The Centers for Disease Control and Prevention and the Pennsylvania Health Department are investing an outbreak of salmonella associated with exposure to small pet turtles.


Sale of turtles with carapaces smaller than four inches has been prohibited in the U.S. since 1975 due to their risk of transmitting salmonella, but the CDC says "they are still available for illegal purchase through transient vendors on the street, at flea mar­kets, and at fairs."


This black-market wildlife trade has resulted in 132 reported cases of human salmonella infections across 18 states between August 2010 and September 2011. More than 60 percent of those cases were in children younger than 10. Of the 56 patients interviewed, 36 reported that they had been exposed to turtles. Fourteen of those patients identified "turtles too small to be legally traded," the CDC reported today in its Morbidity and Mortality Weekly Report.


Further investigation found that the water in turtle tanks in the patients' homes tested positive for this particular strain of salmonella.


As a result of this new outbreak, the CDC is warning that "turtles are not appropriate pets in households with young children or other high risk individuals," such as pregnant women, the elderly and people with weak immune systems.


According to the report, small turtles pose a particularly high salmonella risk because they are tiny enough for children to place them in their mouths and handle them like toys.


This is just the most recent outbreak of salmonella carried by small turtles. An outbreak in 2007 infected 44 people in five states. A 3-week-old baby girl in Florida died in March 2007 after being exposed to her family's pet turtle.


The U.S. Food and Drug Administration also cautions against owning pet turtles, warning that salmonella can cause "diarrhea, fever, stomach pain, nausea, vomiting and headache."


The CDC offers several tips for reducing the risk of turtle-associated salmonellosis, including thoroughly washing hands and any surfaces that turtles come into contact with. The agency recommends handling all turtles as if they could be contaminated with salmonella and warns that a negative salmonella test does not mean a turtle is not infected, as they do not "shed" the bacteria consistently.


As a result of this latest outbreak, the CDC says that increased enforcement against the sale of small turtles and increasing existing penalties could help decrease the likelihood of future infections.