The activity of tetracycline on feline pneumonitis virus infection of chick embryos.

It has been demonstrated that chlortetracycline and oxytetracycline are effective against viruses of the psittacosis-lymphogranuloma group in experimental infections of mice",2 and chick embryos"-6 and that the tetracyclines have been successfully employed clinically.7-10 Chlortetracycline has become the drug of choice in the treatment of human infections caused by these agents. Recently these drugs have shown some promise in field trials in the chemotherapy of natural psittacosis and ornithosis.",12 In experimental infections of laboratory animals and chick embryos, chlortetracycline prolongs the period of survival of the infected animals, thus suppressing but not completely inhibiting the multiplication of these viruses in vivo.",3,' Since it has been demonstrated that chlortetracycline is unstable in vitro at 37 C at neutral or slightly alkaline pH, or in the presence of protein,13,14 Received for publication October 17, 1955. This investigation was supported by a grant-inaid from the Hartz Mountain Corporation, New York City. The author wishes to express his appreciation to Dr. Vincent Groupe and Miss Leonora Pugh for their interest, suggestions, and criticism, to Mr. Michael Chirigos for carrying out certain of the studies reported herein, and to Miss Clara H. Wark and Miss Phyllis Wechezak for technical assistance. 1. Kneeland, Y., Jr. and Price, K. M. 1950, Treatment with chloramphenicol, aureomycin and terramycin of the pneumonia caused by feline pneumonitis virus. J. Immunol. 65: 653-660. 2. Loosli, C. G., Hamre, D., Ritter, G. and Berlin, B. S. 1954-1955, Experimental airborne mouse pneumonitis virus (MPV) infections in mice. II. The prophylactic and therapeutic effect of sulfadiazine and antibiotics. Antibiotics Ann. pp. 474-489. 3. Allen, E. G., Girardi, A. J., Sigel, M. M. and Klein, M. 1953, Studies on the psittacosislymphogranuloma group. III. Effect of aureomycin on propagation of virus in the chick embryo. J. Exper. Med. 97: 783-795. 4. Gogolak, F. M. and Weiss, E. 1950, The effect of antibiotics on agents of the psittacosislymphogranuloma group. II. Effect of aureomycin. J. Infect. Dis. 87: 264-274. 5. Hurst, E. W., Peters, J. M. and Melvin, P. 1950, Therapy of experimental psittacosis and lympho-granuloma venereum (inguinale). 1. Comparative efficacy of penicillin, chloramphenicol, aureomycin and terramycin. Brit. J. Pharm. & Chemotherap. 5: 611-624. 6. Wong, S. C. and Cox, H. R. 1948, Action of aureomycin against experimental rickettsial and viral infections. Ann. N. Y. Acad. Sc. 51: 211-217. 7. Brainerd, H., Lennette, E. H., Meiklejohn, G., Bruyn, H. B., Jr. and Clark, W. H. 1949, The clinical evaluation of aureomycin. J. Clin. Investigation 28: 992-1005. 8. Fitz, R. H., Meiklejohn, G. and Baum, M. D. 1955, Psittacosis in Colorado. Am. J. M. Sc. 229: 252-261. 9. Green, T. W. 1950, Aureomycin therapy of human psittacosis. J.A.M.A. 144: 237-238. 10. Wright, L. T., Sanders, M., Logan, M. A., Prigot, A. and Hill, L. M. 1948, Aureomycin, a new antibiotic with virucidal properties. 1. A preliminary report on successful treatment in twenty five cases of lymphogranuloma venereum. J. A. M. A. 138: 408-412. 11. Meyer, K. F. and Eddie, B. 1955, Chemotherapy of natural psittacosis and ornithosis. Field trial of tetracycline, chlortetracycline and oxytetracycline. Antibiot. & Chemotherap. 5: 289-299. 12. Meyer, K. F. and Eddie, B. 1954-1955, Chemotherapy of natural psittacosis and ornithosis. Field trial of tetracycline (polyotic HC1), chlortetracycline and oxytetracycline. Antibiotics Ann. pp. 544-555. 13. Price, C. W., Randall, W. A. and Welch, H.