If you look at the Calender, Easter was April 24th. Some well meaning parents give their children Chicks or Ducks without thinking of the possible outcome.
Eventually enough cases will spread overtime throughout the States for the "surge" to become noticeable.
See here for case study:
Salmonella can survive on a surface like a cutting board for a week. All bacteria has reservoirs, so, it can stay permanently on living beings. These are called convalescent carriers and it is very rare for humans, but is most commonly seen in turtles and birds.
http://www.scaddistrict.com/?p=1209
Thats why salmonella cases shoot up around Easter. Because people used to give baby chicks as presents on Easter. ---------- Hand washing must be a thing of the past.
My parents warned me years ago that chicks can spread disease. I guess they were right.

Wash your hands before one eats...Simple. Duh!