Catenotaenia dendritica (Cestoda: Catenotaeniidae) and Three Ectoparasite Species in the Red Squirrel, Sciurus vulgaris, from Cheongju, Korea

Parasites are recorded from the red squirrel, Sciurus vulgaris, from Cheongju, the Republic of Korea. A total of 5 road-killed squirrels were thoroughly examined for internal and external parasites from November 2011 to May 2014. Total 4 parasite species, including 1 tapeworm and 3 ectoparasite species were recovered. They were morphologically identified as Catenotaenia dendritica (Cestoda: Catenotaeniidae), Hirstionyssus sciurinus, Leptotrombidium pallidum, and Ceratophyllus (Monopsyllus) indages. Among them, C. dendritica and H. sciurinus are recorded for the first time in the Korean parasite fauna. In addition, the possibility that the red squirrel could act as a reservoir host for a zoonotic disease like tsutsugamushi disease with L. pallidum as its vector has been raised.

Larval Chigger Mites Collected from Small Mammals in 3 Provinces, Korea

A total of 9,281 larval chigger mites were collected from small mammals captured at Hwaseong-gun, Gyeonggi-do (Province) (2,754 mites from 30 small mammals), Asan city, Chungcheongnam-do (3,358 mites from 48 mammals), and Jangseong-gun, Jeollanam-do (3,169 for 62 mammals) from April-November 2009 in the Republic of Korea (= Korea) and were identified to species. Leptotrombidium pallidum was the predominant species in Hwaseong (95.8%) and Asan (61.2%), while Leptotrombidium scutellare was the predominant species collected from Jangseong (80.1%). Overall, larval chigger mite indices decreased from April (27.3) to June (4.9), then increased in September (95.2) and to a high level in November (169.3). These data suggest that L. pallidum and L. scutellare are the primary vectors of scrub typhus throughout their range in Korea. While other species of larval chigger mites were also collected with some implications in the transmission of Orientia tsutsugamushi, they only accounted for 11.2% of all larval chigger mites collected from small mammals.

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

Monthly surveys were conducted to investigate the occurrence of chigger mites and seroprevalence of scrub typhus among small mammals in Jeollanam-do, the southwestern part of Korea, from November 2006 through October 2007. Fifty-eight small mammals, including 57 Apodemus agrarius (98.3%) and 1 Crocidura lasiura (1.7%), were captured, and a total of 4,675 chigger mites representing 4 genera and 8 species were collected from them. The chigger infestation rate among small mammals was 69.0%. The most predominant species in A. agrarius was Leptotrombidium scutellare (54.0%), followed by Leptotrombidium pallidum (39.4%), Leptotrombidium orientale (4.4%), Leptotrombidium palpale (1.1%), Neotrombicula tamiyai (0.6%), Eushoengastia koreaensis (0.3%), Neotrombicula gardellai (0.3%), and Cheladonta ikaoensis (<0.1%). The chigger index of A. agrarius was the highest in October (740.0), followed by November (242.0), September (134.6), March (98.3), February (38.2), January (35.3), December (34.5), April (30.8), and May (1.7). The average antibody positive rate of scrub typhus in wild rodents was 50.0%. The seropositive rates were high in October (100.0%) and November (83.3%), whereas those in other months were relatively low (28.6-57.1%). The chigger index of L. scutellare rapidly increased in September to form an acuminate peak in October, followed by a gradual decline. These results suggest that the outbreak of scrub typhus in the southwestern part of Korean peninsula is mostly due to L. scutellare.

The Value of PCR Method for Diagnosing Tsutsugamushi Disease / 대한피부과학회지

BACKGROUND: Tsutsugamushi disease, is an acute febrile illness caused by the infection of Orientia(O.) tsutsugamushi which is transmitted by mites such as Leptotrombidium(L.) pallidum. Because the antibody titer against O. tsutsugamushi has not risen enough to be detected at the initial stage of tsutsugamushi disease, the early serologic diagnosis of this disease has some difficulties. OBJECTIVE: The aim of this study was to show that the recently introduced technique of polymerase chain reaction(PCR) is excellent for the detection of rickettsial DNA in the patient's blood at the acute phase of illness. METHODS: Nested PCR with Boryong specific 56kDa protein antigen was done with sera from twenty one patients with tsutsugamushi disease and with two groups of mites(L. pallidum). The presence of O. tsutsugamushi DNA in the peripheral blood mononuclear cells of patients with tsutsugamushi disease was also determined by nested PCR during the antibiotic treatment. RESULTS: 1. Positive results with nested PCR with Boryong specific 56kDa protein antigen were found in eleven out of twenty one patients with tsutsugamushi disease and two samples of L. pallidum extracts. 2. After the initiation of antibiotic treatment, all samples(11 patients) were positive on the second day, and seven samples were positive on the seventh day, showing a slow action of the drugs against the rickettsia within the cells. CONCLUSION: Nested PCR is an ideal method for the detection of O. tsutsugamushi DNA during the early phase of tsutsugamushi disease.