In the wake of Brazil's floods, infectious diseases take lives

For the last month, parts of the southern Brazilian state of Rio Grande do Sul have remained underwater. Many residents have been in constant contact with the flood waters, from the intense days of rescue following the torrential rains, until today. But those waters, mixed with sewage, contaminants and the wreckage of the cities, have also carried a more invisible danger: leptospirosis. Michael Fox reports from the city of Porto Alegre on how that and other diseases remain a threat to people in the region.