The agents listed in this group may be present in blood, cerebrospinal fluid, urine and exudates depending on the specific agent and stage of disease. The primary laboratory hazards are exposure to aerosols of infectious solutions and animal bedding, accidental parenteral inoculation, and broken skin contact. Biosafety Level 3 practices, safety equipment, and facilities are recommended for activities using potentially infectious clinical materials and infected tissue cultures, animals, or arthropods. A licensed attenuated live virus is available for immunization against yellow fever and is recommended for all personnel who work with this agent or with infected animals, and those who enter rooms where the agents or infected animals are present. These recommendations are based on documented cases of severe and frequently fatal naturally occurring human infections and aerosoltransmitted laboratory infections.
Arthropods are the natural vectors of the tick-borne encephalitis complex agents.
Work with or exposure to rodents, nonhuman primates, or vectors naturally or experimentally infected with these agents represents a potential source of human infection. The infectious agents may be present in blood, urine, respiratory and throat secretions, semen and tissues from human or animal hosts, and in arthropods, rodents, and nonhuman primates. Biosafety Level 4 practices and facilities are recommended for all activities utilizing known or potentially infectious materials of human, animal, or arthropod origin. SALS has lowered the biohazard classification of Junin virus to BSL 3, provided all at risk personnel are immunized and the laboratory is equipped with HEPA filtered exhaust.