| Omsk hemorrhagic fever | |
|---|---|
| Specialty | Infectious disease |
Omsk hemorrhagic fever is aviral hemorrhagic fever caused by Omsk hemorrhagic fever virus.[1]
It was found inSiberia[2] and was named after an outbreak in the city ofOmsk. First records of the new virus appeared around 1940–1943.
There are a number of symptoms of the virus. In the first 1–8 days the first phase begins. The symptoms in this phase are:
In 1–2 weeks, some people may recover, although others might not. They might experience a focalhemorrhage in mucosa of gingival,uterus, andlungs, apapulovesicular rash on the soft palate,cervical lymphadenopathy (it occurs in the neck which that enlarges the lymph glandular tissue), and occasionalneurological involvement. If the patient still has OHF after 3 weeks, then a second wave of symptoms will occur. It also includes signs of encephalitis. In most cases if the sickness does not fade away after this period, the patient will die. Patients that recover from OHF may experience hearing loss, hair loss, and behavioral or psychological difficulties associated with neurological conditions.
| Omsk hemorrhagic fever virus | |
|---|---|
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| Flavivirus structure and genome | |
Virus classification | |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Kitrinoviricota |
| Class: | Flasuviricetes |
| Order: | Amarillovirales |
| Family: | Flaviviridae |
| Genus: | Orthoflavivirus |
| Species: | Orthoflavivirus omskense |
| Synonyms[3] | |
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Omsk hemorrhagic fever is caused by Omsk hemorrhagic fever virus (OHFV), a member of theFlavivirus genus. The name of the species it belongs to isOrthoflavivirus omskense.[4] The virus was discovered byMikhail Chumakov and his colleagues between 1945 and 1947 inOmsk. The infection is found inWestern Siberia, in places includingOmsk Oblast,Novosibirsk Oblast,Kurgan Oblast,Tyumen Oblast. The virus survives in water and is transferred to humans via contaminated water or an infected tick.
The main hosts of OHFV are rodents like the non-nativemuskrat. OHFV originates in ticks, who then transmit it to rodents by biting them. Humans become infected through tick bites or contact with a muskrat. Humans can also become infected through contact withblood,feces orurine of a dead or sick muskrat (or any type of rat). The virus can also spread through milk from infected goats or sheep. There is no evidence that the virus is contagious among humans.
The virus appears to have evolved within the last 1000 years.[5] The viralgenomes can be divided into 2 clades, A and B. Clade A has fivegenotypes and clade B has one. These clades separated about 700 years ago. This separation appears to have occurred in the Kurgan province. Clade A subsequently underwent division into clade C, D and E 230 years ago. Clade C and E appear to have originated in the Novosibirsk and Omsk Provinces respectively. The muskratOndatra zibethicus which is highly susceptible to this virus was introduced into this area in the 1930s.
Omsk Hemorrhagic Fever could be diagnosed by isolating virus from blood, or byserologic testing using immunosorbent serological assay. OHF rating of fatality is 0.5–3%. Treatment is supportive; there is no specific treatment for OHF. This helps maintain hydration and provides precautions for patients with bleeding disorders.
Preventing Omsk Hemorrhagic Fever consists primarily in avoiding being exposed totick. Persons engaged in camping, farming, forestry, hunting (especially the Siberianmuskrat) are at greater risk and should wear protective clothing or useinsect repellent for protection. The same is generally recommended for persons at sheltered locations.