Looks like this could have started as early as February.
Everyone told Maria del Carmen Hernandez that her kindergartner’s illness was just a regular cold. But it seemed like the whole town of 3,000 was getting sick.
As early as February, neighbors all around her were coming down with unusually strong flu symptoms — and the caseload kept growing. When state health workers came to investigate March 23, some 1,300 people sought their medical help. About 450 were diagnosed with acute respiratory infections and sent home with antibiotics and surgical masks.
http://cnews.canoe.ca/CNEWS/World/20...291331-ap.html