Lately, the Taiwan Centers for Disease Control (Taiwan CDC) has received reports concerning 14 clusters of diarrheal illness in travelers that recently visited South Korea from the Tourism Bureau and local travel agencies. Taiwan CDC has obtained the list of 412 travelers involved in the clusters of diarrheal illness. Among them, 246 people experienced symptoms that include diarrhea, stomachache and vomiting, accounting for an attack rate of 60%. Of the people who experienced symptoms, norovirus has been detected in the stool specimens of four people. Taiwan CDC has advised travel agencies to temporarily replace the restaurants in Korea where the likelihood of norovirus transmission cannot be ruled out and contacted the health authorities in Korea for further investigation of the suspected restaurants and restaurant personnel. In addition, Taiwan CDC reminds travelers visiting or planning to visit Korea to take precautions against norovirus infection, including consuming only thoroughly cooked food, paying attention to food and personal hygiene, washing hands with soap and water regularly while visiting Korea.  

Upon receipt of the case reports, together with the Tourism Bureau, Taiwan CDC immediately conducted epidemiological investigation and health education activities for all travelers displaying suspected symptoms, as well as collected specimens from travelers whose symptoms persisted for laboratory testing. A total of 36 specimens were collected from 28 people. At the time of writing, among the specimens, 4 were tested positive for norovirus and 17 were tested negative for the virus, while the results for the remaining 15 specimens were still pending. According to the results of the preliminary epidemiological investigation, most travelers developed symptoms 3 to 4 days after arriving in Korea. Hence, it is suspected that the cases became infected after dining at the local restaurant. Taiwan CDC has provided relevant information to the Korean health authorities for further investigation. Moreover, Taiwan CDC has also notified travel agencies to temporarily replace the restaurants in Korea where the possibility of norovirus transmission cannot be ruled out. At the moment, the Korean health authorities are investigating the suspected restaurants and have detected norovirus in the specimens of ten travelers from Taiwan who sought medical attention in Korea. Taiwan CDC has also requested local health bureaus to continue to follow up on travelers who have experienced suspected symptoms and returned to Taiwan.  

Noroviruses are a most common cause of gastroenteritis and they are usually active in winter. The viruses are highly contagious and are primarily transmitted through the fecal-oral route by ingesting contaminated food or water or coming into contact with things that have the virus on them. Symptoms of gastroenteritis usually develop about 1 to 3 days after infection depending on the person’s health status. The symptoms may persist up to 10 days. The primary symptoms include watery diarrhea and vomiting, along with headache, fever, abdominal cramp, nausea and muscle aches. Infants, children, elderly and immunocompromised patients may experience more severe symptoms.  

Taiwan CDC warns that norovirus infection can occur anywhere in the world. In the past, outbreaks had occurred in several developed countries. Taiwan CDC recommends travelers visiting or planning to visit Korea to choose restaurants and accommodations carefully, consume only thoroughly cooked food, avoid cross-contamination when grilling meats, drink only bottled or boiled water, and wash hands with soap and water thoroughly before eating and after using the toilet.

If suspected symptoms develop during the trip or upon arriving in Taiwan, please notify the quarantine officer at the quarantine station in the airport immediately and provide the quarantine officer with personal travel and contact history to facilitate the investigation of possible sources of infection. When seeking medical attention, please voluntarily inform the physician of any relevant travel history to facilitate diagnosis and implementation of subsequent prevention measures by relevant health authorities in order to ensure the health and wellbeing of everyone. Additionally, according to the Communicable Disease Control Act and the Regulations Governing Quarantine at Ports, tour guides or tour leaders are required to report to the health authority the list of travelers and tour group members who experience suspected symptoms during the trip or upon arriving in Taiwan along with their contact information and the tour group itinerary to facilitate epidemiological investigation.

For more information, please visit the Taiwan CDC’s website at http://www.cdc.gov.tw or call the toll-free Communicable Disease Reporting and Care Hotline, 1922, or 0800-001922 if calling from a cell phone.