Tularemia in a park, Philadelphia, Pennsylvania.
During the spring and summer of 2006, a total of 14 eastern cottontail rabbits (Sylvilagus floridanus) and 2 woodchucks (Marmota monax) were found dead or trapped and euthanized (2 rabbits only) at a zoological park in Philadelphia, Pennsylvania, USA. The animals were necropsied, and specimens of liver and spleen were sent to the laboratory for F. tularensis culture and PCR. Two years earlier, in the spring of 2004, a single rabbit found dead at this same location had tested positive for F. tularensis. Of the 14 rabbits submitted in 2006 for F. tularensis testing, 6 were positive. Five of these were positive by PCR and culture, and one was positive by PCR alone. F. tularensis was identified only in animals found dead. The two woodchucks were negative. The 2004 isolate and 2006 isolates were identified by the Centers for Disease Control and Prevention as type A F. tularensis and were found genetically identical by pulsed-field gel electrophoresis.