MIAMI — An unusual salmonella outbreak has hit 28 states, running coast-to-coast with no true center, according to the Centers for Disease Control and Prevention.

The outbreak doesn't involve food, but backyard birds such as chicks and ducklings. Of the 44 sickened people interviewed so far, the CDC said, 38 have had contact with such feathery animals.

That's not as unusual or perhaps as concerning as the unusually high percentage of the ill people, 30%, being under the age of 5. Children under 5 and senior citizens tend to get the worst of salmonella infections, which hospitalizes 26,500 with bloody diarrhea and kills 420 each year.

Most of the 1.35 million Americans who get salmonella annually just suffer several days of diarrhea, stomachaches and fever.

As for this outbreak, the 97 known illnesses are spread across the 28 states. The first known case was Feb. 26 and the most recent is May 1.

Geographic patterns haven't emerged, other than in the broadest terms. The highest case count in a state, nine, has happened in Kentucky, in the middle of Midwestern and Southern states with cases; and California, connected by Oregon and Arizona to a Western bloc of states with cases.

Four states — Montana, South Carolina, Tennessee and Virginia — have six cases each. Georgia, Illinois and Utah each have five. Alabama, Mississippi and Oregon each have four. The three case states are Arizona, Nebraska and Wyoming. Two cases: Florida, Indiana, Massachusetts, Michigan, New Mexico and North Carolina. One case: Idaho, Maryland, Minnesota, Ohio, Pennsylvania, Texas and Wisconsin.

Among the CDC's recommendations:

— "Don't kiss backyard poultry or snuggle them and then touch your face or mouth."

— "Don't let backyard poultry inside the house, especially in areas where food or drink is prepared, served, or stored."

— "Set aside a pair of shoes to wear while taking care of poultry and keep those shoes outside of the house."

— "Always wash your hands with soap and water right after touching backyard poultry, their eggs, or anything in the area where they live and roam."

— "Children younger than 5 years of age shouldn't handle or touch chicks, ducklings, or other poultry."