THORACIC RADIOGRAPHIC FINDINGS IN DOGS INFECTED WITH RICKETTSIA-RICKETTSII

Sixteen beagle dogs were injected intradermally with Rickettsia ricket tsii. The dogs were divided into four groups (n = 4): 1) infected, non -treated control; 2) infected, treated with doxycycline; 3) infected, treated with doxycycline and an anti-inflammatory dose of corticostero id; and 4) infected, treated with doxycycline and an immunosuppressive dose of corticosteroid. Thoracic radiographs were made and ocular flu orescein angiography was performed on days 6, 10, 17 post-inoculation. A mild interstitial lung opacity was noted in 4/16 dogs on day 6, 5/1 6 on day 10 and 3/16 on day 17 post-inoculation. Increased retinal vas cular permeability was noted in 8/16 dogs on day 6, 3/16 on day 10 and 1/16 on day 17 post-inoculation. Correlation between the presence of radiographic and retinal lesions was not significant (p = 0.08), Eleve n, naturally infected, dogs with thoracic radiographs and a final diag nosis of RMSF were also evaluated, Four of the 11 dogs had an unstruct ured interstitial pattern, Dogs with acute, experimentally-infected or naturally-occurring RMSF may have subtle pulmonary changes characteri zed by an unstructured interstitial pattern.