According to the surveillance data by Taiwan CDC, as of November 10, 2010, 140 confirmed cases of shigellosis, including 76 imported cases and 64 indigenous cases, have been reported this year. This figure is higher than that reported during the same period in previous years (85 cases in 2008 and 78 cases in 2009). This year, most of the indigenous cases occurred in Huanlin County (25 cases), Taipei County (14 cases), and Yilan County (6 cases). Among them, a total of 7 clusters (34 cases) have been detected, mainly occurred in household and populous institutions.
The incubation period of shigellosis is 12 to 96 hours (1-3days), but sometimes it may last as long as 1 week. Symptoms include mild to severe diarrhea, fever, nausea, vomiting, cramps, rectal tenesmus (difficulty to empty the bowel for defecation) and bloody or watery stools. It is possible to develop no symptoms in some cases. The mode of transmission is mainly through direct or indirect fecal-oral transmission from a symptomatic patient or a short-term asymptomatic carrier. The infectious agents are highly infectious and a low dosage (10-100 bacteria) can cause infection. It is possible to transmit through shaking hands with someone who has failed to wash hands adequately after contact with feces. In the past, several shigellosis clusters revealed a close correlation between the incidence of shigellosis and the cleanliness of local water sources. Most of the sporadic cases have consumed contaminated mountain spring water or underground water that has not been properly treated with chlorine.
To prevent shigellosis clusters, Taiwan CDC urges nursing homes, special education centers and other similar institutions that provide long-term accommodation to remain cautious about shigellosis and other intestinal infectious diseases. Operators or mangers of such institutions should adopt the use of clean tap water for all water usage needs and make sure only boiled water is consumed. Under special circumstances where no tap water is available, the institutions should install their own chlorine disinfection equipments and check the level of chorine residue on a regular basis. A sufficient number of clean wash basins and hand-washing equipments are needed to ensure hygiene. Staff, supervisors or caretakers should be mindful and always wash hands before and after kitchen work, nursing care or contact with waste matter to prevent possible transmission and epidemic outbreaks.
Taiwan CDC would like to advise the public of the following. All individuals should take care of their own personal hygiene and practice good hygiene both at home or while traveling. Raw produce or food purchased from unhygienic street-side stalls or stores should be avoided. Washing hands before and after meals is the key to fend off infections. Do not hesitate to seek medical attention to receive timely diagnosis and treatment when suspicious symptoms develop. 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 Consultation Hotline 1922.