DETECTION OF BABESIA CF. ODOCOILEI, BABESIA CAPREOLI, AND ANAPLASMA PHAGOCYTOPHILUM IN CERVIDS OF THE SCOTTISH HIGHLANDS, UNITED KINGDOM

Outbreaks of suspected tick-borne disease (redwater fever) have been reported in captive deer of the Scottish Highlands. In this pilot study, polymerase chain reaction and amplicon sequencing were used to detect tick-borne pathogens in opportunistically collected blood and spleen samples from 63 (healthy, n = 44; diseased, n = 19) cervids, and 45 questing and feeding ticks (<i>Ixodes ricinus</i>) from the outbreak sites in 2021-2022. Potentially pathogenic <i>Babesia</i> species were detected in deer but not identified in ticks, <i>Anaplasma phagocytophilum</i> was detected in both deer and ticks, and <i>Borrelia afzelii</i> was detected in ticks but not in deer. Sequencing confirmed <i>Babesia capreoli</i> and <i>Babesia</i> cf. <i>odocoilei</i> parasitemia in clinically healthy red deer (<i>Cervus elaphus</i>), <i>B. capreoli</i> parasitemia in clinically healthy domestic reindeer (<i>Rangifer tarandus tarandus</i>), and two cases of <i>B.</i> cf. <i>odocoilei</i>-associated hemolytic anemia in white-lipped deer (<i>Cervus albirostris</i>), of which one was fatal despite imidocarb treatment. White-lipped deer appear to be highly susceptible to babesiosis caused by <i>B.</i> cf. <i>odocoilei</i>. This investigation highlights the importance of disease surveillance, including molecular diagnostics, for the detection of emerging tick-borne pathogens in managed populations of cervids.