Spain Confirms First Human-to-Human Transmission of Mpox Clade 1b Outside Africa

New Delhi — Spanish health authorities have confirmed the first documented case of human-to-human transmission of mpox clade 1b outside Africa, marking a significant development in the global spread of the virus.

Mpox is a viral infectious disease that spreads through close physical contact, particularly skin-to-skin interaction, and is characterised by symptoms such as fever, swollen lymph nodes, and skin rashes. Mpox clade 1b is considered a highly transmissible strain that first emerged during an outbreak in the Democratic Republic of the Congo in 2023.

According to a case report published in the International Journal of Infectious Diseases, the patient is a 49-year-old man who had received two doses of the Imvanex smallpox/mpox vaccine and had no history of travel to endemic African regions. He visited a clinic in Madrid on October 10 after developing a single genital ulcer along with painful swelling of lymph nodes in the groin.

The patient reported having sexual contact with two local partners, neither of whom had travelled to mpox-endemic areas. After ruling out other sexually transmitted infections, health officials confirmed mpox clade 1b through a polymerase chain reaction (PCR) test conducted on the lesion.

“To our knowledge, this is the first report of a case of Mpox clade 1b without any epidemiological history of travel to Africa in the index patient or their previous sexual contacts,” said Jorge-Alfredo Pérez-García of Centro Sanitario Sandoval/Hospital Clínico San Carlos, Spain, in the research paper. He added that earlier cases reported across Europe and other regions were always linked to travel to endemic countries or direct contact with someone who had travelled there.

In Spain, only one other case of mpox clade 1b has been reported so far, involving a patient who had travelled to Tanzania and was exposed within the previous 21 days. Health authorities have confirmed that there is no epidemiological link between that case and the newly documented transmission.

Several African countries continue to report sustained human-to-human transmission of mpox clade 1b. The first case detected outside Africa involved a Swedish national who had travelled to an endemic region. Since then, cases identified outside Africa have largely been associated with recent travel or close contact with travellers from endemic areas.

Spanish health officials have urged the implementation of appropriate preventive measures to reduce both clinical and public health risks, particularly among groups that were disproportionately affected during earlier mpox outbreaks since 2022. These include people living with HIV, men who have sex with men, and individuals with multiple sexual partners.

According to the World Health Organization’s latest update, 2,501 new confirmed mpox cases were reported globally in October across 44 countries, including 12 deaths attributed to the disease.

With inputs from IANS