Chikungunya fever outbreak in Al-Hudaydah, Yemen, 2011: Lessons learned in dengue-endemic countries for early detection and control

Abstract

Background: Little is known about the occurrence of chikungunya virus fever in the Eastern Mediterranean Region of WHO. In January 2011, the Ministry of Public Health and Population (MoPH&P) of Yemen reported to WHO an increasing trend of dengue-like acute febrile illnesses in one of its governorates. Methods & Materials: A field investigation was carried out in Al-Hudaydah governorate between 23-26 January, 2011 by a joint team comprising of representatives from the MoPH&P, Yemen, the Eastern Mediterranean Regional Office of WHO (EMRO/WHO) WHO,Geneva and theU.S.NavalMedical ResearchUnit (NAMRU-3) in Cairo. Results: Al-Hudaydah is the fourth largest governorates of Yemen with an estimated population of 2.1 million. The capital of the governorate is an important port city of the country and is situated on the Red Sea and is known as an epidemic foci for several outbreaks of vector-borne diseases. The findings of the field investigation led by WHO marked the first ever report of chikungunya fever in Yemen and in the Eastern Mediterranean Region of WHO. Appropriate control measures were strengthened following the investigation and the outbreak was contained. Conclusion: In areas of high dengue-endemicity, the epidemic risk for chikungunya fever and other arboviral diseases, that share the same vector for transmission, can be anticipated with a rise in global travel. In limited resource settings, this presents a particular challenge if any early sign of an impending epidemic is missed. This may result in long duration of an epidemic occurrence with large number of morbidities and even mortalities if both viruses are co-circulating at the same time (dengue virus is concurrently circulating during the same outbreak).