Experimental studies on Brucella abortus in moose (Alces alces)

Area of Science:

• Veterinary Pathology
• Infectious Diseases
• Wildlife Health

Background:

• Brucellosis is a significant zoonotic disease affecting livestock and wildlife.
• Understanding susceptibility in non-bovine species like moose (Alces alces) is crucial for disease management.
• Brucella abortus biovar 1 is a causative agent of brucellosis.

Purpose of the Study:

• To determine the susceptibility of moose to Brucella abortus biovar 1.
• To characterize the clinical, serological, bacteriological, hematological, clinical chemistry, and pathological findings in infected moose.
• To assess the potential of moose as a reservoir or dead-end host for brucellosis.

Main Methods:

• Conjunctival inoculation of four moose with B. abortus biovar 1.
• Monitoring of clinical signs, serological responses (buffered antigen plate test, Brewer card test, standard tube agglutination test, complement fixation test), hematology, and clinical chemistry.
• Bacteriological isolation from various tissues.
• Pathological examination of tissues.

Main Results:

• All inoculated moose became infected and were readily detected serologically.
• Clinical signs were absent except for one moose that died acutely from endotoxic shock.
• Hematology and clinical chemistry remained stable and comparable to cattle values, except near death.
• B. abortus was isolated from multiple tissues, particularly lymph nodes, with high colony counts.
• Pathological findings were consistent with endotoxemia.

Conclusions:

• Moose are susceptible to B. abortus biovar 1, with infection leading to significant pathology and potential mortality.
• Standard serological tests used for cattle are effective in detecting infection in moose.
• Moose appear to serve as a dead-end host for B. abortus, with rapid disease progression likely under field conditions.