Federal health investigators are tracking a multistate Salmonella outbreak in which every confirmed patient is a child under 10 years old, and three of them have been hospitalized. The source, according to the epidemiologic data collected so far, is pet turtles. Five of those six reported that the child had contact with a pet turtle in the week before becoming ill. Among the four families who described the turtle's size, three said the shell was less than 4 inches long. CDC does not recommend pet turtles for children younger than 5, adults 65 and older, or people with weakened immune systems.