Clinical and clinicopathological features and outcomes of cats with suspected dietary induced pancytopenia

Background: After a strong epidemiological link to diet was established in an outbreak of pancytopenia in cats in spring 2021 in the United Kingdom, 3 dry diets were recalled. Concentrations of the hemato- and myelotoxic mycotoxins T-2, HT-2 and diacetoxyscirpenol (DAS) greater than the European Commission guidance for dry cat foods were detected in the recalled diets. Objectives: To describe clinical and clinicopathological findings in cats diagnosed with suspected diet induced pancytopenia. Animals: Fifty cats presenting with pancytopenia after exposure to a recalled diet. Methods: Multicenter retrospective case series study. Cats with known exposure to 1 of the recalled diets were included if presented with bi- or pancytopenia and underwent bone marrow examination. Results: Case fatality rate was 78%. Bone marrow aspirates and biopsy examination results were available in 23 cats; 19 cats had a bone marrow aspirate, and 8 cats had a biopsy core, available for examination. Bone marrow hypo to aplasia—often affecting all cell lines—was the main feature in all 31 available core specimens. A disproportionately pronounced effect on myeloid and megakaryocytic cells was observed in 19 cats. Myelofibrosis or bone marrow necrosis was not a feature. Conclusion and Clinical Importance: Mycotoxin induced pancytopenia should be considered as differential diagnosis in otherwise healthy cats presenting with bi- or pancytopenia and bone marrow hypo- to aplasia