Couch, RB; Knight, V; Douglas, RG, Jr; Black, SH; Hamory, BH
Acute respiratory disease of military recruits, designated ARD, was defined as a clinical entity before the discovery of its etiology, now known to be most commonly adenovirus type 4.1 It is an acute febrile illness characterized by cough, hoarseness, sore throat, and constitutional symptoms, and occurs in epidemics usually in January, February, and March. ARD may account for more than 25 per cent of the annual occurrence of respiratory illness in recruits. Despite the apparent ease of contracting the disease, as demonstrated by the occurrence of epidemics, early experimental studies showed that nasal inoculation of volunteers with several serotypes of adenovirus seldom resulted in illness, although asymptomatic nasopharyngeal and intestinal infections were easily produced. In an effort to discover an experimental method for regular production of illness similar to the natural disease, studies were made in volunteers of small particle aerosol inoculation with adenovirus type 4. For comparison, similar studies were made by nasal inoculation. The aerosol used had a median diameter of 1.5 ,u, a size which deposits primarily in the lower respiratory tract. However, a portion of these particles, because of their size, will not deposit but will be exhaled. Nasal inoculation deposits virus direct on the membranes of the nasopharynx. It is possible, however, that some may become resuspended from mucus membranes by forceful inspiration and be carried down into the lung.