Rodent-borne bacterial infections in Gwangju, Korea

Abstract

AbstractBackgroundThis study investigated the prevalence ofOrientia tsutsugamushi, Anaplasma phagocytophilum,andLeptospira interroganin wild rodents through molecular detection in organ samples collected from two distinct sites in Gwangju Metropolitan City, Republic of Korea.Methodology/Principal FindingsA total of 47 wild rodents, identified asApodemus agrarius (A. agrarius), were captured from June to August 2016. The seroprevalence of antibodies against bacterial pathogens in rodent sera was analyzed; 17.4% (8/46) were identified asO. tsutsugamushithrough indirect immunofluorescence assay and 2.2% (1/46) were identified asLeptospiraspp. through passive hemagglutination assay. Using molecular methods, the spleen, kidney, and blood samples were evaluated for the presence ofO. tsutsugamushi, A. phagocytophilum, andL. interrogans. Out of 47 wild rodents, 25.5% (12/47) were positive for bacterial pathogens by PCR, where 19.1% (9/47) were positive forA. phagocytophilumand 6.4% (3/47) were positive forL. interrogans, while none were positive forO. tsutsugamushi. In addition, testing for bacterial infection in different tissues indicated that 8.7% (4/46) were positive forA. phagocytophilumin the blood, 13.3% (6/45) were positive forA. phagocytophilumin the spleen, and 6.4% (3/47) and 2.1% (1/47) were positive forL.interrogansandA. phagocytophilum, respectively, in the kidney.Conclusions/SignificanceIn this study, tropisms forA. phagocytophilumin the spleen andL. interrogansin the kidney were identified. Notably,A. phagocytophilumandL. interroganswere detected in wild rodents living in close proximity to humans in the metropolitan suburban areas. Results of the present study indicate that rodent-borne bacteria may be present in wild rodents in the metropolitan suburban area of Republic of Korea.Author SummaryMany zoonotic diseases are spreading not only in the Republic of Korea (ROK), but also worldwide. Scrub typhus, anaplasmosis, and leptospirosis are well known diseases that are considered common, widespread rodent-borne infectious diseases. Rodents serve as important reservoirs for zoonotic pathogens such asO. tsutsugamushi, A. phagocytophilum, andL. interrogans,which may be fatal to humans. Our study demonstrated the prevalence of these pathogens in wild rodents, through molecular assays and seroprevalence in organ samples. We captured 47 wild rodents in the Gwangju metropolitan city area of ROK. All were identified asA. agrarius. The prevalence of rodent-borne bacteria was 17.4% in the sera, where 25.5% was positively detected as bacterial pathogens via polymerase chain reaction. Our results indicate the importance of detecting rodent-borne bacteria in wild rodents living close to humans in suburban areas of ROK. Our data was limited to only a few samples of rodents in two regions. More samples may have to be collected over longer periods of time, to investigate the infectious nature of these pathogens in detail.