In 2010, Haiti was hit by a devastating earthquake, which left the small Caribbean state in extremely difficult sanitary conditions. Ten months after the earthquake, a cholera epidemic apparently started from scratch, the worst in recent history; in 2010 alone, over 700, 000 people became ill, accounting for 7% of the entire state's population and more than 8, 000 died.
Analyzing the diarrhea samples from people with the disease in different parts of Haiti, some doctors obtained the sequence of the genome of the responsible Vibrio cholerae . These data were compared to the vibro lines present in recent years in Latin America and Asia . Somehow, one could imagine that the bacterium had come from Peru across the sea. The genome of the vibrio isolated in Haiti, however, presented a very high correlation with that of the typically South-Asian lineage.
But how did cholera come from Asia to Haiti? It was shown that it all began in a village bordering on a UN camp, whose staff had just arrived to provide humanitarian assistance from Nepal where, just two weeks earlier, a cholera epidemic had begun. Although none of the volunteers had any symptoms (75% of infected people are asymptomatic), the strain of Vibrio cholerae spread from the discharges of the field, which ended up in the Artibonite river, at that point source of contamination.
