Detection of Rickettsia Typhi and Seasonal Prevalence of Fleas Collected From Small Mammals in the Republic of Korea

Abstract

ABSTRACT:Fleas were collected from live-captured small mammals to identify potential fleaborne pathogens, seasonal prevalence of flea species, and host preference as part of the US military rodent-borne diseases surveillance program conducted at one US military installation and 10 military training sites, northern Gyeonggi Province, Republic of Korea. During 2003-04, 948 fleas (563 females and 385 males) were recovered from 2,742 small mammals (seven rodent and one insectivore species). Apodemus agrarius (striped field mouse) accounted for 88.9% (2,439/2,742) of the small mammals, followed by Crocidura lasiura (4.2%), Mus musculus (2.9%), Microtus fortis (2.2%), Myodes regulus (0.6%), Micromys minutus (0.5%), Tscherskia triton (0.5%), and Rattus norvegicus (0.3%). Small mammal infestation rates (number with fleas/number captured) ranged from 7.7% (M. minutus and T. triton) to 31.3% (M. regulus). Flea indices were highest for M. regulus (0.69/captured rodent), followed by C. lasiura (0.54), M. fortis (0.41), A. agrarius (0.34), and R. norvegicus (0.33). Overall, Ctenophthalmus congeneroides (51.3%) was more frequently collected, followed by Stenoponia sidimi (42.6%), Rhadinopsylla insolita (5.5%), Neopsylla bidentatiformis (0.4%), Rhadinopsylla concava (0.1%), and Doratopsylla coreana (0.1%). Ctenophthalmus congeneroides was more frequently collected from small mammals during the spring and summer, while S. sidimi was more frequently collected during the winter season. Rickettsia typhi, the causative agent of murine typhus, was detected in 3.2% of specimens (7/220 pools from 654 fleas; minimum field infection rate [number of positive pools/total number of fleas] was 1.1%).

Monthly Occurrence of Vectors and Reservoir Rodents of Scrub Typhus in an Endemic Area of Jeollanam-do, Korea

“…In this study, we have shown that A. agrarius (98.3%) accounted for nearly all of the live-captured small mammals in the field. This agrees to previous results that A. agrarius was predominant in rural areas of the Korean peninsula [5,9-11]. Leptotrombidium species, including L. pallidum , L. scutellare , L. palpale , and L. orientale , were known as vectors of scrub typhus in Korea [5,12,13], of which L. pallidum was predominant in the middle and northern parts of Korea, whereas L. scutellare was predominant in the southern parts of Korea [12,13].…”

Detection ofRickettsiaspp. and host and habitat associations of fleas (Siphonaptera) in eastern Taiwan

“…A higher prevalence of flea infestations occurs at higher elevations in central Taiwan (Phillips, 1966). The infestation of fleas on small mammals was also found to be generally higher during winter and spring in Korea and Vietnam (Pham et al , 2009; Kim et al , 2010), but seasonal abundance seems to vary with flea species and some species are more abundant during the summer (Osacar et al , 2001; Krasnov et al , 2002a). The increase in flea abundance during the winter has been hypothesized to represent a consequence of the greater amount of time spent in the nest by hosts or an increase in host density (Murrell & Cates, 1970).…”

Murine Typhus in Returned Travelers: A Report of Thirty-Two Cases

“…2 In the Korean peninsula the striped field mouse (Apodemus agrarius) was the most prevalent (88.9%) rodent compared with the Norway rat (Rattus norvegicus) with 0.3%. 15 The flea species in which R. typhi were detected were Ctenophthalmus congeneroides and Rhadinopsylla insolita. Furthermore, murine typhus has yet another quite different epidemiology with cats and opossums implicated as mammalian hosts with cat fleas as the suggested vector in the United States.…”