Methods for detecting Babesia microti infection in wild rodents

Area of Science:

• Veterinary Medicine
• Parasitology
• Wildlife Disease Ecology

Background:

• Babesia microti is a significant tick-borne pathogen impacting wildlife and potentially humans.
• White-footed mice (Peromyscus leucopus) are key reservoirs for Babesia microti in enzootic regions.
• Accurate detection methods are essential for understanding disease transmission dynamics.

Purpose of the Study:

• To compare the sensitivity and practicality of different diagnostic methods for Babesia microti in wild white-footed mice.
• To identify the optimal time for parasite detection following experimental inoculation in a mammalian host.
• To evaluate the utility of splenectomy in enhancing diagnostic sensitivity.

Main Methods:

• Comparison of direct microscopy of Giemsa-stained blood films from mice.
• Assessment of hamster inoculation with infected mouse blood, with varying post-inoculation observation times.
• Evaluation of hamster splenectomy prior to inoculation.

Main Results:

• Hamster inoculation was the most sensitive method, detecting infections with as few as 300 organisms.
• Optimal detection in hamsters occurred one month post-inoculation.
• Direct microscopy of mouse blood films detected only 61% of infections identified by hamster inoculation.
• Splenectomy did not enhance hamster susceptibility to Babesia microti infection.

Conclusions:

• Hamster inoculation represents a highly sensitive method for detecting Babesia microti in white-footed mice.
• Microscopic examination of Giemsa-stained blood films from hamsters one month post-inoculation is recommended for optimal detection.
• While convenient, direct examination of mouse blood films is less sensitive than the indirect hamster inoculation method.