Case-Control Study of NJ black bears (Ursus Americanus) infected with Babesia spp.

By Shawqui Darwish

Babesia spp. are intraerythrocytic protozoan parasites of animals and humans that cause babesiosis, a zoonotic disease transmitted primarily by ticks.

Although a variety of species or types of Babesia have been described in the literature as causing infection in humans, the rodent parasite Babesia microti has emerged as the focal point of human disease in the United States.

In this study, American black bears (Ursus americanus) in NJ were live-trapped and blood samples were taken from 2006 to 2014.

Throughout this period some animals were first time captures and others were recaptures.

DNA extraction was performed on all samples and amplified using the polymerase chain reaction (PCR) using genus specific primers.

Sixty-four black bears were evaluated.

Of the 22 bears that tested positive for Babesia at baseline, 41% (9/22) cleared the infection and 59% (13/22) persisted with the infection at follow-up.

Of the remaining 41 bears that tested negative for Babesia at baseline, 69% (29/42) remained free of infection and 31% (13/42) acquired infection at follow-up.

All positive samples were sequenced to determine the species of Babesia infecting the black bears. Sequencing analysis revealed that American black bears may acquire chronic infections from the same species of Babesia overtime.

This represents the first longitudinal study conducted on American black bears infected with Babesia spp. and suggests that black bears may be well adapted to babesial infections in regions endemic for tick-borne pathogens.

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