Where did Haiti's cholera come from? Most Haitians believe the bacteria that have so far sickened 286,000 of them - and killed 4870 - were brought in by United Nations peacekeeping troops from Nepal.
And this certainly seemed likely, given where and when the disease broke out, and the fact that regions of Nepal were experiencing cholera outbreaks around the same time that the Nepalese left for Haiti.
Yet the UN mission in the country has consistently denied the allegation. It said natural cholera could have invaded Haiti from the sea, and refused to test its troops.
Now it turns out the Haitians were right. A blue-ribbon panel of scientists nominated by the UN to settle the matter has now reported that "the evidence overwhelmingly supports the conclusion" that someone contaminated Haiti's Meye river with south Asian cholera.
Other scientists, and New Scientist, had already figured as much. But the new report places the issue beyond reasonable doubt. The team combined data on water flow with hospital records to show an "explosive" outbreak started on the Meye 150 metres downstream from the Nepalese base, on 17 October last year and spread through the Artibonite river system in three days - exactly matching the natural flow of water downstream. Nothing suggested it came in from the sea.
The report concludes that sanitation at the Nepalese base was "not sufficient to prevent contamination", to put it mildly. As the UN has insisted, the Nepalese who arrived in Haiti just before the cholera began were indeed given a clean bill of health before they left Nepal. But, the panel now adds, after the health checks and before the troops flew to Haiti they were given 10 days' leave. There was cholera in Kathmandu at the time. Ah.
Then there's the smoking gun. Previously all we knew was that the cholera in Haiti genetically matched strains from south Asia. But the International Vaccine Institute in Seoul, South Korea, sent the panel cholera samples from Nepal. The Haitian strain is a "perfect match" for one from 2009. Read More