Prevalence of Orientia tsutsugamushi, Anaplasma phagocytophilum and Leptospira interrogans in striped field mice in Gwangju, Republic of Korea

This study investigated the prevalence of <i>Orientia tsutsugamushi, Anaplasma phagocytophilum, </i>and <i>Leptospira interrogans</i> in wild rodents through molecular detection using organ samples and through serological assay using blood samples of mice collected from two distinct sites in Gwangju Metropolitan City, Republic of Korea (ROK). A total of 47 wild rodents, identified as <i>Apodemus agrarius (A. agrarius)</i>, were captured from June to August 2016. The seroprevalence of antibodies against bacterial pathogens in <i>A. agrarius</i> sera was analyzed; 17.4% (8/46) were identified as <i>O. tsutsugamushi</i> through indirect immunofluorescence assay and 2.2% (1/46) were identified as <i>Leptospira</i> species through passive hemagglutination assay. Using polymerase chain reaction, the spleen, kidney and blood samples were investigated for the presence of <i>O. tsutsugamushi</i>, <i>A. phagocytophilum</i>, and <i>L. interrogans</i>. Out of the 47 <i>A. agrarius</i>, 19.1% (9/47) were positive for <i>A. phagocytophilum </i>and 6.4% (3/47) were positive for <i>L. interrogans</i>, while none were positive for <i>O. tsutsugamushi</i>. Four out of 46 (8.7%) blood samples, six out of 45 (13.3%) spleen samples, and one out of 47 (2.1%) kidney samples were positive for <i>A. phagocytophilum.</i> Three out of 47 (6.4%) kidney samples were positive for <i>L. interrogans</i>. The sequencing results of PCR positive samples demonstrated &gt; 99% similarity with <i>A. phagocytophilum</i> and <i>L. interrogans </i>sequences. <i>A. phagocytophilum</i> was mostly detected in the spleen, whereas <i>L. interrogans</i> was mostly detected in the kidneys. Notably, <i>A. phagocytophilum</i> and <i>L. interrogans</i> were detected in <i>A. agrarius</i> living in close proximity to humans in the metropolitan suburban areas. The results of this study indicate that rodent-borne bacteria may be present in wild rodents in the metropolitan suburban areas of ROK.