麻疹之群突發調查和感染管制措施

Measles: Outbreak Investigation and Infection Control

麻疹是由麻疹病毒所引起的一種急性高傳染力疾病，近年來麻疹個案在本國已經相當罕見，每年通報案例低於10件，但經由國際間旅遊交通的頻繁便利，加上臨床醫師容易因為疾病罕見而警覺性不足，未能及時發現個案進行防治，導致近年發生了數起境外移入社區及醫療設施內傳播感染事件。麻疹是可以經由疫苗施打預防的疾病。國際間經由施打疫苗施打涵蓋率的提升，有效降低麻疹的發生率和死亡率。麻疹的潛伏期為10至14天（範圍7～18天），可傳染其為發疹前4天到發疹後4天。典型症狀包含高燒、咳嗽、3C症狀（咳嗽cough，鼻炎coryza，和結膜炎conjunctivitis）、倦怠、科氏斑（Koplik’s spots），麻疹典型皮疹是由臉部和耳後開始出現不癢的紅斑丘疹，由上而下蔓延到頸、上肢、軀幹和下肢。接著皮疹逐漸融合，在3～5天後消退。診斷確立可由典型臨床症狀加上血清學，或咽喉拭子、尿液、或全血等的檢體病毒培養結果陽性或RT-PCR試驗結果陽性。本文藉由一個麻疹案例的群突發調查，以了解如何進行調查和落實麻疹感染管制處置。

Measles is a highly contagious disease caused by the measles virus. Although cases occurring in Taiwan are rare, with less than 10 cases reported annually, recent outbreaks in communities and hospitals have occurred owing to the advent of globalization, imported cases, and reduced awareness among physicians. Measles can be prevented readily by vaccination, and major progress has been made globally to reduce incidence and mortality by increasing measles vaccine coverage. Measles have an incubation period of 10-14 days (range, 7-18 days), with a transmissible period of 4 days before and after the onset of rash. Typical prodromal symptoms include high fever; cough, coryza, and conjunctivitis (“the three C’s”); malaise; and Koplik’s spots. The characteristic erythematous maculopapular rash begins on the face and behind the ears, spreads centrifugally to the trunk and extremities, and lasts for 3-5 days. Confirmation of the diagnosis is by clinical presentation and serology, virus cultures, or detection of virus using polymerase chain reaction analysis of nasopharyngeal secretions, blood, or urine. The following illustrates an outbreak investigation and infection control practices through a measles outbreak scenario.