Immunological Anomalies and Thrombocytopenia in 117 Dogs and Cats Diagnosed with Chronic Fatigue Syndrome (CFS)

Retrospective analysis of immune dysfunctions found in 55 dogs and 62 cats diagnosed with Chronic Fatigue Syndrome (CFS), revealed leukopenia in 11% of dogs (n = 6) and 22.5% of cats (n = 14), lymphopenia in 14.5% of dogs (n = 8) and 10% of cats (n = 6), hypogammaglobulinaemia in 9% of dogs (n = 5) and 13% of cats (n = 8) and thrombocytopenia in 20% of dogs (n = 11) and 68% of cats (n = 42). All patients had creatine kinase enzyme levels above the normal range (CK = 5-100 IU/L) and carried micrococcus-like organisms on erythrocytes. Blood cultures proved positive for Staphylococcus spp. in 16 cases. After low-dosage arsenic-based therapy (thiacetarsamide sodium) all animals experienced complete clinical remission. Subsequent controls demonstrated immune restoration in 4 representative FIV-FeLV negative cats, previously diagnosed with CFS associated with leukopenia, lymphopenia, hypogammaglobulinaemia and thrombocytopenia. The main conclusion is that a CFS-like disease in dogs and cats, characterised by the common hallmarks of high CK levels, absence of known causes of chronic fatigue in animals and presence of micrococcus-like organisms in the blood, can be associated with humoral and/or cellular immune deficiencies in 9-22.5% of cases and with thrombocytopenia in 20-68% of cases. Considerations are made on the possible role of micrococci in the aetiology of the condition and on the similarities with CFS in humans.