Omsk hemorrhagic fever

OMsk HEMORRHAGIC FEVER - infectious disease from the group of hemorrhagic fevers; Characterized by a mild hemorrhagic syndrome, fever, cardiovascular and nervous system damage.

Natural foci are located in Western Siberia, north of Omsk in the forest-steppe areas. Omsk hemorrhagic fever is also registered in the Tyumen and Novosibirsk regions.

The causative agent is an arbovirus of the Togaviridae family, close to the tick-borne encephalitis virus. It is slightly resistant to the effects of high temperatures and conventional disinfectants.

The source of the pathogen of infection are small mammals (more than 30 species), more often water vole, on which parasitize ixodid mites, as well as muskrat. Processing and cutting of carcases of infected muskrats can lead to illness, including during the winter months.

A person becomes infected as a result of an attack of an infected ixodid tick Dermacentor pictus, D. Marginatus (during a bloodsucking). The first cases of the disease appear in April, the incidence rate has two peaks - in May and August-September, which corresponds to the dynamics of numbers and activity of ticks.

Clinical picture . The incubation period is from 2 to 14 days (usually 3 to 7 days). The disease begins acutely with fever, intense headache, muscle pain, vomiting. Body temperature during the day reaches 39 -40 0 C, the duration of the febrile period from 3 to 4 days to 2 weeks. A half of patients have a repeated febrile wave. From the first day of the illness, adynamia, bright hyperemia of the face, sclera and conjunctiva, mucous membranes of the soft and hard palate, gums are characteristic.

The petechial rash, hemorrhages in the mucous membranes, nasal, pulmonary, uterine and other bleeding are not permanent. There have been a relative bradycardia , hypotension. Frequently develop pneumonia and CNS damage, manifested by cerebral and meningeal symptoms.

The blood test revealed an increase in hemoglobin, erythrocytosis and severe leukopenia. In the study of urine, hematuria, proteinuria and cylindruria are often found. Complete recovery usually occurs after 2-4 weeks; In severe cases, the disease is more prolonged. Sometimes, within a few weeks after recovery, weakness remains. In the period of convalescence hair is often lost (later restored).

Diagnosis is based on clinical, epidemiological history data and laboratory results - isolation of the virus from the patient's blood during the acute phase and the detection of specific antibodies.

Treatment is symptomatic, conducted in the hospital.

The forecast is usually favorable.

Prevention includes the rehabilitation of natural foci of the disease, in particular, the destruction of water voles and other small mammals (rodents) - possible sources of the virus in muskrat water bodies. To protect people from the attack of ticks Icsod use protective clothing, repellents, as well as self-and mutual examination for the purpose of early detection and removal of ticks from the body and clothing. It is not recommended to take skins and cut carcasses muskrat caught in the foci of Omsk haemorrhagic fever.