VIRUS-BACTERIA COINFECTIONS

Influenza is the best known model of bacterial-viral co-infection Epid emics of influenza result in an increased hospital admission rate for bacterial pneumonia due to pneumococcus, Haemophilus influenzae and St aphylococcus aureus. Similarly, an increased incidence of meningococca l diseases, particularly severe forms, follows the influenza outbreaks , with a two week delay. Though the precise mechanism is not known, th e depression of host's phagocytes bactericidal activity by the influen za virus seems to be involved. An increased incidence of invasive grou p A beta hemolytic streptococcal infections, particularly necrotizing fasciitis and toxic shock syndrome, is also observed in relation with chickenpox. The reason for this association is unclear and appears not to be limited to the disruption of the cutaneous barrier which leads to the cutaneous infections in this disease. Bacterial-viral co-infect ion is not a justification for a systematic antibiotic prescription in viral diseases. Severe bacterial disease will be best prevented throu gh viral immunization, thus encouraging the development of viral vacci nes and immunization campaigns.