CHARACTERIZATION OF AVIAN MYCOPLASMA *

Although most of the work on characterization of avian mycoplasma has been done in recent years, a number of earlier observations of their involvement in diseases of poultry have been recorded. Dodd (1905) described “swollen head” as part of a disease syndrome in turkeys as early as 1905. Graham-Smith (1907) again described “swollen head,” and was able to reproduce sinusitis in turkeys by the inoculation of sinus exudate from naturally infected birds into susceptible turkeys. Tyzzer (1926) was apparently the first to describe sinusitis in turkeys in the United States. In a series of papers, Nelson (1933, 1935, 1936 a, b, c, 1938) reported on studies of coryza in chickens. He demonstrated coccobacilliform bodies in nasal exudates of birds with coryza and was able to cultivate the agents in embryonated eggs and chicken embryo tissue culture. Beach and Schalm (1936) and Schalm and Beach (1936) reported that they were able to produce sinusitis in turkeys after the intranasal inoculation of nasal exudate from chickens with coryza. In retrospect it appears that all of these workers were dealing with M. gallisepticum either in pure form or in conjunction with other bacteria. The name “infectious sinusitis” (IS) was given to the disease in turkeys by Dickinson and Hinshaw (1938). Delaplane and Stuart ( 1943) reported on the isolation and propagation of a virus in embryonated chicken eggs that was capable of causing a chronic respiratory disease (CRD) of chickens. The agents of IS and CRD were referred to as a virus, a rickettsia or an agent resembling the chlamydozaceae group of organisms by most workers until Markam and Wong (1952), and Van Roekel and Olesiuk (1952) reported on the successful cultivation of the agents of CRD and IS in Edward’s (1947) medium. Markam and Wong (1952) stated that the agents were morphologically similar and were members of the pleuropneumonia group. Comparative studies of avian mycoplasma by Jacobs et al., (1953). White et al., (1954), and Gainforte et al., (1955), indicated that there was only one serotype or species until Adler et al., (1957) first suggested the possibility of at least two different types of mycoplasma being present in chicken and turkey tissues. The two isolates were serologically distinct with one being pathogenic for turkeys while the other was nonpathogenic. Adler and Yamamoto (1957) further reported on the isolation of two strains of mycoplasma obtained from a turkey sinus exudate sample. One strain was readily grown on artificial media and was not pathogenic for chickens or turkeys while the second did not readily colonize on serum enriched media and was capable of producing IS in turkeys. * Approved for publication as Scientific Journal Series, Paper 5972, Minnesota Agricultural Experiment Station. This investigation was supported, in part, by a Public Health Service postdoctoral fellowship (No. EPD-10,617) from the National Institute of Allergy and Infectious Diseases, Public Health Service, and grants from Animal Disease and Parasite Research Division, Animal Disease Eradication Division, A M , U.S.D.A., and Minnesota Turkey Growers Association. t Studies in partial fulfillment of Ph.D. degree. Present address-Virology Section, Commumcable Disease Center, Atlanta, Georgia 30333.