[Network for the epidemiological survey of the enteroviruses in sewage (author's transl)]

Abstract

Poliomyelitis still occurs each year in France: 27 cases in 1973, 21 cases in each of 1974 and 1975, 8 cases in 1976. Because of the risk, a survey of the spread of poliovirus in healthy populations and in sewage was organized by the Ministry of Health according to the departmental note DGS/HP/1st/250, 9-2-73. The Laboratoire d'Epidémiologie Virale of the Laboratoire National de la Santé was in charge of the technical aspects of the survey. A preliminary questionnaire was sent to each D.D.A.S.S. (Direction Départementale de l'Action Sanitaire et Sociale) in order to find out the local possibilities for sampling and preliminary treatment of the sewage samples. In 1974, all the samples were sent to the Laboratoire d'Epidémiologie Virale. Since 1975, samples have been sent to a local virology laboratory when available. The sewage samples were concentrated according to SHUVAL's or LUND's methods depending on the local conditions. Both methods tested in our laboratory were found equally efficient. In order to improve their technical laboratory methods, the virologists collaborating in this survey joined together in a working group "Virus et Eaux". For isolating the enteroviruses, we recommend the inoculation of each concentrated sample into primary monkey kidney cells grown in vials; an overlay of agar is added after inoculation. This plaque method allowed us to isolate several strains from one sample. It was possible to demonstrate that polioviruses differing in serotypes and thermosensitivity might be detectable in the same sample. Few of the isolated polioviruses (11/272) showed the same thermoresistance as did the wild strains. Certain enterovirus serotypes are known to be responsible for epidemics of meningitis and neurological disorders. It was of interest to identify non-poliomyelitic enteroviruses isolated from sewage. The study of enterovirus spread in sewage in comparison with that in healthy children is in progress.