Malignant Catarrhal Fever - Iowa State University

Iowa State University Veterinarian Article 1

Volume 37 | Issue 1

1975

Malignant Catarrhal Fever

Bruce Rafoth

Iowa State University

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Recommended Citation

Rafoth, Bruce (1975) "Malignant Catarrhal Fever," Iowa State University Veterinarian: Vol. 37: Iss. 1, Article 1.
Available at: http://lib.dr.iastate.edu/iowastate_veterinarian/vol37/iss1/1

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Malignant Catarrhal Fever

by

Bruce Rafoth *

This paper was written not because of On Sunday, June 30, the dyspnea was
the common occurrence of malignant ca- more severe and a catarrhal stringy exu-
tarrhal fever but because of its c10se re- date was coming from her nostrils. Rec-
semblance to the more common diseases tal temperature was 10S.5°F. and the eyes
IBR and BVD. It is imperative, therefore, were becoming cloudy at the corneoscleral
that the practitioner keep malign'ant 'Ca- junction but sight was still evident in both
tarrhal fever in, the back of his mind as eyes. A blood sample was drawn 'and the
a differential diag.nosis when considering differential blood count revealed a leuco-
IBR or BVD. If this is. brought to the at- penia. A tentative diagnosis of IBR was
tention of just a few 'practitioners, the made.
purpose of this paper will be accomp-
lished. On Monday, July 1, there was severe
dyspnea and a temperature of 105°F. The
Summary cloudiness in the eyes, which appeared to
be pus, in the anterior chamber, was in-
Malignant catarrhal fever is an infec- creasing to the point where sight was lost
tious, usually fatal, disease of cattle in the right eye. The scleral vessels were
caused by a virus and characterized by a injected and the catarrhal exudate from
catarrhal, mu'copurulent inflammation, of the nostrils revealed necrotic tissue pres-
the upper resp~ratory tract, keratoconjunc- ent.
tivitis, encephalitis, and enlargement of
the superficial lymph nodes. A tentative On Tuesday, July 2, the dyspnea was
diagnosis can be made on clinical signs not as severe and the temperature was
concurrent with a persistent high temper- 104.5°F. The cloudiness in the eyes was
ature but must be confirmed by histo- progressing and there was 'a mucopurulent
pathology. There is no treatment and nasal discharge. By this time it appeared
mortality is 100% in most cases. that this cow had something more severe
than IBR. Upon further questioning of
Case History the client, we found that he had housed
his sheep in the barn with the cows last
This summer I was working at the Sum- winter.
ner Veterinary Clinic. On Saturday, June
29, we were called out to a client's farm On Wednesday, July 3, both eyes ap-
because he had a cow off feed. The cow peared blind, the nasal mucosa was erod-
was a four year old Holstein and had ing away and there was a mucopurulent
been fresh for about five months. Physical nasal discharge. The cow died later that
examination revealed slight lung conges- day and a postmortem was done that eve-
tion and slight dyspnea along with a rec- ning. Gross lesions were suggestive of ma-
tal temperature of 105.5°F. Rectal exam lignant catarrhal fever and formalinized
reveale~ she was about 60 days pregnant samples of brain, liver, heart, kidney, and
but nothing else ~nusual. the eyes were sent to the Iowa State Di-
agnostic Lab. The diagnosis of malignant
~~foth is a fourth year student in the College of catarrhal fever was confirmed by the diag-
nostic lab by histopathology on July 19.
Veterinary Medicine at Iowa State University.
Both sexes and all breeds of cattle are
4 suscep1tible. Incidence is highest in cattle

Iow'a State University Veterina.rian

six months to four years of age with the involved beginning with areas of necrosis
disease rarely occurring in cattle less than around the nostrils w'hich soon coalesce
six months of age. Sheep do not develop causing tenacious scabs over the entire
the disease but appear to be a carrier of muzzle. Similar lesions may be seen at
the virus. Deer can also contract the dis- the coronary band and between the toes.
ease and show clinical signs sinlilar to In acute cases, skin on the teats may
cattle as well as serve as 'a wild reservoir slough and some animals develop' a derma-
of the virus. Malignant catarrh can occur titis. Superficial lymph nodes are usually
any time of year but is most common in enlarged.
fall and spring and occurs in most coun-
tries of the world. The disease has a very The consistency of the feces varies from
low morbidity and a very high nlortality. constipation to severe diarrhea and occa-
sionally melena. Corneal opacity is al-
Etiology and Pathogenesis ways present to some degree. Jt starts as
a narrow gray ring at the corneoscleraI
The cause of malignant catarrh is a vi- junction al1d spreads centripetally. Per-
rus that is classified in the herpesvirus sistent fever (greater than 103°F.) is char-
group. It is very difficult to isolate from acteristic of malignant catarrhal fever.
the blood because it is closely associated Some animals develop an encep,halitis and
with mononuclear leukocytes as well as may show abrupt temperament changes.
lymphoid tissue cells of nodes and spleen
but is not found in secretions or excre- Most of the gross lesions are caused by
tions. The route of entry of the virus i11to a necrotizing vasculitis which is due to
the bovine is not know11 but experiment- the virus attacking the adventitia of the
ally when it is administered parenterally it blood vessels. Gross lesions involve:
first attacks lymphoid tissue and repli-
cates here. Many small lymphocytes are EYE: conjunctivitis and keratitis.
destroyed and germinal centers depieted MUZZLE: encrusted and eroded
resulting in a leukopenia. This leuko- SKIN: exanthema-exuded lymph gives
penia occurs at the same time that there
is a rise in body temperature. The virus appearance of sweati11g.
also attacks the vascular adventitia caus- RESPIRATORY SYSTEM:
ing necrosis of the vessels which account 1. Nasal cavity-serous to mucopurulent
for the gross lesions.
inflammation with ulcers and pseudo-
Clinical Signs and Post-Mortem Lesions membranes.
2. Trachea-hyperemia to petechia and
The incubation period in natural infec- ulcers.
tion varies from three weeks to five DIGESTIVE SYSTEM:
months or even longer in some cases. The 1. Oral cavity and esophagus-erosions
course of the disease is usually between and ulcers.
four and 14 days. There are four fonus 2. Abomasum-hemorrhage and ulcers.
of malignant head catarrh-peracute, al- 3. Intestines-erosions, petechiae and ex-
imentary form, head-and-eye form, and cess mucus.
the mild form, with the head-and-eye form 4. Liver-mottled with less than Imm
being the most commOl1. III this form, on- white foci.
set is usually sudden with anorexia, agal- URINARY SYSTEM:
actia, high fever (106-107°F.), rapid 1. Kidney-2-4mm white foci.
pulse (100-120jmin.), a profuse muco- LYMPH NODES: retropharyngeal nodes
purulent nasal discharge, blep:harospasm are consistently enlarged.
and congestion of scleral vessels. Microscopic lesions are a generalized
vasculitis with cellular accumulations in
Superficial necrosis is evident in the the adventitia.
anterior nasal mucosa and on the buccal
mucosa. The skin of the muzzle is usually Diagnosis

A presumptive diagnosis of malignant
catarrhal fever can be made when the

Issue No.1, 1975 5

nasal, oral, and ocular lesions are observed Treatment and Control
along with a persistent high temperature,
enlargement of peripheral lymph nodes, Because malignant catarrhal fever is
and terminal encephalitis. The diagnosis caused by a virus, treatment is of little or
can be confirmed histologically by demon- no value.
strating perivascular, mononuclear cell ag-
gregations in brain, liver, heart, and kid- Because association with sheep is usu-
ney tissues. ally in the history, separation of cattle and

The differential diagnosis should in- sheep herds is recommended and has re-
clude BVD-MD, Rinderpest, Infectious
Stomatitides, IBR, and Pneumonic Pas- sulted in the disappearance of the disease
teurellosis. BVD-MD, Rinderpest, and the in some cases. The introduction of sheep
Infectious Stomatitides are not accompan-
ied by the typical ocular lesions, lymph from areas where the disease has occurred
node enlargement, or encephalitis and should be avoided. Very few animals sur-
they each have a distinctive histopathol-
ogy. IBR is not usually fatal, recovery is vive, but those that recover are immune
rapid, the lesions are restricted to the up-
per respiratory tract and the disease is to further infection for four to eight
readily transmitted. Pneumonic Pasteurel-
losis is not accompanied by oral, nasal, or months.
ocular lesions and responds well to treat-
ment. Bibliography

1. Ramsey, F. K. and Kluge, .T. P., Class notes, 1973.

2. Blood, D. C. and Henderson, J. A., Veterinary :Medi-
cine, Third Edition, Williams and \Vilkins Co., Balti-

more, 1971, pp. 479-482.
3. Jensen, Rue and l\'Iackay, Donald R., Diseases of Feed-

lot Cattle, Second Edition, Lea and Febiger, Philadel-
phia, 1971, pp. 18-24.
4. Gibbons, W. J., Catcott, E. J., and Smithcors, J. F.,
Bovine l\!Iedicine and Surgery, First Edition, American
Veterinary Publications, Inc., 1970, pp. 85-90.
5. The :Merck Veterinary :Manual, Fourth Edition, :Merck
and Co., Inc., Rahway, N.J., 1973, pp. 266-268.

History as a Diagnostic Aid
in Canine Epilepsy

by

Paul Anderson *

R. W. Carithers D.V.M., M.S., Ph.D.t

Summary coupled with clinical signs, neurological
examination, blood chemistry, cerebro-
Diagnosis of the etiology of an epileptic spinal fluid evaluation, and urinalysis.
dog involves prudent history acquisition
The histories of five clinical cases are
*' ~1r. Anderson is a fourth year student in the College presented to show the variations in the
amnesis and the significance these varia-
of Veterinary :Medicine at Iowa State University. tions might have.

t Dr. Carithers is an Assistant Professor in Veterinary Iowa State University Veterinaria1l

Clinical Sciences, Iowa State University.

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