Spontaneous cataracts in laboratory rabbits.

OBJECTIVE

To document the occurrence and incidence of spontaneously occurring cataracts in older New Zealand White (NZW) and New Zealand White x New Zealand Red (NZW x NZR - F1) rabbits during prescreening examinations at Alcon Laboratories.

PROCEDURES

A retrospective study was conducted on prescreening examination records of NZW and NZW x NZR (F1) rabbits at Alcon Laboratories between April 1999 and May 2001.

RESULTS

A total of 946 rabbits (670 NZW and 276 NZW x NZR) ranging in age from 77 to 288 days were examined. Of the NZW rabbits, 333 were males and 337 were females. Of the NZW x NZR (F1) rabbits, 139 were males and 137 were females. Thirty-eight NZW rabbits (23 males and 15 females) exhibited immature cataracts in one or both eyes, and three NZW x NZR (F1) rabbits (one male and two females) exhibited cataracts in one or both eyes. The overall incidence of cataracts was 4.3% of all rabbits. Males and females were equally affected, but a significant difference in the incidence of cataracts existed between the NZW and NZW x NZR (F1) rabbits with 5.7% of the NZW rabbits affected and 1.1% of the NZW x NZR (F1) rabbits affected.

CONCLUSION

Spontaneous juvenile cataracts occur in rabbits and may develop as incidental lesions during toxicologic studies. The incidence of cataracts noted in our studies is consistent with an autosomal recessive mode of inheritance, but further studies are needed to confirm the mode or modes of inheritance. Hybrid pigmented rabbits (F1 or NZW x NZR) exhibited a significantly lower incidence of cataracts.