[Experimental latent tularemia in common voles]

Area of Science:

• Veterinary Microbiology
• Infectious Diseases
• Zoonotic Diseases

Background:

• Tularemia is a zoonotic disease caused by Francisella tularensis.
• Rodents, including voles, can act as reservoirs for Francisella tularensis.
• Understanding the dynamics of tularemia infection in common voles is crucial for epizootiological surveillance.

Purpose of the Study:

• To investigate the course and persistence of tularemia infection in common voles (Microtus subarvalis).
• To assess the potential for bacterial carriership and prolonged shedding of Francisella tularensis in infected voles.

Main Methods:

• Experimental infection of common voles with a moderately virulent strain of Francisella tularensis via ingestion of infected carcasses.
• Monitoring of infected voles for clinical signs, mortality, and development of nonlethal infections.
• Bacteriological examination for Francisella tularensis in urine and tissues to determine carriership and persistence.

Main Results:

• Nonlethal tularemia infection occurred in 14 out of 433 common voles.
• A high proportion of infected voles (11/13) became bacterial carriers, with 8/11 exhibiting bacteriuria for up to 2 months.
• Francisella tularensis persisted in the host tissues for 6-11 months post-infection.

Conclusions:

• Common voles can develop persistent, subclinical tularemia infections with prolonged bacterial shedding.
• Latent tularemia infections in common voles may have significant epizootiological implications for disease transmission.
• Further research is needed to fully elucidate the role of common voles in the epidemiology of tularemia.