Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Disease Prevention and Control, Ministry of Health, Department of Health and Medical Services, Preventive Medicine, Al Ain Medical District, Preventive Medicine Department, Preventive Medicine Department, Division of Infectious Diseases, H. H. Shaikh Khalifa Research Centre for Racing Camels, Atlanta, Georgia, United Arab Emirates
A multi-faceted investigation was conducted in the United Arab Emirates to characterize the epidemiologic and ecologic factors underlying an outbreak of Crimean-Congo hemorrhagic fever (CCHF) noted in November 1994 among abattoir workers. A chart review was conducted among hospitalized suspected cases of viral hemorrhagic fever with onset between January 1994 and March 1995 coupled with serologic testing of available specimens for the presence of virus antigen and IgG and IgM antibodies by ELISA. Livestock handlers and animal skin processors were interviewed and tested for the presence of IgG antibody. Sera from imported and domestic ruminants were examined for antibody for CCHF virus, and ticks collected from these animals were tested with an antigen-capture ELISA. Thirty-five suspected cases of CCHF were identified (case fatality = 62%). Livestock market employees, abattoir workers, and animal skin processors accounted for 16 (57%) of 28 cases with known occupational status. Serologic evidence of past asymptomatic infection was noted in 12 (4%) of 291 livestock and abattoir workers but in none of the controls. Nineteen (7%) of 268 animals were positive for CCHF virus antibodies by ELISA including 12 ruminants from Somalia and Iran and five indigenous camels. One Hyalomma impeltatum and two H. excavatum from Somali cattle and one H. anatolicum from a Somali goat were positive for CCHF virus antigen.