CHOLERA

CASES of cholera are increasing, with 22 countries around the world experiencing an outbreak. After many years of decline, incidences rose in 2022 due to vaccine shortages, climate change and escalating conflict. It is a trend that is expected to continue.

. Science Book

Some 26,000 cholera cases were reported in Africa during the first 29 days of January 2023. This is already 30 per cent of the continent’s total in 2022. At the end of February, the World Health Organisation (WHO) said that more than 1 billion people across 43 countries are at risk.

Overall, Malawi appears to be the worst-hit country, with the highest number of deaths. It reported just under 37,000 cholera cases and 1,210 fatalities from 3 March 2022 to 9 February 2023.

This was triggered by a cyclone that hit in March 2022. This led to wastewater contaminating drinking water supplies.

Cholera is spread by the ingestion of food or water that is contaminated with the bacterium Vibrio cholerae. When it enters the body, some types of V. cholerae release a toxin that interacts with the cells lining the surface of the intestine, leading to diarrhoea.

In some cases, this can result in severe dehydration and death. In Malawi, 3.3 per cent of people with cholera die of the infection. With treatment, this is typically around 1 per cent.

In 2022, Malawi vaccinated millions of people in districts that were facing cholera outbreaks, but the cyclone has allowed the disease to spread to all of its districts, putting unvaccinated people at risk.

Extreme weather, driven by climate change, means many more countries are at risk of wastewater contamination. Cyclone Freddy, which hit Mozambique on 24 February, is expected to exacerbate the country’s cholera outbreak.

Climate change-driven droughts in countries such as Kenya and Ethiopia have also forced people to rely on water sources that may be contaminated with V. cholerae, according to UNICEF. Many people in these regions are malnourished, which affects their immune health, leaving them more vulnerable to severe cholera complications.

Displacement, whether due to conflict in countries like the Democratic Republic of the Congo or disasters such as the earthquake that hit part of Syria on 6 February, can also play a role in cholera outbreaks if people are forced to move to less sanitary areas, or if already infected people take the bacteria with them.

The destruction of health facilities and infrastructures [in Syria] that bring water to people could lead to more cases. According to the United Nations, the country reported more than 37,700 suspected cases in the cities of Idlib and Aleppo from 25 August 2022 to 7 January 2023 – 18 per cent of which were in people in displaced camps.

The unprecedented scale of the cholera outbreaks in 2022 – with 30 countries reporting cases, compared with an average of fewer than 20 in the previous five years – has also depleted global vaccine supplies. Only 37 million doses are available.

The International Coordinating Group on Vaccine Provision, which manages the WHO’s global vaccine stockpile, therefore recommends that at-risk people be vaccinated with a single dose of a cholera vaccine rather than the typical two doses. The one-dose regimen gives only about one year of protection, compared with three years with two doses. If the outbreaks continue as they are, this year of protection might not be enough time to get them under control.

Cholera has always been an issue, which prompted the UN to publish a road map in 2017 to cut 90 per cent of cholera deaths globally by 2030.

Several countries have made progress. The fact that Malawi has detected cholera outbreaks so quickly points to the work that officials have done to increase health surveillance.

But with just seven years to go until 2030, many aren’t convinced that the UN’s target will be reached. They say there hasn’t been enough investment in water infrastructure around the world to reach those goals.