Geneva: A major cholera outbreak in Tanzania has now infected nearly 10,000 people and killed 150, the World Health Organisation said on Friday, voicing concern that predicted flooding risked spreading the disease internationally.
Since the beginning of the outbreak in August, at least 9,871 people have become infected and 150 have died, the UN health agency said, citing laboratory confirmed figures from Tanzanian health authorities.
That marks a doubling of the figures provided a month ago, when WHO put the number of cases at 4,922, including 74 deaths.
The east African country's largest city Dar es Salaam was most affected, with nearly 4,500 cases, WHO spokeswoman Fadela Chaib told reporters in Geneva.
Cholera, which is transmitted through contaminated drinking water and causes acute diarrhoea, has spread across the country, including to two islands in the Zanzibar archipelago.
Chaib stressed that a "very aggressive" campaign to manage the outbreak, including water chlorination and increased surveillance to quickly identify affected areas, had begun bringing down the number of daily reported cases.
But she pointed out that a strong El Nino, a natural phenomenon that sparks global climate extremes, along with the upcoming rainy season in Tanzania was expected to "bring extensive flooding and unusually high rainfalls, (which could) increase the transmission and international spread of the disease."
Cholera is endemic in the region, so the fear that the disease could spread beyond Tanzania's borders is justified.
The last time there was a massive outbreak in eastern Africa was in the late 1990s, also during a strong El Nino event, some 200,000 people were infected across four countries and some 8,000 people died.
More than 40,000 of those cases were in Tanzania.
Despite fears that deteriorating weather conditions could increase the spread of cholera, Chaib said there were currently no plans to begin vaccinating against the disease in Tanzania.
WHO earlier this month helped Iraq launch a massive vaccination campaign to stem a smaller cholera outbreak there, with over 2,500 cases.
More than 230,000 people, mainly in camps for refugees and internally displaced people, had received the first of two doses, in a bid to hinder cholera from spreading to neighbouring countries and especially chaos-wracked Syria.
Chaib stressed though that vaccination was only one of several measures used to fight cholera, and said the situation in Tanzania, where cholera was not concentrated in certain areas but widespread, did not lend itself well to vaccination.
The vaccine used to fight cholera epidemics is also scarce and can only be used in rare cases to urgently stop the spread of the disease.
Last year the sole producer of the vaccine, Indian firm Shantha Biotechnics, made just two million doses enough to protect one million people.
WHO estimates that around 40 million people in Africa alone live in areas where they are exposed to cholera.