Kyu-Sung Ahn

First report of feline intestinal trichomoniasis caused by Tritrichomonas foetus in Korea.

Feline intestinal tritrichomoniasis by Tritrichomonas foetus was first recognized in USA in 1999 and has so far been reported from UK, Norway, Switzerland, and Australia, but not from the Far East Asian countries. In November 2008, 2 female and male littermate Siamese cats, 6-month old, raised in a household in Korea were referred from a local veterinary clinic with a history of chronic persistent diarrhea. A direct smear examination of fecal specimens revealed numerous trichomonad trophozoites which were isolated by the fecal culture in InPouch TF-Feline medium. A PCR testing of the isolate based on the amplification of a conserved portion of the T. foetus internal transcribed spacer (ITS) regions (ITS1 and ITS2) and the 5.8S rRNA gene, and the molecular sequencing of the PCR amplicons confirmed infection with T. foetus. This is the first clinical case of feline intestinal trichomoniasis caused by T. foetus in Korea.

Comparison of selected canine vector-borne diseases between urban animal shelter and rural hunting dogs in Korea

A serological survey for Dirofilaria immitis, Anaplasma phagocytophilum, Ehrlichia canis, and Borrelia burgdorferi infections in rural hunting and urban shelter dogs mainly from southwestern regions of the Republic of Korea (South Korea) was conducted. From a total of 229 wild boar or pheasant hunting dogs, the number of serologically positive dogs for any of the four pathogens was 93 (40.6%). The highest prevalence observed was D. immitis (22.3%), followed by A. phagocytophilum (18.8%), E. canis (6.1%) and the lowest prevalence was B. burgdorferi (2.2%). In contrast, stray dogs found within the city limits of Gwangju showed seropositivity only to D. immitis (14.6%), and none of the 692 dogs responded positive for A. phagocytophilum, E. canis or B. burgdorferi antibodies. This study indicates that the risk of exposure to vector-borne diseases in rural hunting dogs can be quite high in Korea, while the urban environment may not be suitable for tick infestation on dogs, as evidenced by the low infection status of tick-borne pathogens in stray dogs.

An Outbreak of Caparinia tripilis in a Colony of African Pygmy Hedgehogs (Atelerix albiventris) from Korea

In February 2010, dermatitis characterized by scale and self-trauma due to puritis was recognized in a group of 22 four-toed hedgehogs (Atelerix albiventris Wagner, 1841) from a local pet shop in Gwangju, Korea. Microscopic examinations of skin scraping samples showed numerous mites of all developmental stages. Morphologically, pedicels of adult mites were short and unjointed. Tarsal caruncles were bell-shaped on all legs of males while they were absent on legs III and IV of females. Three long setae on the third pair of legs in both sexes were present. Adult males had posterior end of the abdomen with trilobate projection on each side, each lobe with a long seta. Based on these features, the mites were identified as Caparinia tripilis. This is the first report of caparinic mite infestation in hedgehogs from Korea. Identification keys for the family Psoroptidae and the genus Caparinia are provided.

Zoonotic Intestinal Trematodes in Stray Cats (Felis catus) from Riverside Areas of the Republic of Korea

The present study was performed to survey the infection status of zoonotic intestinal trematode (ZIT) in stray cats from 5 major riverside areas in the Republic of Korea. Total 400 stray cats were captured with live-traps in riverside areas of Seomjingang (‘gang’ means river) (203 cats) from June to October 2010, and of Yeongsangang (41), Nakdonggang (57), Geumgang (38), and Hangang (61 cats) from June to October 2011, respectively. Small intestines resected from cats were opened with a pair of scissors in a beaker with 0.85% saline and examined with naked eyes and under a stereomicroscope. More than 16 ZIT species were detected in 188 (92.6%) cats from Seomjingang areas, and the number of worms recovered was 111 per cat infected. In cats from riverside areas of Yeongsangang, Nakdonggang, Geumgang, and Hangang, more than 9, 8, 3, and 5 ZIT species were recovered, and the worm burdens were 13, 42, 11, and 56 specimens per infected cat, respectively. As the members of family Heterophyidae, more than 10 species, i.e., Metagonimus spp., Pygidiopsis summa, Heterophyes nocens, Stellantchasmus falcatus, Heterophyopsis continua, Acanthotrema felis, Centrocestus armatus, Procerovum varium, Cryptocotyle concava, and Stictodora lari, were recovered. More than 5 species of echinostomes, i.e., Echinostoma hortense, Echinochasmus japonicus, Echinochasmus sp., Echinoparyphium sp., and unidentified larval echinostomes, were collected. Plagiorchis spp. were detected in cats from areas of Seomjin-gang and Yeongsangang. From the above results, it has been confirmed that stray cats in 5 major riverside areas of Korea are highly infected with various species of ZITs.

Effects of Kimchi Extract and Temperature on Embryostasis of Ascaris suum Eggs

To determine the effects of kimchi extracts at different temperatures on larval development, Ascaris suum eggs were mixed with soluble part of 7 different brands of commercially available kimchi and preserved at either 5℃ or 25℃ for up to 60 days. A. suum eggs incubated at 25℃ showed marked differences in larval development between kimchi extract and control group. While all eggs in the control group completed embryonation by day 21, only 30% of the eggs in the kimchi extract group became embryonated by day 36 and about 25% never became larvated even at day 60. At 5℃, however, none of the eggs showed larval development regardless of the incubation period or type of mixture group. To determine the survival rate of A. suum eggs that showed no embryonation after being preserved at 5℃, eggs preserved in kimchi extracts for 14, 28, and 60 at 5℃ were re-incubated at 25℃ for 3 weeks in distilled water. While all eggs in the control group became larvated, eggs in the kimchi extract group showed differences in their embryonation rates by the incubation period; 87.4 % and 41.7% of the eggs became embryonated after being refrigerated for 14 days and 28 days, respectively. When refrigerated for 60 days, however, no eggs mixed in kimchi extract showed larval development. Our results indicate that embryogenesis of A. suum eggs in kimchi extract was affected by duration of refrigeration, and that all eggs stopped larval development completely in kimchi kept at 5℃ for up to 60 days.

Efficacy of a combination of 10% imidacloprid and 1% moxidectin against Caparinia tripilis in African pygmy hedgehog (Atelerix albiventris)

BackgroundThe efficacy and safety of a combination formulation of 10% imidacloprid + 1.0% moxidectin spot-on (Advocate® for Cats, Bayer Animal Health GmbH, Leverkusen, Germany) was tested in 40 African pygmy hedgehogs (Atelerix albiventris) naturally infested with Caparinia tripilis.MethodsThe optimal dosage level of the combination for hedgehogs was determined by assigning 20 hedgehogs into three treatment groups (0.1, 0.4 and 1.6 ml/Kg b.w.), and one untreated control group of 5 hedgehogs each. Twenty naturally infested hedgehogs were then randomly assigned to either treatment or control group with 10 animals each, and the number of live mites was counted from 13 body regions on day 0, 3, 9, 16, and 30 after single treatment at the dosage level of 0.1 ml/Kg.ResultsBefore the chemotherapy, the highest density of mite was observed in external ear canals followed by the dorsal and the lowest in the ventral regions of the body surface. The dosage level of 0.1 ml/Kg, which corresponded to the recommended dosage level for cats, containing 10 mg imidacloprid and 1 mg moxidectin was also the optimal dosage level for hedgehogs. No hedgehogs in the treatment group showed live mites from day 3 post treatment. Side effects such as ataxia, depression, nausea, and weight fluctuation were not observed during the whole period of study.ConclusionsThis report suggests that a combination formulation of 0.1 ml/Kg of 10% imidacloprid + 1% moxidectin spot-on for cats is also useful for the control of Caparinia tripilis infestation in hedgehogs.

Effects of Disinfectants on Larval Development of Ascaris suum Eggs

The objective of this study was to evaluate the effects of several different commercial disinfectants on the embryogenic development of Ascaris suum eggs. A 1-ml aliquot of each disinfectant was mixed with approximately 40,000 decorticated or intact A. suum eggs in sterile tubes. After each treatment time (at 0.5, 1, 5, 10, 30, and 60 min), disinfectants were washed away, and egg suspensions were incubated at 25˚C in distilled water for development of larvae inside. At 3 weeks of incubation after exposure, ethanol, methanol, and chlorohexidin treatments did not affect the larval development of A. suum eggs, regardless of their concentration and treatment time. Among disinfectants tested in this study, 3% cresol, 0.2% sodium hypochlorite and 0.02% sodium hypochlorite delayed but not inactivated the embryonation of decorticated eggs at 3 weeks of incubation, because at 6 weeks of incubation, undeveloped eggs completed embryonation regardless of exposure time, except for 10% povidone iodine. When the albumin layer of A. suum eggs remained intact, however, even the 10% povidone iodine solution took at least 5 min to reasonably inactivate most eggs, but never completely kill them with even 60 min of exposure. This study demonstrated that the treatment of A. suum eggs with many commercially available disinfectants does not affect the embryonation. Although some disinfectants may delay or stop the embryonation of A. suum eggs, they can hardly kill them completely.

First Feline Case of Otodectosis in the Republic of Korea and Successful Treatment with Imidacloprid/Moxidectin Topical Solution

In April 2010, pruritic symptoms were recognized in 3 privately-owned Siamese cats raised in Gwangju, Korea. Examination of ear canals revealed dark brown, ceruminous otic exudates that contain numerous live mites at various developmental stages. Based on morphological characteristics of adult mites in which caruncles were present on legs 1 and 2 in adult females and on legs 1, 2, 3, and 4 in adult males while the tarsus of leg 3 in both sexes was equipped with 2 long setae, the mite was identified as Otodectes cynotis. Ten ear mite-free domestic shorthaired cats were experimentally infected with O. cynotis to evaluate the efficacy of 10% imidacloprid/1% moxidectin spot-on. Live mites were recovered from 1 of 10 treated cats on day 9 post-treatment (PT) while no live mites were observed from the ear canals of treated cats on days 16 and 30 PT. The efficacy of 10% imidacloprid/1% moxidectin spot-on on O. cynotis in cats was, therefore, 90% on day 9 and 100% on days 16 and 30 PT. This is the first report of otodectosis in 3 cats naturally infested with O. cynotis in Gwang-ju, Korea. Both natural and experimental infestations were successfully treated with 10% imidacloprid/1% moxidectin spot-on.

Efficacy of ronidazole for treatment of cats experimentally infected with a Korean isolate of Tritrichomonas foetus.

To evaluate the efficacy of ronidazole for treatment of Tritrichomonas foetus infection, 6 Tritrichomonas-free kittens were experimentally infected with a Korean isolate of T. foetus. The experimental infection was confirmed by direct microscopy, culture, and single-tube nested PCR, and all cats demonstrated trophozoites of T. foetus by day 20 post-infection in the feces. From day 30 after the experimentally induced infection, 3 cats were treated with ronidazole (50 mg/kg twice a day for 14 days) and 3 other cats received placebo. Feces from each cat were tested for the presence of T. foetus by direct smear and culture of rectal swab samples using modified Diamonds medium once a week for 4 weeks. To confirm the culture results, the presence of T. foetus rRNA gene was determined by single-tube nested PCR assay. All 3 cats in the treatment group receiving ronidazole showed negative results for T. foetus infection during 2 weeks of treatment and 4 weeks follow-up by all detection methods used in this study. In contrast, rectal swab samples from cats in the control group were positive for T. foetus continuously throughout the study. The present study indicates that ronidazole is also effective to treat cats infected experimentally with a Korean isolate of T. foetus at a dose of 50 mg/kg twice a day for 14 days.

Efficacy of silver ions against Sacbrood virus infection in the Eastern honey bee Apis cerana

Although silver is known to be a broad-spectrum biocidal agent, the effects of this metal against Sacbrood virus have not yet been investigated. In this study, we evaluated the efficacy of silver ions against natural Korean sacbrood virus (KSBV) infection of Apis (A.) cerana. Ten KSBV-infected colonies containing A. cerana with similar strength and activity were selected from an apiary located in Bosung-gun (Korea). Among these, five colonies were randomly assigned to the treatment group that was fed sugar syrup containing 0.2 mg/L silver ions. The other colonies were assigned to the untreated control group in which bees were given syrup without the silver ions. To assess the efficacy of the silver ions, colony strength, colony activity, and the number of dead larvae per hive were measured. During the experimental period, the test group maintained its strength and activity until day 32 while those of bees in the control group decreased sharply after day 8 to 16. Survival duration of the test group was significantly longer (40 days) than that of the control group (21 days). These results strongly indicated that silver ions are effective against KSBV infection in A. cerana.