Tarello, W · Acta veterinaria Hungarica · 2003 · DOI
This study looked at blood test results from 117 pets (dogs and cats) diagnosed with a fatigue syndrome similar to ME/CFS in humans. The researchers found that many of these animals had low blood cell counts and low platelets, along with high muscle enzyme levels and unusual bacteria-like organisms in their blood. When treated with a specific arsenic-based medication, all the animals recovered completely and their immune systems improved.
This study provides evidence that CFS-like illnesses in animals share biological markers (elevated CK, blood abnormalities, potential infectious agents) with human ME/CFS, supporting the hypothesis that ME/CFS may have an infectious or immune component. The complete remission following targeted treatment suggests that immune dysfunction in CFS-like conditions may be treatable, offering potential therapeutic leads for human research.
This study does not establish that the micrococcus-like organisms or Staphylococcus are definitively causative of CFS-like illness; they may be markers or secondary findings. It also does not prove that arsenic-based therapy would be safe or effective in humans with ME/CFS, nor does it demonstrate that human and animal CFS-like syndromes share the same etiology. The observational, retrospective design cannot establish causation.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Tarello, W (2003). Immunological anomalies and thrombocytopenia in 117 dogs and cats diagnosed with chronic fatigue syndrome (CFS).. Acta veterinaria Hungarica. https://doi.org/10.1556/AVet.51.2003.1.6
BibTeX
@article{mecfsatlas-tarello-2003-immunological-anomalies,
author = {Tarello, W},
title = {Immunological anomalies and thrombocytopenia in 117 dogs and cats diagnosed with chronic fatigue syndrome (CFS).},
journal = {Acta veterinaria Hungarica},
year = {2003},
doi = {10.1556/AVet.51.2003.1.6},
note = {PubMed: 12688127},
url = {https://www.mecfsatlas.com/evidence/tarello-2003-immunological-anomalies},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/tarello-2003-immunological-anomalies
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