Molecular investigation of a multisource outbreak of Crimean–Congo hemorrhagic fever in the United Arab Emirates

Abstract. During the investigation of an outbreak of Crimean-Congo hemorrhagic fever (CCHF) in the United Arab Emirates (UAE) between 1994 and 1995, blood samples from suspected CCHF cases and ticks collected from livestock were tested for CCHF virus by antigen-capture ELISA and by a reverse transcription-polymerase chain reaction. Phylogenetic analysis of partial small (5) segment nucleotide sequences from four ticks and five human samples showed that with one exception, all the human and tick viruses clustered along with samples from Pakistan and Madagascar in one distinct lineage. Within this lineage, sequences from the UAE patients were identical or closely related to those from three Hyalomma spp. ticks obtained from livestock recently imported from Somalia. Another sequence from a UAE patient was more closely related to a CCHF virus from Nigeria. These data indicate that the 1994—1995 CCHF epidemic in the UAE was a multisource outbreak possibly associated with importation of CCHF virus-infected livestock and ticks. Crimean-Congo hemorrhagic fever (CCHF) virus is a member of the genus Nairovirus in the family Bunyaviridae, and causes hemorrhagic fever in humans with mortality rates of up to 50%. â€T̃he virus can be transmitted to humans either by bites of Ixodid ticks (mostly of the genus Hyalomma) o