[Viral contamination in laboratories and hospital units]

Viral contamination is at least as important in hospital laboratories and wards as contamination by bacteria or microscopic fungi, but it is much more insidious and sometimes unrecognized. There are two main types: The first has a purely technical effect and only interest the virologist. This is contamination of reagents, reference strains, cell cultures, etc.., by foreign viral agents. It may be the cause of errors on diagnosis or regrettable errors of interpretation of certain experimental data. It is most difficult to detect, if not to avoid. The second is much more worrying as it is liable to cause disease in man, which may induce severe, and even fatal infections in patients or in the medical, para-medical and technical personnel. This is the case with type B hepatitis virus which tends to invade surgical units using extra-corporeal circulation, hemodialysis units and transplantation units, blood transfusion centres, dental units and even causes victims in routine laboratories. However, type B hepatitis is not the only virus which may lead to severe infections; other viruses include: poxvirus, cytomegalovirus, arbovirus, etc. Finally, other often severe accidents may occur in research laboratories and in the pharmaceutical industry, owing to manipulation of dangerous viruses or by contact with experimental animals, e.g. rodents, or monkeys, which contain the virus in a latent state, e.g. lymphocytic choriomeningitis, Sabin virus, Marburg virus, type A hepatitis virus, etc. With regard to such accidents, we are almost completely powerless from the therapeutic point of view and, even poorly equipped, from the point of view of prophylaxis.