On October 3, 2017, the Taiwan Centers for Disease Control (Taiwan CDC) announced this year’s first indigenous cholera case. The case is an over-50-year-old male who resides in central Taiwan. In late September, he developed abdominal pain, diarrhea and watery stool. He was hospitalized after seeking medical attention. Laboratory tests confirmed infection with V. cholerae O1 Ogawa in the case. According to the epidemiological investigation, the case does not consume raw food and drinks only boiled tap water. However, his family uses the same chopping board for both raw and cooked foods. On the day of symptom onset, he consumed clams he bought from the market. To identify the possible source of infection, the local health authority is conducting further investigation. As of now, the case is still hospitalized for treatment. None of the contacts residing in the same household has developed any suspected symptoms. Their specimens are being tested. Taiwan CDC will continue to follow up on their health.

Thus far this year, as of October 3, a total of 1 indigenous cholera case has been confirmed in Taiwan, which is the lowest during the same period in the recent 5 years (2012-2016). The numbers of indigenous cases confirmed in the last 5 years respectively are 3, 5, 4, 8, and 8. In addition, during the past 5 years, a total of 1 imported case was confirmed. The case developed symptoms in 2015 and acquired the infection in Vietnam.

Cholera is an acute bacterial enteric disease with sudden onset of profuse watery diarrhea, vomiting, rapid loss of body fluids that leads to dehydration, acidosis, and circulatory collapse. The incubation period can vary from a few hours to five days with an average of 2-3 days. Transmission of cholera typically occurs by consuming food or water that is undercooked and contaminated with the feces of an infected person or carrier. The onset of cholera is related to the number of bacteria ingested and the host immunity. Typically, a large amount of bacteria must be ingested to cause cholera in a normal healthy adult. However, a little amount of bacteria is enough to cause infection in people with lowered gastric acidity/ People at increased risk of cholera include elderly, patients with chronic diseases, cancer, weakened immune system, gastric hypoacidity, and people who have had gastrectomy. Without treatment, the fatality rate for severe cases can be over 50%. With early and proper treatment, the fatality rate can be lowered to below 1%.

As the Mid-Autumn Festival and the Double Ten Day holiday approach, the opportunity for barbeque gatherings increases, Taiwan CDC reminds the public that the cholera bacteria (Vibrio cholera) survive well in water and may remain viable in shellfish and crustacean. Hence, consuming raw seafood contaminated with the bacteria can lead to infection. To prevent infection, avoid consuming raw fish and oyster and undercooked shellfish. The public is advised to consume thoroughly cooked food, store food safely and refrigerate when necessary, avoid cross-contamination—mixing raw food with cooked food, and drink only boiled or bottled water.

If suspected symptoms develop, please seek immediate medical attention and be sure to inform the physician of food consumption history to facilitate diagnosis and case reporting. For more information, please visit the Taiwan CDC website at http://www.cdc.gov.tw or call the toll-free Communicable Disease Reporting and Consultation Hotline, 1922 (or 0800-001922).