Laryngeal Papillomatosis in Adults: Assessment for Ten Years at the ENT Department of the National University Hospital of Fann (Dakar, Senegal).

OBJECTIVES: The aim of this study was to describe the epidemiological, diagnostic, and therapeutic aspects of adult laryngeal papillomatosis in Senegal. Patients and Methods. This is a retrospective descriptive study of patients aged above 18 years with laryngeal papillomatosis and followed at the ENT department of the NUH of Fann between 01 January 2009 and 31 December 2018. RESULTS: The mean age at diagnosis was 37.74 years and a sex ratio of 0.93. The 20-29 age group was the most represented (45.2%). The average consultation delay was 8.34 years. All patients had dysphonia at the moment of the diagnostic and in 35.5% of cases, and it was associated with laryngeal dyspnea. Glottis localization was present in all our patients, i.e., 100% of the cases. A tracheotomy was performed in 9.67% of cases. All of our patients have had their papilloma peeled per endoscopic with tweezers. No cases of malignant degeneration were found in our study. CONCLUSION: Laryngeal papillomatosis is the most common benign tumor of the larynx in both children and adults. Despite the progress of endoscopy and antiviral treatments, its treatment poses many problems in our undermedicalized countries.

GloPID-R report on chikungunya, o'nyong-nyong and Mayaro virus, part 2: Epidemiological distribution of o'nyong-nyong virus.

The GloPID-R (Global Research Collaboration for Infectious Disease Preparedness) chikungunya (CHIKV), o'nyong-nyong (ONNV) and Mayaro virus (MAYV) Working Group has been established to identify gaps of knowledge about the natural history, epidemiology and medical management of infection by these viruses, and to provide adapted recommendations for future investigations. Here, we present a report dedicated to ONNV epidemiological distribution. Two large-scale ONNV outbreaks have been identified in Africa in the last 60 years, interspersed with sporadic serosurveys and case reports of returning travelers. The assessment of the real scale of ONNV circulation in Africa remains a difficult task and surveillance studies are necessary to fill this gap. The identification of ONNV etiology is made complicated by the absence of multiplex tools in co-circulation areas and that of reference standards, as well as the high cross-reactivity with related pathogens observed in serological tests, in particular with CHIKV. This is a specific obstacle for seroprevalence studies, that necessitate an improvement of serological tools to provide robust results. The scarcity of existent genetic data currently limits molecular epidemiology studies. ONNV epidemiology would also benefit from reinforced entomological and environmental surveillance. Finally, the natural history of the disease deserves to be further investigated, with a specific attention paid to long-term complications. Considering our incomplete knowledge on ONNV distribution, GloPID-R CHIKV, ONNV and MAYV experts recommend that a major effort should be done to fill existing gaps.

Evidence of West Nile virus circulation among humans in central northern Algeria.

West Nile Virus (WNV) is the most widely distributed flavivirus worldwide. It is a mosquito-borne virus, and birds constitute its natural reservoir. Humans and equines are considered accidental hosts. Human WNV infections are usually asymptomatic or express as a mild febrile syndrome; however, in around 1% of cases they are responsible for more serious neurological diseases with a potentially lethal outcome. In the Mediterranean basin the virus circulation is regarded as endemic. Outbreaks of WNV meningoencephalitis are regularly notified, especially during summer and autumn seasons. In Algeria, although some surveys have reported WNV activity in the Sahara, to date few data are available about virus circulation in the northern part of the country. We conducted this study to detect possible WNV activity in this part of Algeria. For this purpose, in 2010 a total of 164 human sera were collected from native patients of the Algiers district and surrounding areas, then tested retrospectively for IgG anti-WNV by ELISA. Plaque reduction neutralization technique (PRNT) was used for result confirmation. In this cohort, 9.8% of the 164 collected sera returned positive for anti-WNV IgG; after confirmation by PRNT; 6.7% had specific neutralizing antibodies. No statistically significant difference was observed according to the sex or transfusion status of the patients. In conclusion, these data show for the first time serological evidence of WNV circulation in Algiers and its surrounding areas. They also highlight the need for implementing an integrated surveillance programme covering all aspects of WNV disease in order to better understand the circulation dynamics of WNV in this region. Other flaviviruses antigenically related to WNV should be investigated, given the evidence of serological cross-reaction, as specific IgG antibodies decrease after PRNT confirmation.

Efficacy and Safety of Manual Partial Red Cell Exchange in the Management of Severe Complications of Sickle Cell Disease in a Developing Country.

INTRODUCTION: The realization of red cell exchange (RCE) in Africa faces the lack of blood, transfusion safety, and equipment. We evaluated its efficacy and safety in severe complications of sickle cell disease. PATIENTS AND METHOD: Manual partial RCE was performed among sickle cell patients who had severe complications. Efficacy was evaluated by clinical evolution, blood count, and electrophoresis of hemoglobin. Safety was evaluated on adverse effects, infections, and alloimmunization. RESULTS: We performed 166 partial RCE among 44 patients including 41 homozygous (SS) and 2 heterozygous composites SC and 1 S/ß0-thalassemia. The mean age was 27.9 years. The sex ratio was 1.58. The regression of symptoms was complete in 100% of persistent vasoocclusive crisis and acute chest syndrome, 56.7% of intermittent priapism, and 30% of stroke. It was partial in 100% of leg ulcers and null in acute priapism. The mean variations of hemoglobin and hematocrit rate after one procedure were, respectively, +1.4 g/dL and +4.4%. That of hemoglobin S after 2 consecutive RCE was -60%. Neither alloimmunization nor viral seroconversion was observed. CONCLUSION: This work shows the feasibility of manual partial RCE in a low-resource setting and its efficacy and safety during complications of SCD outside of acute priapism.

Usefulness of Dried Blood Spots (DBS) to perform hepatitis C virus genotyping in drug users in Senegal.

The aim of this pilot study was to analyze the Hepatitis C Virus (HCV) genotypes circulating in Senegal among Drug User (DUs), using Dried Blood Spots (DBS) as RNA source for molecular assays. Heroin and/or cocaine users (n = 506) were recruited in Dakar from April to July 2011, using a Respondent Driven Sampling (RDS) method. DBS preparation consisted of five drops of whole blood from finger applied to a Whatman paper card. HCV infection was screened by the detection of anti-HCV antibodies, using a rapid immune-chromatographic test. HCV RNA was quantified on anti-HCV positive DBS, using the Abbott RealTime HCV® Genotyping was performed on DBS with detectable viral load with Versant® HCV Genotype 2.0 Assay (LiPA) and Abbott RealTime HCV Genotype II assay®. Among the 506 participants, 120 were tested as positive for anti-HCV antibodies and their samples were analyzed for HCV RNA viral load and genotype. Out of the 120 DBS tested, HCV RNA was detected on 25 (20.8%). The median viral load was 15,058 IU/ml (ranging from 710 to 766,740 IU/ml). All positive DBS were suitable for the genotyping assay, that showed a predominance of genotype 1 (21/25) including 16 genotypes 1a and 5 genotypes 1b. HCV genotype 1 prevails in a DU population in Dakar. DBS could be useful for HCV RNA genotyping, but optimal storage conditions should required avoiding RNA impairment. Acknowledging this limitation, DBS could be a great interest for detecting and genotyping HCV viremic patients. J. Med. Virol. 89:484-488, 2017. © 2015 Wiley Periodicals, Inc.

[Profil course of SC sickle-cell patients in Dakar: a case-control study with SS sickle cell form]. / Profil evolutif de la drepanocytose SC A Dakar: étude cas-témoin avec la forme SS.

AIMS: The study aim to describe the epidemiological, clinico-biological and evolutionary aspects of SC sickle cell patients compared to SS sickle cell disease. PATIENTS AND METHODS: We realized a case-control study of 12 months duration including 98 major sickle cell patients (49 SC and 49 SS sickle cell patients). SS sickle cell patients were randomly selected according to age and sex. Socio-demographic, clinico-biological and evolutionary data were noted for each patient. RESULTS: Mean age was 24.7 years (5 - 53). Sex ratio was 0.8. Mean number of transfusions was 0.06 of SC patients and 0.34 for SS patients (p=0.0008). Mean number of vaso-occlusive crisis per year was 2.24 of SC patients and 2.37 of SS patients (p=0.3). Mean basic hemoglobin level was 10.8 of SC patients and 7.8 of SS patients (p=0.0000). Priapism was found in 2.04% of SC patients and 4.04% of SS patients (p=0.3) and acute anemia in 2.04% of SC and 24.48% of SS patients (p=0.003); 26.53% of SC patients had a chronic complication compared to 18.36% of SS patients (p=0.0001). CONCLUSION: This study shows that SC sickle cell patients are less symptomatology compared to SS patients, however they would develop more chronic complications from where the utility for regular follow-up.

BUTS: Le but de notre étude était de décrire les aspects épidémiologiques, clinico-biologiques et évolutifs des patients SC comparés aux patients SS. PATIENTS ET MÉTHODES: Il s'agissait d'une étude cas témoins d'une durée de 12 mois portant sur 98 patients (49 SC et 49 SS8). Les témoins SS étaient choisis de façon aléatoire après appariement selon l'âge et le sexe. Pour chaque patient nous avons noté les aspects sociodémographiques, clinicobiologiques et évolutifs. RÉSULTATS: L'âge moyen était de 24,7 ans (5 - 53). Le sex ratio était de 0,8. Le nombre moyen de transfusions était de 0,06 chez les SC et 0,34 chez les SS (p=0,0008). Le nombre moyen de CVO/an était de 2,24 chez les SC et 2,37 chez les SS (p=0,3). Le taux moyen d'hémoglobine de base était de 10,8 chez les SC et 7,8 chez les SS (p=0,0000). Le priapisme était trouvé chez 2,04% des SC et 4,04% des SS (p=0,3) et l'anémie aigue chez 2,04% des SC et 24,48% des SS (p=0,003); 26,53% des SC souffraient d'une complication chronique contre 18,36% des SS (p=0,0001). CONCLUSION: Cette étude montre que les drépanocytaires SC ont une symptomatologie moindre par rapport aux patients SS, cependant ils développeraient plus de complications chroniques d'où l'utilité d'un suivi régulier.

Evaluation of transfusion practices in sickle cell disease in Senegal: cohort study of 1078 patients with sickle cell disease.

Blood transfusion is an essential therapeutic tool in the treatment of sickle cell disease. Its indications and modalities vary from one country to another as a function of the clinical severity of the disease and the availability of blood products. This study seeks to evaluate the frequency and modalities of blood transfusions as well as their indications in patients with sickle cell syndrome at the Dakar hematology department from 1995 through 2015. This retrospective study reviewed the records of a cohort of 1078 patients with SS, SC, Sß0 and Sß + thalassemia sickle cell syndromes and collected data about the type of blood products, indications, modalities, and acute transfusion complications. The frequency of transfusion was adjusted for age, sex, and sickle cell profile. The patients' mean age was 23 years (2-44 years) and the sex ratio 0.9. SS disease was predominant (87.4 %); 28.5% had transfusions during the study period. Patients older than 20 years received more transfusions (P = 0.047). The frequency of transfusions did not differ significantly by gender (P = 0.12), but did by profile: a higher percentage of patients with SS disease required transfusion (P = 0.043). Acute anemia was the most common indication for transfusion (50.03 %). Acute transfusion complications were rare (5.8 %). This study shows that less than one third of sickle cell anemia patients in Senegal have transfusions, a finding that confirms that our patients have fewer transfusions than patients in other countries in Africa or in the West. This limited use of transfusion therapy may be related to a less severe level of disease among patients in Senegal, but also to the availability of blood products.

Syndrome d'activation macrophagique secondaire chez l'enfant. Rapport de 5 cas sénégalais

Le Syndrome d'Activation Macrophagique (SAM) est défini comme la traduction clinico-biologique d'une prolifération et d'une activation non-spécifique des macrophages du système réticulo-histiocytaire avec phagocytose des éléments figurés du sang. Nous rapportons 5 cas de SAM secondaires chez des enfants hospitalisés dans le service de pédiatrie de l'hôpital Aristide le Dantec entre août 2015 et avril 2016. Il s'agissait de 3 filles et 2 garçons âgés de 7 ans à 14 ans. Cliniquement, la fièvre, l'altération de l'état général et la splénomégalie étaient constantes. Quatre patients ont présenté des adénopathies et chez 2 patients une hépatomégalie a été retrouvée. Au niveau de l'hémogramme, l'anémie était constante, la thrombopénie et la leuco-neutropénie étaient retrouvées chez 3 patients et le frottis sanguin révélait 36% de blastes chez un patient. L'hémophagocytose médullaire était retrouvée chez tous les patients, l'hyper ferritinémie était constante et chez trois patients une hypertriglycéridémie avec un taux élevé de lactate déshydrogénase (LDH) ont été notés. Le diagnostic était surtout guidé par le médullogramme et basé sur les critères de l'hemophagocytic histiocytosis et les étiologies étaient infectieuses et néoplasiques. Chez trois patients, le SAM était d'origine infectieuse et les germes retrouvés étaient le Streptococcus, l'Escherichia coli et le Mycobacterium tuberculosis alors que les deux autres cas étaient d'origines néoplasiques secondaires à une leucémie aiguë myéloïde et à un lymphome hodgkinien. Le traitement était basé sur l'antibiothérapie (cas 1 et 2), les antituberculeux (cas 3) et la chimiothérapie (cas 4 et 5). L'évolution était favorable chez tous nos patients

Dépistage des lésions précancéreuses du col utérin et micro-organismes associés dans trois communes de Nouakchott

Introduction : Le cancer du col de l'utérus emporte plus de 266.000 femmes chaque année dans le monde et 70% des victimes de cette affection vivent dans des pays à revenu faible ou intermédiaire. Cette maladie peut être prévenue grâce à un test de frottis cervico-vaginal. Les objectifs de cette étude était de déterminer la prévalence des lésions précancéreuses du col utérin et des micro-organismes associés dans la population étudiée et d'aider à une meilleure prise en charge de la maladie aussi bien dans la prévention que dans le traitement à l'échelle nationale. Patientes et méthodes : Cet article porte sur un échantillon de 500 femmes venant de 3 communes de Nouakchott (Arafat, Riad et Sebkha). Il ressort de notre étude que les infections spécifiques étaient prédominées par celles au Gardnerella vaginalis (58,44%). Elles étaient suivies respectivement par celles au Candida albicans (16,25%), Trichomonas vaginalis (14,29%) et HPV (12,98%). Les lésions pré-cancéreuses représentaient 14,29% des lésions spécifiques avec une forte association du HPV (95,4%).Conclusion : Il importe de vulgariser le test de FCV, en passant par la formation de cyto-techniciens capables de réaliser des FCV et multiplier les sites de dépistage à l'intérieur du pays

[Evaluation of the efficacy of medical screening of blood donors on preventing blood transfusion-transmitted infectious agents]. / Évaluation de l'efficacité de la sélection médicale des donneurs de sang dans la prévention des agents infectieux.

BACKGROUND: The aim of this study was to evaluate the efficacy of medical screening to retain blood donors in window period by comparing the seroprevalence of infectious agents (HIV, hepatitis B and C, syphilis) in deferred versus accepted blood donors. MATERIALS AND METHODS: This prospective and transversal study was performed during 4 months in the National Blood Transfusion Center in Dakar (Senegal). We conducted a convenience sampling comparing the seroprevalence of infectious agents (HIV, HBsAg, HCV and syphilis) in deferred versus accepted blood donors after medical selection. RESULTS: In total, 8219 blood donors were included. Medical selection had authorized 8048 donors (97.92%) and deferred donors were 171 (2.08%). The prevalence of HIV was higher in the deferred than in accepted blood donors (1.75% vs. 0.05%) (P=0.0003; OR=35.91), as well as for HBsAg (12.87% vs. 7.35%) (P=0.006; OR=1.86). HCV antibodies were present in 0.71% of accepted blood donors and 0.58% in deferred blood donors (P=0.65; OR=0.82). Only accepted donors had brought the infection of syphilis (0.34%) (P=0.56; OR=0). CONCLUSION: Medical selection is efficient to exclude blood donors at high risk of HIV transmission and to a lesser extent of HBV. However, current medical screening procedures do not allow us to exclude donors asymptomatic carriers of HCV and syphilis.

Observational study on immune response to yellow fever and measles vaccines in 9 to 15-month old children. Is it necessary to wait 4 weeks between two live attenuated vaccines?

BACKGROUND: The use of 2 live attenuated vaccines (LAV) is recommended to be simultaneous or after an interval of at least four weeks between injections. The primary objective of this study was to compare the humoral response to yellow fever (YF) and measles vaccines among children vaccinated against these two diseases, either simultaneously or separated by an interval of 7-28 days. SUBJECTS AND METHODS: A prospective, multicenter observational study was conducted among children aged 9-15 months. The primary endpoint was the occurrence of positive yellow fever antibodies after YF vaccine by estimating the titers of neutralizing antibodies from venous blood samples. Children vaccinated against YF 7-28 days after receiving the vaccine against measles (test group) were compared with children vaccinated the same day against these two diseases (referent group). RESULTS: Analysis was performed on 284 children. Of them, fifty-four belonged to the test group. Measles serology was positive in 91.7% of children. Neutralizing antibodies against YF were detected in 90.7% of the test group and 92.9 of the referent group (p=0.6). In addition, quantitative analysis of the immune response did not show a lower response to YF vaccination when it took place 1-28 days after measles vaccination. DISCUSSION: In 1965, Petralli showed a lower response to the smallpox vaccine when injected 4-20 days after measles vaccination. Since then, recommendations are to observe an interval of four weeks between LAV not injected on the same day. Other published studies failed to show a significant difference in the immune response to a LAV injected 1-28 days after another LAV. These results suggest that the usual recommendations for immunization with two LAV may not be correct. CONCLUSION: In low income countries, the current policy should be re-evaluated. This re-evaluation should also be applied to travelers to yellow fever endemic countries.

Development of a Usutu virus specific real-time reverse transcription PCR assay based on sequenced strains from Africa and Europe.

Usutu virus (USUV) has been isolated in several African and European countries mainly from mosquitoes and birds. However, previous benign and two recent severe cases of human infections point out the need of a tool for the identification of USUV in human samples. A published real-time reverse transcription (RT) PCR assay for the detection of USUV in human blood or cerebrospinal fluid does not take into account the genetic variability of USUV in different geographic regions. Therefore, this article presents a quantitative real-time RT-PCR assay based on sequences from Europe and Africa. Primers and probe were designed in conserved regions among USUV strains that differed from closely related flaviviruses. The specificity of the assay was investigated by testing 16 other flaviviruses circulating in Africa. The sensitivity was determined by testing serial dilutions of virus and RNA standard. Intra- and inter-assay coefficients of variation were evaluated by 10 reactions in a same and in different assays, respectively. The assay provides high analytical specificity for USUV and detection limits of 1.2pfu/reaction for virus dilutions in L-15 medium or human serum and 60 copies/reaction for the RNA standard. The assay needs to be evaluated in a clinical context and integrated in standard diagnosis of flaviviral diseases.

[Diagnostic and evolutionary aspects of hemorrhagic syndromes of the newborn in Dakar]. / Aspects diagnostique et évolutif des syndromes hémorragiques du nouveau-né à Dakar.

BACKGROUND: Hemorrhage is a common and serious symptom in the neonatal period. In developing countries, means of exploration are insufficient. Our purpose was to describe the epidemiological, diagnostic, therapeutic, and evolutionary aspects of hemorrhagic syndromes of the newborn in Dakar, Senegal, to identify the risk factors and diseases associated with them in order to propose recommendations for their management. METHODS: We conducted a case-control study of 82 newborns with 41 cases of hemorrhagic syndromes and 41 controls. We first described the epidemiological, diagnostic, therapeutic, and evolutionary parameters of the group that submitted a hemorrhagic syndrome and compared their diagnostic data with those of the control group to highlight the risk factors associated with the occurrence of hemorrhagic syndrome. RESULTS: The prevalence of hemorrhagic syndrome among hospitalized newborns was 9.2%, the sex-ratio (M/F) was 1.9. Preterm infants accounted for 26.8%. We often found early onset of bleeding (46.4% before 72h of life). Visceral bleeding was predominant, especially respiratory (34.1%), digestive (31.7%), and cerebral (17%), followed by cutaneous hemorrhages (26.8%). The risk factors identified were respiratory distress, shock, and a stained amniotic fluid. The concomitant diagnoses were dominated by neonatal infection (58.5%), hemorrhagic disease of the newborn (21.9%), and disseminated intravascular coagulation (19.5%). The mortality rate was high (34.1%), most often associated with disseminated intravascular coagulation. CONCLUSION: This study reveals the high mortality due to hemorrhagic syndromes caused by these three diseases for which prevention must be stressed.

Re-emergence of Rift Valley fever virus in Barkedji (Senegal, West Africa) in 2002-2003: identification of new vectors and epidemiological implications.

The Rift Valley fever virus (RVFV) is a threat that must not be neglected, as the consequences of RVFV are dramatic, both for human and animal health. This virus is a zoonotic virus that already has demonstrated a real capacity for re-emerging after long periods of silence, as observed in Barkedji (Senegal, West Africa) in 2002. In this article we present the 2nd emergence in Barkedji after the 1st manifestation in 1993, and for the 1st time the circulation of RVFV during 2 consecutive years among mosquito populations in Senegal. As part of the entomological surveillance program undertaken since 1990 to detect circulation of the RVFV in Barkedji, 108,336 mosquitoes belonging to 34 species and 5 genera were collected in 2002-2003. Aedes vexans and Culex poicilipes, previously known to be vectors of RVFV in Senegal, comprised 88.7% of the total collection. In 2002, Ae. vexans was the most abundant mosquito, followed by Cx. poicilipes; the opposite situation was observed in 2003. In 2002, 29 and 10 RVFV isolates were obtained from Cx. poicilipes (minimum infection rate [MIR] = 0.13%) and Ae. vexans (MIR = 0.02%) pools, respectively and the MIR for the 2 species were significantly different (chi2 = 34.65; df = 1, P < 0.001). In 2003, 7 RVFV strains were isolated from Cx. poicilipes (3, MIR = 0.03), Mansonia africana (2, MIR = 0.08), Ae. fowleri (1), and Ma. uniformis (1, MIR = 0.05). The 3 latter species were found to be associated with RVFV for the 1st time in Senegal. A significant decrease in MIR was observed from 2002 to 2003 (chi2 6.28; df = 1, P = 0.01) for Cx. poicilipes, the only species involved in the transmission during the 2 sampling years.

Evaluation of the efficiency of bird-baited traps for sampling potential West Nile fever mosquito vectors (Diptera: Culicidae) in Senegal.

The efficiency of bird-baited traps and collection heights for sampling potential West Nile mosquito vectors was studied during the 2006 rainy season (between September 27 and November 26) in Barkedji area situated in the sahelian area of Senegal (West Africa). Each night, two traps were set on the ground-level and two on the canopylevel (approximately 3 m) each containing either a chicken or a pigeon, the traps being rotated the following nights. A total of 1,030 mosquitoes were collected using 66 traps-nights. Culex species were predominant and represented 92.2% of the fauna of which 63% belonged to Cx. neavei group Theobald whereas 23.8% were Cx poicilipes (Theobald). The species of the Cx. neavei group were mainly collected by the pigeon-baited trap at canopy while Cx. poicilipes was captured similarly by pigeons and chickens placed at the canopy and ground. The implication of these results in West Nile vectors surveillance is discussed.

Environmental risk factors of West Nile virus infection of horses in the Senegal River basin.

In 2005, a serological study was carried out on horses in five ecologically contrasted zones of the Senegal River basin (Senegal) to assess West Nile virus (WNV) transmission and investigate underlying environmental risk factors. In each study zone, horses were randomly selected and blood samples taken. A land-cover map of the five study areas was built using two satellite ETM+ images. Blood samples were screened by ELISA for anti-WNV IgM and IgG and positive samples were confirmed by seroneutralization. Environmental data were analysed using a principal components analysis. The overall IgG seroprevalence rate was 85% (n=367; 95% CI 0.81-0.89). The proximity to sea water, flooded banks and salted mudflats were identified as protective factors. These environmental components are unfavourable to the presence of Culex mosquitoes suggesting that in Senegal, the distribution of the vector species is more limiting for WNV transmission than for the hosts' distribution.

[Residual risk of transmission of HIV and HBV, in Senegalese national blood bank from 2003 to 2005]. / Risque résiduel de transmission du VIH et du VHB par transfusion sanguine entre 2003 et 2005 au Centre national de transfusion sanguine de Dakar (Sénégal).

BACKGROUND AND AIM: Using of safety blood products did not stop improving these last years. The use of effective methods as well immunologicals as virologicals ones really reduces risk associated to blood transfusion. However, it persists residual risk (RR) of transfusion transmitted viral diseases. The aim of our study was to detect cases of seroconversion for HIV,and HBV among donors in the Senegalese national blood bank. And then, we estimated the RR of these virus. METHODS: We led a transverse retrospective study from 2003 (January 1st) to 2005 (December 31st). Had been included donors with at least two donations of blood during the period of study. They had to be seronegative for HIV and HBV after the first donation. All donors with only one donation had been excluded. RR was estimated by multiplying incidence rates by the durations of the window periods. RESULTS: During 3 years, we collected 425,503 donations; 388 were positive for HIV and 4240 for HBV. But we noted only two cases of seroconversion for HIV and 23 for HBV. So, RR estimated was 3,5 in 100,000 donation for HIV and 102,45 in 100,000 donations for VHB. CONCLUSION: It emerges from this study that the risk of blood transmitted virus is always high. Introduction of more sensitive tests (as nucleic acid testing) would allow us to deliver more safety products.