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

The objective of the study was to report on a fatal case of feline toxoplasmosis with coinfection with the feline leukemia virus (FeLV). A domestic cat (Felis silvestris catus) presented intense dyspnea and died three days later. In the necropsy, the lungs were firm, without collapse and with many white areas; moderate lymphadenomegaly and splenomegaly were also observed. The histopathological examination showed severe necrotic interstitial bronchopneumonia and mild necrotic hepatitis, associated with intralesional cysts and tachyzoites of Toxoplasma gondii that were positive by anti-T. gondii immunohistochemical (IHC) evaluation. The bone marrow showed chronic myeloid leukemia and the neoplastic cells were positive by anti-FeLV IHC evaluation. DNA extracted from lungs was positive for T. gondii by PCR targeting REP-529. T. gondii was characterized by PCR-RFLP and by the microsatellites technique. ToxoDB-PCR-RFLP #10, i.e. the archetypal type I, was identified. Microsatellite analysis showed that the strain was a variant of type I with two atypical alleles. This was the first time that a T. gondii clonal type I genotype was correlated with a case of acute toxoplasmosis in a host in Brazil.

Fatal toxoplasmosis in an immunosuppressed domestic cat from Brazil caused by Toxoplasma gondii clonal type I / Toxoplasmose fatal em um gato doméstico imunossuprimido do Brasil causada por Toxoplama gondii clonal tipo I

Abstract The objective of the study was to report on a fatal case of feline toxoplasmosis with coinfection with the feline leukemia virus (FeLV). A domestic cat (Felis silvestris catus) presented intense dyspnea and died three days later. In the necropsy, the lungs were firm, without collapse and with many white areas; moderate lymphadenomegaly and splenomegaly were also observed. The histopathological examination showed severe necrotic interstitial bronchopneumonia and mild necrotic hepatitis, associated with intralesional cysts and tachyzoites of Toxoplasma gondii that were positive by anti-T. gondii immunohistochemical (IHC) evaluation. The bone marrow showed chronic myeloid leukemia and the neoplastic cells were positive by anti-FeLV IHC evaluation. DNA extracted from lungs was positive for T. gondii by PCR targeting REP-529. T. gondii was characterized by PCR-RFLP and by the microsatellites technique. ToxoDB-PCR-RFLP #10, i.e. the archetypal type I, was identified. Microsatellite analysis showed that the strain was a variant of type I with two atypical alleles. This was the first time that a T. gondii clonal type I genotype was correlated with a case of acute toxoplasmosis in a host in Brazil.

Resumo O objetivo deste estudo foi relatar um caso de toxoplasmose felina fatal com coinfecção com o vírus da leucemia felina (FeLV). Um gato doméstico (Felis silvestris catus) apresentou intensa dispneia e morreu três dias depois. Na necropsia, observaram-se pulmões firmes, não colabados e com múltiplas áreas brancas, além de linfoadenomegalia e esplenomegalia moderadas. No exame histopatológico, evidenciaram-se broncopneumonia intersticial necrótica acentuada e hepatite necrótica discreta associada a cistos e taquizoítas de T. gondii intralesionais positivos na imuno-histoquímica (IHC) anti-T. gondii. Evidenciou-se ainda, na medula óssea, leucemia mieloide crônica com IHC anti-FeLV positiva nas células neoplásicas. O DNA extraído dos pulmões foi positivo para T. gondii por meio da PCR-REP-529. T. gondii foi caracterizado por PCR-RFLP e pela técnica de microssatélites. Foi identificado o genótipo ToxoDB-PCR-RFLP #10, i.e., o arquétipo tipo I. A análise por microssatélites mostrou que a cepa era uma variante do tipo I, com dois alelos atípicos. Esta é a primeira vez que T. gondii clonal tipo I foi relacionado com um caso agudo de toxoplasmosis em um hospedeiro no Brasil.