Researchers find source of deadly cholera epidemic
In Yemen, the world’s worst cholera outbreak has been traced to eastern Africa, Kate Kelland ,of Reuters, reports.
SCIENTISTS have found that a strain of cholera causing an epidemic in Yemen — the worst in recorded history — came from eastern Africa and was probably brought into Yemen by migrants.
Using genomic sequencing techniques, researchers at Britain’s Wellcome Sanger Institute and France’s Institut Pasteur said they should now be better able to estimate the risk of future cholera outbreaks in regions such as Yemen, giving health authorities more time to intervene.
‘‘Knowing how cholera moves globally gives us the opportunity to better prepare for future outbreaks,’’ said Nick Thomson, a professor at Sanger and the London School of Hygiene and Tropical Medicine who coled the work.
Nearly four years of war between a Saudiled coalition and the Iranianaligned Houthi group have crippled healthcare and sanitation systems in Yemen, where some 1.2 million suspected cholera cases have been reported since 2017, with 2515 deaths.
The World Health Organisation warned in October the outbreak was accelerating again with roughly 10,000 suspected cases reported per week, double the average rate for the first eight months of 2018.
To explore the origins of the outbreak, Sanger and Pasteur researchers sequenced the genomes of cholera bacteria samples collected in Yemen and nearby areas.
They included samples from a Yemeni refugee centre on the Saudi ArabiaYemen border and 74 other cholera samples from south Asia, the Middle East and eastern and central Africa.
The team, whose findings were published in the journal Nature earlier this month, then compared these sequences to a global collection of more than 1000 cholera samples and found the strain causing the Yemen epidemic was related to one first seen in 2012 in south Asia that had spread globally.
However, the Yemeni strain did not arrive directly from south Asia, the scientists found, but was circulating and causing outbreaks in eastern Africa in 201314, before appearing in Yemen in 2016.
‘‘Genomics enabled us to discover that the strain of cholera behind the devastating and ongoing epidemic in
Yemen is likely linked to the migration of people from eastern Africa into Yemen,’’ Thomson said.
However, from the samples available, the team was not able to pinpoint exactly which countries in eastern Africa the strain had come from.