Phylogenetic analysis in a recent controlled outbreak of Crimean-Congo haemorrhagic fever in the south of Iran, December 2008

Crimean-Congo haemorrhagic fever (CCHF) is a viral zoonotic disease with a high mortality rate in humans. The CCHF virus is transmitted to humans through the bite of Ixodid ticks or contact with blood or tissues of CCHF patients or infected livestock. In December 2008, a re-emerging outbreak of CCHF occurred in the southern part of Iran. Five people were hospitalised with sudden fever and haemorrhaging, and CCHF was confirmed by RT-PCR and serological assays. One of the cases had a fulminant course and died. Livestock was identified as the source of infection; all animals in the incriminated herd were serologically analysed and more than half of them were positive for CCHFV. We demonstrated that two routes of transmission played a role in this outbreak: contact with tissue and blood of infected livestock, and nosocomial transmission. Phylogenetic analyses helped to identify the origin of this transmission. This outbreak should be considered as a warning for the national CCHF surveillance system to avoid further outbreaks through robust prevention and control programmes.