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The small hive beetle (SHB), Aethina tumida Murray, is a parasite of honey bee colonies and causes the fermentation of honey as well as colony collapse. Outbreaks have been confirmed in Africa, America, Europe as well as Asia, where an outbreak was reported in the Philippines and South Korea in 2014 and 2017, respectively. In South Korea, in September 2016, this honey bee parasite was first identified in apiaries in Miryang, Gyeongnam Province. However, the invasion pathway of SHB has not been identified, and honey bee pathogens harbored by SHB have not been well characterized. Therefore, phylogenetic analysis of SHB with the use of COI gene and detection of fourteen common honey bee pathogens were conducted in this study. The confirmation of the fourteen honey bee pathogens in SHB showed that this beetle carries black queen cell virus and deformed wing virus. Therefore, SHB could have a role in the spread of these viruses. The way of entry of the SHB to South Korea remains undetermined, but the phylogenetic analysis of the COI gene revealed that it was most similar to species found in the USA. There is an urgent need for national-level monitoring and quarantine measures for preventing the spread of SHB infestation in South Korea.

Genotyping of

Migratory birds disperse ticks and associated tick-borne pathogens along their migratory routes. Four selected pathogens of medical importance (Coxiella burnetii, Rickettsia spp., Francisella tularensis, and Toxoplasma gondii) were targeted for detection in 804 ticks (365 pools) collected from migratory birds at Hong and Heuksan Islands in the Republic of Korea (ROK) from 2010 to 2011 and 2016. Toxoplasma gondii and Rickettsia spp., were detected in 1/365 (0.27%) and 34/365 (9.32%) pools of ticks, respectively. T. gondii and five rickettsial species were recorded in ticks collected from migratory birds for the first time in ROK. The five rickettsial species (R. monacensis, Candidatus Rickettsia longicornii, R. japonica, R. raoultii, and R. tamurae) were identified using sequence and phylogenetic analysis using ompA and gltA gene fragments. Rickettsia spp. are important pathogens that cause rickettsiosis in humans, with cases recorded in the ROK. These results provide important evidence for the potential role of migratory birds in the introduction and dispersal of T. gondii and Rickettsia spp. along their migratory routes and raise awareness of potential transmission of zoonotic tick-borne pathogens associated with migratory birds in the ROK.

Honey bees are important pollinators for the conservation of the ecosystem and agricultural products and provide a variety of products important for human use, such as honey, pollen, and royal jelly. Sacbrood disease (SD) is a devastating viral disease in Apis cerana; an effective preventive measure for SD is urgently needed. In this study, the relationship between the gut microbiome of honey bees and SD was investigated by pyrosequencing. Results revealed that sacbrood virus (SBV)-resistant A. cerana strains harbour a unique acetic acid bacterium, Bombella intestini, and the lactic acid bacteria (LAB) Lactobacillus (unclassified)_uc, Bifidobacterium longum, B. catenulatum, Lactococcus lactis, and Leuconostoc mesenteroides in larvae and Hafnia alvei, B. indicum, and the LAB L. mellifer and Lactobacillus HM215046_s in adult bees. Changes in the gut microbiome due to SBV infection resulted in loss of bacteria that could affect host nutrients and inhibit honey bee pathogens, such as Gilliamella JFON_s, Gilliamella_uc, Pseudomonas putida, and L. kunkeei in A. cerana larvae and Frischella_uc, Pantoea agglomerans, Snodgrassella_uc, and B. asteroides in adult bees. These findings provide important information for the selection of probiotics for A. cerana larvae and adults to prevent pathogenic infections and keep honey bees healthy.

The extended distribution and potential introduction of exotic ticks and associated tick-borne pathogens along the northern and southern routes of migratory birds pose zoonotic tick-borne disease r...

Monofloral honey is produced from the nectar of a single predominant botanical species in a particular season and has certain unique properties. Valuable monofloral honey produced in a particular season with unique properties is often targeted for adulteration. Herein, a method for the identification of monofloral honey and determination of its production season was developed. Major nectar plants, including Prunus sp., Robinia pseudoacacia, Castanea sp., and Kalopanax sp., were selected to evaluate the honey produced between April and July in South Korea. Results showed that the highest amount of DNA from each plant was detected in the corresponding flowering season. The pollens tended to accumulate in the honeycomb after the flowering season. The accumulations result in an increase in the diversity of pollen detected in honey. Additionally, DNA quantity of each plant decreased in the samples as the number of plant DNA types increased from May to July. Moreover, the authenticity of the commercial monofloral honey samples showed only cherry blossom honey was found authentic, which exhibited the expected high amount of Prunus sp. DNA. This molecular tool is expected to be useful in verifying the origin of monofloral honey and its production season.

The outbreak of human toxoplasmosis can be attributed to ingestion of food contaminated with Toxoplasma gondii. Toxoplasmosis recently increased in domestic and stray dogs and cats. It prompted studies on the zoonotic infectious diseases transmitted via these animals. Sero- and antigen prevalences of T. gondii in dogs and cats were surveyed using ELISA and PCR, and B1 gene phylogeny was analyzed in this study. Toxoplasmosis antibodies were measured on sera of 403 stray cats, 947 stray dogs, 909 domestic cats, and 2,412 domestic dogs collected at nationwide regions, Korea from 2017 to 2019. In addition, whole blood, feces, and tissue samples were also collected from stray cats (1,392), stray dogs (686), domestic cats (3,040), and domestic dogs (1,974), and T. gondii-specific B1 gene PCR was performed. Antibody prevalence of stray cats, stray dogs, domestic cats, and domestic dogs were 14.1%, 5.6%, 2.3%, and 0.04%, respectively. Antigen prevalence of these animals was 0.5%, 0.2%, 0.1%, and 0.4%, respectively. Stray cats revealed the highest infection rate of toxoplasmosis, followed by stray dogs, domestic cats, and domestic dogs. B1 gene positives were 5 of stray cats, and identified to high/moderate pathogenic Type I/III group. These findings enforce that preventive hygienic measure should be strengthened at One Health level in dogs and cats, domestic and stray, to minimize human toxoplasmosis infections.

Genotyping of Coxiella burnetii using multispacer sequence typing (MST) and multiple locus variable number tandem repeat analysis (MLVA) was conducted from infected animals for the first time in the Republic of Korea. C. burnetii was detected by real-time PCR, and followed by MST and MLVA genotyping. The result showed that detected C. burnetii all had the same MLVA genotype, 6-13-2-7-9-10 for markers MS23-MS24-MS27-MS28-MS33-MS34, respectively, and genotype group 61 for MST. The same genotypes were previously identified in Poland. Importantly, this MLVA type was detected in humans in France, suggesting that the Korean strain can also potentially cause Q fever in humans. MST and MLVA were very useful tools for analyzing the molecular epidemiology of C. burnetii and helpful for interpreting the epidemiological relationship between isolates from domestic and international resources.

Background: Tick-borne diseases (TBDs) can be fatal to humans as well as to animals causing severe economic losses globally to livestock industries. Many countries conduct regular surveill...

The small hive beetle (SHB), Aethina tumida, is an invasive pest species in most Northern Hemisphere countries, including Korea. SHB causes serious damage to apiaries by destroying overwintering honey bee colonies. To obtain basic information for efficient management of SHB, genes encoding conventional insecticide targets, specifically the voltage-sensitive sodium channel α-subunit (VSSC) and acetylcholinesterase (AChE), and RNA interference (RNAi)-related components were annotated and characterized following analysis of transcriptomes of adults and larvae. A single VSSC gene was identified but no apparent mutations associated with pyrethroid resistance were detected. Genes encoding two AChEs (AtAChE1 and AtAChE2) were identified from the SHB transcriptome. No apparent mutations associated with resistance to organophosphorus and carbamate insecticides were identified in the AtAChE1 gene, whereas the S238G mutation, originally identified from the Colorado potato beetle, was detected in the AtAChE2 gene. Native polyacrylamide electrophoresis in conjunction with western blotting revealed that AtAChE1 was the main catalytic enzyme and therefore a toxicologically more relevant target. AtAChE1 was determined to exist in both membrane-anchored and soluble forms. The main components of RNA interference (RNAi) were identified, suggesting that RNAi is likely functional in SHB and an RNAi-based approach is a feasible alternative control measure.

Ticks are important vectors of various pathogens that result in clinical illnesses in humans and domestic and wild animals. Information regarding tick infestations and pathogens transmitted by ticks is important for the identification and prevention of disease. This study was a large-scale investigation of ticks collected from dogs and their associated environments in the Republic of Korea (ROK). It included detecting six prevalent tick-borne pathogens (Anaplasma spp., A. platys, Borrelia spp., Babesia gibsoni, Ehrlichia canis, and E. chaffeensis). A total of 2293 ticks (1110 pools) were collected. Haemaphysalis longicornis (98.60%) was the most frequently collected tick species, followed by Ixodes nipponensis (0.96%) and H. flava (0.44%). Anaplasma spp. (24/1110 tick pools, 2.16%) and Borrelia spp. (4/1110 tick pools, 0.36%) were detected. The phylogenetic analyses using 16S rRNA genes revealed that the Anaplasma spp. detected in this study were closely associated with A. phagocytophilum reported in humans and rodents in the ROK. Borrelia spp. showed phylogenetic relationships with B. theileri and B. miyamotoi in ticks and humans in Mali and Russia. These results demonstrate the importance of tick-borne disease surveillance and control in dogs in the ROK.

Background The microsporidian parasite Nosema ceranae is a global problem in honeybee populations and is known to cause winter mortality. A sensitive and rapid tool for stable quantitative detection is necessary to establish further research related to the diagnosis, prevention, and treatment of this pathogen. Objectives The present study aimed to develop a quantitative method that incorporates ultra-rapid real-time quantitative polymerase chain reaction (UR-qPCR) for the rapid enumeration of N. ceranae in infected bees. Methods A procedure for UR-qPCR detection of N. ceranae was developed, and the advantages of molecular detection were evaluated in comparison with microscopic enumeration. Results UR-qPCR was more sensitive than microscopic enumeration for detecting two copies of N. ceranae DNA and 24 spores per bee. Meanwhile, the limit of detection by microscopy was 2.40 × 10⁴ spores/bee, and the stable detection level was ≥ 2.40 × 10⁵ spores/bee. The results of N. ceranae calculations from the infected honeybees and purified spores by UR-qPCR showed that the DNA copy number was approximately 8-fold higher than the spore count. Additionally, honeybees infected with N. ceranae with 2.74 × 10⁴ copies of N. ceranae DNA were incapable of detection by microscopy. The results of quantitative analysis using UR-qPCR were accomplished within 20 min. Conclusions UR-qPCR is expected to be the most rapid molecular method for Nosema detection and has been developed for diagnosing nosemosis at low levels of infection.

The extended distribution and potential introduction of exotic ticks and associated tick-borne pathogens along the northern and southern routes of migratory birds pose zoonotic tick-borne disease risks to wild and domestic animals and incidentally to humans. A knowledge of bird migratory patterns, species of attached ticks, and associated pathogens during their migrations to and from their feeding and nesting grounds is central to understanding associated tick-borne disease risks. Tick-borne disease surveillance was conducted from 2010 to 2011 and 2016 at Hong-do (do = island), Heuksan-do, and Nan-do, major stopovers for migratory birds in Republic of Korea (ROK), as part of the Migratory Birds Research Center bird-banding program for studying bird migration patterns in the ROK. A total of 877 ticks belonging to three genera and nine species were collected

Background The microsporidian parasite Nosema ceranae is a global problem in honeybee populations and is known to cause winter mortality. A sensitive and rapid tool for stable quantitative detection is necessary to establish further research related to the diagnosis, prevention, and treatment of this pathogen. Objectives The present study aimed to develop a quantitative method that incorporates ultra-rapid real-time quantitative polymerase chain reaction (UR-qPCR) for the rapid enumeration of N. ceranae in infected bees. Methods A procedure for UR-qPCR detection of N. ceranae was developed, and the advantages of molecular detection were evaluated in comparison with microscopic enumeration. Results UR-qPCR was more sensitive than microscopic enumeration for detecting two copies of N. ceranae DNA and 24 spores per bee. Meanwhile, the limit of detection by microscopy was 2.40 × 104 spores/bee, and the stable detection level was ≥ 2.40 × 105 spores/bee. The results of N. ceranae calculations from the infected honeybees and purified spores by UR-qPCR showed that the DNA copy number was approximately 8-fold higher than the spore count. Additionally, honeybees infected with N. ceranae with 2.74 × 104 copies of N. ceranae DNA were incapable of detection by microscopy. The results of quantitative analysis using UR-qPCR were accomplished within 20 min. Conclusions UR-qPCR is expected to be the most rapid molecular method for Nosema detection and has been developed for diagnosing nosemosis at low levels of infection.

In this study, the gut microbiome of healthy adult honeybees, Apis cerana, was investigated by sequencing the V3 – V4 region in 16S rRNA gene using Illumina Miseq platform. The total of 37,853 reads for 16S rRNA gene were obtained and 30,121 (79.6%) reads were valid with 25,291 (84.0%) reads that were classified into 116 species belonging to four major phyla. The relative abundances of the bacterial isolates in honeybee samples were phylum Proteobacteria (70.7%), Actinobacteria (10.7%), Firmicutes (10.3%), and Bacteroidetes (8.4%), respectively. Lactic acid bacteria comprised 18.95% with 10 groups including Bifidobacterium asteroides, B. indicum, Fructobacillus fructosus, Lactobacillus apinorum, L. apis, L. helsingborgensis, L. kimbladii, L. kullabergensis, and L. kunkeei. The presence of beneficial bacteria in the gut highlighted their role in the honeybee and suggested that they can be promising candidates for the development of probiotics for health improvement, infection control and disease management of honeybees.

Four species of the subgenus Aethina Erichson sensu stricto are recognized in Korea, including two species new to Korea: Aethina (s.str) aeneipennis, and the small hive beetle (SHB), A. (s.str) tumida. This is the first report of the small hive beetle in the Far Eastern Asia, which has been recently spreading worldwide, causing big economic loss in beekeeping industry. Comments on external and genital structures, brief biology, illustrations of the genitalia of both male and female, and a key to species of the subgenus Aethina s. str. are provided. As SHB becomes worldwide issues in apiculture, the invasion history of A. tumida into Korea and its larval description are also provided.

We studied the prevalence and distribution of seven honey bee viruses, namely: acute bee paralysis virus (ABPV); cloudy wing virus (CWV); Israeli acute paralysis virus (IAPV); Kashmir bee virus (KBV); sacbrood virus (SBV); black queen cell virus (BQCV); and deformed wing virus (DWV), in healthy colonies from ten provinces in Vietnam. Colonies from each apiary were randomly selected to check viral infection. To confirm virus infection, samples were tested by Reverse Transcription Polymerase Chain Reaction using specific primer pairs. The positive products were sequenced and compared with the reference sequences using Basic Local Alignment Search Tool for molecular confirmation. In 360 Apis cerana samples, we found that the most prevalent virus was SBV (in 18.33% of samples), followed by BQCV (6.11%) and DWV (3.33%). The other four viruses, ABPV, CWV, IAPV, and KBV, were not detected in any sample. Infection rates were higher in adult bees than in larvae. The prevalences of SBV, BQCV, and DWV were 25.00, 10...

There is a lack of comprehensive studies on the seroprevalence of tick-borne pathogens in the Republic of Korea. Therefore, the aim of this study was to investigate the seroprevalences of Anaplasma spp. (A. phagocytophilum/A. platys), Borrelia burgdorferi sensu lato, Babesia gibsoni, Ehrlichia spp. (E. canis/E. ewingii), and Ehrlichia chaffeensis in dogs across the Republic of Korea in 2017 and 2018. A total of 2215 serum samples collected from 938 companion dogs, 969 shelter dogs, and 308 military working dogs were examined using commercial enzyme-linked immunosorbent assay (ELISA) and indirect fluorescence immunoassay (IFA) kits. Data collected for each animal, including breed, sex, age, region, season, and dog type, were used for statistical analysis. The overall seroprevalence was highest for Anaplasma spp. (15.1 %), followed by Ehrlichia spp. (10.3 %), B. burgdorferi sensu lato (6.4 %), E. chaffeensis (2.3 %), and B. gibsoni (1.7 %). One hundred and sixty-one dogs had antibodies against two or three different pathogens. The most common combinations were Anaplasma spp. - Ehrlichia spp. (2.1 %), Anaplasma spp. - E. chaffeensis (1.4 %), and Anaplasma spp. - B. burgdorferi sensu lato (1.2 %). Season was significantly associated with the seroprevalences of B. burgdorferi sensu lato and Ehrlichia spp., with dogs presenting the highest percentage of positive results during summer. Anaplasma spp. and B. gibsoni were significantly more prevalent in the northern and southern regions, respectively. The seroprevalences of Anaplasma spp., B. burgdorferi sensu lato, and Ehrlichia spp. were significantly higher in military working dogs, while the seroprevalence of E. chaffeensis was higher in companion dogs. The current findings are important for future surveillance of canine tick-borne pathogens and designing appropriate approaches for the diagnosis and control of these pathogens in the Republic of Korea.

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.

Sacbrood virus (SBV) is one of the most common viral infections of honeybees. The entire genome sequence for nine SBV infecting honeybees, Apis cerana and Apis mellifera, in Vietnam, namely AcSBV-Viet1, AcSBV-Viet2, AcSBV-Viet3, AmSBV-Viet4, AcSBV-Viet5, AmSBV-Viet6, AcSBV-Viet7, AcSBV-Viet8, and AcSBV-Viet9, was determined. These sequences were aligned with seven previously reported complete genome sequences of SBV from other countries, and various genomic regions were compared. The Vietnamese SBVs (VN-SBVs) shared 91–99% identity with each other, and shared 89–94% identity with strains from other countries. The open reading frames (ORFs) of the VN-SBV genomes differed greatly from those of SBVs from other countries, especially in their VP1 sequences. The AmSBV-Viet6 and AcSBV-Viet9 genome encodes 17 more amino acids within this region than the other VN-SBVs. In a phylogenetic analysis, the strains AmSBV-Viet4, AcSBV-Viet2, and AcSBV-Viet3 were clustered in group with AmSBV-UK, AmSBV-Kor21, and AmSBV-Kor19 strains. Whereas, the strains AmSBV-Viet6 and AcSBV-Viet7 clustered separately with the AcSBV strains from Korea and AcSBV-VietSBM2. And the strains AcSBV-Viet8, AcSBV-Viet1, AcSBV-Viet5, and AcSBV-Viet9 clustered with the AcSBV-India, AcSBV-Kor and AcSBV-VietSBM2. In a Simplot graph, the VN-SBVs diverged stronger in their ORF regions than in their 5′ or 3′ untranslated regions. The VN-SBVs possess genetic characteristics which are more similar to the Asian AcSBV strains than to AmSBV-UK strain. Taken together, our data indicate that host specificity, geographic distance, and viral cross-infections between different bee species may explain the genetic diversity among the VN-SBVs in A. cerana and A. mellifera and other SBV strains.

Purpose The aim of this study was to establish normative values and to identify age-related change in physical examinations that are commonly used while evaluating patients with cerebral palsy (CP). Materials and methods One hundred four healthy volunteers (mean age 36 years, standard deviation 15 years) were enrolled and divided into four age groups: 13-20, 21-35, 36-50, and 51 years and older. The eighteen physical examination tests for CP were selected by five orthopedic surgeons in consensus-building session. The measurements were taken by three orthopedic surgeons. Results There was no significant difference in the measures of physical examination among all the age groups, except for the Staheli test (p=0.002). The post hoc test revealed that the mean hip extension was 2.7° higher in the 13-20-year-old group than in the other age groups. The bilateral popliteal angle had a tendency to increase in those over 36-years-old. There were 31 participants (30%) with a unilateral popliteal angle greater than 40°. Conclusion We documented normative values that can be widely used for evaluating CP in patients 13 years and older.

Kashmir bee virus (KBV) is one of the most common viral infections in honeybees. In this study, a phylogenetic analysis was performed using nine partial nucleotide sequences of RdRp and the structural polyprotein regions of South Korean KBV genotypes, as well as nine previously reported KBV genotypes from various countries and two closely related genotypes of Israeli acute paralysis virus (IAPV) and Acute bee paralysis virus (ABPV). The Korean KBV genotypes were highly conserved with 94-99 % shared identity, but they also shared 88-95 % identity with genotypes from various countries, and they formed a separate KBV cluster in the phylogenetic tree. The complete genome sequence of Korean KBV was also determined and aligned with previously reported complete reference genome sequences of KBV, IAPV, and ABPV to compare different genomic regions. The complete Korean KBV genome shared 93, 79, and 71 % similarity with the complete reference genomes of KBV, IAPV, and ABPV, respectively. The Korean KBV was highly conserved relative to the reference KBV genomes in the intergenic and 3' untranslated region (UTR), but it had a highly variable 5' UTR, whereas there was little divergence in the helicase and 3C-protease of the nonstructural protein, and the external domains of the structural polyprotein region. Thus, genetic recombination and geographical distance may explain the genomic variations between the Korean and reference KBV genotypes.

Deformed wing virus (DWV) is one of the most common viral infection in honeybees. Phylogenetic trees were constructed for 16 partial nucleotide sequences of the structural polyprotein region and the RNA helicase region of South Korean DWVs. The sequences were compared with 10 previously reported DWV sequences from different countries and the sequences of two closely related viruses, Kakugo virus (KGV) and Varroa destructor virus-1 (VDV-1). The phylogeny based on these two regions, the Korean DWV genomes were highly conserved with 95-100% identity, while they also shared 93-97% similarity with genotypes from other countries, although they formed a separate cluster. To investigate this phenomenon in more detail, the complete DWV genome sequences of Korea-1 and Korea-2 were determined and aligned with six previously reported complete DWV genome sequences from different countries, as well as KGV and VDV-1, and a phylogenetic tree was constructed. The two Korean DWVs shared 96.4% similarity. Interestingly, the Korea-2 genome was more similar to the USA (96.5%) genome than the Korea-1. The Korean genotypes highly conserved with USA (96%) but low similarity with the United Kingdom3 (UK3) genome (89%). The end of the 5' untranslated region (UTR), the start of the open reading frame (ORF) region, and the 3' UTR were variable and contained several substitutions/transitions. This phenomenon may be explained by intramolecular recombination between the Korean and other DWV genotypes.

Phylogenetic trees were constructed for 24 partial nucleotide sequences of the nonstructural polyprotein (ORF1) and structural polyprotein regions (ORF2) of Korean IAPV genotypes, as well as eight previously reported IAPV sequences from various countries. Most of the Korean genotypes formed a distinct cluster, separate from other country genotypes. To investigate this phenomenon in more detail, three complete IAPV genome sequences were identified from different regions in Korea, i.e., Korea1, Korea2, and Korea3. These sequences were aligned with eight previously reported complete genome sequences and various genome regions were compared. The Korean IAPVs were very similar to those from China and Israel, but highly diverged from USA and Australian genotypes. Interestingly, they showed greater variability than the USA and Australian genotypes in ORF1, but highly similar to the Australian genotype in the ORF2 region. Thus, genetic recombination may account for the spatial distance between the Korean IAPV genotypes and those from other countries.

This study was carried out to identify the tick species that infest grazing cattle and to determine the presence of tick-borne pathogens transmitted by these ticks in Korea. A total of 903 ticks (categorized into 566 tick pools) were collected from five provinces during 2010-2011. The most prevalent tick species was Haemaphysalis longicornis, followed by three Ixodes spp. ticks. The collected ticks were infected with both rickettsial and protozoan pathogens. In all, 469 (82.9%) tick pools tested positive for the Anaplasma/Ehrlichia 16S rRNA gene, whereas 67 (11.8%) were positive for the Babesia/Theileria 18S rRNA gene. Among the rickettsial pathogens, E. canis was detected with the highest rate (22.3%), followed by A. platys (20%), E. chaffeensis (19.4%), E. ewingii (19.3%), Rickettsia sp. (12.4%), A. phagocytophilum (5.5%) and E. muris (0.5%). Among the protozoan pathogens, T. equi was detected with the highest rate (7.2%), followed by T. sergenti/T. buffeli (3.7%) and B. caballi (0.35%). Simultaneous infections with up to seven pathogens were also identified. In particular, ticks infected with rickettsial pathogens were also infected with protozoan pathogens (22 samples). All five provinces investigated infected with tick-borne pathogens.

Species composition, standing crop and dominant species of phytoplankton were investigated at 6 sites of Galgok stream and Incheon river which run into Gomso Bay, Jeollanam-do in April, August and November 2007. Total of 210 taxa were found which were classified as 6 classes, 12 orders, 25 families, 66 genera, 177 species, 27 varieties, 5 forms and 1 unidentified species. These river and stream had lower concentration of T-N and T-P compared to that of others; however, the site 2 of Galgok stream in summer was hypertrophic in T-P and also near hypertrophic in TN, and the site 1 in Incheon river during fall appeared to be hypertrophic in T-N, and the site 3 in summer showed near hypertrophic level in T-P. Determining the trophic status of the water quality based on chlorophyll a (chl-a), the site 3 of Galgok stream in spring and the site 3 of Incheon river in fall were oligotrophic; moreover, 6 sites including the site 2 and 3 of Galgok stream in summer were mesotrophic, and 9 sites including all sites of Galgok stream in fall turned out to be eutrophic. Particularly, the site 1 of Galgok stream in summer was hypertrophic, having 58.19 mg chl-a m. There was a conspicuous difference between two values of standing crops based on chl-a and cell counting. This discrepancy may have occurred because of abundant cyanophytes and exclusion of picoplankton cells in cell counting. In the study, 5 cyanophytes, Synechocystis aquatilis, Microcystis aeruginosa, M. flos-aquae, Oscillatoria angustissima, O. limnetica and 2 diatoms, Thalassiosira bramaputrae and Navicula viridula var. rostellata were abundant. Based on the T-N, T-P values, standing crops and cell counting in Galgok stream and Incheon river were between mesotrophic and eutrophic conditions.

Acarapis mites, including Acarapis woodi, Acarapis externus, and Acarapis dorsalis, are parasites of bees which can cause severe damage to the bee industry by destroying colonies and decreasing honey production. All 3 species are prevalent throughout many countries including UK, USA, Iran, Turkey, China, and Japan. Based on previous reports of Acarapis mites occurring in northeast Asia, including China and Japan, we investigated a survey of Acarapis mite infestations in honey bees in Korean apiaries. A total of 99 colonies of Apis mellifera were sampled from 5 provinces. The head and thorax of 20 bees from each colony were removed for DNA extraction. PCR assays were performed with 3 primer sets, including T, A, and K primers. Results indicated that 42.4% (42/99) of samples were Acarapis-positive by PCR assay which were sequenced to identify species. Each sequence showed 92.6-99.3% homology with reference sequences. Based on the homology, the number of colonies infected with A. dorsalis was 32 which showed the highest infection rate among the 3 species, while the number of colonies infected with A. externus and A. woodi was 9 and 1, respectively. However, none of the Acarapis mites were morphologically detected. This result could be explained that all apiaries in the survey used acaricides against bee mites such as Varroa destructor and Tropilaelaps clareae which also affect against Acarapis mites. Based on this study, it is highly probable that Acarapis mites as well as Varroa and Tropilaelaps could be prevalent in Korean apiaries.

Sacbrood virus (SBV), a causative agent of larval death in honeybees, is one of the most devastating diseases in bee industry throughout the world. Lately the Korean Sacbrood virus (KSBV) induced great losses in Korean honeybee (Apis cerana) colonies. However, there is no culture system available for honeybee viruses, including SBV, therefore, the research on honeybee viruses is practically limited until present. In this study, we investigated the growth and replication of SBV in cell cultures. The replication signs of KSBV after passages from mammalian cells was identified and confirmed by using combined approaches with nested, quantitative, negative-strand PCR and electron microscopy along with in vivo experiment. The results revealed that mammalian cell lines, including Vero cells could support the replication KSBV. Although there were no signs of cytopathic effect (CPE) in cells, it was for the first time demonstrated that SBV could be replicated in cells through the sequential passages linked with cell adaptation. KSBV from the present study would be a valuable source to understand the mechanism of pathogenicity of sacbrood virus in the future.