Karelian fever( Okeelbo disease) - Causes, symptoms and treatment. MF.
Jun 10, 2018
Karelian fever( Okeelbo disease) is an acute, transmissible viral disease, which is infected by mosquito bites, and is characterized by rash and joint damage occurring against a background of febrile-intoxication syndrome.
The causative agent was first isolated from mosquitoes, with an epidemic outbreak in central Switzerland( in the village of Okelbo) in 1980.A similar outbreak was registered in 1982 in Finland, and then in Karelia. All these territories are at the same geographical latitude / longitude, which allowed to suspect the natural foci. But in the study of the disease, the work was suspended and in the scientific texts there were still gaps: the structure of the virus and the mechanism of pathogenesis are not fully understood, the reservoir of the virus, the ways of infection, some questions about immunity remain open. Perhaps, scientific works were terminated due to the fact that after this disease, disabling or life-threatening consequences are not formed.
The causative agent of the Karelian fever
The causative agent is the Edsbyn S / 82 virus, belongs to the Togaviridae family( togaviruses), and the genus Alphavirus. Some factors and properties of this family and genus explain the pathogenesis:
• the causative agent is enveloped due to the presence of a capsule consisting of C-protein, which protects the virus from phagocytosis by fusing its shell with the lysosome coat( immune system cell).
• Speciespecific supercapsidic glycoprotein E2 forms spines, by which the virus is absorbed at the protein receptors of the host cell to transmit its genetic information, and also participate in protection against phagocytosis.
• Supercapsid glycoprotein E1 - hemagglutinin, causes gluing of red blood cells.
Stability: unstable in the external environment, stored for several hours at room temperature, rapidly kills when pH changes, is unstable to temperature changes, and dies even at 60 ° C.Also, his death is caused by UVD, the actions of disinfectants, in particular ether and formalin.
Mostly adult men and women are susceptible. Concerning the prevalence, as already mentioned, there is a natural focality in the Scandinavian countries and North-West Russia. There is also an increase in the incidence in the summer.
Causes of Karelian fever
Source - mosquitoes, the role of man in transmission of infection is not fully understood. The path is transmissive( ie, when mosquito bites), aerogenic is in question.
Symptoms of Karelian fever
There is also insufficient information regarding staging and symptoms, but here are the facts that are known at the moment:
• the incubation period is not established;
• The disease begins acutely, with pain in the joints and exanthematous manifestations( rash), which indicate the spread of the pathogen after the mosquito bite.
• Fever-intoxication syndrome is considered a rare manifestation of Karelian fever and is registered only in 14% of infected;
• Nature of the flow of arthralgia: tenderness of the joints, swelling and restriction in movement - but these manifestations are not disabling, ie without tissue / structural changes and pass without a trace after the cure. Often there are many affected joints of different calibrations - that is, polyarthritis occurs. These symptoms may persist from 2 weeks to 24 months - all in different ways.
• Character of exanthema - appears immediately after arthralgia, i.e. in the first 3 days of the disease and persists for 10 days. First, spots appear up to 10 mm in diameter, not prone to fusion, then on these spots papules( inflamed nodules) form, some of them turn into vesicles( vesicles).It is believed that the rash is formed simultaneously, that is, without stepping and podsypaniya, so its character is truly polymorphic - that is, when the patches appear on the body with different characteristics( papules, pustules, vesicles, and spots).Also, with this exanthema, there is no fusion of rash and itching.
Diagnosis of Karelian fever
• Consider epidemiological prerequisites, which consider seasonality, morbidity and stay in an epidemic area.
• The clinical picture is not difficult, because arthralgia and exanthema are almost instantaneous.
• Serological diagnosis( Immunoenzyme analysis - ELISA) is aimed at determining the growth of antibody titer in 4 times or more - only in this case the diagnosis can be considered eligible. The presence of IgM which can be determined for 4 years or more indicates a prolonged stay of the virus, that is, of carrier.
Treatment of Karelian fever
The issue of specific treatment remains open, but it is possible to approbate the etiropic treatment suitable for the family of voviruses: the use of viricide( arbidol, isoprinosine), immunomodulators( interferon, viferon) and immunostimulants( cycloferon, anaferon).
And also symptomatic treatment, appointed depending on the dominant symptoms: antipyretic, SCS( with severe intoxication with articular and skin manifestations).
There are no scientifically valid data for
does not have a septic prophylaxis, and nonspecific is reduced only to protection against mosquito bites.
Whether the disease is transmitted from person to person - no data. After the transferred disease, life-long immunity is formed and there are no repeated diseases.
Therapist doctor Shabanova I.Е.