Russian medical experts have been left baffled by a mystery virus sweeping across the country, as fears of a new pandemic grow.

Symptoms include high fevers of 39C and coughing up blood, leaving people bedridden for over 10 days.

Despite rising concern, health authorities have remained tight-lipped, refusing to disclose the number of infections and hospital admissions caused by the illness.

Medical professionals are recording cases under the classification “acute upper respiratory tract infection, unspecified” (ARVI).

Those stricken by the virus report a wide range of symptoms, which include general weakness, as well as aches and pains.

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