Mpox threat intensifies as new mutated strain spreads to China

As China grapples with surging Human Metapneumovirus (HMPV) cases, the East Asian nation’s health authorities announced on Thursday the detection of a new mutated Mpox strain, known as clade 1b.

While the discovery marks another milestone in the detection and management of emerging viruses, it highlights the magnitude and challenges in the global fight against disease outbreaks, particularly if the COVID-19 pandemic is anything to go by.

According to China’s Centre for Disease Control and Prevention (CDC), a cluster outbreak of the clade 1b subclade, which began with a traveller from the Democratic Republic of Congo (DRC), has already infected four others through close contact. Clade 1b also exhibits genetic and epidemiological characteristics that favour human-to-human transmission.

This development comes as the World Health Organisation (WHO) raises concerns over the virus’s spread, particularly in Africa, where the situation remains “especially concerning.” The continent has recorded 13,769 confirmed cases across 20 countries, with 60 deaths reported as of December 15, 2024. The DRC, serving as the epicentre of the outbreak, accounts for 9,513 of these cases.

The virus exists in two primary forms: clade 1 and clade 2. The newer clade 1b variant, first detected in eastern DRC in September 2023, has proven particularly worrisome due to its enhanced transmissibility and higher mortality rate of 3.6 per cent.

The clade 1b variant appears to spread more easily through routine close contact, including sexual contact.

The strain has since spread from the DRC to neighbouring countries, including Burundi, Kenya, Rwanda, and Uganda. This has triggered an emergency declaration from the WHO. The strain has also been detected in eight countries outside Africa, including Sweden and Thailand, suggesting a concerning pattern of global spread. “Geographical expansion of clade 1b Mpox virus (MPXV) continues to be reported outside the DRC,” the WHO said. “Much remains to be understood about the transmissibility and sustainability of transmission of the clade 1b MPXV,” the WHO stated, specifying earlier that the mortality rate of the clade 1b MPXV was estimated at 3.6 per cent, much higher than previous strains.

The Africa CDC reports that clade 1 has been identified in Kenya, Burundi, the Central African Republic, Congo, the Democratic Republic of Congo, Rwanda, and Uganda. Clade 2 has been reported in Côte d’Ivoire, Liberia, Nigeria, and South Africa. Both clade 1 and clade 2 have been detected in Cameroon, while the specific clade in Gabon has not yet been identified.

The World Health Organisation declared an emergency for the more lethal clade 1 due to its increasing spread of cases in Africa, including areas where it had never been detected before, and the emergence of a new subtype, clade 1b.

Kenya has emerged as another hotspot, with 28 confirmed cases spread across 12 counties. The Ministry of Health reports that the distribution shows particular concentration in Nakuru (5 cases) and Mombasa (4 cases), with other affected areas including Kajiado, Bungoma, Nairobi, and Taita Taveta.

The country has reported one fatality.

Health authorities are actively monitoring 204 contacts, with 147 completing the required 21-day follow-up period. “Currently, eight individuals are under management while 17 have fully recovered,” said Health Cabinet Secretary Deborah Barasa in a recent statement.

In August 2024, the Director General for Health, Dr Patrick Amoth, reassured the public that healthcare facilities are fully prepared to diagnose and manage the disease.

China has implemented stringent measures, classifying Mpox as a Category B infectious disease. While the DRC, the outbreak’s epicentre, has seen a relatively stable epidemic trend in recent weeks, the WHO still warned that plateauing and declining trends should be interpreted cautiously, given possible reporting delays.

This designation allows officials to impose emergency measures, including restricting gatherings and suspending work and school when necessary. The country has also enhanced screening of people and goods at entry points. The WHO emphasises that while Mpox typically presents with mild symptoms such as skin rash, blisters, and flu-like conditions, it can prove fatal in rare cases.