Spontaneous cataracts in laboratory rabbits.

Area of Science:

• Veterinary ophthalmology
• Toxicologic pathology
• Genetics of ocular diseases

Background:

• Spontaneously occurring cataracts can affect laboratory animals, potentially confounding toxicologic study results.
• Understanding the incidence and inheritance of such conditions is crucial for animal welfare and research integrity.

Purpose of the Study:

• To document the occurrence and incidence of spontaneous juvenile cataracts in New Zealand White (NZW) and hybrid NZW x New Zealand Red (NZW x NZR - F1) rabbits.
• To analyze the incidence rates between different rabbit strains during prescreening examinations.

Main Methods:

• A retrospective study analyzed prescreening examination records of NZW and NZW x NZR (F1) rabbits from April 1999 to May 2001.
• Data from 946 rabbits (670 NZW, 276 NZW x NZR) aged 77-288 days were evaluated for cataract presence.

Main Results:

• Overall cataract incidence was 4.3% (41/946 rabbits).
• New Zealand White rabbits had a 5.7% incidence (38/670), while hybrid NZW x NZR (F1) rabbits had a significantly lower incidence of 1.1% (3/276).
• Cataracts occurred equally in male and female rabbits across both groups.

Conclusions:

• Spontaneous juvenile cataracts are incidental findings in rabbits and can occur during toxicologic studies.
• The observed incidence suggests a possible autosomal recessive mode of inheritance, warranting further investigation.
• Hybrid pigmented rabbits (NZW x NZR) demonstrate a significantly reduced incidence of cataracts compared to purebred NZW rabbits.