Table 3.

Gwaltney’s and Hendley’s proposed postulates for respiratory virus transmission [19].

Postulate Number One Microbial growth at the proposed anatomic site of origin.

Postulate Number Two Microbes present in secretions or tissues shed from the site of origin.

Postulate Number Three Microbes contaminate and survive in or on environmental substance or object.

Postulate Number Four Contaminated substance or object reaches portal of entry of new host.

Postulate Number Five Interruption of transmission by hypothesized route reduces incidence of natural infection.