RESUMEN
Little is known about the occurrence of chikungunya fever in the Eastern Mediterranean Region of the World Health Organization [WHO]. In January 2011, the Ministry of Public Health and Population [MoPH and P] of Yemen reported to WHO an increasing number of "dengue-like" acute febrile illnesses of unknown origin from one of its coastal governorates. An epidemiological investigation was conducted in Al-Hudaydah governorate between 23 and 26 January 2011 by a joint team of WHO, the MoPH and P of Yemen and the U.S. Naval Medical Research Unit [NAMRU-3] in Cairo, Egypt. The investigation led to the detection of an outbreak of chikungunya in Yemen which was the first time ever from any of the 22 countries in the Eastern Mediterranean Region of WHO. Appropriate public health control measures were strengthened following the investigation, and the outbreak was contained. This paper provides a short description of the outbreak and its epidemiological characteristics and highlights the important lessons that were learned for early detection and control of chikungunya in countries where competent vectors for transmission of the virus exist