A case of fatal systemic toxoplasmosis in a cat being treated with cyclosporin A for feline atopy

Abstract

Acute systemic toxoplasmosis was diagnosed in a 4-5-year-old, male, Domestic Short Hair cat, which had been on cyclosporine A immunomodulatory therapy for feline atopy, over an 8-month period. Cyclosporin A (CsA) has shown promising results as a immunosuppressive agent in the cat for the treatment of eosinophilic plaque and granulomas, allergic cervico-facial pruritus, feline atopy and other immune-mediated dermatoses. However, inhibition of T-lymphocyte function by CsA is believed to have predisposed this cat to the development of a newly acquired, acute Toxoplasma gondii infection, as characterized by severe hepatic and pancreatic pathology in conjunction with the heavy parasite load demonstrated on immunohistochemical (IHC) stains for T. gondii. Cats on CsA therapy appear to be at risk of developing fatal systemic toxoplasmosis.

Fatal toxoplasmosis in an immunosuppressed domestic cat from Brazil caused by Toxoplasma gondii clonal type I

“…This was also the most significant lesion observed in these other reports and also in an experimental study on cats with coinfection caused by FIV (DAVIDSON et al, 1993). Lymphadenomegaly and splenomegaly, which were seen in the present case, are also frequent lesions in cases of feline toxoplasmosis (DAVIDSON et al, 1993;HENRIKSEN et al, 1994;LAST et al, 2004;SPYCHER et al, 2011;JOKELAINEN et al, 2012;COHEN et al, 2016). The main histological lesions in the present case were necrotic interstitial pneumonia and necrotic hepatitis, which were similar to the lesions described in the reports from the authors cited above.…”

“…The definitive diagnosis was obtained after the patient's death, by means of histopathological analysis, like in most other cases that have been reported (HENRIKSEN et al, 1994;LAST et al, 2004;SPYCHER et al, 2011;JOKELAINEN et al, 2012;NAGEL et al, 2013;COHEN et al, 2016). However, cytological analysis on the bronchoalveolar lavage to directly detect tachyzoites might have elucidated the clinical case (HARTMANN et al, 2013).…”

“…The main histological lesions in the present case were necrotic interstitial pneumonia and necrotic hepatitis, which were similar to the lesions described in the reports from the authors cited above. However, in some cases, necrosis was described in the spleen and lymph nodes, along with myocarditis, pancreatitis, adrenalitis, meningoencephalitis and uveitis (DAVIDSON et al, 1993;HENRIKSEN et al, 1994;LAST et al, 2004;SPYCHER et al, 2011;JOKELAINEN et al, 2012;NAGEL et al, 2013;COHEN et al, 2016). These lesions were not observed in the present study.…”

“…However, fatal systemic cases have been reported in immunocompetent cats (SPYCHER et al, 2011;JOKELAINEN et al, 2012;NAGEL et al, 2013;COHEN et al, 2016) and in immunocompromised cats after administration of immunosuppressant drugs (LAST et al, 2004) and kidney transplantation (BERNSTEEN et al, 1999). Coinfection with immunosuppressant retroviruses such as FIV has also been reported to be a risk factor for development of a clinical condition of toxoplasmosis (DAVIDSON et al, 1993).…”

Fatal disseminated toxoplasmosis in an immunocompetent cat

“…Current literature suggests that an immunocompromised state, such as in cats with feline immunodeficiency virus (FIV), and/or feline infectious peritonitis (FIP), or those subject to potent inhibitors of cell-mediated immunity such as cyclosporin, is the main factor predisposing to the development of disseminated disease (Barrs, Martin & Beatty 2006;Davidson et al 1993;Foster et al 1998;Heidel et al 1990;Lappin et al 1992;Last et al 2004;Nordquist & Aronson 2008;Park et al 2007;Patton et al 1991;Toomey et al 1995). Fatal toxoplasmosis can develop during acute intracellular replication and systemic dissemination of tachyzoites.…”