ObjectivesThe aim of this study was to characterize the pathogens responsible for causing diarrhea according to season, region of isolation, patient age, and sex as well as to provide useful data for the prevention of diarrheal disease.MethodsStool specimens from 14,886 patients with diarrhea were collected to identify pathogenic bacteria from January 2014 to December 2014 in Korea. A total of 3,526 pathogenic bacteria were isolated and analyzed according to season, region of isolation, and the age and sex of the patient.ResultsThe breakdown of the isolated pathogenic bacteria were as follows: Salmonella spp. 476 (13.5%), pathogenic Escherichia coli 777 (22.0%), Vibrio parahaemolyticus 26 (0.74%), Shigella spp. 13 (0.37%), Campylobacter spp. 215 (6.10%), Clostridium perfringens 508 (14.4%), Staphylococcus aureus 1,144 (32.4%), Bacillus cereus 356 (10.1%), Listeria monocytogenes 1 (0.03%), and Yersinia enterocolitica 10 (0.3%). The isolation rate trend showed the highest ratio in the summer season from June to September for most of the pathogenic bacteria except the Gram-positive bacteria. The isolation rate of most of the pathogenic bacteria by patient age showed highest ratio in the 0–19 year age range. For isolation rate by region, 56.2% were isolated from cities and 43.8% were isolated from provinces.ConclusionHygiene education should be addressed for diarrheal disease-susceptible groups, such as those younger than 10 years, aged 10–19 years, and older than 70 years, and monitoring for the pathogens is still required. In addition, an efficient laboratory surveillance system for infection control should be continued.

Three cases of cholera occurred in South Korea during a period of three weeks in August 2016. All the cases were associated with the consumption of raw seafood in southern coastal area of South Korea. Epidemiologic investigations were performed to track the spread of cholera, including persons in contact with the cholera patients, seafood, and seawater from the fish tank and marine environments. A microbiological investigation demonstrated that cholera isolated from the three patients and a seawater sample at the Korea Strait showed identical serotype (O1 Ogawa), biotype (El tor), and toxin (-positive). Pulsed-field gel electrophoresis analysis showed that the three clinical strains are identical (100%) and shared 97% identity with the seawater sample.

Measles elimination in South Korea was approved by the World Health Organization (WHO) in 2014.However, small sporadic outbreaks of measles continue to occur, mostly driven by imported cases [1].Measles introduced from abroad spreads to susceptible populations, such as infants or young adults who are insufficiently vaccinated or in cases where the vaccine effect has waned. The number of foreignborn individuals in South Korea has increased sharply (1,271,807 foreigners with long-term stay in 2019), of which approximately 10% are marriage migrants [2]. Marriage migration has increased rapidly since the mid-1990s as the government officially encouraged international marriages between foreign women and Korean men to resolve the rural bride shortage. Earlier, most foreign brides were Chosunjok (ethnic Koreans from China), but recently, their country of origin has diversified. As of January 2019, out of a total of 132,748 foreign-born women married to Korean men and living in South Korea, the most common country of origin was China (34.7%), followed by Vietnam (30.4%), Japan (9.4%), Philippines (8.6%), Cambodia (3.2%), Thailand (3.3%), and others (10.3%) [3]. Measles vaccination rates worldwide have increased over time, but are still lower in low-or middle-income countries than in developed countries. The estimated first-dose measles-containing vaccine (MCV1) coverage in Vietnam was 84.4% to 93.3% between 2000 and 2019, but the second-dose measlescontaining vaccine (MCV2) administration only started in 2007 [4,5]. The estimated MCV1 coverage in Cambodia was 63.7% to 91.1% between 200063.7% to 91.1% between and 201963.7% to 91.1% between , and MCV2 administration only started in 2012. These suboptimal measles vaccine coverage rates in the countries of origin of marriage migrant women suggest the possible influx of measles-susceptible populations into South Korea. Since marriage migrant women frequently become pregnant, give birth, take care of children, and travel overseas to their country of origin, immunity to measles becomes particularly important. However, thus far, there has been no information regarding measles immunity in marriage migrant women in South Korea.