Isthmiophora hortensis (Digenea: Echinostomatidae) is a dominant echinostome in animal reservoir hosts and humans in the Republic of Korea (Korea). We intended to investigate the infection status with this echinostome species in the several species of wild animals and describe the morphological characteristics in the faunistic view point. A total of 175 animal carcasses belonging to 3 families, i.e., Canidae, Felidae and Mustelidae, were collected from the southern regions of Korea from March 2010 to July 2017. Isthmiophora spp. worms were recovered from the small intestines of each animal under a stereomicroscope after washing of intestinal contents. Isthmiophora hortensis was recovered from 4 species of wild carnivores, i.e., Nyctereutes procyonoides (3/107: 2.8%), Mustela sibirica (11/31: 35.5%), Meles lucurus (2/3: 33.3%) and Martes flavigula (1/2: 50%). The other 3 carnivores comprising stray dogs, cat and leopard cat were negative for I. hortensis infection (0/2, 0/10 and 0/12, respectively). Specimens obtained from the Lutra lutra (6/8: 75%) were identified as a distinct species, I. inermis, by morphological comparison. Isthmiophora inermis has thinner body, elongate testes and different anterior limits of vitelline fields. Detailed morphological descriptions and comparisons with the morphological characteristics are provided. Conclusively, it was confirmed for the first time that 3 species of mustelid mammals, i.e., M. sibirica, M. lucurus, and M. flavigula, are to be the new definitive hosts of I. hortensis in Korea. Additionally, I. inermis is to be newly added in the Korean echinostome fauna.
Animals ; Animals, Wild ; Canidae ; Cats ; Dogs ; Felidae ; Gastrointestinal Contents ; Humans ; Intestine, Small ; Korea ; Mammals ; Mustelidae ; Otters ; Panthera ; Raccoon Dogs ; Republic of Korea ; Testis ; Vitellins

Since 2000, large amounts of rabies bait vaccine have been distributed in two provinces where raccoon dog-mediated rabies has occurred. A total of 146 raccoon dogs were caught in Gangwon and Gyeonggi Provinces from January 2017 to June 2018, and raccoon dog blood samples were collected. Of the 146 raccoon dogs, 13.7% (20/146) had rabies antibodies. In Gyeonggi and Gangwon provinces, the rate of rabies antibody was 8.5% (5/59) and 17.2% (15/87), respectively. Considering these results, it would be desirable to improve the distribution method or use a new bait vaccine to prevent animal rabies in South Korea.
Animals ; Antibodies ; Gangwon-do ; Gyeonggi-do ; Korea ; Methods ; Rabies ; Raccoon Dogs ; Raccoons

Canine adenovirus type 2 (CAV-2) is the cause of a major respiratory illness in dogs. In this study, we analyzed adenovirus infections in dogs using 2000–2017 data from the Animal and Plant Quarantine Agency (APQA) and conducted a serological survey of CAV-2 infection in six animal species in Korea. In total, 38 of the 3,179 dog samples were confirmed as canine adenovirus infections. In serological survey, 1,028 dog sera, 160 raccoon dog sera, 100 cattle sera, 257 sow sera, 206 horse sera, and 106 cat sera, collected from January 2016 to July 2018, were screened for the presence of anti-CAV-2 antibodies by virus neutralization test. The seropositivity rates for dogs, raccoon dogs, cattle, sows, horses, and cats were 88.5% (910/1,028), 51.3% (82/160), 85.0% (85/100), 48.6% (125/257), 35.0% (72/206), and 2.8% (3/106), respectively. Among dogs and raccoon dogs, 1.9% (20/1,028) and 8.8% (14/160), respectively, had a virus-neutralizing antibody (VNA) titer of over 1:256. A high CAV-2 VNA titer indicates a repeated vaccination or natural infection in Korean dogs and circulation of CAV-2 in raccoon dog populations.
Adenoviridae Infections ; Adenoviruses, Canine* ; Animals* ; Antibodies ; Cats ; Cattle ; Dogs ; Horses ; Incidence* ; Korea ; Neutralization Tests ; Plants ; Quarantine ; Raccoon Dogs ; Vaccination

Present study was performed to describe the morphological and molecular characterization of Toxocara tanuki (Nematoda: Ascaridae) from Korean raccoon dog, Nyctereutes procyonoides koreensis, naturally infected in the Republic of Korea (Korea). Juvenile and adult worms of T. tanuki were recovered in 5 out of 10 raccoon dogs examined and the larval worms were detected in 15 out of 20 muscle samples (75%). Small lateral alae were observed on the cranial end of the body in male and female adults and 2 long spicules (3.0–3.5 mm) were characteristically observed in the posterior end of males. In SEM observation, 18 pairs of proximal precloacal, a precloacal median, a postcloacal median and 5 pairs of postcloacal papillae were uniquely revealed in the posterior portion of males, but the proximal papillae were not shown in the lateral ends of females. Molecular analysis on the 18S rRNA partial DNA sequences was revealed the same finding in both samples, adult worms and muscle larvae, which are closely related to T. tanuki. In conclusion, it was confirmed for the first time that T. tanuki is indigenously distributed, the Korean raccoon dog is acted as the natural definitive host of this nematode in Korea and the morphological characteristics of T. tanuki were shown in specific structure for single postcloacal median papilla in male.
Adult ; Base Sequence ; Female ; Humans ; Korea ; Larva ; Larva Migrans ; Male ; Raccoon Dogs ; Raccoons ; Republic of Korea ; Toxocara

Infections of Toxoplasma gondii and Babesia microti are reported in many wild animals worldwide, but information on their incidence and molecular detection in Korean wild fields is limited. In this study, the prevalence of T. gondii and B. microti infection in blood samples of 5 animal species (37 Chinese water deer, 23 raccoon dogs, 6 roe deer, 1 wild boar, and 3 Eurasian badgers) was examined during 2008–2009 in Gangwon-do (Province), the Republic of Korea (=Korea) by using serological and molecular tests. The overall seropositivity of T. gondii was 8.6% (6/70); 10.8% in Chinese water deer, 4.3% in raccoon dogs, and 16.7% in roe deer. PCR revealed only 1 case of T. gondii infection in Chinese water deer, and phylogenic analysis showed that the positive isolate was practically identical to the highly pathogenetic strain type I. In B. microti PCR, the positive rate was 5.7% (4/70), including 2 Chinese water deer and 2 Eurasian badgers. Phylogenetic analysis results of 18S rRNA and the β-tubulin gene showed that all positive isolates were US-type B. microti. To our knowledge, this is the first report of B. microti detected in Chinese water deer and Eurasian badger from Korea. These results indicate a potentially high prevalence of T. gondii and B. microti in wild animals of Gangwon-do, Korea. Furthermore, Chinese water deer might act as a reservoir for parasite infections of domestic animals.
Animals ; Animals, Domestic ; Animals, Wild* ; Asian Continental Ancestry Group ; Babesia microti* ; Babesia* ; Deer ; Gangwon-do* ; Humans ; Incidence ; Korea* ; Mustelidae ; Parasites ; Polymerase Chain Reaction ; Prevalence ; Raccoon Dogs ; Republic of Korea ; Sus scrofa ; Toxoplasma* ; Water

PURPOSE: Rabies is one of the most fatal diseases, but it is 100% preventable in animals by vaccination. In this study, we present the epidemiological features of, and national preventive measures against, rabies in Korea. MATERIALS AND METHODS: Data related to rabies and the population density of raccoon dogs in Korea were collected from the Animal and Plant Quarantine Agency, the Korean Centers for Disease Control and Prevention, and the National Institute of Environmental Research. Rabies diagnosis was confirmed with a fluorescent antibody test using brain samples of animals in accordance with the procedures described by the World Organization for Animal Health. Serological assays for dogs and cattle were conducted using the fluorescent antibody virus neutralization test. RESULTS: From 1993 to 2016, a total of seven human rabies cases and 437 animal rabies cases in five different species were reported. An increase in the distribution of bait vaccine seemed to be related to a dramatic decrease in rabies prevalence in endemic rabies regions. Two Korean provinces and the capital city, Seoul, were involved in rabies outbreaks. Korean rabies strains are most closely related to the eastern Chinese strain belonging to the Arctic-like lineage. The yearly seropositive rates ranged from 50.4% to 81.2% in dogs and from 25% to 60.5% in cattle residing in endemic rabies regions. CONCLUSION: This study indicates that national preventive measures, including mass vaccination and distribution of bait vaccines, have contributed to a substantial decrease in the number of rabies cases in Korea.
Animals ; Asian Continental Ancestry Group ; Brain ; Cattle ; Centers for Disease Control and Prevention (U.S.) ; Diagnosis ; Disease Eradication ; Disease Outbreaks ; Dogs ; Epidemiology ; Humans ; Korea* ; Mass Vaccination* ; Neutralization Tests ; Plants ; Population Density ; Prevalence ; Quarantine ; Rabies* ; Raccoon Dogs ; Seoul ; Vaccination ; Vaccines

The present study was performed to record new definitive hosts of Isthmiophora hortensis, and to describe morphological characteristics derived from a variety of worm samples for clarification of its taxonomic validity. Morphological characteristics with dimensions were observed in worm samples (n=21) from naturally infected wild animals, including a raccoon dog Nyctereutes procyonoides from Gimhae-si (City), Gyeongsangnam-do, stray cats and a striped field mouse from several localities, and a wild boar Sus scrofa, from Gurye-gun (County), Jeollanam-do. In addition, adult flukes (n=45) recovered in albino rats experimentally infected with the metacercariae from a freshwater fish species were also subjected to morphological studies. The mean ratios of the body length (BL) to body width (BW) were 5.86 and 5.76 in worms from wild animals and experimental rats, respectively. Those of the ventral sucker to oral sucker were 2.92 and 3.01 in worms from 2 groups. The mean percentages of the hindbody length (HBL) to BL were 42.1 and 41.2 in 2 groups. Those of uterine fields to BL were 9.8 and 12.2 in the 2 worm groups. By the present study, the 2 species of wild animals, the raccoon dog and wild boar, have been added as new definitive hosts for I. hortensis. The morphological characteristics of adult flukes derived from a variety of host source were redescribed to support the taxonomic validity of this echinostome species.
Adult ; Animals ; Animals, Wild ; Cats ; Fresh Water ; Gyeongsangnam-do ; Humans ; Jeollanam-do ; Metacercariae ; Mice ; Raccoon Dogs ; Rats ; Sus scrofa ; Trematoda

Wild raccoon dogs (Nyctereutes procyonoides koreensis) may play a role transmitting several pathogens to humans and pet animals. Information concerning the incidence of rabies, canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus type 2 (CAdV-2), canine parainfluenza virus type 5 (CPIV-5), and canine herpesvirus (CHV) is needed in wild raccoon dogs. In total, 62 brain samples of raccoon dogs were examined for rabies virus (RABV) and CDV, and 49 lung samples were screened for CDV, CAdV-2, CPIV-5, and CHV. No RABV, CAdV-2, CPIV-5, or CHV was identified, but nine CDV antigens (8.1%, 9/111) were detected. Moreover, 174 serum samples from wild raccoon dogs were screened for antibodies against the five major viral pathogens. The overall serosurveillance against CDV, CPV, CAdV-2, CPIV-5, and CHV in wild raccoon dogs was 60.3%, 52.9%, 59.8%, 23.6%, and 10.3%, respectively. Comparisons of the sero-surveillance of the five pathogens showed that raccoon dogs of Gyeonggi province have slightly higher sero-positive rates against CDV, CPV, and CHV than those of Gangwon province. These results indicate high incidences of CDV, CPV, and CAdV-2 in wild raccoon dogs of two Korean provinces and a latent risk of pathogen transmission to companion and domestic animals.
Adenoviruses, Canine ; Animals ; Animals, Domestic ; Antibodies ; Brain ; Disease Transmission, Infectious ; Distemper ; Distemper Virus, Canine ; Friends ; Gangwon-do ; Gyeonggi-do ; Humans ; Incidence ; Lung ; Paramyxoviridae Infections ; Parvovirus, Canine ; Rabies ; Rabies virus ; Raccoon Dogs* ; Raccoons*

PURPOSE: The development of a genetically modified live rabies vaccine applicable to wild raccoon dogs is necessary for the eradication of rabies in Korea. Thus, we constructed a recombinant rabies virus (RABV) called the ERAGS strain, using a reverse genetic system and evaluated its safety and efficacy in mice and its safety and immunogenicity in raccoon dogs. MATERIALS AND METHODS: ERAGS, which has Asn194Ser and Arg333Glu substitutions in the glycoprotein, was constructed using site-directed mutagenesis. Mice were inoculated with the ERAGS strain (either 10(5.0) or 10(7.0) FAID(50)/mL) via intramuscular (IM) or intracranial injections and then challenged with a virulent RABV. Raccoon dogs were administered the ERAGS strain (10(8.0) FAID(50)/mL) either orally or via the IM route and the immunogenicity of the strain was evaluated using fluorescent antibody virus neutralization tests. RESULTS: The ERAGS strain inoculated into murine neuroblastoma cells reached 10(7.8) FAID(50)/mL at 96-hour post-inoculation. The virus was not pathogenic and induced complete protection from virulent RABV in immunized 4- and 6-week-old mice. Korean raccoon dogs immunized with the ERAGS strain via IM or oral route were also safe from the virus and developed high titer levels (26.4-32.8 IU/mL) of virus-neutralizing antibody (VNA) at 4 weeks post-inoculation. CONCLUSION: The ERAGS RABV strain was effectively protective against rabies in mice and produced a high VNA titer in raccoon dogs.
Animals ; Glycoproteins ; Korea ; Mice* ; Mouth ; Mutagenesis, Site-Directed ; Neuroblastoma ; Neutralization Tests ; Rabies Vaccines ; Rabies virus* ; Rabies* ; Raccoon Dogs* ; Raccoons* ; Vaccines

PURPOSE: New rabies vaccine bait for both pets and raccoon dogs residing in Korea is needed to eradicate rabies infection among animals. In this study, we constructed a recombinant rabies virus (RABV), the ERAG3G strain, using a reverse genetics system. Then we investigated the efficacy of this strain in mice after oral administration and the safety of this strain in cats after intramuscular administration. MATERIALS AND METHODS: The ERAG3G strain was rescued in BHK/T7-9 cells using the full-length genome mutated at the amino acid position 333 of the glycoprotein gene of RABV and helper plasmids. Four-week-old mice underwent one or two oral administrations of the ERAG3G strain and were challenged with the highly virulent RABV strain CVSN2c 14 days after the second administration. Clinical symptoms were observed and body weights were measured every day after the challenge. RESULTS: All mice showed complete protection against virulent RABV. In addition, cats intramuscularly inoculated with the ERAG3G strain showed high antibody titers ranging from 2.62 to 23.9 IU/mL at 28-day postinoculation. CONCLUSION: The oral immunization of the ERAG3G strain plays an important role in conferring complete protection in mice, and intramuscular inoculation of the ERAG3G strain induces the formation of anti-rabies neutralizing antibody in cats.
Administration, Oral ; Animals ; Antibodies, Neutralizing ; Body Weight ; Cats ; Genome ; Glycoproteins ; Immunization* ; Korea ; Mice* ; Plasmids ; Rabies ; Rabies Vaccines* ; Rabies virus ; Raccoon Dogs ; Reverse Genetics