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TECHIICAL REPORT

72·89·FL

OBSERVATIONS ON THE OCCURRENCE

OF A DERMATOMYCOSIS IN A COLONY

OF LONG-EVANS RATS

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clbttUtutlo n v n II mit. d.

I by

W. 8. Pollock

Foo� Laboratory

FL-180 I

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ORIGINATING ACTIVITY (Corporale author) U. REPOVT 119CURITY CLASIFICATION

U. So Army Natick Laboratories UNCLASSIFIEDNatick, Massachusetts 01760 2b. G-OUP

3 RERCOPT "ITL

Observations on the Occurrence oi a Dermatomycosis in a Colony of Long.Evans Rats

4 Oms4RIPTIVA NOTKS (7rj& Of teort and Inoluoi*r d~ee)I* AU TW6IORISI (rst dzMf, o- lddl* initial, is it naeft-i)

William B, Pollock

- R%1POR- VAAR 7 . TOTAL NO OF PAGES lb. NO OP REFS

May 1972 17 51141 CONTAC T OR GRANT NO, q . ')RIQIN4TORn' REPORT NUM'"CRIS)

. - o, . J061102A71C TR-72..69-k L

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FL-160

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U. S, Army Natick LaboratoriesNatick, Massachusetts 01760

13 ABSTRACT

The gross lesions associated with a Dermatomycosis are discussed. The occurrence ofthe spores within the hair shaft (endothrix) is demonstrated, while the inability togrow the organism on artificial media is noted.

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pow 3 REPLACES 00 01=4 td-8. I JAN4 4. WHICH IS

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IJNCLLSSIPIEDUecu~yClaulfcson

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alopecia 3spores 3

UNCLASSIFIED

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TECHNICAL REPORT

72-69-FL

OBSERVATIONS ON THE OCCURRENCE OF ADERMATOMYCOSIS IN A COLONY OF LONG-EVANS RATS

by

W. B. Pollock

Series: FL-160

Project Reference: May 1972iJ061 102A7 IC

Food LaboratoryU. S. ARMY NATICK LABORATORIESNatick, Massachusetts 01760

I€

FOREWORD

The work being reported here is based on observations made after a to

40% decrease in running time of rats on a treadmill was noted. The importance of the pathogenesis is discussed. The importance of dermatological problems in relation to the experimental results and the experimenter are discussedo The literature is deficient on both points.

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The work reported was conducted under Project No. 1J06ll02A71Co

In conducting the research described in this report, the investigator adhered to the 11Guide for Laboratory Animal Facilities and Care11 as promulgated by the Committee on the Guide for Laboratory Animal Resources, National Academy of Sciences - National Research Council, and by the National Society for Medical Research.

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ABSTRACT

The gross lesions associated with a Dermatomycosis are discussed. Theoccurrence of the spores within the hair shaft (endothrix) is demonstrated,while the inability to grow the organism on artificial media is noted.

INTRODUCT ION

A colony of 46 male Long-Evans (350-375 gms) conventional rats was housed

individually in galvanized cages. Water and feed were provided ad libitum.These rats were trained to run on a treadmill for an experiment involving tread-

mill performance with respect to varyiiig mineral ratios in the diet.

Approximately 12 weeks after initiation of the experiment, alopecia wasfirst noted in several of the animals and at the same time a sharp drop-off of25 to 40% occurred in running times. In all, 14 out of the 46 animals wereultimetely involved - five animals fed Purina Lab Chow and nine from the treat-ment groups.

FINDINGS

The animals were found to have areas of alopecia over wide areas of theirbodies: ventral thorax, ventral abdomen, latero-dornal thorax, lateral cervical,submandibular regions. The spots of alopecia varied in size from minute to areasas large as 2 cm x 6 cm (see figure 1). Examination with Wood's light revealedno flourescence. There was a steady progression of the pathological processes.As the disease progressed in any given animal, the areas of intense pruritisbecame evident. The subsequent scratching produced local trauma with secondarypyro;erma (see figures 1, 2, 3, and 4). Scab formation in these areas was common(see figure 5).

Skin scrappings were obtained and found to be negative for external para-sites. Howeve', examination ot the hair shafts with 10% KOH revealed suspiciousopaque objects within the hair shafts. Mycelia were not seen. Further, samplesof hair were examined by our mycology group (see figure 6) and a pres-Imptivediagnosis of Trichophyton mentagraphytes infection was made on the basis )f thehistory, clinical signs and microscopic examination of the hair shafts (seefigures 1, 2, 3, 4, and 5). Attempts to grow the organism on sabaurauds mediahave failed, thus preventing the formation of a conclusive diagnosis0

Four apparently normal animals (albino, Holtzman males at 350 grams) werechosen as subjects in an attempt to transfer the process from one animal toanother, One animal was placea in the cage with an infected animal for a periodof four hours. Two animals were exposed by first handling infected animals andthen handling normal animals. The fourth animal was exposed by contaminatinghis cage environment with hair from an infected animal. Results from these trialswere equivocal. The first animal started developing alopecia and pruritis in thelatero-dorsal aspect of the left thorax within two weeks as did one of the nexttwo, However, the other two (one handled, one with contaminated environment)exhibited no sign- of alopecia after six weeks.

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DISCUSSION

This disease process, although lacking a definitive diagnosis, was importantfrom two standpoints: (1) t.hc animals affected were unable to perform as expected,greatly affecting the experiment; and (2) the contagous aspect of the diseasethreatened other experiments in the building. One nf the workers was diagnosedas having "ringworm" at about the time the performance of the rats was affected.Prompt treatment took care of this problem. Hygienic practices were reviewedwith the workers and further outbreaks were contained by improved personal hygiene.

Previously reported discussions of dermatomycoses have been limited in theirscope and pathogenesis his been a neglected area (2, 3, 4, 5, and 6). Figure 5indicates that te pruritis apparently is tha most important clinical sign. Theitching is so intense that the animals appear to be more interested in satisfyingthe scratch reflex than in eating or performing. The pruritis is important fromthe aspect that the resulting scratching produces trauma and the attending pyoderma.

Problems with "ringworm" have not occurred in subsequent treadmill experi-ments conducted with Ceasarian-Derived Barrier Sustained rats. As shown in thispaper, ringworm presents a definite hazard to both the experiment and the experi-menter, therefore, it is recommended that: (i) gnotobiotic animals be used;(2) animals be examined at time of delivery and at frequent intervals thereafter;and (3) proper hygienic techniques be reviewed with workers per-odically.

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FIGURE 1

Rat with Alopecia of right shoulder region

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FIGURE 2

The Alopecia has progressed. The pruritis has triggered the scratch reflex and trauma has resulted.

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FIGURE 3

An advanced case showing trauma, scab formation and pyoderma

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FIGURE 4

A case showing advanced pyoderma

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FLOW CHART

Decrease in work performance

FIGURE 5

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Grouth of Organism

� Damage to follicle DesJ:uction of hair shaft

AloJkecia and pruritis

Scratching

� Trauma ,t. �/ Pyoderma Skin necrosis

FIGURE 6

Photomicrograph (X430) of hair shaft of affected rat. Brown spots are thought to be spores of mycotic organism (endothrix).

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REFERENCES

1. Cohrs, P. 1967. In Textbook of t�e2P.ecial P.�t.ho1.9_&1!.31. An��'?!!L2LDo��:!.:: tic Animals, p. 984. Pe�gamoP Press, Oxford. ·

2. Hull, T. G. 1963. In Disea&es Transmitted f�cm Animals to MdnL 5th ed, p. 490. Charle& c. Thomas, Springfield.

3. Jobb, K. u. F. a .. -' Vannedy , P. C. 1970. b Pctr·o·.oSJ._£f_D,�E_ti<.. Ani'l1alf;, 2nd ed.y Vol. 2, p. 618. Academic Press, New York.

4. National Research CounciL !97L A report of the Corran�.ttt>e en l.abo�atc·�y Animal Disease - A Guide t� Infectious Diseases of Mtee and Rats, P• 28. National Academy of Science/National Research Council� Wa�hi-;gt�n, D. C.

s. Pover, M. L. 1965. albino Norway rats.

Ringworm (.!_ .. mentagra�e!_>) infection in a colony of Lab. Anim. Care 1(4): 264.

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