Reoviruses, genus orbits

The family Reoviridae consists of 3 genera:

• reoviruses,
• rotaviruses,
• orbits.

[1], [2], [3], [4]

Characteristics of the virus

Representatives of the orbiviruses - Colorado tick-borne fever viruses, Kemerovo group viruses, etc. - are typical arboviruses transmitted by Aedes mosquitoes, sores and mites. These viruses are mostly of veterinary importance, but some of them can cause mild febrile illness in humans. Orbiviruses have a spherical shape, the diameter of the virion is 60-80 nm. The genome is represented by a double-stranded RNA consisting of 10 fragments and having a molecular weight of 12 MD. There is a virion transcriptase. The two-layer capsid, 32 ring-shaped capsomers (Latin orbis-ring) are packed in an icosahedron. Fluffy, difficult to discern even in electron microscopy, the protein layer covers the outside of the main capsid. Supercapsid is absent. The replicative cycle is similar to the cycle of reoviruses. Orbiviruses are sensitive to low pH values, inactivated at pH less than 3.0.

[5], [6], [7], [8], [9], [10], [11]

Colorado Tick Fever

The disease is recorded on the Pacific coast of the United States, mainly in mountainous rural areas. The virus is transmitted through the bites of the infected tick Dermacentor andersoni and circulates in the blood in the acute stage of the disease. The incubation period is 4-6 days. The onset of acute - chills, myalgia, headache, nausea, vomiting. Fever has a two-wave character, leukopenia is observed. The outcome is favorable. Immunity after the disease is humoral, prolonged.

[12], [13], [14], [15], [16], [17], [18],

Laboratory diagnostics

During the first 14 days of the disease, the virus is isolated from the blood by intracerebral or intraperitoneal infection of young hamsters or newborn mice. Complement-binding and viral neutralizing antibodies appear at the 2 nd week. Disease and persist up to 3 years.