A second American tested positive for the new highly-mutated BA.2.86 Covid variant that has been causing global alarm over its rapid transmission.

The positive case was detected in an asymptomatic patient in Virginia who was tested August 10 after returning to the US from Japan.

Scientists identified the case in a database that contains test samples from a small number of travelers entering the US. Independent experts told DailyMail.com they believe the new strain is spreading more widely and in more US states.

The new variant, also spotted in Michigan last week, is causing concern because it stems from an 'earlier branch' of the coronavirus, so it differs from the variants targeted by current vaccines.

That concern, combined with an uptick in positive tests across the US, has spooked an Atlanta college and the Hollywood studio Lionsgate into mandating face masks again. But while Covid rates are rising in the US — hospital admissions are up for the fifth week in a row — they remain at near-historic lows.

Test positivity — the share of tests that come back positive for the virus — has doubled in the US in the past month and searches for Covid symptoms on Google have spiked in the past few weeks.

But doctors on the ground say that while they are seeing an increase in patients with the virus, their symptoms are milder than at any point previously in the pandemic.

The case, the second to date in the US, was diagnosed in a patient in Virginia. Experts warn that the variant could be more widespread across the US (Pictured: A man being tested for Covid in Richmond, Virginia, back in April 2020)

The second case had recently returned to the US from a trip to Japan. At present, the country has reported no new cases of the variant (Pictured above are people wearing face masks in Tokyo, Japan, in June 2020)

Hospitalizations across the US have risen for the fifth week in a row, but they are also barely a third of the levels from this time the previous year

Covid deaths remain static at present after having risen four percent in a week. They are hovering around record low levels

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Dr Aaron Glatt, a medic at Mount Sinai in New York City, said the fact that two cases had been confirmed in the US signaled there are 'many more' not being picked up.

Asked whether there were more cases of BA.2.86 in the US, he told DailyMail.com: 'This is certainly very possible, it would be surprising if it didn't spread.'

On the number of cases already in the US, he said: 'It's certainly possible that there are tens of cases, and it is certainly very possible that there are more.

'The only question is how important that is. Does this variant have a survival advantage over other strains?'

Only a fraction of positive swabs are tested for variants, meaning many cases with this strain are likely going undiagnosed.

The Virginia case marks the second to be spotted in the US after an older patient with a mild illness in Michigan was also diagnosed with the strain. They were not hospitalized.

So far three other countries — Israel, Denmark and the UK — have detected the strain, but most countries don't have the infrastructure to pick up on new variants.

The new variant is yet to be detected in Japan, but official data from the country shows that cases and hospitalizations are rising.

Latest data shows there were 22,000 Covid patients in the country's hospitals on August 16, which was double the 10,000 from the week before.

This was, however, still below the 35,000 reported at the same time last year.

The Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) have both said they are tracking the mutant strain.

The Virginia case was detected in America's Traveler Based Genomic Surveillance Program.

This analyzes positive samples taken from passengers who have been tested for Covid to check for variants.

Travelers are also surveyed on their travel history and whether they have any symptoms.

The program operates at seven airports — including Dulles International Airport in Washington, DC — with the CDC saying it can act as an 'early warning system' for which variants are entering the US.

BA.2.86 has more than 30 mutations on its spike protein — the part the virus uses to infect people — that separate it from the currently dominant strains, which is feared make it better at escaping the immune system.

The mutant strain set off alarm bells when it was spotted last week, immediately prompting calls from some quarters for masks to return.

Other experts said its emergence was 'reminiscent' of when Omicron first appeared, pointing out that this strain was also quite genetically different compared to the others that were circulating at the time.

This weekend former FDA commissioner Dr Scott Gottlieb also voiced alarm, saying he was 'pretty concerned' by the new strain and that it may well be more transmissible than other variants that are currently circulating.

Wastewater surveillance shows that Covid detections have risen 28 percent over the last fortnight nationwide

There has also been an uptick in search for Covid symptoms, suggesting anecdotally that more people are being infected with the virus

Three cases were initially reported — two in Denmark and one in Israel — but this tally has now grown to six after infections were reported in the US and UK.

Experts say there are still too few cases to calculate whether the strain is more transmissible or more likely to cause severe disease.

But they add that, previously, the virus has evolved to become better at spreading while being less likely to cause severe disease.

Covid vaccines and immunity from previous infections will still provide protection against severe disease and death, they said.

The mutations may make antibodies less effective, but other parts of the immune system — like T-cells — will still be able to mount a response and attack the virus.

Dr Marc Elieson, a medical director at Baylor Scott and White Health in Texas, said earlier this week that his colleagues are seeing Covid patients with less severe illness than at any point during the pandemic.

'What viruses and other organisms do over time [is] they become more contagious but have less power to kill and to hurt people,' he told FOX44.

Nationally, the most up-to-date official data shows hospitalizations are rising — albeit from record low levels.

There were 12,613 admissions in which the patient tested positive for Covid in the week up to August 12, marking the fifth week in a row hospitalizations for the virus had risen and an increase of a fifth on the week prior.

But this was still barely a third of the levels recorded at the same time last year, when there were about 40,000 admissions every week.

Deaths remain static with 479 reported in the latest week that data is available, July 22, compared to 484 in the previous seven-day spell.

And doctors have been reporting that patients seen in recent weeks are not as sick as those they treated during earlier waves of the pandemic.

Lionsgate, a Hollywood studio, has ordered nearly half of its employees to start wearing face masks once again. The rule is in place until further notice at their building in Santa Monica

Morris Brown College, a private liberal arts school in Atlanta, Georgia, has also ordered staff and students to wear masks again in corridors and lecture halls.

There are also concerns over another Covid variant — EG.5 — which is dominant in the US and estimated to be behind at least a fifth of all infections.

Scientists say this strain is more transmissible and could be driving an uptick in cases. But they caution it may be overtaken by BA.X.

Amid more alarm bells ringing over Covid, there are now signs that some organizations are starting to bring back face masks.

Yesterday, Lionsgate — behind franchises Saw and the Hunger Games — announced employees would now need to wear face masks at their office in Santa Monica, California.

They said staff would also need to self-test before heading to the office, and let their managers know whether they have tested positive or have symptoms of the disease.

Lionsgate said the rules were in response to positive cases emerging among employees.

They followed in the footsteps of Morris Brown College, a private liberal arts school in Atlanta, Georgia, which has also ordered staff and students to wear masks again in corridors and lecture halls.

The college said the rules would be in place for two weeks and have been triggered because of 'reports of positive cases among students'.

Students are also being told to maintain social distancing and all parties and large gatherings have been banned.

The number of Covid cases in Georgia have increased for three weeks in a row, but overall, the number of infections and hospitalizations remains low.