최근 국내에서는 꿀벌 대량소실 현상이 2022년부터 전국적으로 발생하고 있다. 우리나라 뿐 만 아니라, 전세계 적으로 양봉산업에 큰 위협이 되고 있는 봉군붕괴현상은 2016년 미국에서 세계 최초로 보고되었다. 국내에서는 2022년 민관 합동조사 결과, 이상기온, 응애, 말벌 등이 주요 원인으로 지목되었다. 대량소실 현상을 보인 양봉농 가와 정상 농가의 병원체 검출 비교 결과, 유의성있게 검출이 증가되는 병원체는 발견되지 않았다. 그러나, Tyrophagus mite, Trypanosome, Lake Sinai virus, Apis mellifera filamentous virus 등의 신종 응애, 원충 및 바이러 스 감염이 추가로 확인되었다. 국내에서 새롭게 감염이 확인된 기생충과 병원체가 대량소실, 나아가 봉군붕괴현 상에 직간접적으로 영향을 주었을 것으로 사료되며, 지속적인 조사와 연구개발을 통해 기후등 환경변화에 따른 신종 질병 검색과 대책을 마련해야 할 것이다.

Regarding to diagnosis for bovine brucellosis, more than one serological test should be conducted to confirm the infection by Brucella with a reliable result due to various factors including false positive serological reactions. In this study, we compared confirmatory serological tests to determine the appropriate way to detect and confirm the Brucella infection in South Korea. Several serological tests, including serum agglutination test (SAT), indirect (I)- and competitive (C)-ELISA, and fluorescence polarization assay (FPA), for detection of bovine brucellosis were performed with sera from 537 cattle. In addition, comparison of diagnostic efficacy was performed with bacterial isolation represented true positive. Of 537 serum samples, 426 (79.3% of prevalence), 433 (80.6%), 414 (77.1%), and 409 (76.2%) sera were positive for SAT, C-ELISA, I-ELISA, and FPA respectively. Based on the results of serology, the correlation among the serological tests revealed observed agreements of more than 92% with kappa (k) value of more than 0.77. The correlation between serological tests with bacterial isolation appeared observed agreements of between 79.9% and 84.7% with k value of between 0.42 and 0.59. Particularly, FPA recorded almost perfect agreements with C-ELISA and I-ELISA as well as the highest correlation with bacterial isolation. Accordingly, this investigation presented the comparison of correlation and diagnostic efficacy of serological tests for bovine brucellosis in South Korea. We suggest this finding will be a useful data to re-establish the potential serological diagnostic methods that can apply to maintain the low prevalence.

The detection of Mycobacterium bovis (M. bovis) in environmental samples with precision is imperative to control bovine tuberculosis (bTB) infections at the herd level, as residual M. bovis remains one of the major causes of recurring infections. In this study, a nested PCR method for the detection of M. bovis in environmental samples was applied to identify potential environmental reservoirs of the bacterium. A set of 200 environmental samples (167 fecal samples and 33 water samples) from 39 herds with a history of bTB outbreak was analyzed using a nested PCR method to detect residual M. bovis. Amplicon libraries of the IS6110 target gene fragment were amplified from M. bovis DNA using two established primer sets. A positive nested PCR result was observed in 69.5% of fecal samples and 66.7% of water samples, thus showing that residual M. bovis was present in the environmental samples of bTB-positive herds in a high proportion. This study is the first to demonstrate high levels of M. bovis DNA in environmental samples and to show that environmental reservoirs of this pathogen contribute to recurring outbreaks of bTB. Environmental monitoring of herds in which bTB outbreaks have occurred with high sensitivity and specificity is expected to help prevent the recurrence of potential bTB disease and improve the herd environment.

Brucellosis is the most common zoonosis worldwide, which is caused by Brucella spp. In humans, it can be mainly occurred by direct contact with infected animals or consumption of contaminated dairy products. This study focused on human brucellosis caused by B. melitensis discovered from Chinese worker in Korea in 2015. We investigated molecular epidemiological evidence to find the infection source. We first performed several PCR methods including 16S rRNA PCR, multiplex PCR and real-time PCR to identify Brucella species. We also conducted MLVA typing for epidemiological trace-back analysis. The isolate from the patient was confirmed to B. melitensis through Brucella-specific PCR. In clustering analysis with B. melitensis from foreign countries, this human isolate was correlated with B. melitensis isolates from humans and sheep in China by 99.9% similarity. Thus, we assumed the brucellosis patient has been already infected in China followed by migration to Korea according to molecular epidemiological analysis with history evidence. Moreover, we suggest it needs to take measures to reduce the risk for intercountry transmission of brucellosis due to the influx of infected people from abroad.

A 26-month-old male mixed-breed dog of Korean origin was subjected to necropsy following death after a history of decreased appetite and weight loss. Necropsy revealed generalized lymphadenopathy and splenomegaly. Histopathological examination of samples from the spleen, mandibular lymph nodes, liver, kidney, and large intestine showed granulomas with numerous macrophages containing intracytoplasmic Leishmania amastigotes. Transmission electron microscopy revealed Leishmania amastigotes in the macrophage cytoplasm. All tissues with granulomas were positive for Leishmania spp, which was confirmed to be Leishmania infantum by conventional polymerase chain reaction (PCR), real-time PCR, and in situ hybridization. To our knowledge, this is the second case of canine visceral leishmaniasis in Korea.

A tissue sample of a laryngopharyngeal mass from a 9-year-old male Dachshund dog was submitted to the Animal, Plant and Fisheries Quarantine and Inspection Agency for histopathologic evaluation. The mass measured was 3.1×3.0× 5.0 ㎝ in diameter and was first detected by computed tomography. Histopathologically, the nodules consisted of large round and polygonal cells with abundant eosinophilic cytoplasm. The mitotic index was 1～3 per view under a high power field (400×). Immunohistochemically, tumor cells were positive for vimentin and desmin, but negative for cytokeratin, S-100, and α-Smooth Muscle Actin (α-SMA). Based on these findings, the tumor was confirmed as Laryngopharyngeal Rhabdomyosarcoma. To the best of our knowledge, this is the first case report in Korea.

Epidemic models on disease spread attempt to simulate disease transmission and associated control processes. This study reviewed published papers on epidemiological models for the management of foot-and-mouth disease in the world. In addition, an individual animal-based, spatially-explicit, stochastic disease transmission model, the Davis Animal Disease Simulation (DADS) model, was described in the frame of an international collaborative research project participating three countries: Republic of Korea, USA, and New Zealand. In this project, the Korean team is aiming at developing the most appropriate parameters for livestock and epidemiology of foot-and-mouth disease outbreaks. On the other hand, the purpose of foreign counterparts is validating their models: DADS (USA) and InterSpread Plus (New Zealand). Classification of farm types and preliminary estimations on the frequency of intra-herd contacts were also presented. This research project is expected to provide precious information to plan a strategy that will facilitate the eradication of foot-and-mouth disease from Korea.

Grossly, a lot of soft white nodules, 0.5～1.5 cm in diameter, were randomly scattered in liver of a slaughtered Korean Native Cattle. The surface of liver was roughened by those nodules. Histopathologically the nodules were consisted of numerous mature blood vessels, which had variable size and wall thickness, and which were encircled by much connective tissue. Masson's trichrome stain clearly revealed the proliferated blood vessels and perivascular stroma and, immunohistochemical staining revealed that endothelial cells of proliferated blood vessels were positive for Von Willebrand Factor. Based on gross and histopathological lesions, and immunohistochemical staining, the case was confirmed as hepatic vascular hamartoma and it is the first case report in Korea, as far as we know.

Toxocara (T.) canis, round worm of dogs and cats, is probably the most common gastrointestinal helminthes of domestic canid and is ascarid nematodes in the order Ascaridida, family Toxocaridae. The prevalence of patent toxocariasis is highest in the young dogs and much less common in adult dogs. There are few reports on the status of T. canis prevalence of dogs in Korea. Few cases of human visceral larva migrans also reported in Korea. However, as far as we know, there is no report on the canine toxocariasis case determined by pathological findings in Korea until now. In this research, we diagnosed canine toxocariasis by fecal egg test and pathologic findings in 2-month old two Pointer dogs. Typical T. canis eggs were detected in the fecal test. Numerous adult ascarids in the lumen of small intestine and stomach in one dog and multifocal white necrotic lesions in lung, liver, and kidney in another dog were observed grossly. Histologically, multifocal necrosis, eosinophilic inflammation and intralesional ascarid larva were prominent findings in the lung, liver and kidney.