Epidemiologic Investigations with Respiratory Disease Virus RI-67

Abstract

Infection with viruses of the RI-67 group appears to be responsible for a large portion of cases of cold-agglutinin-negative, primary, atypical pneumonia and undifferentiated acute respiratory disease (ARD) among U.S. Army populations during the contemporary period and constitutes a problem of no small proportion among newly recruited soldiers undergoing basic training. These illnesses, unlike influenza, are prevalent in some areas during the warm months as well as the cold season of the year and epidemics, in which both influenza and RI-67 infections are of etiological importance, may occur simultaneously in the same population. Most recruits in a company of men who underwent basic training at Fort Dix, New Jersey, during the Winter of 1954 presented serological evidence of infection with RI-67 or related viruses during the first 8 weeks in the company. In about 1/4 of the men, illness was severe and required hospitalization while the disease in another 1/4 of the persons was sufficiently mild to permit treatment at the dispensary. The remaining 1/2 of the soldiers suffered either a very mild or inapparent infection. Antibody surveys showed that prior experience with RI-67 group or other related viruses, such as the adenoid and tonsil degenerative agents of Rowe, Heubner et al., is widespread in the population and that infection is most common during middle years of life with less occurrence during periods which precede or follow. While infection with these viruses certainly occurs among civilian as well as military persons, the magnitude of the problem in the former group remains to be determined. The RI-67 family of viruses comprises a group of agents which are heterogeneous antigenically when compared by serum neutralization but share a common, group-specific, complement-fixing (CF) antigen which is also elaborated by the latent tonsil and adenoid degenerative agents. The RI-67 CF procedure provides a simple diagnostic test for infection with this group of viruses which is ready for widespread employment by the routine serology laboratory at such time that antigen becomes more readily available. The neutralization test, which may also be used to detect increase in antibody, is more laborious and expensive to perform and requires use of a "battery" of antigenically different strains of viruses of the group. For this reason, the neutralization test is less readily applicable for routine diagnostic purpose than the (CF) method but it remains the only procedure presently available for identification and antigenic analysis of newly recovered viral strains.