Jean-Pierre Hervé

Caractéristiques des souches du virus de la fiévre jaune isolées des ceufs et des larves d'une tique Amblyomma variegatum, récoltée sur le bétail à Bangui (Centrafrique)

Abstract The authors reported briefly the isolation circumstances of six strains of yellow fever virus from eggs and larvae of a tick, Amblyomma variegatum , collected from cattle at the slaughterhouses in Bangui, and from sera of a monkey infected with these larvae. Isolation conditions and characteristics of these strains are compared to strains previously isolated in Central Africa. Their viral and immunological properties are similar. The epidemiological interest of these isolements which demonstrate the transovarial and transtasial transmission of the yellow fever virus in A. variegatum was suggested.

Le virus pétévo, un nouvel arbovirus du groupe palyam isolé en république centrafricaine à partir de la tique Amblyomma variegatum

Summary A new arbovirus, Petevo virus (ArTB-2032) has been isolated from a pool of 20 male Amblyomma variegatum collected from cattle at the slaughterhouses in Bangui. Chemical properties of Petevo virus, especially its resistance to lipid solvents and sensitivity to pH 3.0 were identical to that of orbiviruses. Its group relation was established by complement fixation tests with other viruses of the Palyam group. Its distinctness from other Palyam group viruses was determined by neutralization test. This isolation extends the distribution of Palyam group viruses to Africa. For the first time a tick appears as vector of a Palyam group virus. Neutralizing antibodies were found in cattle sera but not in 69 human sera tested.

Le virus Bozo (ArB 7343) : un nouvel arbovirus du groupe Bunyamwera isolé en République Centrafricaine; sa transmission expérimentale par Aedes aegypti

Summary Bozo virus (ArB 7343), a new arbovirus, was isolated in 1975 from a pool of 100 Aedes opok collected near the village of Bozo in a forest-gallery of semi-humid savannahs in the south of Central African Republic. Its group relation was established by complement fixation test within the Bunyamwera group; its distinctness from other Bunyamwera viruses was determined by neutralisation test. Subsequently 55 strains were isolated from Aedes gr. africanus (52 strains) Culex pruina (2 strains) and Anopheles funestus (1 strain). Transmission of Bozo in suckling mice by orally infected A. aegypti was demonstrated. Virological and serological studies in the Bozo region established the existence of a selvatic cycle for Bozo virus in which principally Aedes gr. africanus and monkeys occur. The support mechanism which maintains the Bozo virus in the gallery-forests is discussed.

Intérêt de la technique d'inoculation intrathoracique à Aedes aegypti dans l'isolement et le réisolement des arbovirus

Summary Direct intrathoracic inoculation of Aedes aegypti with wild Central Africa mosquito pools was used for primary multiplication of viruses. The systematic use of this method permitted the isolation of 4 yellow fever strains in December 1978. The virus titration during the isolation exhibited a minimal increase of 3 log 10 DL 50 with this technique as compared to direct inoculation of suckling mice. The strains studied belonged to yellow fever, Zika, West-Nile, Orungo, Chikungunya and Bunyamwera serogroup viruses.

Isolements du virus de la fièvre jaune à partir de moustiques du groupe Aedes (Stegomyia) Africanus (theobald) en République Centrafricaine au cours de l'année 1978

Summary Ten strains of yellow fever virus were isolated during the year 1978, from 24 977 Aedes africanus and A. opok alloted in 906 pools, collected in the field station of Bozo (Central African Republic). Eight strains were isolated using direct inoculation into suckling mice; two more were obtained by multiplication in A. aegypti before inoculation into suckling mice. This method was used for reisolation of strains. Its interest is discussed. The present report describes the virological and immunological properties of this strains. The average survival time (5 days) is the same as that of all yellow fever viruses isolated in Central Africa.