A CASE OF THE CHRONIC FATIGUE SYNDROME IN A HORSE FROM USA EXAMINED IN DUBAI (UAE).
Author: W. Tarello , DVM, C.P. 1644, 06129 PERUGIA 5 (ITALY)
Accepted for Poster presentation at the THIRD INTERNATIONAL CLINICAL AND SCIENTIFIC MEETING: Chronic Fatigue Syndrome, a serious legitimate diagnosis. Sydney, 1-2 December 2001. ABSTRACT - A six-year old castrated male warm-blood horse with a two-year history of CFS-resembling disease tested negative for Equine Herpes viruses type 1 and 4, Sarcocystis neurona and Equine Arteritis virus. High level of Streptococcus equi aspecific antibodies were detected. Symptoms were: resistance to perform the normal activity, fever, apathy, tender and enlarged head and neck lymph nodes, sweats, hives, laminitis and abscesses in hind hooves.
Recurrences occurred following several attempted therapies with current medicaments. All biochemistry tests were normal with the exception of high neutrophils, platelets counts, CK and LDH activities at rest. Fresh blood smears from the horse’s blood were sent unstained from the USA to this author in Dubai (UAE). After staining with the Wright technique, slides were microscopically examined (x100) showing the presence of micrococci-like organisms on 5-6% of Red Blood Cells, and the absence of alternative causes of chronic fatigue
in horses (Babesia and Ehrlichia spp.) Taken together these observations led to a diagnosis of Chronic Fatigue Syndrome.Following treatment with Potassium Arsenite 0.5% intravenously given at low dosage (0.025 ml/Kg/day) for three days the horse’s health rapidly improved. Clinical and laboratory checks made 15 days and 2 months later confirmed complete recovery.
INTRODUCTION Chronic Fatigue Syndrome is not widely known to affect animals, although there
have been a number of anecdotal and scientific reports  indicating that the
condition may have zoonotic and veterinary implications [2-7].
In order to provide further comparative information on the similarities between
CFS in animals and humans, the equine case reported here is emblematic and
Hobbes is a six-year-old castrated warm-blood horse living in Minnesota (USA)
and weighing 1760 lb (800 Kg), which developed increasing resistance to be
ridden and generalized fatigue in April 1999, three weeks after being purchased.
By the time of referral (June 2001) the condition persisted during two consecutive
years and was dominated by severe chronic fatigue, with the simultaneous
occurrence of the following symptoms, all of which have persisted or recurred
during two consecutive years and have not predated fatigue: low-grade fever,
tender and enlarged lymph nodes of head and neck, muscular and joint pain (stiff
gait, inability to jump, painful muscles), un-refreshing sleep (early morning
apathy and somnolence), post-exertional malaise (rapid exhaustion after moderate
physical activity) and consistent evidence of abnormalities in mood and
personality (shyness, indifference to the environment) and neurological symptoms
(seizure, shivering, head shaking, movement incoherence) .
Collateral symptoms and signs were: weight loss, episodic difficulty to remain
standing, muscle tremors, anorexia, heavy sweating and breathing,
anaemia, distended colon with gas, hives on legs, bad hair-coat conditions,
laminitis and recurrent abscesses in hind hooves. Worsening of symptoms were
The method used to establish the presence of these symptoms was based on
spontaneous reporting by the owner accompanied by complete biochemical and
haematological screening (Table I), showing high neutrophils and platelets
counts, anaemia and serum evidence of muscular dysfunction (high CK and LDH
Exclusion of other neurological and fatigue-causing equine diseases was carefully
done: the horse was regularly de-wormed and vaccinated annually against Rabies,
Influenza, Rhino-pneumonitis, Potomac Horse Fever, Eastern and Western
Encephalomyelitis and Tetanus, and also tested negative for Equine Herpes
Viruses type 1 and 4, Sarcocystis neurona, Equine Arteritis virus and Equine
Infectious Anaemia (caused by a retrovirus of the Lentivirus genus). High level of
Streptococcus equi serum specific antibodies (1.83 and 1.4, respectively before
and after absorption with the ELISA Se-M test) led initially to the suspect of
Purpura Haemorragica although the case was missing some standard symptoms,
such as the blue/purple blotches on the gums. The diagnosis was subsequently
discharged on the basis of negative result of a similar test, run at the University of
Kentucky in May 2001, which determined the absence of any infection caused by
Streptococcus equi. A neurological exam showing anomalies in the coordination
of hind quarters led to a suspicion of Wobbler’s Syndrome grade 2 to 3 (out of 5)
which was however not confirmed in subsequent neurological exams.
Microscopic examination of fresh blood smears (x100) prepared in August 2001
and stained with the Wright technique revealed the unusual presence of
micrococci-like organisms, 0.3-0.5 µm in diameter, attached to the outer surface
of 5-6 % of erythrocytes (Fig. 1) meanwhile Babesia and Ehrlichia – like
Diagnosis of Equine CFS was based upon the above criteria, on exclusionary
conditions  and on the presence of micrococci-like organisms adhering to the
external surface of some red blood cells (Fig. 1), as previously observed in other
animal [2-4, 6-7] and human CFS cases  in which this anomaly was the main
haematological difference observed between healthy and ‘chronically fatigued’
patients. Although the CDC clinical definition  is intended only for human
purposes, this case seems also to fulfil the current criteria for CFS diagnosis,
because the clinically evaluated and unexplained chronic fatigue (biochemically
confirmed by high CPK and LDH activities) lasted for more than 6 months
accompanied by the following symptoms: (1) tender and enlarged head and neck
lymph nodes, (2) muscle pain, (3) multi-joint pain, (4) un-refreshing sleep, (5)
post-exertional malaise lasting more than 24 hours, (6) impairment in memory
and concentration with evident abnormalities in mood and personality.
During the last two years , the horse had relapsed after previous standard therapies
with current medicaments, which included long-term courses with dexamethasone
(Azium powder, 1-2 tablespoon/day), prednisone (4-8 tabs/day) non steroid anti-
inflammatory drugs (Banamine, 1000# dose), Naxcel (25 ml/day), Penicillin,
Gentamycin, Benadryl, DMSO IV, oatmeal bath, SMZ tablets (26 tabs 2x daily
for 14 days), Ranitidine (18 tabs 2x daily) and surgery for a colic caused by
abdominal kidney and spleen displacements.
Following previous therapeutic experiences with arsenical drugs in low dosage
against CFS [2-7], Potassium arsenite 0.5% was intravenously injected at 0.025
ml/Kg/day on date 5, 6 and 7 September 2001. No adverse effects were noticed
Fifteen days later (21 September) the owner noticed that she was able to ride the
horse again, and that the animal definitely seemed to feel better, running and
bucking in the pasture, showing an improvement in his neurological symptoms
from grade 4 (out of 5) to grade 3 ataxia of his hind and fore limbs.
A control blood sample revealed an increased haematocrit (PCV = 34.2%),
normalization of platelet count and CPK activity at rest, and a sharply decreased
number of erythrocytes (0.5-1%) carrying micrococci in the blood (Table I).
During the same day the horse received his summer booster for Flu/Rhino and
Rabies vaccines and he did well, without manifesting negative side reactions.
Based on the owner’s statement usually the horse experienced a worsening of
symptoms after getting his vaccinations: in the past it has broken out in hives, ran
Two months after therapy (2 November), a second clinical check revealed
complete remission from the chronic state of fatigue and all associated symptoms,
including fever, muscle and multi-joint pain, recurrent abscess in hooves, bad hair
coat condition and hives. The lymph nodes of head and neck had decreased their
size and the neurological symptoms had improved to a consistent grade 0-1: it
was evident to the owner that the horse had more control over his hind limbs
while moving, running and turning. The horse’s owner noticed also that since the
treatment with potassium arsenite Hobbes had not pulled out even one shoe and
had grown a thick winter coat, while previously he was used to pull shoes at least
every 2-3 weeks and the winter moulting was insufficient and poor.
Repeated fresh blood smears showed concurrent disappearance of micrococci
from the red blood cell surfaces, along with the maintained normalization of
anaemia, CPK level, platelets and neutrophils counts (Table I).
A horse diagnosed with Chronic Fatigue Syndrome, relapsed after extensive prior
therapy and meeting the CDC current human criteria for CFS definition, was
found to carry unusual micrococci-like organisms in the blood (Fig. 1) and
experienced complete remission after intravenous treatment with low dosage
potassium arsenite 0.5% (Fowler’s solution ½; 0.025 ml/Kg/day for 3 days) used
as single drug (Table 1). In two controls made after treatment and cure,
micrococci decreased and disappeared from the blood, contemporary with the
normalization of muscular enzyme values (CPK, LDH) and of haematology
parameters (PCV, neutrophil and platelet counts). There is no direct evidence that
these bacteria caused the disease but, apparently their presence in the blood was
linked to the condition, being the most remarkable haematological difference
between pre- and post arsenical treatment (Fowler’s solution ½) in this subject.
Although no blood-culture could be performed to confirm and specify such
presumptive bacterial presence, the micrococci-like organisms observed in this
horse were similar in shape, size and colour to those previously observed in other
horses , dogs [4,7], cats [4,6] , falcons  and humans  affected by CFS, in
which several blood cultures proved also positive for Staphylococcus intermedius
(S. aureus if of human origin) [3,4, 7], S. xylosus [3, 4], S. epidermidis, S. cohnii, S. chromogenes, S. lugdunensis .
Furthermore, Babesia and Ehrlichia spp. were not observed in the blood smears
from this patient and it is acknowledged that microrganisms similar to micrococci,
like the members of Anaplasma and Eperythrozoon genus have never been
reported in horses or other equines and usually show a different symptoms
It has been noted that people  and animals  without symptoms of CFS or
affected by different diseases , do not have micrococci in the blood.
Consequently it has been suggested that the observation of their presence on the
erythrocytes could be used as a coadjutor tool in the diagnosis of CFS [2-7] .
These results agree with recent advances in human research that implicate a
possible causative role of toxic-producing staphylococci on chronic pain/fatigue
sorders  as well as in CFS . They seem to confirm the recent reports of
bacteria claimed to be present in low number in the blood of healthy individuals
 and in high number in the blood of those who have CFS  or Multiple
Sclerosis : a reduction in these bacteria is associated with clinical
improvement and an increase corresponds with increased symptoms.
Taken together these observations seem also to exclude a psychiatric origin for
CFS, because animals do not suffer from somatization, depression or anxiety.
Although the neuro-cognitive signs are difficult to evaluate in animals, inability to
perform the normal activity, indifference to the environment and mood alterations
have already been observed in horses , dogs  and cats  diagnosed with
CFS and it is acknowledged that these alterations may be confused with
psychiatric diseases in people with CFS.
Eight feline cases meeting the current criteria for CFS diagnosis in humans have
already been described in recent literature [4,6], nonetheless this is apparently the
first report on the efficacy of potassium arsenite 0.5% in a horse fulfilling the
same criteria  which relapsed after extensive prior therapy with current
The Merck Index  lists several arsenical compounds as ‘tonics’ for horses and
‘general stimulant in nervous diseases’. Sodium arsenate was also indicated for
rheumatism  and there have been reports on the improved appearance of skin
and hair in horses supplemented with arsenic . These dated notions are not in
contrast with the results obtained in this horse, which found complete cure from
the chronic state of fatigue and associated skin ailments, including hives,
recurrent abscesses in hind hooves and rough haircoat, after a short and low-
dosage potassium arsenite 0.5% treatment. However, no relationship has ever
been established in the past between arsenic-responsive diseases and presence of
Although commonly known for its toxicity, arsenic is an essential element to
some species, including humans  and low serum arsenic is correlated with
central nervous system disorders and some kind of cancers . The arsenic
derivatives are today rediscovered against a huge variety of haematological and
solid cancers and arsenic trioxide has been recently approved by the FDA in the
treatment of relapsed or refractory acute promyelocytic leukaemia . This may
be the key stone in supporting the approval of these medicaments even against
Chronic Fatigue Syndrome. Inhibition of production of superoxide and of
inflammatory mediators, such as Tumor Necrosis Factor, are obtained at low
concentration of arsenic  and it has been recently noted that sodium arsenite
reduces proliferation of human activated T-cells by the inhibition of the secretion
Taken together these observations seem to indicate that arsenical derivatives may
be strongly promising therapeutic agents against CFS in both humans and
 Glass T. The human/animal interaction in Myalgic Encephalomyelitis/Chronic
Fatigue Syndrome: a look at 127 patients. J Chron Fat Synd 2000; 6: 2, 73-81.
 Tarello W. Chronic Fatigue Syndrome (CFS) in horses: diagnosis and
treatment of 4 cases. Comp Immunol Microbiol Infect Dis 2001; 24: 1, 57-70.
 Tarello W. Chronic Fatigue and Immune Dysfunction Syndrome associated
with Staphylococcus spp. bacteremia responsive to thiacetarsamide sodium in
eight birds of prey. J Vet Med B 2001; 48: 267-81.
 Tarello W. Chronic Fatigue Syndrome (CFS) in 15 dogs and cats with specific
biochemical and microbiological anomalies. Comp Immunol Microbiol Infect Dis
 Tarello W. Chronic Fatigue Syndrome (CFS) associated with Staphylococcus spp. bacteremia, responsive to potassium arsenite 0.5% in a veterinary surgeon
and his coworking wife, handling with CFS animal cases. Comp Immunol Microbiol Infect Dis 2001; 24: 4 (In Press).
 Tarello W. Chronic Fatigue Syndrome (CFS) in cats: symptoms, diagnosis and
treatment of 7 cases. Revue Méd Vét 2001; 152: 11 (In Press)
 Tarello W. Chronic Fatigue Syndrome (CFS) associated with Staphylococcus
spp. bacteremia, responsive to thiacetarsamide sodium in 7 dogs. Revue Méd Vét
 N.I.A.I.D. Chronic Fatigue Syndrome. Information for physicians. NIH
publication n. 96-484. National Institute of Allergy and Infectious Diseases, Sept,
 Butt H.L., Dunstan R.H., McGregor N.R., Roberts T.K., Zerbes M., Klineberg
L.J. An association of membrane-damaging toxins from coagulase-negative
Staphylococci and chronic orofacial muscle pain. J. Med. Microbiol. 1998; 47:
10] Dunstan R.H., McGregor N.R., Roberts T.K., Butt H.L., Niblett S.H.,
Rothkirsh T. The development of laboratory-based tests in Chronic Pain and
Fatigue: 1. Muscle catabolism and Coagulase negative Staphylococci which
produce membrane damaging toxins. J Cron Fat Synd 2000; 7: 1, 23-27.
 McPhee K. The human bloodstream is not sterile. Proc 7th Annual Blood Products Safety Conference , McLean, Virginia, USA, February 5-7, 2001.
 Jouravleva E., McPhee K. Quantitation of HBB1 directly from human blood
through reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Proc of the 101st Annual Meeting of the American Society for Microbiology, Orlando,
 The Merck Index. An encyclopedia of chemicals and drugs. Ninth edition.
Rahway, NJ, USA, Merck & Co. Inc., 1976.
 Sollman T. Manual of Pharmacology. W.B. Saunders, Philadelphia, 1953.
 Emsley J. The Elements. 2nd Ed, Clarendon Press, Oxford, 1991, pp 22-23.
 Uthus E.O. Arsenic essentiality and factors affecting its importance. In:
Chappel W.R., Abernathy C.O. and Cothern C.R. (Eds.) Arsenic Exposure and
Health, pp- 199-208. Science and Technology Letters , Northwood, UK.
 Antman K.H. Introduction: the history of arsenic trioxide in cancer therapy.
Oncologist 2001; 6: Suppl. 2, 1-2.
 Lantz R.C., Parliman G., Chen G.J., Carter D.E. Effect of arsenic exposure
on alveolar macrophage function. I. Effects of soluble As(III) and As(V). Environ
 Vega L., Ostrosky-Wegman P., Fortoul T.L., Diaz C., Madrid V., Saavedra
R. Sodium arsenite reduces proliferation of human activated T-cell by inhibition
of the secretion of interleukin-2. Immunopharmacol Immunotoxicol 1999; 21:
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