings suggest no clear evidence of the protective role of anti-TRAP antibodies in uncomplicated malaria, possibly due to the limited persistence of these antibodies under natural situations.

Antibodies, Protozoan↗
PubMed2003

[Epidemiology of malaria in a village of Sudanese savannah area in Mali (Bancoumana). 2. Entomo-parasitological and clinical study ].

We carried out five cross sectional surveys between 1993 and 1994 to assess the epidemiology of malaria in the village of Bancoumana, located in the Sudanese savannah areas of Mali. Each survey included a collection of entomological, clinical, parasitological and immunological data. The study population involved 1600 children from six months to 9 years of age. The main vector was Anopheles gambiae s.l., man bite rate and entomological inoculation rate were maximum respectively in August (peak of the transmission season) and October (end of transmission season). Plasmodium. falciparum was the main parasite species observed. Spleen enlargement rate, parasite rate, gametocyte rate and parasite density varied significantly with age and season. The parasite rate, gametocyte rate and parasite density were significantly low in October 1994 compared with October 1993 while the entomologic parameter did not show any variation over the two years. This reduction of parasitologic index between 1993 and 1994 may be related to an increase of anti-malarial drug use in the population. Our results show that malaria is hyperendemic in the village of Bancoumana.

Animals↗
PubMed2003

[Systemic scleroderma: 92 cases in Dakar].

We performed a retrospective study in order to characterize epidemiological data and signs of systemic scleroderma in Sénégal. All patients with the diagnosis according the ACR's criteria of scleroderma were recruited. We included 92 patients, the mean age was 33 years and sex ratio male to female was 0.19 (15 men and 77 women). There were 8 children in our series (8.9%). The initial complaints were cutaneous manifestations (64%) and Raynaud's syndrome (16.3%). Clinical manifestations at admission were muco-cutaneous (100%), osteo-articular and muscular (59%) and Raynaud's syndrome (57%). Focal hypopigmentation was common (70%). Anti-nuclear antibodies were present in 67.4% of patients. Skin biopsy was contributive in all patients in which it was performed (79 cases). Electrocardiogram was abnormal in 55%, non specific inflammatory syndrome was present in 44% and pulmonary function was abnormal in 52%. Our data suggest that systemic scleroderma is more common in younger people in black population. Disorders of pigmentation are common and Raynaud's syndrome is uncommon.

Adolescent↗
PubMed2003

[Behçet's disease in Dakar (Senegal): epidemiological and clinical features].

We report epidemiological and clinical characteristics of 17 consecutives patients with Behçet disease during 26 years in Dakar(Sénégal). All the patients were black, with a mean age of 27.5 years (11- 42 years) and the disease was more common between 20 and 30 years. The sex ratio was 2.4 (12 men -5 women). The majority live in cost area (64.7). Clinical features frequencies were as follow muco-cutaneous (94.11%), ocular (58.82%) neurological (47.05%) articular (47.05) psychiatric (41.17%) vascular (35.29%) digestives (11.76%). Epidemiological characteristics of Behçet disease in Sénégal are common however, the important frequency of neuropsychiatrics manifestations is remarkable.

Adolescent↗
PubMed2002

Use of reverse transcriptase PCR in early diagnosis of Rift Valley fever.

Reverse transcriptase PCR (RT-PCR) for diagnosis of Rift Valley fever (RVF) was evaluated by using 293 human and animal sera sampled during an RVF outbreak in Mauritania in 1998. Results of the RT-PCR diagnostic method were compared with those of virus isolation (VI) and detection of immunoglobulin M (IgM) antibodies. Our results showed that RT-PCR is a specific, sensitive tool for RVF diagnosis in the early phase of the disease and that its results do not differ significantly from those obtained by VI. Moreover, the combined results of RT-PCR and IgM antibody detection were in 100% concordance with the results of VI.

Animals↗
PubMed2001

Arbovirus surveillance from 1990 to 1995 in the Barkedji area (Ferlo) of Senegal, a possible natural focus of Rift Valley fever virus.

Surveillance for mosquito-borne viruses was conducted in Barkedji area from 1990 to 1995, following an outbreak of Rift Valley fever (RVF) virus in southern Mauritania. Mosquitoes, sand flies, and midges were collected from human bait and trapped by solid-state U.S. Army battery-powered CDC miniature light traps baited with dry ice or animals (sheep or chickens) at four ponds. Overall, 237,091 male and female mosquitoes representing 52 species in eight genera, 214,967 Phlebotomine sand flies, and 2,527 Culicoides were collected, identified, and tested for arboviruses in 9,490 pools (7,050 pools of female and 331 of male mosquitoes, 2,059 pools of sand flies and 50 pools of Culicoides). Viruses isolated included one Alphavirus, Babanki (BBK); six Flaviviruses, Bagaza (BAG), Ar D 65239, Wesselsbron (WSL), West Nile (WN), Koutango (KOU), Saboya (SAB); two Bunyavirus, Bunyamwera (BUN) and Ngari (NRI); two Phleboviruses, Rift Valley fever (RVF) and Gabek Forest (GF); one Orbivirus, Ar D 66707 (Sanar); one Rhabdovirus, Chandipura (CHP); and one unclassified virus, Ar D 95537. Based on repeated isolations, high field infection rates and abundance, Culex appeared to be the vectors of BAG, BBK, Ar D 65239 (BAG-like), and WN viruses, Ae. vexans and Ae. ochraceus of RVF virus, Mansonia of WN and BAG viruses, Mimomyia of WN and BAG viruses, and Phlebotomine of SAB, CHP, Ar D 95537, and GF viruses. Our data indicate that RVF virus circulated repeatedly in the Barkedji area.

Animals↗