Epizootic HPAIV, H5N6, and H5N8 infections produced severe loss in poultry and wild birds in the Republic of Korea from 2016 to 2017. But pathological lesions and antigen distribution of the novel HPAIV H5N6 clade 220.127.116.11 in natural cases have been rarely reported. Herein, we describe the pathological lesions and antigen localization in chickens (layer and Korean native), ducks, and Japanese quail naturally infected by HPAIV H5N6. Grossly, severe reddening, swelling, and some necrotic foci, which were similar to septicemia or viremia, were observed in skin and many visceral organs including trachea, lung, liver, spleen, and pancreas. Histopathologically, pulmonary congestion and edema, as well as necrotizing hepatitis, splenitis, pancreatitis, myocarditis, and encephalitis were observed. Immunohistochemically, numerous HPAIV antigens were detected in necrotic parenchymal cells and in blood vessels of the respiratory, lymphoid, digestive, urinary, nervous, and cardiovascular systems. The results indicate that HPAIV H5N6 spread to the entire body via blood and caused severe damage throughout the entire body. The HPAI H5N6 clade 18.104.22.168 virus was isolated from samples of all four cases.
A simulation model of the 2010/11 foot-and-mouth disease (FMD) epidemic in the city of Andong, Republic of Korea was constructed to evaluate the epidemiologic effectiveness of FMD-control strategies. Seven FMD-control strategies were evaluated with respect to a number of epidemiologic indicators relating to the outbreak, including the number of infected animals, number of infected farms, and epidemic duration. The FMD-control strategies in the model consisted of pre-emptive slaughtering, movement restriction, and vaccination; however, levels of each control option differed. The constructed model was not perfectly representative of the 2010/11 FMD epidemic, although it was considered to mimic the actual FMD epidemic in its prediction of two outcomes: the median number of simulated FMD-detected farms was 294 (range 207–515), which was close to the number of farms detected (299) during the actual FMD epidemic (x2=87.239, df=98, p = 0.774); and the simulated epidemic curve was visually similar to the actual epidemic curve of the 2010/11 FMD epidemic. The effectiveness evaluation of simulated FMD-control strategies emphasized the amount the FMD outbreak size could have increased if the radius of the pre-emptive slaughtering area or the duration of movement restriction were decreased.
Oriental medicine uses many herbs with biological activity. Among these, some have anti-inflammatory activities, but their action mechanisms have yet to be fully elucidated. Therefore, in this study, we harvested mouse bone marrow cells (BMs) and treated them with lipopolysaccharide (LPS), after which they were treated with the extracts of four medicinal herbs. The metabolic activity, cell death ratio, and tumor necrosis factor (TNF)-alpha production of the BMs was then evaluated. Among the four medicinal herbs, Caesalpinia sappan (CS) significantly decreased the metabolic activity, mitochondrial membrane potential of BMs, and production of TNF-alpha, especially in the presence of LPS. Moreover, CS increased the cell death of BMs stained with propidium iodide. Taken together, these findings indicate that CS inhibited the biological activities of LPS-treated BMs in multiple assays, confirming that CS has anti-inflammatory activity.
In the current study, a total of 102 common Todarodes pacificus squid caught in the East Sea were investigated for parasitological research. The results revealed that 33 (32.35%) out of 102 squid were infected by Nybelinia surmenicola, the mean intensity was 5.58 parasites per squid, and the maximum abundance was 11. Morphological analysis using a field emission scanning electron microscope showed the characteristic features of N. surmenicola. Molecular identification based on the 28S rRNA gene confirmed the isolated parasite as N. surmenicola, while phylogenetic analysis revealed that N. surmenicola isolated in this study was clustered with N. surmenicola isolated from Japan. This is the first report of phylogenetic characterization of N. surmenicola isolated from Korea.
Foreign hazardous substances are likely to enter the country through imported foods as food trade between countries increases. The Sanitary and Phytosanitary Agreement allows countries to take preventive measures to protect the health of the people based on the Appropriate Level of Protection (ALOP). Thus, the country may establish its own food safety objective within the scope of the ALOP and implement more efficient food safety management system to achieve food safety goal. Therefore, more stringent control measures such as Hazard Analysis and Critical Control Point (HACCP) like systems should be applied to set and meet performance objectives at each stage of the food chain.
Poultry play an important role in meeting the protein demand through the supply of chicken meat and eggs, and antimicrobial-resistant bacteria can be transmitted from poultry to humans through the food chain. In this study, 716 E. coli isolates were collected from poultry industry in Korea during the period from 2016-2018. Among the cephalosporin antimicrobial, the rate of resistance to first-cephalosporins (cefazolin and cephalexin) was more than 18.0% but secondcephalosporins (cefoxitin and cefuroxime) and four-cephalosporins (cefepime) was less than 10.0%, without any differences based on the poultry. In quinolone antimicrobial, the rate of resistance to nalidixic acid was more than 46.0% in all poultry but ciprofloxacin was more than 44.0% in broiler farm and chicken meat and less than 18.0% in layer farm and egg. In addition, the rate of resistance to ampicillin and tetracycline was more than 30.0% without any differences in poultry, but the rate of resistance to amoxicillin - clavulanate, trimethoprim - sulfamethoxazole, imipenem and gentamicin was higher in broiler farm and chicken meat than in layer farm and egg. MDR was detected in 120 (60.6%), 113 (79.6%), 80 (37.0%), and 75 (46.9%) isolates from broiler farm, chicken meat, layer farm, and egg, respectively, with an overall prevalence of 54.2% (388/716).
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a food-borne bacterial pathogen that causes various diseases in both humans and animals such as hemorrhagic colitis and hemolytic uremic syndrome. Because cattle are the main reservoir of this microorganism, undercooked meat and meat byproducts contaminated with EHEC O157:H7 are most commonly associated with epidemic disease outbreaks. As an enteric pathogen, EHEC O157:H7 enters the body via a fecal-oral route and must survive passage through the gastric stomach at pH 1.5 to 3.5 to establish an infection within the gastrointestinal tracts. Therefore, the ability to resist such acidic environments is important to the pathogenesis of EHEC O157:H7 during a host infection. In this review, we will discuss on the acid resistance (AR) mechanisms induced by EHEC O157:H7 when E. coli encounters acidic environments.