Tularemia as a cause of fever in a squirrel monkey

A 3-year-old female squirrel monkey (Saimiri sciureus sciureus) was examined because of sudden onset of lethargy and fever.

On initial examination, the monkey was weak and febrile and had petechiae on both thoracic limbs. Following collection, blood samples were slow to clot. During the next week, the monkey developed anemia and thrombocytopenia; Francisella tularensis was isolated from blood samples.

Treatment with gentamicin resulted in the monkey's gradual return to health, but inguinal lymphadenopathy developed after drug administration was discontinued. Francisella tularensis was isolated from a fine-needle aspirate of an enlarged lymph node. Treatment with streptomycin resulted in resolution of infection. By use of biochemical and molecular tests, the microbial isolate was characterized as F tularensis subsp holarctica. Results of a microagglutination assay confirmed that the monkey had developed serum antibodies against F tularensis.

With timely diagnosis, treatment of tularemia in the squirrel monkey was successful. Francisella tularensis is the cause of a highly infectious zoonotic disease, and infection with this microorganism is enzootic in wildlife throughout the Northern Hemisphere. Tularemia should be considered in the differential diagnosis of febrile disease in animals of any species. Even limited or indirect exposure of humans or other animals to outdoor environments in which reservoir hosts and arthropod vectors are present can lead to transmission of F tularensis. Francisella tularensis is a class A agent of bioterrorism, and all cases of tularemia (regardless of species) should be reported to public health officials.