Min-Goo Seo

Hyo-Min Woo, Beoul Kim, You-Jeong Lee, Jae-Woo Choi, In-Soo Choi, Jimin Gimm, Kyoung-Mook Kang, Hae-Chul Park, Jeong Soo Choi, Min-Goo Seo. Korean J. Vet. Serv. 2026;49:267-77. https://doi.org/10.7853/kjvs.2026.49.3.267

Toxoplasma gondii is a widely distributed zoonotic parasite at the human–animal interface. However, studies simultaneously evaluating animal-associated workers and companion animals remain limited in South Korea. This multi-regional cross-sectional study aimed to estimate the apparent seroprevalence of T. gondii and explore associated factors among selected animal-associated workers, shelter animals, and companion animals. A total of 259 human participants and 1259 animals were enrolled. Structured questionnaires were used to assess occupational and behavioral risk factors, and serum samples were tested using commercial ELISA kits. The apparent seroprevalence was 15.1% (95% CI 11.2–19.9) in humans, 20.6% (95% CI 12.5–32.2) in animal shelter workers, and 13.3% (95% CI 9.2–18.7) in livestock disease control workers; the difference between the occupational groups was not statistically significant. Seroprevalence increased significantly with age ( p = 0.0003). A history of dog bites or dog-related injuries outside the workplace was independently associated with seropositivity (adjusted OR, 6.54; 95% CI 1.11–38.48; p = 0.04). The apparent seroprevalence was 14.1% (95% CI 11.5–17.3) in shelter dogs, 16.3% (95% CI 13.2–20.0) in companion dogs, 3.0% (95% CI 0.5–15.3) in shelter cats, and 3.2% (95% CI 1.6–6.4) in companion cats. Because the participants and animals were selected non-randomly, the findings should not be generalized to the overall human or animal populations of South Korea. These results support continued monitoring and targeted risk-awareness and preventive education for animal-associated occupational groups.

Dirofilaria spp. are mosquito-borne filarial nematodes that primarily infect mammals. Here, we describe a filarial nematode infection in a female little egret (Egretta garzetta) from Jeju, Korea. Necropsy revealed multiple slender nematodes (4–6 cm) in the subcutaneous tissues of both legs. Histopathological examination demonstrated granulomatous inflammation with intralesional parasites. Morphologically, the nematodes exhibited a thick multilayered cuticle with prominent longitudinal ridges, consistent with members of the genus Dirofilaria. Molecular analysis based on 18S rRNA and mitochondrial c oxidase subunit I (cox1) gene sequences indicated that the parasite was most closely related to D. repens; however, the level of sequence divergence precluded definitive species-level identification. Phylogenetic analysis further demonstrated that the isolates clustered within the Dirofilaria clade and were clearly separated from avian-associated filarioid nematodes. This study provides molecular and histopathological evidence of a Dirofilaria sp. infection in an avian host and supports incidental infection under natural exposure conditions.

Rodent-associated Trypanosoma spp. are widely distributed in wild rodents, but their epidemiology in the Republic of Korea remains incompletely characterized. This study investigated the prevalence, spatiotemporal distribution, and genetic characteristics of Trypanosoma spp. in 1169 wild micromammals representing 12 taxa, including 1010 Apodemus agrarius, collected from 18 sites across the Republic of Korea between 2022 and 2025 using molecular methods. Trypanosoma spp. DNA was detected in 58 (5.7%) Apodemus agrarius; all other micromammal species examined were negative. Fifty-seven samples were identified as T. grosi and one sequence was designated as a T. lewisi-like genotype. No significant regional differences in prevalence were observed. Annual prevalence estimates were presented descriptively because the seasonal and geographic composition of sampling differed among study years. When the seasonal comparison was restricted to 2022, 2023, and 2025, prevalence was significantly higher in autumn than in spring. The single T. lewisi-like genotype showed 98.5–99.7% nucleotide identity with reference T. lewisi sequences and clustered within the T. lewisi clade. Because species assignment was based on a single genetic marker, the sequence was conservatively designated as a T. lewisi-like genotype. To the best of our knowledge, this study provides the first molecular evidence of a T. lewisi-like genotype in a wild micromammal in the Republic of Korea. These findings provide updated epidemiological information on rodent-associated Trypanosoma spp. in the Republic of Korea.

Q fever is a zoonotic disease associated with reproductive losses in ruminants. This study investigated a 2025 outbreak on a Boer goat breeding farm in South Korea and compared its molecular characteristics with those of a separate 2024 outbreak. Conventional PCR targeting the IS1111 insertion element was used to test 87 goats, three female farm dogs, and four barn-level composite environmental samples. Positive goat samples underwent multiple-locus variable-number tandem-repeat analysis and multispacer sequence typing. Coxiella burnetii was detected in 60 of 87 goats (69.0%) and in one environmental sample, whereas dogs were negative. Two multiple-locus variable-number tandem-repeat profiles were identified among four goat samples, and two goats from different barns shared a profile provisionally designated MST77-like because it clustered near, but was not identical to, the MST77 reference profile. After movement restrictions, oxytetracycline treatment, environmental management, and serial monitoring, 11 of 57 previously positive goats remained positive at the second screening, and none of these 11 goats tested positive at the final examination. Complete herd clearance and the independent effect of antimicrobial treatment could not be confirmed because previously negative goats were not retested and no untreated comparison group was available. These findings support farm-wide testing, strengthened biosecurity, and follow-up monitoring.

Ticks are important vectors of numerous zoonotic pathogens, yet integrated molecular surveillance of wildlife hosts and their parasitizing ticks remains limited in Korea. In this study, we investigated the occurrence of major tick-borne bacterial pathogens in wildlife and their associated ticks. Blood samples were collected from Korean water deer (Hydropotes inermis), raccoon dogs (Nyctereutes procyonoides), and wild boars (Sus scrofa), and a total of 246 ticks were obtained from these 34 animals. Molecular analyses identified multiple bacterial pathogens, including Anaplasma phagocytophilum, Ehrlichia canis, Bartonella schoenbuchensis, Rickettsia raoultii, Rickettsia monacensis, and Candidatus Rickettsia longicornii. Notably, E. canis was detected for the first time in blood samples from raccoon dogs and wild boars in Korea, and B. schoenbuchensis was identified in ticks for the first time in the country. In addition, R. monacensis exhibited a remarkably high minimum infection rate in Ixodes nipponensis, and all positive ticks were collected from raccoon dogs. Strikingly, Ca. R. longicornii was detected at a very high prevalence (94.1%) in wildlife blood samples, suggesting extensive circulation among wildlife hosts in the study area. These findings indicate that wildlife and their parasitic ticks may serve as important reservoirs of diverse tick-borne bacteria in Korea and highlight the importance of continuous molecular surveillance within a One Health framework.