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.

However, by the third or fourth day, patients describe an abrupt worsening of their condition.

One patient told the Russian Telegram channel SHOT that she began coughing blood five days into her illness.

Despite testing for both influenza and Covid-19, her results were negative, with doctors unable to identify the pathogen.

Some experts believe the illness could be linked to mycoplasma pneumonia, a bacterial infection that caused a spike in hospitalisations in Russia late last year.

Reports suggest that numerous patients across different cities have displayed similar symptoms.

In the absence of an official diagnosis, healthcare providers are advising caution and urging people with severe symptoms to seek medical help immediately.

Russia was hit hard by the Covid pandemic and experts at the Center for Global Development believe that there is a 47–57% probability of another deadly one within the next 25 years.

The outbreak of the virus comes at a time when healthcare services are being cut back, as the Kremlin prioritises military spending and the war in Ukraine.

At least 160 hospitals across Russia have been closed, as medical staff have been reassigned to the battlefield in Ukraine.

Analysts at the UK's Ministry of Defence said the list of closed hospitals includes 18 maternity centres and at least 10 children’s clinics.

“Russian civilians in small towns and villages have frequently been left with reduced or unavailable medical care as a result of the closures, including now-limited pre-hospital services,” they said.

The Kremlin’s prioritisation of the war in Ukraine has “highly likely” resulted in insufficient funding for health care throughout the country.

It has led to critical shortages of medical staff, expertise and equipment in the Russian medical system, British officials said.