Pasteurella and Rabbits

Pasteurellosis is one of the most common and severe diseases of rabbits. It can account for mortalities greater than 15-20% of fryers (young weaned rabbits). Pasteurellosis will also reduce feed efficiency and increase the number of days to market. It is characterized by disease of the respiratory system, pyogenic lesions affecting various organs, enteritis or septicaemia. Many rabbits are carriers of Pasteurella multocida and breeding does are the main reservoir. The acute manifestations of the disease are associated with high stocking density, poor ventilation, and high ammonia and humidity levels.

Research from France shows:

• P. multocida can be isolated from the middle ear of 60% of breeding does (1);
• the main transmission of P. multocida in rabbits is directly from the doe to the kits; (The term kit is used for baby rabbits prior to weaning while fryer is used post weaning.)
• airborne transmission does not have a major role in transmission of the bacteria(1); and
• only 1-2% of rabbits have the infection in their middle ear by 56 days of age (2).

There are no approved antibacterial agents or vaccines for use in rabbits in Canada. However, since kits could be weaned as early as 28 days, it may be worth examining the segregated-medicated-early-weaning management systems adopted by the pork industry.

The following hypothesis may be useful in reducing losses of fryers to pasteurellosis. Kits of similar age, for example 30-35 days, could be weaned as a group to a separate location (e.g., other barn, shed, or green house-like structure). Under the direction of a veterinarian, they would be treated with an antibiotic such as tetracycline in the feed or water for five days. The segregation might prevent the transmission of the bacteria in most of the kits and the tetracycline could eliminate or prevent pasteurella infections from starting. The antibiotic would have 30-40 days to be removed from the fryers before they go to market. Since the withdrawal time for tetracycline used at standard levels for other species is five days, there might be sufficient time for the medication to clear the system. A veterinary-supervised monitoring program could also be put in place to ensure that there are no residual inhibitors in market age fryers. When the fryers are ready for market, they should all be removed to market at once. A complete clean up would follow in preparation for the next group. Should a pasteurella outbreak occur, the segregated weaning would limit its spread to other groups.

This system could be useful in developing minimum disease breeding stock and could minimize the risk of pasteurella infection in breeding does. Medicating the does may also be useful prior to kindling (giving birth) and during the lactation period to reduce the transmission of pasteurella to the kits (3,4).

References:

1. Coudert P, Rideaud P, Kpodekon M. Pasteurellosis in the Rabbit: present situation. World Rabbit Science 1999; 7: 7.
2. Rideaud P, Coudert P, Raboteau D. Frequency patterns of Pasteurella multocida otitis of the rabbit after weaning without clinical signs of disease. World Rabbit Science 1998; 6: 13.
3. McKay SG, Morck DW, Merrill JK, Olson ME, Chan SC, Pap KM. Use of tilmicosin for treatment of pasteurellosis. AJVR 1996; 57 (7): 1180-1184.
4. Suckow MA, Martin BJ, Bowersock TL, Douglas FA. Derivation of Pasteurella multocida-free rabbit litters by enrofloxacin treatment. Veterinary Microbiology 1996; 51: 161-168.

Copyright October, 1999. Permission is granted to use and reproduce this article in its entirety provided credit is given as follows: Dr. Bob Wright, Ontario Ministry of Agriculture and Food, Fergus, Ontario, Canada. Material may not be changed without the permission of the author.