In 1967, attention was focused on arbovirus infections of laboratory workers when an article was written by a Subcommittee on Laboratory Infections of the American Committee on Arthropod-borne Viruses (ACAV). (The word “arboviruses” is a contraction of “arthropod-borne viruses,” which are animal viruses transmitted among vertebrates by infected blood-sucking arthropods.) This subcommittee made the following points: 1. Arboviruses can be dangerous to laboratory workers. The article described the extent of the danger and made reference to information on physical containment. The subcommittee suggested that sera of laboratory staff be tested regularly for antibodies to viruses handled by the staff to detect inapparent infections, and that persons accidentally exposed to arboviruses in laboratories be passively immunized immediately with specific antibodies. 2. Unlike natural arbovirus infections, which result from bites of arthropods, laboratory infections usually are caused by skin-penetrating accidents or exposures to aerosols of virus. 3. “Laboratory-adapted” strains of arboviruses which have been passed through animals many times can still be pathogenic for humans.