Climate change causes cholera to soar in Africa

The cholera epidemic continues to spread in eastern and southern Africa

Climate change causes cholera to soar in Africa

The cholera epidemic continues to spread in eastern and southern Africa. Twelve countries are facing an “acute phase” of its spread, according to the World Health Organization (WHO), which announced on Friday January 26 the dispatch of 140 additional experts and 20 tons of emergency equipment. Regional cooperation will be strengthened. From Ethiopia to Mozambique, Kenya, Sudan and eastern Democratic Republic of Congo (DRC), more than 240,000 cases have been reported since the start of 2023 and at least 4,000 deaths.

Two days earlier, the Zambian government had once again had to postpone the start of the school year, depriving more than 4 million children of education. The epidemic that appeared in October 2023 now affects nine of the country's ten provinces and is considered one of "the worst in twenty years." Five hundred people died among the 13,000 infected, according to the report established by Unicef.

In neighboring Zimbabwe, where nearly 20,000 cases and 400 presumed deaths have been recorded, a state of emergency was declared in the capital Harare and a drilling campaign was launched in the country's worst-affected areas to provide drinking water to the populations. “Cholera is the indicator of a society that is going badly. Like Kinshasa, whose population increased from 2 million inhabitants in 1960 to 15 million today, the centers of cholera infection combine a demographic boom and deficient health infrastructure,” observes Didier Bompangue, professor of ecology of infectious diseases at the Faculty of Medicine of the University of Kinshasa and specialist in the evolution of cholera in the Great Lakes region. Cholera, now endemic in several countries, only appeared in the 1970s on the continent.

“Environmental Transformation”

This diarrheal disease caused by the ingestion of water or food contaminated by the Vibrio cholerae bacteria recurs during the rainy season in densely populated areas lacking a sanitation network and access to drinking water. But the violent rainfall observed in recent months and the floods that followed have favored its spread.

The impact of global warming is regularly highlighted by scientists. “It is one of the rare infectious diseases for which we have managed to characterize a cause and effect link between the transformation of the environment and its propagation,” points out biologist Benjamin Roche, research director at the Institute of research for development (IRD).

At the beginning of December, Didier Bompangue published with other colleagues an article in The Panafrican Medical Journal to warn of the possible consequences of the El Nino episode currently underway. This phenomenon, which originates in the South Pacific by causing a warming of surface waters, also has consequences in Africa. It is associated with increased rainfall in East Africa and peaks of drought in more southern regions.

“The previous episode of El Nino which occurred in 2016 coincided the following year with a particularly high number of cases,” he recalls. The Rift Valley, where lakes of volcanic origin follow one another, constitutes a biotope conducive to the reproduction of the bacteria. The lake waters heat up and transform into culture broth. It only takes heavy rains to cause flooding on overcrowded shores for the disease to spread. »

For most scientists, however, the link between El Nino and cholera outbreaks in dry areas of southern Africa is not established with such certainty. Some researchers therefore argue that the drying up of drinking sources forces populations to drink contaminated water.

Vaccine shortage

Faced with the seriousness of the situation, African countries are trying to accelerate their immunization campaigns in a context of global vaccine shortage. In October 2022, the International Coordination Group (ICG), which manages emergency supplies, was forced to suspend the two-dose vaccination strategy to be able to protect more people, even if immunity was reduced. A shortage that will continue until the end of 2025, as demand exceeds supply.

The increase in epidemics, also due to conflicts with their massive population movements, has caused needs to explode. But also the increasingly systematic use of the vaccine as a prevention tool in national strategies. Production followed, increasing tenfold in a decade, to the breaking point. “The crises of 2021 and 2022 alone required 48 million doses, or 10 million more than during the entire previous decade,” warns the WHO. The shortage is now all the more glaring as the South Korean Eubiologics has been the only supplier since January. The French company Sanofi ceased its production at the end of 2023.

Even if investments have been made to allow Eubiologics to increase its production, the year 2025 promises to be perilous. The arrival of a new manufacturer is not expected until 2026. This puts prevention at the heart of the fight against the emergence of new outbreaks and underlines the urgency for African states to invest massively in sanitation infrastructures.