Molecular Detection of Anaplasma phagocytophilum and Ehrlichia Species in Ticks Removed from Humans in the Republic of Korea

Abstract

Human granulocytic anaplasmosis (HGA) and human monocytic ehrlichiosis (HME) are zoonotic tick-borne diseases transmitted via tick bites. To determine the state of human Anaplasma and Ehrlichia infections caused by tick bites in the Republic of Korea (ROK), we conducted a nationwide investigation of human cases of tick bites in 2020. A total of 180 ticks were obtained, comprising Haemaphysalis longicornis (70.0%), Amblyomma testudinarium (17.8%), Ixodes nipponensis (6.1%), H. flava (4.4%), and I. persulcatus (1.7%). In three cases (1.7%; 95% CI: 0.3–4.9), A. phagocytophilum was detected in Ixodes ticks using primers for Anaplasma-specific genes (16s rRNA, ankA, and msp4). Conversely, Ehrlichia sp. was only detected in H. longicornis, in two cases (1.1%; 95% CI: 0.1–4.0). To the best of our knowledge, this is the first record of Ehrlichia sp. in ticks parasitizing humans in the ROK. As concerns remain about the possibility of HGA and HME transmission, continuous monitoring and management of the pathogens and vectors are necessary.