This study aimed to inspect norovirus contamination of groundwater treatment systems used in food-catering facilities located in South Korea. A nationwide study was performed in 2010. Water samples were collected and, for the analysis of water quality, the temperature, pH, turbidity, and residual chlorine content were assessed. To detect norovirus genotypes GI and GII, RT-PCR and semi-nested PCR were performed with specific NV-GI and NV-GII primer sets, respectively. The PCR products amplified from the detected strains were then subjected to sequence analyses. Of 1,090 samples collected in 2010, seven (0.64%) were found to be norovirus-positive. Specifically, one norovirus strain was identified to have the GI-6 genotype, and six GII strains had the GII, GII-3, GII-4, and GII-17 genotypes. The very low detection rate of norovirus most likely reflects the preventative measures used. However, this virus can spread rapidly from person to person in crowded, enclosed places such as the schools investigated in this study. To promote better public health and sanitary conditions, it is necessary to periodically monitor noroviruses that frequently cause epidemic food poisoning in South Korea.

Widespread outbreaks of foot-and-mouth disease and avian influenza occurred in South Korea during 2010. In response to the culling of many animals to attenuate the spread of disease, South Korea used mass burial sites to dispose of the large number of carcasses; consequently, concerns about groundwater contamination by leachate from these burial sites are increasing. Groundwater is one of the main sources of drinking water, and its cleanliness is directly related to public health. Thus, this study aimed to evaluate the safety of groundwater around the burial sites (total of 600 sites). A total of 1,200 groundwater samples were collected though the country, and microbial analysis was conducted during two time periods: during the spring (n = 600; April to June 2012) and after rainfall (n = 600; August to October, 2012; fall). Fecal coliform and Escherichia coli were detected in 173 (14.4%) and 85 (7.1%) of the 1,200 samples, respectively. Salmonella spp. and Shigella spp. each were detected only once (0.083%). Clostridium perfringens was detected from 7 groundwater samples (0.583%), and E. coli O157:H7 was not detected. With respect to norovirus, only the GII type was detected from six groundwater samples (0.5%), and enterovirus was detected in 15 groundwater samples (1.25%). The frequency of E. coli that we detected was lower than that found in previous studies conducted in South Korea, but we detected higher frequency of fecal coliform than that observed in a previous report. The contamination frequencies of Salmonella spp. and Shigella spp. were very low, but C. perfringens, which could be an indicator of fecal pollution, was detected in seven regions. Overall, the results of the present study indicate a low possibility of contamination from burial sites. However, consistent monitoring is required to prevent microbial contamination of groundwater near the burial sites.

RT-PCR, nucleotide sequencing, and phylogenetic analysis were performed for genotyping and molecular characterization of noroviruses isolated from Korean groundwater. Among 160 samples collected from 80 sites between 2008 and 2010, 14 samples (8.7 %) from 12 sites were positive for noroviruses (NoVs). The percentages of NoV-positive samples in 2008, 2009, and 2010 were 22.2, 3.2, and 0 %, respectively, representing a yearly decrease. GII-positive samples (n = 9, 5.6 %) outnumbered GI-positive samples (n = 5, 3.1 %). The genotypes of the GI NoVs were GI.2, GI.5, and GI.6, and the genotypes of the GII NoVs were all GII.4. One sample, HM623465, was very similar to CUK-3 and CBNU2 and two GII.4 sequences isolated from the stool of Korean gastroenteritis patients. A BLASTN search revealed several nucleotide sequences highly similar to those of NoVs isolated in this study. The original isolation sources for these similar NoVs were mostly stool (n = 731, 80.0 %) and groundwater (n = 135, 14.8 %), and all the countries from which they were isolated were almost in Asia (96.0 %); specifically, China (n = 192, 21.0 %), Japan (n = 383, 41.9 %), Korea (n = 296, 32.4 %), and other Asian countries (n = 6, 0.7 %). These results suggest that Korean groundwater might be contaminated with NoVs from the stool of infected patients and that these NoVs in turn cause new cases of gastroenteritis through a typical fecal-oral route with region-specific circulation. Therefore, it is important to properly treat sewage, which may include waterborne viruses and manage point sources in groundwater for national health and sanitation. In addition, continuous molecular surveillance remains important for understanding circulating NoVs.

Group C rotaviruses are an important cause of acute gastroenteritis in humans and animals. Fecal samples were collected from a porcine herd in July, 2009. Group C rotavirus RNA was detected using RT-PCR for the VP6 gene. The identified strain was further characterized by sequencing and phylogenetic analysis of the partial VP4, and complete VP6 and VP7 gene sequences. The partial VP4 and complete VP6 gene sequences of the CUK-5 strain were most closely related to those of the CUK-6 strain of group C rotaviruses. Phylogenetic analysis of the VP7 gene of the 2 strains (CUK-5 and CUK-6) and reference strains of group G rotavirus by the neighbor-joining method also confirmed that CUK-5 and CUK-6 belonged to type G5 and G1 strains, respectively. This study provides useful data for the prediction of newly appearing variants of porcine group C rotaviruses in neighboring countries through comparisons with GCRVs and fundamental research for vaccine development.

Life on Earth are greatly affected by the dynamics of climate system, especially the Earth's surface climate. In particular, infectious pathogens are emerging as a source of issue as many aspects of public health accompanying the climate change are widely recognized [1,2]. The term pathogen covers a wide range of disease agents, such as virus, bacteria, parasitic germs, and fungi that can affect human beings either directly or indirectly through influencing the habitat, environment, or by competing with other pathogens. Climate change is a global phenomenon and is expected to accelerate in the future, especially in situations where the extent of climate change on Korean peninsula is relatively large (e.g., temperature rise, rainfall change, etc.) [3]. The annual mean temperature has been increasing at a rate of 0.52°C per decade and is significantly larger over urbanized areas [4], and it is anticipated that the incidence and geographic distribution of vector-borne diseases will change as a result [5].Shigella is a genus of gram-negative pathogenic enterobacteria and a pathogenic variant of Eschericha coli comprising four groups, Shigella boydii, S. dysenteriae, S. sonnei, and S. flexneri [6]. Shigella species are water-Climate change is expected to affect not only availability and quality of water, the valuable resource of human life on Earth, but also ultimately public health issue. A six-year monitoring (total 20 times) of Escherichia coli O157, Salmonella enterica, Legionella pneumophila, Shigella sonnei, Campylobacter jejuni, and Vibrio cholerae was conducted at five raw water sampling sites including two lakes, Hyundo region (Geum River) and two locations near Water Intake Plants of Han River (Guui region) and Nakdong River (Moolgeum region). A total 100 samples of 40 L water were tested. Most of the targeted bacteria were found in 77% of the samples and at least one of the target bacteria was detected (65%). Among all the detected bacteria, E. coli O157 were the most prevalent with a detection frequency of 22%, while S. sonnei was the least prevalent with a detection frequency of 2%. Nearly all the bacteria (except for S. sonnei) were present in samples from Lake Soyang, Lake Juam, and the Moolgeum region in Nakdong River, while C. jejuni was detected in those from the Guui region in Han River. During the six-year sampling period, individual targeted noxious bacteria in water samples exhibited seasonal patterns in their occurrence that were different from the indicator bacteria levels in the water samples. The fact that they were detected in the five Korea's representative water environments make it necessary to establish the chemical and biological analysis for noxious bacteria and sophisticated management systems in response to climate change.