CHAPTER 8 - Bacterial Diseases

Abstract

Bacteria are responsible for an important group of naturally occurring diseases of rabbits. These diseases cause substantial morbidity and mortality, and thus interfere with the use of rabbits for many purposes. Even when subclinical, bacterial infections may render rabbits unsuitable for certain types of research. Bacterial diseases of rabbits most often involve the respiratory and gastrointestinal systems. This chapter discusses the diseases affecting these systems, including pasteurellosis, enterotoxemia, Tyzzer's disease, and colibacillosis. Pasteurella multocida is the most common bacterial pathogen of laboratory rabbits. Most often, P. multocida is harbored in the nasal cavity of rabbits, resulting either in rhinitis or an asymptomatic chronic infection. Occasionally, infection extends from the nasal cavity to other parts of the body. This can result in a variety of clinical manifestations, including pneumonia, otitis media, conjunctivitis, abscesses, genital tract infections, and septicemia. Enteric diseases are second only to pasteurellosis as a health problem in domestic rabbits. The primary clinical sign of these diseases is diarrhea, which is sometimes accompanied by sudden death. Tyzzer's disease is caused by Bacillus piliformis, a poorly characterized filamentous bacterial organism. The disease can occur in many species, including mice, rabbits, rats, hamsters, gerbils, cats, and rhesus monkeys. Clinically, it is usually characterized by profuse diarrhea and rapid death. Lesions are most common in the liver and cecum. Gross necropsy findings in colibacillosis include thickening of the wall of the ileum, cecum, and colon. Paintbrush hemorrhages are sometimes evident on the serosal surface, and mesenteric lymph nodes may be swollen. Cecal contents are watery and brown.