Mpox is spread by physical contact and causes a characteristic lumpy rash, fever, aches and pains and in some immune-compromised patients can be fatal.
The first human case was detected in northwest DRC in 1970 when a nine-year-old boy developed a nasty rash that reminded medics of smallpox. Scientists have since identified two different clades in Africa.
Clade 2 is found in West Africa and in 2022 sparked a global epidemic and its own PHEIC, when it spread to more than 100 countries, predominantly affecting gay and bisexual men.
However the strain at the centre of the current alert is clade 1. Outbreaks of clade 1, which has a higher death rate, were at first often limited to a few households in remote areas and associated with families killing and eating wild forest animals, known as bushmeat.
Scientists have, however, been warning that annual cases of clade 1 in DRC have been rising steadily for years. And as numbers have risen, researchers confirmed a new strain, named clade 1b, in eastern DRC early this year.
‘I knew this was something different’
Medics in the region report that during late 2023, they saw a spike in mpox patients with severe symptoms – including widespread lesions, high fevers, and a higher death rate. It does not require sexual contact to spread and has infects children as well as adults.
“I knew this was something different because the symptoms were so different from clade 1 – what we normally see in the DRC,” said Dr Leandre Murhula Masirkika, a local scientist who has pioneered research on the ground.
“We are seeing a lot of deaths, a lot of miscarriages, and rapid transmission through the community.”
Dr Masirkika and a small team of local researchers traced the first case of clade 1b back to a bar in Kamituga and a single patient – a local barman.
The man, said to be a pimp, regularly had intercourse with female sex workers. In September, he had intercourse with three women at the same time – all of which shortly afterwards presented to the hospital with a severe form of the disease.
Since then, thousands of patients have presented at clinics and hospitals in South Kivu with severe symptoms, including many children. According to Dr Masirkika, the death rate is as high as 5 per cent in adults and 10 per cent in children – compared to just 0.2 per cent for clade 2.
Understanding the dynamics of the new strain and the outbreak have been clouded by a lack of sequencing and because the original clade 1 strain also seems to be surging.
Piero Olliaro, professor of poverty-related diseases at Oxford, said: “These are two parallel outbreaks of two variants with different modes of transmission and at-risk groups, thus requiring different strategies for containment. They also differ in morbidity and mortality.”
Seven in 10 of DRC’s cases are children, and the disease is rife in overcrowded hospitals, Save the Children said this week.