Omsk haemorrhagic fever
Omsk haemorrhagic fever is caused by a flavivirus transmitted mainly by Dermacentor reticulatus ticks that are associated with muskrats (Ondatra zibethicus) which are actually secondary hosts themselves.
- Superkingdom Viruses
The tick hosts are Dermacentor reticulatus and Dermacentor marginatus (southern and western Siberia). Omsk haemorrhagic fever virus has also been isolated from mosuitoes, gamasid mites and the taiga tick. A wide range of vertebral primary hosts are possible with natural foci being the water vole Arvicola terrestris and narrow-skulled vole Microtus gregalis. Asymptomatic carrier animals include rats, mice, hedgehogs, birds of prey and gulls.
Typically fever above 39C about 3-7 days after contact, although with some strains the viraemia can be nonspecific in up to 18%. Headache, cough, myalgia, meninigism, neuro-psychiatric, gastrointetinal upset and mucosal and skin haemorrhages may follow. The 30 to 50% who do not recover after the first two weeks have a relapse, typically with worsening haemorrhage and meninigism, and sometimes pneumonitis. Mortality is less than 2.5% but there is often prolonged dehabilitation.
- Supportive and isolation
- ↑ a b Růžek D, Yakimenko VV, Karan LS, Tkachev SE. Omsk haemorrhagic fever. Lancet. 2010 Dec 18; 376(9758):2104-13.(Link to article – subscription may be required.)
- ↑ Chávez JH, Silva JR, Amarilla AA, Moraes Figueiredo LT. Domain III peptides from flavivirus envelope protein are useful antigens for serologic diagnosis and targets for immunization. Biologicals : journal of the International Association of Biological Standardization. 2010 Nov; 38(6):613-8.(Link to article – subscription may be required.)
- ↑ Bossi P, Tegnell A, Baka A, Van Loock F, Hendriks J, Werner A, Maidhof H, Gouvras G. Bichat guidelines for the clinical management of haemorrhagic fever viruses and bioterrorism-related haemorrhagic fever viruses. Euro surveillance : bulletin européen sur les maladies transmissibles = European communicable disease bulletin. 2004 Dec; 9(12):E11-2.(Epub)