Detection of Rickettsia monacensis from Ixodes nipponensis collected from rodents in Gyeonggi and Gangwon Provinces, Republic of Korea

Abstract

A total of 1,305 ticks were collected from wild rodents captured monthly, except July and August, during 2008 at three US-ROK operated military training sites and three US military installations in Gyeonggi and Gangwon Provinces, the Republic of Korea (ROK). Ixodes nipponensis was the most frequently collected tick (n = 1,299, 99.5 %), followed by Ixodes pomerantzevi (n = 6, 0.5 %). The ticks were pooled (1-15/sample) and tested by nested polymerase chain reaction (nPCR) for spotted fever group (SFG) rickettsiae with primer sets targeting the outer membrane protein B (ompB), citrate synthase (gltA), and 17-kDa antigen gene loci. A total of 115/197 (58.4 %) pools were positive by nPCR for the outer membrane protein ompB. Nucleotide sequence analysis of 105/115 (91.3 %) ompB targeted nPCR positive products showed a high degree of similarity to Rickettsia monacensis (99.3-100 %, n = 87) and R. japonica (99.5-100 %, n = 18). From the 87 positive samples demonstrating a high degree of similarity to R. monacensis, 15 were selected and analyzed by nPCR for gltA and the 17-kDa genes. A total of 12/15 pooled samples were positive for by nPCR for gltA, with amplicons demonstrating a high degree of similarity to R. monacensis (99.3-99.7 %). A total of 13/15 pooled samples were positive by nPCR for the 17-kDa gene, with amplicons demonstrating a high degree of similarity to R. monacensis (99.4-100 %). These findings demonstrate that R. monacensis is distributed throughout Gyeonggi and Gangwon Provinces in the ROK. Furthermore, data suggest a relative high prevalence of R. monacensis in the tick, I. nipponensis.

Molecular detection of Rickettsia species in ticks collected from the southwestern provinces of the Republic of Korea

“…With increased interest in tick-borne diseases, surveillance of ticks from reptiles, mammals, birds, and vegetation has led to the identification of known and yet to be described pathogens belonging to genera of Ehrlichia , Anaplasma , Bartonella , Borrelia , Babesia and Rickettsia , in addition to viruses [10, 18–20, 30–36]. Rickettsia akari , a mite-borne pathogen isolated from a rodent, was first reported in Korea in 1957 [37, 38].…”

“…Moreover, R. japonica and R. monacensis were detected in H. longicornis by nPCR and sequence analysis of the gltA , ompB , and 17 kDa antigen genes [16, 17]. More recently, Rickettsia species have been detected in various arthropods and tick species in Korea that were collected from small mammals, reptiles, and the environment (by tick drag) [10, 18–20]. …”

Ticks Collected from Wild and Domestic Animals and Natural Habitats in the Republic of Korea

“…I. nipponensis was infrequently collected in this study; however, it is the primary tick collected from small mammals [10,12] and has been implicated in the transmission and maintenance of tick-borne pathogens to humans in the ROK [10,12,13,14,15,16]. …”

Ixodes nipponensis Kitaoka and Saito and Amblyomma testudinarium Koch (Acari: Ixodida: Ixodidae) Collected from Reptiles (lizards, skinks, and snakes) in the Republic of Korea, 2016

“…Habitat restoration and alteration, including a major reforestation program initiated in the 1960s and rapid urbanization following the end of the Korean War in 1953, have led to changes in landscape ecology conducive to higher populations of wild animals, such as small mammals (e.g., rodents, soricomorphs, rabbits, and weasels), larger mammals (e.g., deer, wild pigs, raccoon dogs, badgers, and feral dogs and cats), local and migratory birds, and reptiles (e.g., lizards, skinks, and snakes) that are hosts to various species of ticks (Kim et al 2010b, Chong et al 2013a, 2013b, Kang et al 2013, Shin et al 2013. Ticks harbor numerous zoonotic pathogens, e.g., viruses, bacteria and protozoa, that are of veterinary and medical importance, and as humans encroach upon the habitats of wild animals and birds, they and their pets/domestic animals may be exposed to ticks and associated tick-borne pathogens (Kang et al 1982, Yun et al 2012.…”

“…Ticks harbor numerous zoonotic pathogens, e.g., viruses, bacteria and protozoa, that are of veterinary and medical importance, and as humans encroach upon the habitats of wild animals and birds, they and their pets/domestic animals may be exposed to ticks and associated tick-borne pathogens (Kang et al 1982, Yun et al 2012. Based on recent case increases for a number of tick-borne diseases, e.g., SFTS, which increased from 36 cases in 2013 to >250 cases in 2017, tick bites and illnesses due to tick-borne pathogens appear to be underreported in the ROK (Jang et al 2004, Choi et al 2005, Shin et al 2013 Yi et al 2016). Because human tick bites from I. nipponensis and A. testudinarium are reported more frequently for patients seen at medical clinics in the ROK, these two species may play an important role in the transmission of tick-borne pathogens to humans and domestic animals (Kang et al 1982, Lee et al 1989, Cho et al 1994, 1995, Yamada et al 1996, Ryu et al 1998, Chae et al 2000, Yun et al 2001, Ko et al 2002, Chang et al 2006, Kim et al 2010a, 2014b, Suh et al 2013.…”