CTX-M-15–Producing Escherichia coli in Dolphin, Portugal

of immunosuppression. Thus, the most likely explanation is increased exposure to the parasite. Sources of infection for red squirrels are not known; however, oocysts shed in cat feces may contaminate the nuts, fungi, shoots, and berries that constitute the diet of the squirrel. Stray, unspayed cats are common in the Dutch countryside. More than 3 million domestic cats (Felis domesticus) exist in the Netherlands, including several tens of thousands of free-roaming cats that reproduce (9). Determining the exact source of infection is important because humans also harvest wild fruits, nuts, and fungi from these areas. This outbreak highlights that contamination of the environment with T. gondii oocysts is of concern not only from a public health viewpoint but from a biodiversity perspective as well (1,10).