D.M.Y. Meunier

Antibody prevalence against haemorrhagic fever viruses in randomized representative central african populations

Between 1985 and 1987, 5,070 randomly selected persons living in 6 central African countries (Cameroon, Central African Republic, Chad, Congo, Equatorial Guinea and Gabon) were checked for serological evidence of haemorrhagic fever. Rural and urban areas were studied, including ecoclimatic zones ranging from dry savana to tropical rain forest. Virus-reactive antibodies were found with all antigens tested, and the global prevalence of positive sera was distributed as follows: Crimean-Congo haemorrhagic fever virus, 0.22%; Rift Valley fever virus, 0.18%; Ebola virus, 12.40%; Marburg virus, 0.39%; Lassa virus, 0.06%; and Hantaan virus, 6.15%. A significant variation in antibody prevalence was observed within the study regions. Association between the viruses was not observed.

Fatal hepatitis from West Nile virus

Summary Four cases of clinical hepatitis confirmed by biological and pathological examination are documented. In all cases, West Nile virus was isolated from blood and liver biopsies. Two patients died, while 2 others recovered. This is the first report on West Nile virus involvement in fatal acute hepatitis.

Thermostability and efficacy in the field of a new stabilized yellow fever virus vaccine

Samples of the new, stabilized 17D virus vaccine from Pasteur Vaccins, France were stored for up to six months at +10 +/- 2 degrees C in the hospital of Bouar, Central African Republic. Each month during this study, the vaccine ampoules were put into an ice box without ice and taken into the field to be used as part of a vaccination programme. No significant loss of infectious virus titre was observed under these conditions. Efficacy of the vaccine was determined from percent seroconversions in vaccinated children. No loss of efficacy of the vaccine was observed after five months storage at +10 degrees C and five trips in the field, confirming the high heat stability of the new vaccine.

Antibodies to Lassa and Lassa-like viruses in man and mammals in the Central African Republic.

715 human sera from different locations in the Central African Republic were tested by indirect immunofluorescence against the three African arenaviruses, Lassa, Mobala and Mopeia. Four were positive for Lassa, seven for Mobala, and one for both Lassa and Mopeia. The epidemiology of African arenaviruses is discussed.

Antibodies to lav in various population groups of the Central African Republic

Resume La recherche danticorps anti-LAV a ete effectuee par deux techniques dans trois populations de Republique Centrafricaine. Le premier groupe (temoin) comporte 136 personnes en bonne sante, venues a lHopital pour vaccination; le second, 36 malades hospitalises pour divers symptomes non specifiques, tels asthenie, fievre, diarrhees, etc.; le troisieme, 10 personnes presentant un sarcome de Kaposi. Nos resultats montrent quenviron 5% de la population temoin, 45%des patients hospitalises et le tiers des personnes atteintes du sarcome de Kaposi, sont seropositifs. Cette etude preliminaire demontre la presence du virus LAV en Republique Centrafricaine, son association avec les differents symptomes non specifiques deja associes au SIDA, et surtout le fait que ce virus sest propage de facon preoccupante dans la population generale.

Surveillance sérologique des fièvres hémorragiques virales dans le Haut-Ogooue (Gabon)

Summary In 1985, 213 serum samples were collected from inhabitants of the village of Ambinda, Haut-Ogooue province in Eastern Gabon and tested by indirect immunofluorescence for Congo-CHF, Rift Valley fever (RVF), Ebola, Lassa and Marburg viruses. No antibody against Congo-CHF or Marburg, 0.9% against Lassa and 1.4% against RVF were detected in these sera, but 10.3% of sera had antibodies against Ebola virus. They were particularly reactive against the Ebola-Zaire isolate (9.4%), whereas only 0.9 % reacted with the Ebola-Sudan isolate. These results are comparable to those from Cameroon and the Congo, but not as high as those found in Zaire, Sudan, Chad and the Central African Republic. They confirm that Ebola virus is widespread in Central Africa, and that its activity in this province has slightly increased since 1980.

Rift Valley fever virus and Haemorrhagic fever in the Central African Republic

Summary Rift Valley fever virus (RVFV), primarily identified in the Central African Republic as Zinga virus, has been isolated from arthropods and humans, among whom it may be responsible for either mild disease or haemorrhagic fever. We were recently able to isolate RVFV in four patients presenting haemorrhagic symptoms, with subsequent evolution to death in three cases and one recovery. Over the past eight years, human and animal sera from CAR have been screened for RVFV antibodies using indirect immunofluorescence. Fluorescent antibodies ranged from 0 % to 4.5 % depending on the area surveyed. The dramatic increase in livestock over the past five years represents a potential domestic reservoir for the virus. This new epidemiological status is analysed and then discussed.