Optimization of cottontail rabbit papilloma virus challenge technique

Disease induced by Cottontail Rabbit Papilloma Virus (CRPV) scarification i n domestic rabbits shares many attributes with disease induced by human pap illoma virus (HPV). CRPV induces squamous papillomas in domestic rabbits, o f which similar to 70% transform into invasive carcinomas. In advanced tumo rs, virus is often undetectable, and occasionally, some rabbits undergo spo ntaneous regression of papillomas. Techniques utilized to scarify rabbit sk in are diverse, often labor intensive and time consuming with the possibili ty for significant variability. Using four unique infection techniques, res ultant papilloma incidence, time to onset, and total papilloma volumes were compared to determine an optimal challenge method. Five rabbits were each infected with CRPV via a tattoo gun with and without ink, an intradermal in jection, manual use of a tattoo needle, or a sterile blade followed by manu al use of a tattoo needle. Papilloma formation was monitored weekly after i noculation for 6 weeks. CRPV papillomas began as pinpoint foci at 3 weeks p ost challenge and grew exponentially throughout the course of measurement. Individual foci coalesced rapidly to form larger papilloma aggregates. Alth ough intradermal injection was well tolerated and easily performed, it was the worst method of papilloma. production (2.2 mm(3) at 6 weeks). The best method, a sterile blade followed by manual use of a tattoo needle, produced significantly larger papillomas over all time periods ( > 1100 mm(3) at 6 weeks, P < 0.01). Inoculation of CRPV using this method produces highly rep eatable papillomas beginning 3 weeks post-infection. (C) 2001 Elsevier Scie nce B.V. All rights reserved.