Omsk haemorrhagic fever

Omsk haemorrhagic fever is an acute viral disease prevalent in some regions of western Siberia in Russia. The symptoms of this disease include fever, headache, nausea, severe muscle pain, cough, and moderately severe haemorrhagic manifestations. A third of patients develop pneumonia, nephrosis, meningitis, or a combination of these complications. The only treatments available are for control of symptoms. No specific vaccine has been developed, although the vaccine against tick-borne encephalitis might provide a degree of protection against Omsk haemorrhagic fever virus. The virus is transmitted mainly by Dermacentor reticulatus ticks, but people are mainly infected after contact with infected muskrats (Ondatra zibethicus). Muskrats are very sensitive to Omsk haemorrhagic fever virus. The introduction of this species to Siberia in the 1930s probably led to viral emergence in this area, which had previously seemed free from the disease. Omsk haemorrhagic fever is, therefore, an example of a human disease that emerged owing to human-mediated disturbance of an ecological niche. We review the biological properties of the virus, and the epidemiological and clinical characteristics of Omsk haemorrhagic fever.

Durch Zecken �bertragene humanpathogene und bisher als apathogen geltende Mikroorganismen in Europa

The importance of tick-borne encephalitis (TBE) and Lyme borreliosis-the main European tick-borne diseases-is steadily growing. This fact is due to many different factors including climate changes. However, across Europe many other human pathogenic viruses, bacteria, and parasites are found in ticks. This article gives an overview of tick-borne human pathogenic viruses present in Europe as well as those considered nonpathogenic. It also deals with the various species of vector-competent ticks. Among these ticks, viruses from 6 families encompassing 8 genera and 35 species are found,whereby the families Flaviviridae, Bunyaviridae, and Reoviridae with the genera flavivirus, nairovirus, and orbivirus are the most prevalent. Because of their special importance Omsk hemorrhagic fever, louping-ill disease, tick-borne encephalitis, and Crimean-Congo hemorrhagic fever are discussed in detail. Although West Nile virus is mainly transmitted to man by mosquitoes, it is discussed in detail, because West Nile fever has become a good example for a new and rapidly spreading vector-borne disease in the USA and for a recurrent one in Europe. Secondly, besides the mosquito-bird cycle an interesting tick--bird cycle is emerging. The overview clearly demonstrates that in Europe (particularly in Germany) tick-borne viruses, with the exception of TBE, constitute an extremely ignored research subject. This lack of attention is in contrast to their importance and results in a lack of necessary scientific data.

[The clinico-epidemiological characteristics of Omsk hemorrhagic fever in 1988-1992]

Materials on morbidity in Omsk hemorrhagic fever at the period of 1988-1992 in the districts of the Novosibirsk region are presented. Cases of the disease were registered mainly in September-October (83.3% of cases). Transmission of the disease by contact played the leading role in the epidemiology of Omsk hemorrhagic fever. The disease took the course of medium severity with faintly pronounced hemorrhagic syndrome.

Viral haemorrhagic fever in Sweden: experiences from management of a case

The first recognized case in Scandinavia with potential man to man transmission of viral haemorrhagic fever occurred in Linköping, Sweden, in January 1990. Following a visit to Kenya a 21-year-old male student suffered a very severe illness including extremely prolonged high grade fever, rash, disseminated intravascular coagulation with thrombocytopenia and severe bleedings. This necessitated one month of intensive care support including respirator treatment. The patient was discharged after 2 1/2 months in good condition, with a partial femoral nerve paresis. About 100 medical personnel were exposed to aerosol or blood before a strict containment regimen was established. No secondary cases occurred.

[Experience with using the indirect hemagglutination reaction in studying natural foci of tick-borne encephalitis]

Using the indirect hemagglutination test, tick-borne encephalitis (TBE) virus could be detected in the nutrient medium of the infected cell cultures, in brain suspensions of the infected suckling mice and in most specimens of suspensions of Ixodid ticks containing active virus. Positive results were obtained only with erythrocyte immunoglobulin diagnostic preparation to TBE virus but not with the diagnostic preparation for Omsk hemorrhagic fever. In the indirect hemagglutination inhibition test sera from human patients similarly inhibited antigens of tick-borne encephalitis and Omsk hemorrhagic fever.