Yellow fever and dengue fever serotype 3 viruses cocirculation in Côte d'Ivoire in 2008

Abstract Aim of study. To describe the emergence of dengue 3 virus in Côte d'Ivoire during a yellow fever outbreak which occurred in 2008. Materials and methods. Sera from suspected cases of yellow fever as well as contacts of yellow fever confirmed cases and imported dengue fever cases were tested for immunoglobulin M (IgM) antiyellow fever virus and anti-dengue virus (for IgM antibodies to yellow fever and dengue viruses) and by a specific real time RT-PCR (Bio-Rad) for yellow fever virus and dengue virus viral RNA detection. Results. Of the 511 sera from suspected cases of yellow fever tested, 21 (4.1%) were confirmed positive for yellow fever virus antibody, while 33 (7.6%) of the 432 sera tested were positive for dengue virus antibody. Thirteen viremic subjects, one for yellow fever virus and 12 for dengue 3 virus, were detected by RT-PCR. The majority of the confirmed cases of yellow fever (85%) and dengue 3 fever (93%)were adults, and resided in the city of Abidjan and its regions. Conclusion. These results indicate the existence of transmission foci of these arboviruses diseases in Cˆote d'Ivoire and the essential contribution of molecular tests for their diagnosis

[Epidemiological and virological aspects Rotavirus diarrhoea in Abidjan, Côte d'Ivoire (1997-2000)]. / Aspects épidémiologiques et virologiques des diarrhées dues aux Rotavirus à Abidjan, Côte d'Ivoire (1997-2000).

Viruses, mainly rotaviruses are aetiological agents in more than 80% of the cases of acute diarrhoea in children. In order to determine the epidemiological characteristics and genotypes of human rotaviruses involved in gastroenteritis in diarrheic children aged from 0 to 5 years old in Abidjan, 642 specimens of stools were collected between 1997 and 2000 in the urban health centres and University Teaching Hospitals in Abidjan. The antigenic detection of rotaviruses carried out by ELISA test was followed by the antigenic (VP6 sub-groups) and molecular characterization: polyacrylamide gel electrophoresis and genetic typing. The general prevalence of Rotavirus diarrhoea was 27.9%. Among the children who were found positive, those whose age ranged from 0 to 11 months old accounted for 45.8% against 41.3% and 12.9% for those whose age ranged from 1 to 2 and 3 to 5 years old respectively proving thus the precocity of rotavirus infection. From an electrophoretypical and antigenic point of view 74.5% of 141 extracts of RNA had a "long" profile and belonged to the VP6 II sub-group against 24.8% of "short" profile belonging to sub-group I. The electrophoretypes with short profile were identified in majority in infants whose age ranged from 0 to 2 years old. Out of the P genotypes identified, the P [8] genotype (59.6%) was predominant followed by the P [6] genotype (26.2%), P [4] (2.8%) and one mosaic genotype P[6,8] which represented 11.4%. These results will need to be completed by the determination of VP7 genotypes in order to provide interesting information on rotaviruses before the introduction of anti-Rotavirus vaccines in the country.

[Detection of anti-Lassa antibodies in the Western Forest area of the Ivory Coast]. / Detection des anticorps anti-virus de Lassa dans l'ouest forestier de la Côte d'Ivoire.

Lassa fever is an African viral hemorrhagic fever (VHF) known to be endemic in a number of West African countries including Nigeria, Sierra Leone, Liberia and Guinea. Despite having common borders with Liberia and Guinea, Côte d'Ivoire has never reported any cases of Lassa fever. In March 2000, as part of a research project on VHF--mainly yellow fever, Lassa fever and Ebola fever--in Guinea and Cote d'Ivoire, an exploratory survey was conducted to assess knowledge about VHF and immunological status against Lassa virus among forest workers in the Duekoue and Guiglo regions. One hundred and sixty-three male forest workers were interviewed using a questionnaire designed to assess risk factors for VHF exposure and personal medical history over the last 12 months. Detection of IgG antibodies against Lassa virus was performed by immunofluorescence assay with Lassa virus antigens from the Josiah and Las/AV strains. The overall prevalence of IgG antibodies was 26% (42/161). Among the Lassa IgG positive subjects, 38.5% were loggers including 20% that were positive at a serum dilution of 1/40 and 46.7% were national park workers or forest rangers including 69% that were positive at a dilution of 1/40 and more. Forty-one percent of subjects had heard of VHF including 14% who attributed it to animals and 2% who attributed it to plants. Contact with rodents was frequent and more than 50% of subjects had either eaten or skinned rodents. Although the prevalence of anti-Lassa IgG antibodies seemed high in the study population, no conclusion can be about level of exposure to Lassa virus.

Detection des anticorps anti-virus de Lassa dans l'ouest forestier de la Cote d'Ivoire

La fievre de Lassa est une fievre hemorragique virale (FHV) africaine endemique en Afrique de l'Ouest; notamment au Nigeria; en Sierra Leone; au Liberia et en Guinee. La Cote d'ivoire qui part age des frontieres avec le Liberia et la Guinee n'a jamais notifie de cas de fievre de Lassa. Dans le cadre d'un projet de recherche sur les fievres hemorragiques virales principalement la fievre jaune; la fievre de Lassa et la fievre Ebola en Guinee et en Cote d'Ivoire; une enquete a ete realisee en mars 2000 chez des travailleurs forestiers des prefectures de Guiglo et Duekoue; dans le but de determiner le niveau de connaissance sur les fievres hemorra-giques virales et le statut immunitaire vis a vis du virus de Lassa. Cent soixante-trois sujets de sexe masculin professionnels de la foret ont ete interroges a l'aide d'un questionnaire sur les facteurs de risque d'exposition aux FHV et leurs antecedents medicaux des 12 dern i e rs mois. Les anticorps seriques de type IgG anti-virus de Lassa ont ete detectes par technique d'immunofluorescence utilisant les antigenes Lassa des souches Josuah et LAS/AV. La prevalence globale en IgG obtenue etait de 26(42/161). Pa rmi les sujets positifs; 38;5etaient des bucherons dont 20positifs au 1/40; 46;7des agents du parc national ou gardes forestieres dont 69positifs au 1/40 et plus. De plus; 41des sujets avaient entendu parler des FHV; 14ont attribue leur origine a des animaux et 2a des plantes. Les contacts avec les rongeurs etaient frequents et plus de 50des personnes ont deja consomme ou depece des rongeurs. La proportion de sujets porteurs d'anticorps IgG anti-virus de Lassa dans cette population semblait elevee. Cependant cette prevalence ne permet pas de conclure a une exposition particuliere au virus de Lassa

[Detection and management of the yellow fever epidemic in the Ivory Coast, 2001]. / Detection et gestion de l'epidemie de fievre jaune en Cote d'Ivoire, 2001.

From March to December 2001, an outbreak of yellow fever was observed in Cote d'Ivoire. Sentinel surveillance for hemorrhagic fever allowed detection of the first case in the Duekoue health district in the heavily wooded western part of the country. A weekly reporting system was established. For each suspected case recorded and reported to the Epidemiological Surveillance Department at the National Institute of Public Hygiene, a sample was collected and sent for confirmation at the Pasteur Institute of the Cote d'Ivoire. The outbreak progressed from West to East reaching Abidjan, the economic capital of the country located in the southeast. The epidemic emergency plan consisted of setting up a crisis committee to implement epidemiological, entomological and virological surveillance, mass vaccination campaigns in areas around confirmed cases, and vector control. A total of 280 cases were reported including 32 confirmed cases and 6 deaths. Eleven out of 62 districts were affected with most cases occurring in cities with more than 10000 inhabitants. Over 3.7 million persons were vaccinated for an overall coverage of 92.2% in the areas where campaigns were carried out. As a result of this outbreak, surveillance for potentially epidemic diseases has been reinforced and surveillance of viral transmission is now being considered. A vaccination program for adults has also been established.

[Investigation surrounding a fatal case of yellow fever in Côte d'Ivoire in 1999]. / Investigation autour d'un cas mortel de fièvre jaune en Côte d'Ivoire en 1999.

Côte d'Ivoire is an endemic country for yellow fever, but no case was officially notified in recent years. In July 1999, however, one fatal case was reported. A German citizen was infected in the national park of Comoe, in the north eastern area of the country. In order to evaluate the extent of amaril virus circulation and the risk for local people, a virological, entomological and epidemiological investigation was carried out by the ministry of health, the OCCGE, the Côte d'Ivoire Pasteur Institute (IPCI) and the World Health Organisation in the area where the fatal case had been staying. 18 suspected and 24 confirmed mosquito catchers were identified by interview and a blood specimen was collected from each of them. In addition, 159 batches of mosquitoes from which 94 batches of potential vectors were collected; among the suspected cases, 22% were immunised against yellow fever. Serological and virological analyses were made at IPCI and the Paris Pasteur Institute by ELISA technique and isolation on cells cultures and newborn mice. All the suspicious sera and 87.5% of the catchers were positive for IgG anti-amaril virus. One catcher's serum was positive for IgM anti-amaril virus. 11 suspected sera were positive for IgG anti-dengue virus with 1 positive for IgM. 1 strain of amaril virus and 3 strains of Zika virus were isolated from mosquitoes at IPCI and confirmed by CRORA in Dakar. These results indicated that there is a yellow fever and dengue virus are prevalent among the human and vector populations in the study area. Preventive measures must be adopted to protect human beings at risk for amaril infection.

Electropherotypes of Rotaviruses in Children less than 5 years old in Abidjan, Cote D'ivoire in 1997.

Rotaviruses Are associated with gastroenteritis in human infants and the young of many species. In this study, we analysed the circulating strains of human rotavirus isolated from young children in Abidjan by electrophoresis of the viral RNA genome in agarose gels. Rotavirus strains were identified in 33 children less than two years of age in the Yopougon district of Abidjan, Cote d'lvoire. Viral RNA was extracted from the stools by phenol-chloroform treatment at 56 degrees C, followed by centrifugation at 12 OOOrpm. The electrophoresis was performed in 1.5 % agarose gels stained with 5 % ethidium bromide and Tris-acetate as the running buffer. Ten ul of each sample was loaded onto the gels which were run at lOOv for 30min. In total, 17 of the 33 specimens yielded an RNA electropherotype. Seven different RNA profiles were observed with 14 (82.4% ) long profiles and 3 (17%) short profiles. These RNA profiles represented the group A rotavirus pattern. No mixed infections were seen. There was no correlation between the age and sex of the patient with the RNA electropherotype. Serogroup A rotaviruses were the principle strains circulating in this study. Further characterization of these strains at the subgroup and serotype level will be conducted.

Electropherotypes of rotaviruses in children less than 5 years old in Abidjan, Côte d'Ivoire in 1997

Rotaviruses Are associated with gastroenteritis in human infants and the young of many species. In this study, we analysed the circulating strains of human rotavirus isolated from young children in Abidjan by electrophoresis of the viral RNA genome in agarose gels. Rotavirus strains were identified in 33 children less than two years of age in the Yopougon district of Abidjan, Cote d'lvoire. Viral RNA was extracted from the stools by phenol-chloroform treatment at 56 degrees C, followed by centrifugation at 12 OOOrpm. The electrophoresis was performed in 1.5 % agarose gels stained with 5 % ethidium bromide and Tris-acetate as the running buffer. Ten ul of each sample was loaded onto the gels which were run at lOOv for 30min. In total, 17 of the 33 specimens yielded an RNA electropherotype. Seven different RNA profiles were observed with 14 (82.4% ) long profiles and 3 (17%) short profiles. These RNA profiles represented the group A rotavirus pattern. No mixed infections were seen. There was no correlation between the age and sex of the patient with the RNA electropherotype. Serogroup A rotaviruses were the principle strains circulating in this study. Further characterization of these strains at the subgroup and serotype level will be conducted

[Incidence of sporadic hepatitis E in Ivory Coast based on still problematic serology]. / Fréquence de l'hépatite sporadique E en Côte d'Ivoire, vue au travers d'une sérologie encore problématique.

The first well-documented outbreak of viral hepatitis E in Africa was described in 1986 in Côte d'lvoire. Subsequently, no other outbreaks have been observed in the country. Côte d'lvoire therefore offers an excellent opportunity to evaluate the prevalence of sporadic viral hepatitis E in a country where the frequency of non-A, non-B, non-C viral hepatitis appears to be high. The study was carried out in Abidjan, the most populous city, and involved 111 hospitalized patients suffering from non-A, non-B and presumed non-C acute viral hepatitis. Screening for leptospirosis or a toxic etiology was carried out and the risk of including such patients eliminated. Diagnosis of viral hepatitis A was excluded from the absence of IgM anti-HAV antibodies. Patients with HBsAg and anti-HCV antibodies were not included in the study, although co-infection in asymptomatic HBV carriers or subsequent infection in patients who had recovered from a past HCV infection remained possible. There was a risk that some patients with late appearance of anti-HCV antibodies were included since PCR tests could not be performed. Cytomegalovirus or Epstein-Barr virus was not involved, since no specific IgMs against these viruses were detectable. Large discrepancies between the two commercial enzyme-linked immunosorbent assays (ELISAs) available for serological diagnosis of hepatitis E (Abbott and Genelabs) were observed. Among the 53 sera screened using both tests, only 20 gave positive results in both, and all such sera were confirmed using a domestic immunological test involving inhibition of labelled, well-documented anti-HEV-specific human IgG. Immunological confirmation was obtained for only half of the sera with discordant results in the commercial ELISAs. Full agreement between both commercial tests was observed for only 59% of the sera studied. The minimal incidence of sporadic viral hepatitis E among hospitalized patients in Abidjan with an acute hepatitis was estimated to be 27%.

Increase of the prevalence of hepatitis B virus surface antigen related to immunodeficiency inherent in acquired immune deficiency syndrome (AIDS).

During the period from January to December 1987, 2,191 serum samples were collected from different groups of the population in the Ivory Coast (1,126 healthy people selected from the general population, 416 blood donors, 112 healthy anti-HIV carriers, 173 AIDS patients, and 364 patients suffering from icterigenic hepatitis) and tested for anti-HIV (HIV-1 and HIV-2) antibodies, HBsAg, HBeAg, delta antigen (HDAg), and anti-delta (anti-HD) antibody. Anti-HIV antibodies were found in 30 (2.6%) of the general population. 55 (13.2%) blood donors, and 93 (25.5%) patients suffering from icterigenic hepatitis. HBsAg was observed in 103 (9.1%) of the general population, 45 (10.8%) blood donors, 15 (13.4%) healthy anti-HIV carriers, 59 (34.1%) AIDS patients, and 45 (40%) icterigenous hepatitis patients. The simultaneous presence of anti-HIV and HBsAg was noted in 4 (0.4%) of the general population, 8 (2%) blood donors, 15 (13.4%) healthy anti-HIV carriers, 59 (34.1%) AIDS cases, and 36 (10%) patients suffering from icterigenic hepatitis. A high prevalence of HBeAg and serological markers of infection by the delta agent were noted in the different groups. HDAg was noted only among AIDS patients or those suffering from icterigenic hepatitis, with a higher frequency among anti-HIV carriers. Our conclusion from this study is that healthy anti-HIV carriers are no more likely to be HBsAg carriers than the HIV-seronegative subjects. However, immunodeficiency induced previously by HIV infection is likely to be responsible for the high prevalence of HBsAg among AIDS patients.

[Epidemiology of infections caused by human immunodeficiency viruses HIV-1 and HIV-2 in the Ivory Coast]. / Epidemiologie des infections par les virus de l'immunodeficience humaine VIH1 et VIH2 en Côte d'Ivoire.

A study of antibodies to HIV1 and HIV2 has been performed among selected groups in Ivory Coast from January to December 1987. In total, 2,578 serum samples were examined. A seropositivity to HIV1 and/or HIV2 was observed in 32 (2.4%) of 1.334 healthy subjects of the general population from 5 different areas, 9 (3.6%) of 246 pregnant women, 58 (12.3%) of 471 blood donors, 72 (34.3%) of 210 female prostitutes, 23 (35.3%) of 65 patients with sexual transmitted diseases, 21 (35.6%) patients with chronic renal insufficiency and 98 (50.7%) patients with severe pulmonary tuberculosis. Among the 313 HIV antibodies carriers, the frequency of HIV1 infection (6.7%) was higher than HIV2 infection (2%). However, 3.4% had a double seropositivity HIV1 and HIV2.

Blood transfusions and HIV infections (HIV1, HIV2/LAV2) in Ivory Coast.

Sera from 500 blood donors, 67 multiply-transfused children with sickle-cell anaemia and 320 healthy children who had not been transfused were tested for HIV1 and HIV2 antibodies. Amongst blood donors, 49 (9.8%) exhibited antibodies to retroviruses: 12 (2.4%) to HIV1, 17 (3.4%) to HIV2 and 20 (4%) to both HIV1 and HIV2. Fifteen (22.4%) of the 67 multiply-transfused children had retroviral antibodies: five (7.4%) to HIV1 four (6%) to HIV2 and six (9%) to both HIV1 and HIV2. In contrast, among 320 non-transfused children only two (0.62%) exhibited HIV1 infection. These results suggest that children with sickle-cell anaemia who have been repeatedly transfused, constitute a high risk group for HIV1 and HIV2 infections in Ivory Coast.

[Rubella in pregnant women in Abidjan (Ivory Coast)]. / L'infection rubéolique chez les femmes enceintes à Abidjan (Cote-d'Ivoire).

1,143 serums samples collected from pregnant females at first term were tested for the presence of rubella haemagglutination inhibition antibodies. Rubella antibodies were present in 679 (59.4%) of the pregnant females and 464 (40.6%) were seronegative. No statistically significant difference was found in the prevalence of rubella specific antibodies in three age categories considered. 155 positive serum samples for rubella antibodies (IHA) were tested afterward retrospectively for rubella-specific IgM by ELISA technic, and 14 (9.03%) were positive.

[Seroepidemiology of rubella in the Ivory Coast. Geographic distribution]. / Séroépidémiologie de la rubéole en Cote-d'Ivoire. Distribution géographique.

A total of 3,473 serum samples were collected from healthy subjects in five geographical areas of Côte-d'Ivoire, between July 1985 and August 1986, and were analysed for the presence of rubella haemagglutination inhibition antibodies. Rubella antibodies were present in 1,994 of the samples giving a prevalence of 57.4%. The distribution of this prevalence appeared to be influenced by the climatic conditions and the density of population. The areas of Korhogo and Sinematiali in the north with a hot and dry climate had high prevalences, while the areas of Bouake and Bondoukou in the Centre and Centre-east respectively had low prevalences. The prevalence of rubella antibodies increases with age until it reaches a relatively low level from the age of 15 onward. The analysis of the data by the chi 2 test indicates that there was a statistically significant variation in the prevalence of rubella antibodies between urban and rural communities (p less than 0.001). In the areas of Korhogo and Sinematiali the rubella virus appeared to be best circulate in the rural communities, while the reverse was observed in the areas of Bouake and Bondoukou. In this study, there was not a sex influence in immunity to rubella, because no difference immunity to the virus was observed between males and females. In women of child-bearing age (15 to 44 years) the rubella immunity was relatively low (61.2%).