Saturday, 6 October 2012

Crimean-Congo Haemorrhagic fever virus comes to Glasgow

This week saw Glasgow's first case of Crimean-Congo Heamorrhagic Fever virus (CCHFV), a virus belonging to the family Bunyaviridae which can cause (as the name suggests) a haemorrhagic disease. 

A man arrived from Dubai, having been bitten by a tick in Afghanistan, and a couple of days later went to hospital where it was confirmed that he had CCHFV. Sadly news has just surfaced that he's died, highlighting what a severe virus this can be. Headache, muscle and joint pains, vomiting, diarrhea, bruising and bleeding are all associated, to a lesser or greater extent, with CCHFV, along with a fatality rate of up to 30%.

CCHFV is a tick-borne virus which is hugely widespread; the rather bizarre name reflects its discovery in both Crimea and Congo at (roughly) the same time. Eastern Europe, large swathes of Asia and the Indian subcontinent and Africa are all affected by, or at least have some evidence of, CCHFV. 

The world distribution of Crimean-Congo Haemorrhagic fever virus
Perhaps it's their relative unfamiliarity compared with mosquitoes and midges, perhaps it's the way they lock on to a host for extended amounts of time, but there always seems something rather repulsive about ticks. They seem to be everywhere, but not all seem to be infected by CCHFV, which tends to infect species of the genus Hyalomma. If it's not via a tick bite, then an alternative way to become infected is contact with the blood of an infected animal. But if it's not endemic to western Europe and the UK, would it ever be a problem here? Can it infect the ticks here? A few years ago people thought it would be more or less unthinkable that Bluetongue virus would ever reach northern Europe and the UK, an assumption dismissed emphatically in the last few years. Similarly, Schmallenberg virus is another arbovirus that has swept across Europe (incidentally, SBV is from the same family of viruses as CCHFV).

Is it possible that it would ever establish itself here? I'd guess it's pretty unlikely right now. But with climate change, species of tick that are known to be capable of being infected by CCHFV might be on the move, and based upon the climates in other areas, the climate of western Europe might just suffice.