Δcps1 vaccine protects dogs against experimentally induced coccidioidomycosis
Lisa F. Shubitz, Edward J. Robb, Daniel A. Powell, Richard A. Bowen, Angela M. Bosco‐Lauth, Airn E. Hartwig, Stephanie Porter, Hien T. Trinh, Hilary Moale, Helle Bielefeldt‐Ohmann, James J. Hoskinson, Marc J. Orbach, Jeffrey A. Frelinger, John N. Galgiani
Abstract
Coccidioidomycosis is a significant health problem of dogs and humans in endemic regions, especially California and Arizona in the U.S. Both species would greatly benefit from a vaccine to prevent this disease. A live avirulent vaccine candidate, Δcps1, was tested for tolerability and efficacy to prevent pulmonary coccidioidomycosis in a canine challenge model. Vaccine injection-site reactions were transient and there were no systemic effects observed. Six of seven vaccine sites tested and all draining lymph nodes were sterile post-vaccination. Following infection with Coccidioides posadasii, strain Silveira, arthroconidia into the lungs, dogs given primary and booster vaccinations had significantly reduced lung fungal burdens (P = 0.0003) and composite disease scores (P = 0.0002) compared to unvaccinated dogs. Dogs vaccinated once had fungal burdens intermediate between those given two doses or none, but disease scores were not significantly different from unvaccinated (P = 0.675). Δcps1 was well-tolerated in the dogs and it afforded a high level of protection when given as prime and boost. These results drive the Δcps1 vaccine toward a licensed veterinary vaccine and support continued development of this vaccine to prevent coccidioidomycosis in humans.