California patient is first in the US to be infected with deadlier strain of mpox

A deadly strain of monkeypox has been detected in the United States for the first time.

CDC scientists said a patient in California had tested positive for the Clade I mpox strain, which kills up to one in 10 people it infects.

The CDC said the patient had recently returned to the US from East Africa, where there is a monkeypox outbreak, and was treated in San Mateo County.

The patient was initially treated in the hospital, but has now been discharged home for recovery and told to isolate.

Officials said the risk to the public was ‘low’, saying the disease only spreads via direct skin-to-skin contact or contact with contaminated towels or bedding.

No further details about the patient were revealed, including when they had returned to the US, how they became infected, or their symptoms.

But scientists said they were expected to make a full recovery.

The Clade I strain is more severe than the Clade II type, which is currently circulating in the US and was behind the 2022 outbreak. That strain has a fatality rate of less than three percent and has killed 63 Americans since the 2022 outbreak. 

In its alert, the CDC said: ‘The risk of clade I mpox to the public remains low, and there continue to be sporadic clade II mpox cases in the United States.

‘Casual contact, like you might have during travel, is unlikely to pose significant risks for transmission of mpox.’

More than 34,000 people have been infected with Clade II monkeypox since the outbreak began in 2022, and at least 63 people have died so far.

Officials rolled out vaccines to gay or bisexual men — among whom most cases were diagnosed — during the outbreak to slow infections.

But the CDC continues to record ‘sporadic’ cases in the US, with 2,368 infections detected this year — and 72 in just the last month.

The overall fatality rate in the US is currently 1.85 percent, with scientists saying treatments and the vaccination drive have helped to keep it low.

The California patient came to the US from Africa, where there is currently a major outbreak of the Clade I strain in central and eastern regions, primarily in the Democratic Republic of Congo, with more than 47,000 suspected cases.

But cases began to spread outside the DRC over the summer to neighboring countries including Burundi, the Republic of the Congo, the Central African Republic, Rwanda and Uganda.

WHO officials raised the alarm over the outbreak in August, officially declaring it a public health emergency.

More than 50,000 monkeypox cases have been recorded in the region’s outbreak to date, and 1,100 people have died from the infections.

Officials are trying to stem the outbreak through rolling out vaccines to boost immunity to the virus. More than 5.85million doses are expected to be delivered to the region by the end of the year. 

And vaccines are currently being tested in Africa that are administered to people after they have been exposed to the virus. Researchers are investigating whether these can stop an infection from developing. 

Scientists say the spread is being driven largely by skin-to-skin sexual contact with rashes caused by the disease.

Symptoms take three to 21 days to develop, and tend to be a rash that forms on the infected area — including the genitals, anus, or chest or hands.

Other symptoms include a severe headache, fever and muscle and back ache.

There is no cure, but doctors may treat symptoms using anti-viral drugs that target viruses like monkeypox.

Patients may also receive IV drips and supportive rest to help their bodies fight off the disease.