RESUMEN
Toxoplasma gondii infections are common in a range of mammalian and avian species, but clinical disease has been reported only rarely in domestic rabbits. Two cases of toxoplasmosis in domestic rabbits from the same premises were submitted to a diagnostic pathology facility in Athens, GA, USA. Both rabbits died after exhibiting clinical signs of gastrointestinal stasis. The gross findings observed in both rabbits comprised miliary, random, white-to-tan, necrotic foci throughout the spleen, liver, and lungs. Histologically, tachyzoites were observed within necrotizing inflammatory foci in the spleens of both rabbits, and in various other organs (tracheobronchial lymph node, lung, heart, and cecal appendix) of one rabbit. In both cases, the tachyzoites were immunoreactive with anti-Toxoplasma gondii antibodies. In addition, T. gondii DNA was detected via PCR and sequencing from a fresh lung sample from one rabbit and formalin-fixed, paraffin-embedded spleen, liver, femoral bone marrow, and haired skin from the second rabbit. Given that T. gondii can cause disease in domestic rabbits and is also a concern for other potential intermediate hosts (e.g., humans, other domestic animals), this parasite warrants consideration in the diagnostic evaluation of lagomorph tissues with compatible lesions.
RESUMEN
A 3-y-old, intact female, American Pit Bull Terrier was presented because of acute onset of anorexia and a large subcutaneous submandibular mass that had been present for 3 wk. The submandibular mass, 2 engorged black-legged ticks on the dorsum of the neck, pyrexia, and icterus were seen on physical examination. Abnormal laboratory test results included a positive Anaplasma antibody test, severe thrombocytopenia, mild nonregenerative anemia, hyperbilirubinemia, and elevated liver enzyme activities. Cytology of the mass was interpreted as marked septic purulent inflammation with acute hemorrhage. Treatment with doxycycline for anaplasmosis was unsuccessful, and the patient died at an emergency follow-up visit 2 d after the initial presentation. Autopsy and histopathology revealed widespread metastasis of a presumptive histiocytic neoplasm with associated hemophagocytosis seen in lymph nodes (LNs), liver, and spleen. Immunohistochemistry yielded a definitive diagnosis of a CD3+/CD18+ T-cell lymphoma. In this case of canine lymphoma-associated hemophagocytic syndrome, hemophagocytes were observed as >2% of neoplastic cells in the liver, spleen, and LN histologically, a scarce or unreported finding, to our knowledge. The prognosis was grave, with a short survival time after the onset of clinical signs.
