precaution

The panel of [WHO.sup.2] suggests that the minimum ventilation rate is to be set as 24 ach for airborne precaution rooms when natural ventilation is used, doubling the ventilation requirement relative to mechanical airborne negative pressure isolation rooms.

Among those case-patients for whom a specific form of isolation was specified, most were admitted to high-security containment facilities or negative-pressure rooms with airborne precautions. Although these forms of isolation can prevent secondary transmission of Lassa virus, simple barrier or contact precautions

However, airborne precautions, including use of N95 respirators and placement of patients in negative pressure isolation rooms, offers the theoretical benefit of limiting airborne transmission.

* Airborne precautions for protection against inhalation of tiny infectious droplet nuclei:

Airborne precautions should be taken for all suspected cases of measles./The incubation period usually lasts for four to 12 days during which there are no symptoms.

Health-care personnel providing care to suspected measles patients (i.e., patients with febrile illness and generalized maculopapular rash or known contacts with prodromal symptoms) should apply appropriate isolation practices, including airborne precautions, in addition to taking standard precautions for such patients.

* Airborne precautions, including possible use of isolation rooms with negative pressure to keep airborne traces of the infection from traveling to patients or visitors and use of respirators for suspect SARS patients

* Airborne precautions, including an isolation room with negative pressure relative to surroundings and the use of an N-95 respirator for persons entering the room.