Susceptibility of laboratory animals to infection by spotted fever group rickettsiae

Area of Science:

• Veterinary Microbiology
• Infectious Diseases
• Animal Models

Background:

• Spotted fever group rickettsiae are tick-borne pathogens causing significant human disease.
• Identifying suitable animal models is crucial for understanding rickettsial pathogenesis and developing countermeasures.

Purpose of the Study:

• To evaluate various animal species as potential models for studying spotted fever group rickettsiae infections.
• To determine which animals exhibit characteristic disease signs relevant to rickettsial pathogenesis.

Main Methods:

• A range of inbred and outbred animals, including mice, guinea pigs, ferrets, gerbils, hamsters, rabbits, cotton rats, sheep, and miniature swine, were experimentally inoculated.
• Animals were monitored for overt clinical signs indicative of disease following exposure.

Main Results:

• Only specific strains of mice (e.g., Mai:(S), BALB/cJ) and guinea pigs (e.g., Hla:(HA)) displayed the desired disease characteristics.
• Sheep and rabbits were suitable for antiserum production but did not show significant signs of illness.
• Several other tested species showed little to no apparent effect from the rickettsiae.

Conclusions:

• Certain mouse and guinea pig strains are valuable animal models for investigating spotted fever group rickettsiae.
• The lack of overt disease in other species suggests their potential role as asymptomatic reservoirs for these pathogens.
• Further research is needed to elucidate the reservoir dynamics of tick-borne rickettsiae.