Mpox (Monkeypox) and Epidemic in Africa

by Prof. Hervé Fleury, MD-PhD | Ventum Biotech Scientific Board Member

The African Center for Disease Control and Disease (African CDC) is sounding the alarm on the Mpox epidemic in Africa, which has increased by 160% since 2023. A total of 14,250 cases have been reported (2645 confirmed, 14,250 suspected) with 456 deaths from 10 countries: Burundi, Cameroon, DRC, Congo, DRC, Ghana, Liberia, Nigeria, Rwanda and South Africa.

The mortality rate is higher in Africa than on other continents; the dominant virus from the Kivu province (DRC) is 1b, which is more transmissible and dangerous than strain 2, which was implicated in the 2022 pandemic.

The DRC is the first country concerned and the virus has recently spread to neighboring Congo, which is logical given the long and permeable border that separates the two countries.

Transmission takes place through intra-family contact as well as in sexual relationship networks (prostitution and gays). Children under the age of 15 pay a heavy price and account for 67% of cases and 75% of deaths in the DRC.

It is known that Mpox is close to the smallpox virus that disappeared after 1980 following global vaccinia vaccination campaigns. The virus is present in rodents (it was discovered in a monkey, hence its name Monkeypox, then Mpox) and is transmitted to humans through skin or respiratory contact; human-to-human transmission occurs through skin contact and sexual contact; the cross-immunity between smallpox and Mpox meant that vaccinia contained Mpox for a long time; but with the suppression of smallpox vaccination, human populations found themselves infected in contact with animal reservoirs in Africa; In 2022, the virus led to a global pandemic, especially in gay circles.

The disease resembles smallpox with lesions of the mucous membranes and then a rash that begins in the face and spreads to the extremities in a centrifugal manner. Skin lesions turn into vesicles, then pustules, then scabs. Recovery is achieved in 3 to 4 weeks.

Management includes smallpox vaccination in the first 4 days of a contact with an infected patient and, if necessary, the use of specific immunoglobulins and/or antiviral molecules such as tecovirimat and cidofovir in infected patients at risks of complications.

Figure from the Africa CDC; in green, the 1b strain, which originates from Central Africa and from the DRC; in red, the countries concerned by strain 2; in orange (Cameroon) double circulation of 1b and 2.

Previous update on Mpox—June 10, 2022

This virus belongs to the group of Orthopox viruses including the smallpox virus. It has been known since 1958 to have been identified in an African monkey hence the name monkeypox. In fact its main reservoirs are rodents (rats, mice) and squirrels.

The virus is rampant in Central and West Africa: DRC, Gabon, Ivory Coast, Liberia, Nigeria, Benin, Cameroon, Sierra Leone, Sudan. There are two main strains with different mortality for humans (Central Africa 10% and West Africa 1% mortality).

Humans become contaminated by contact with rodents (bites, aerosols) and by handling monkey meat; in Africa, risk factors include forest or rural habitat, monkey meat handling and care for patients, and non-vaccination (vacciniatric vaccination protects against monkeypox; it was stopped in 1980 by the WHO after the last case of smallpox observed in Somalia in 1977; young populations are therefore no longer protected by cross-vaccination against monkeypox this which explains the current emergence of human cases, particularly in Nigeria). Human-to-human secondary transmission is much lower than that of smallpox. Infected patients returning to Europe or the USA as well as other parts of the world were until now patients who had been contaminated from the animal reservoir. An extra-African episode took place in the USA in 2003 where 70 humans were infected from prairie dogs that had been in contact with rodents imported from West Africa.

As of 8 June 2022, WHO has reported 1200 cases, including 321 in the UK, 198 in Portugal, 191 in Spain, 113 in Germany, 100 in Canada, 66 in France, 54 in the Netherlands and 39 in the USA (list not complete).