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Ram epididymitis: A clinical report
THERIOCENOLOCY
RAM EPIDIDYMITIS:
A CLINICAL REPORT
Brinton L. Swift, Frank Craddock, Heman A. Hancock Rue Jensen, George M. Thomas, Malcolm S. Trueblood and John Weibel Division of Microbiology and Veterinary Medicine and Division of Animal Science University of Wyoming Laramie, Wyoming 82071 Received for publication: Accepted: ABSTRACT
October 1, 1981 Janllary 14, 1982
Two hundred and five ram lambs originating from several sources were assembled for a ram performance trial. All rams were immunized with a commercial Brucella avis bacterin. Four rams developed clinical evidence of epididymitis during the 150 day trial. Actinobacillus seminis was identified as the causative agent. INTRODUCTION Epididymitis in sheep is an infectious, contagious, progressive disease of rams characterized by an inflammation of the e ididymis and resulting in testicular degeneration and infertility. P The lesions may be unilateral or bilateral. Bilaterally infected rams are usually sterile.2 Numerous etiologic agents have been identified, including Brucella ovis,3,4 Actinobacillus seminis,5~6~7~8 Corynebacterium ovis,VHistophilus o-and Pasteurella sp. 9 Intracytoplasmic epididymitis.11
inclusion bodies have been observed in rams with
The gross lesions caused by 5. _ovis include an enlargement of the tail of the epididymis with or without changes in the tunica vaginalis. Microscopicallyl* leukocytes are observed in the exudate and intraepithelial cysts are formed in the tubal epithelium of the epididymis. Spermatic granulomas are formed around extraPublished with the approval of the Director, Wyoming Agricultural Experiment Station as Journal Article No. 1161.
MARCH
1982 VOL. 17 NO. 3
343
THERIOCENOLOCY vasated sperm cells. Atrophy of the seminiferous tubules follows the chronic changes of the epididymis. Infection with A. seminis is manifested by an acute or chronic orchitis, epididymo-orchitis,or epididymitis. Clinical signs are usually followed by loss of condition of fleece, and fistulation of the scrotum on the affected side. After the acute stage the affected side remains enlarged and hard. The affected testicle usually atrophies.' The purpose of this paper is to report the incidence of epididymitis in ram lambs immunized with -B. ovis bacterin. MATERIAL AND METHODS Two hundred and five ram lambs, ranging in age from 6-9 months, were delivered to the University of Wyoming for the purpose of a ram performance trial. Nearly all ram lambs were Rambouillets. The lambs were raised by 32 different producers from Colorado, New Mexico, Texas, Utah, South Dakota, and Wyoming. Soon after arrival all rams were examined for clinical signs of disease including epididymitis, blood samples were collected, and a commercial g. ovis bacterin (Ram Epididymitis Bacterin, Colorado Serum Co., Denver, CO) was administered. All rams were periodically weighed and reexamined monthly for the presence of epididymitis unt1.lthe trial terminated at 150 days. Blood sera were examined for the presence of complement fixing (CF) antibodies. Serial two-fold dilutions ranging from 1:lO to 1:640 were titrated in microtiter plates with 2. ovis antigen (U.S.D.A. Veterinary Services Laboratory, Ames, Iowa), and allowed to incubate overnight at 4C. Sensitized sheep red blood cells were added and the plates incubated in a water bath at 37C for 30 minutes. Two groups of rams (24 of 205 head) had been previously immunized with s. ovis bacterin prior to arrival at the site of the ram performance trial. All rams received a second injection of the bacterin two weeks following the first injection. Rams that developed clinical evidence of epididymitis were removed from the performance trial and slaughtered. The scrotal contents were dehydrated in graded concentrations of ethyl alcohol, cleared in chloroform, imbedded in paraplast, sectioned and stained with hematoxlyn and eosin, Nochts, and periodic acid Schiff, for histopathologic examination. The epididymal lesions from one ram were minced and inoculated onto second passage ovine testicular cells. Three serial passages on ovine cells were examined for the presence of cytopathology. Selected fluids and tissues were cultured on 5% sheep blood agar aerobically and anaerobically at 37C.
MARCH 1982 VOL. 17 NO. 3
THERIOGENOLOCY
RESULTS Of the 205 ram lambs, 19 were serologically positive at the 1:20 dilution or greater to B. e. Thirteen of nineteen had been previously immunized prior to their arrival at the performance site. One hundred eighty-six rams were serologically negative including 11 which had been previously immunized. Six non-vaccinated rams with complement fixing titers ranging from 1:20 to 1:40 did not develop clinical signs of epididymitis. Five rams developed clinical signs of scrotal pathology. Four rams had lesions of unilateral epididymitis and one ram a testicular abscess. A. seminis was identified as the causative agent in four rams with epididymitis and one ram with the testicular abscess. The isolate was tentatively identified as A. seminis on the basis of gram stain, morphology and initial isolation in an aerobic atmosphere. The organism did not ferment lactose or dextrose, was indole negative and did not grow on Mueller-Hinton media. Cytopathic agents were not observed on three serial passages on ovine tissue culture cells. DISCUSSION Epididymitis of rams continues to be an important disease in range and farm flocks of the Rocky Mountain west. A few owners and operators have initiated control programs which includes immunization, when commercial products are available, and culling of rams with gross lesions. In the trial reported here all of the rams were immunized with B. ovis bacterinandnone of the rams developed epididymitis due to B. ovis. The rams were assembled from several sources and allowed to cohabit; therefore, there was opportunity for In the previous year 173 non-vaccinated rams spread of the disease. were assembled at the Dniversity of Wyoming for a similar trial, of B. ovis this number 12 developed clinical evidence of epididymitis. was recovered from 5, A. seminis from 1, and no pathogenic organisms were recovered from 6 of the infected rams. Immunization may have protected all of the rams from B. ovis infection in the study reported here. Earlier studies indzcate approximately 75% protection among iyized rams receiving experimental Immunization apparently prechallenge with homologous isolates. vented brucellary epididymitis but not actinobacillary epididymitis; This may therefore epididymitis was not controlled by immunization. occur in flocks where immunization with B. ovis bacterins is practiced and culture and identification of etiologic agents is not practiced. The identification of the etiologic agents is a necessary and important aspect of assessing control measures for epididymitis.
MARCH 1982 VOL. 17 NO. 3
345
THERIOCENOLOCY The results of this study further indicate the immunization with 2. ovis apparently offers some protection from B. ovis infection but other etiologic agents may cause similar lesions and additional control measures may be necessary. The incidence of A. seminis infection in rams in Wyoming is unknown. The pathogenesisof the disease is conjectural, but as this study indicates it may be of importance in establishing control programs for the prevention of epididymitis. In the clinical examination of infected rams in the early stage of the disease there are clinical features that differentiate B. ovis infection from A. seminis infection. At the onset of clinical-signs rams with 4. ~seginis infection have a periorchitis involving the tunics surrounding the testicles. The palpable swelling in the live animal appears to involve the entire testicle. After the initial swelling subsides the epididymis remains firm, swollen and adhesed. Most of this firmness occurs in the tail of the epididymis. B. ovis infection usually does not involve the tunics and the inflammztory lesions are frequently confined to the epididymis, especially the tail. Pain is frequently evident in the early stages of A. seminis infection.
346
MARCH 1982 VOL. 17 NO. 3
THERIOGENOLOGY
REFERENCES 1.
Swift, B.L. Ram Epididymitis. Research Journal 24, Agricultural Experiment Station, University of Wyoming, l-11 (1968).
2.
Swift, B.L., and Weyerts, P.R. Ram Epididymitis. Infertility. Cornell Vet., -55: 204-214 (1969).
3.
Buddle, M.B., and Boyes, B.W. A Brucella Mutant C,ausing Genital Disease of Sheep in New Zealand. Austr. Vet. J. -29: 145-153 (1953).
4.
Simmons, G.C., and Hall, W.T.K. Preliminary Studies on the Occurrence and Pathogenicity of a Brucella-like Organism. Aust. Vet. J. -29: 33-40 (1953).
5.
Baynes, I.D., Simmons, G.C. Ovine Epididymitis by A. seminis (n. sp.) Aust. Vet. J.: -36: 454-459 (1960).
6.
Tonder van, E.M., and Bolton, T.W.F. Epididymitis in Rams Caused by Actinobacillus seminis. Jr. S. Afr. Vet. Med. Assn. 39: 87-90 (1968).
7.
Livingston, C.W., and Hardy, W.T. Isolation of Actinobacillus Am. J. Vet. Res. -25: 660-663 seminis from Ovine Epididymitis. (1964).
8.
Tonder van, E.M. Infection of Rams with Actinobacillus Jr. S. Afr. Vet. Med. Assn. -44: 235-240 (1973).
9.
Jansen, B.C. The Aetiology of Ram Epididymitis. J. Vet. Res. -47: 101-107 (1980).
A Study on
seminis.
Onderstepoort
10.
Claxton, P.D., and Everett, R.E. Recovery of an Organism Resembling Histophilus ovis from a Ram. Aust. Vet. Jr. -42: 457-458 (1953).
11.
Anderson, C.K., and Lozano, E.A. Histopathologic Observation on Proc. Second Annual Western Conference for Food Ram Epididymitis. Fort Collins, Co., 30 (Jan. 1981). Animal Veterinary Medicine.
12.
13.
Kennedy, P.C., Frazier, L.M., and McGowan, B. Epididymitis in Cornell Vet. -46: 303-319 (1956). Rams. Pathology and Bacteriology. Swift, B.L., and Maki, L.R. Immunologic Studies on Three Ram Cornell Vet. -58: 659-665 (1968). Epididymitis Bacterins.
MARCH
1982VOL.17NO.3
347
RAM EPIDIDYMITIS:
A CLINICAL REPORT
Brinton L. Swift, Frank Craddock, Heman A. Hancock Rue Jensen, George M. Thomas, Malcolm S. Trueblood and John Weibel Division of Microbiology and Veterinary Medicine and Division of Animal Science University of Wyoming Laramie, Wyoming 82071 Received for publication: Accepted: ABSTRACT
October 1, 1981 Janllary 14, 1982
Two hundred and five ram lambs originating from several sources were assembled for a ram performance trial. All rams were immunized with a commercial Brucella avis bacterin. Four rams developed clinical evidence of epididymitis during the 150 day trial. Actinobacillus seminis was identified as the causative agent. INTRODUCTION Epididymitis in sheep is an infectious, contagious, progressive disease of rams characterized by an inflammation of the e ididymis and resulting in testicular degeneration and infertility. P The lesions may be unilateral or bilateral. Bilaterally infected rams are usually sterile.2 Numerous etiologic agents have been identified, including Brucella ovis,3,4 Actinobacillus seminis,5~6~7~8 Corynebacterium ovis,VHistophilus o-and Pasteurella sp. 9 Intracytoplasmic epididymitis.11
inclusion bodies have been observed in rams with
The gross lesions caused by 5. _ovis include an enlargement of the tail of the epididymis with or without changes in the tunica vaginalis. Microscopicallyl* leukocytes are observed in the exudate and intraepithelial cysts are formed in the tubal epithelium of the epididymis. Spermatic granulomas are formed around extraPublished with the approval of the Director, Wyoming Agricultural Experiment Station as Journal Article No. 1161.
MARCH
1982 VOL. 17 NO. 3
343
THERIOCENOLOCY vasated sperm cells. Atrophy of the seminiferous tubules follows the chronic changes of the epididymis. Infection with A. seminis is manifested by an acute or chronic orchitis, epididymo-orchitis,or epididymitis. Clinical signs are usually followed by loss of condition of fleece, and fistulation of the scrotum on the affected side. After the acute stage the affected side remains enlarged and hard. The affected testicle usually atrophies.' The purpose of this paper is to report the incidence of epididymitis in ram lambs immunized with -B. ovis bacterin. MATERIAL AND METHODS Two hundred and five ram lambs, ranging in age from 6-9 months, were delivered to the University of Wyoming for the purpose of a ram performance trial. Nearly all ram lambs were Rambouillets. The lambs were raised by 32 different producers from Colorado, New Mexico, Texas, Utah, South Dakota, and Wyoming. Soon after arrival all rams were examined for clinical signs of disease including epididymitis, blood samples were collected, and a commercial g. ovis bacterin (Ram Epididymitis Bacterin, Colorado Serum Co., Denver, CO) was administered. All rams were periodically weighed and reexamined monthly for the presence of epididymitis unt1.lthe trial terminated at 150 days. Blood sera were examined for the presence of complement fixing (CF) antibodies. Serial two-fold dilutions ranging from 1:lO to 1:640 were titrated in microtiter plates with 2. ovis antigen (U.S.D.A. Veterinary Services Laboratory, Ames, Iowa), and allowed to incubate overnight at 4C. Sensitized sheep red blood cells were added and the plates incubated in a water bath at 37C for 30 minutes. Two groups of rams (24 of 205 head) had been previously immunized with s. ovis bacterin prior to arrival at the site of the ram performance trial. All rams received a second injection of the bacterin two weeks following the first injection. Rams that developed clinical evidence of epididymitis were removed from the performance trial and slaughtered. The scrotal contents were dehydrated in graded concentrations of ethyl alcohol, cleared in chloroform, imbedded in paraplast, sectioned and stained with hematoxlyn and eosin, Nochts, and periodic acid Schiff, for histopathologic examination. The epididymal lesions from one ram were minced and inoculated onto second passage ovine testicular cells. Three serial passages on ovine cells were examined for the presence of cytopathology. Selected fluids and tissues were cultured on 5% sheep blood agar aerobically and anaerobically at 37C.
MARCH 1982 VOL. 17 NO. 3
THERIOGENOLOCY
RESULTS Of the 205 ram lambs, 19 were serologically positive at the 1:20 dilution or greater to B. e. Thirteen of nineteen had been previously immunized prior to their arrival at the performance site. One hundred eighty-six rams were serologically negative including 11 which had been previously immunized. Six non-vaccinated rams with complement fixing titers ranging from 1:20 to 1:40 did not develop clinical signs of epididymitis. Five rams developed clinical signs of scrotal pathology. Four rams had lesions of unilateral epididymitis and one ram a testicular abscess. A. seminis was identified as the causative agent in four rams with epididymitis and one ram with the testicular abscess. The isolate was tentatively identified as A. seminis on the basis of gram stain, morphology and initial isolation in an aerobic atmosphere. The organism did not ferment lactose or dextrose, was indole negative and did not grow on Mueller-Hinton media. Cytopathic agents were not observed on three serial passages on ovine tissue culture cells. DISCUSSION Epididymitis of rams continues to be an important disease in range and farm flocks of the Rocky Mountain west. A few owners and operators have initiated control programs which includes immunization, when commercial products are available, and culling of rams with gross lesions. In the trial reported here all of the rams were immunized with B. ovis bacterinandnone of the rams developed epididymitis due to B. ovis. The rams were assembled from several sources and allowed to cohabit; therefore, there was opportunity for In the previous year 173 non-vaccinated rams spread of the disease. were assembled at the Dniversity of Wyoming for a similar trial, of B. ovis this number 12 developed clinical evidence of epididymitis. was recovered from 5, A. seminis from 1, and no pathogenic organisms were recovered from 6 of the infected rams. Immunization may have protected all of the rams from B. ovis infection in the study reported here. Earlier studies indzcate approximately 75% protection among iyized rams receiving experimental Immunization apparently prechallenge with homologous isolates. vented brucellary epididymitis but not actinobacillary epididymitis; This may therefore epididymitis was not controlled by immunization. occur in flocks where immunization with B. ovis bacterins is practiced and culture and identification of etiologic agents is not practiced. The identification of the etiologic agents is a necessary and important aspect of assessing control measures for epididymitis.
MARCH 1982 VOL. 17 NO. 3
345
THERIOCENOLOCY The results of this study further indicate the immunization with 2. ovis apparently offers some protection from B. ovis infection but other etiologic agents may cause similar lesions and additional control measures may be necessary. The incidence of A. seminis infection in rams in Wyoming is unknown. The pathogenesisof the disease is conjectural, but as this study indicates it may be of importance in establishing control programs for the prevention of epididymitis. In the clinical examination of infected rams in the early stage of the disease there are clinical features that differentiate B. ovis infection from A. seminis infection. At the onset of clinical-signs rams with 4. ~seginis infection have a periorchitis involving the tunics surrounding the testicles. The palpable swelling in the live animal appears to involve the entire testicle. After the initial swelling subsides the epididymis remains firm, swollen and adhesed. Most of this firmness occurs in the tail of the epididymis. B. ovis infection usually does not involve the tunics and the inflammztory lesions are frequently confined to the epididymis, especially the tail. Pain is frequently evident in the early stages of A. seminis infection.
346
MARCH 1982 VOL. 17 NO. 3
THERIOGENOLOGY
REFERENCES 1.
Swift, B.L. Ram Epididymitis. Research Journal 24, Agricultural Experiment Station, University of Wyoming, l-11 (1968).
2.
Swift, B.L., and Weyerts, P.R. Ram Epididymitis. Infertility. Cornell Vet., -55: 204-214 (1969).
3.
Buddle, M.B., and Boyes, B.W. A Brucella Mutant C,ausing Genital Disease of Sheep in New Zealand. Austr. Vet. J. -29: 145-153 (1953).
4.
Simmons, G.C., and Hall, W.T.K. Preliminary Studies on the Occurrence and Pathogenicity of a Brucella-like Organism. Aust. Vet. J. -29: 33-40 (1953).
5.
Baynes, I.D., Simmons, G.C. Ovine Epididymitis by A. seminis (n. sp.) Aust. Vet. J.: -36: 454-459 (1960).
6.
Tonder van, E.M., and Bolton, T.W.F. Epididymitis in Rams Caused by Actinobacillus seminis. Jr. S. Afr. Vet. Med. Assn. 39: 87-90 (1968).
7.
Livingston, C.W., and Hardy, W.T. Isolation of Actinobacillus Am. J. Vet. Res. -25: 660-663 seminis from Ovine Epididymitis. (1964).
8.
Tonder van, E.M. Infection of Rams with Actinobacillus Jr. S. Afr. Vet. Med. Assn. -44: 235-240 (1973).
9.
Jansen, B.C. The Aetiology of Ram Epididymitis. J. Vet. Res. -47: 101-107 (1980).
A Study on
seminis.
Onderstepoort
10.
Claxton, P.D., and Everett, R.E. Recovery of an Organism Resembling Histophilus ovis from a Ram. Aust. Vet. Jr. -42: 457-458 (1953).
11.
Anderson, C.K., and Lozano, E.A. Histopathologic Observation on Proc. Second Annual Western Conference for Food Ram Epididymitis. Fort Collins, Co., 30 (Jan. 1981). Animal Veterinary Medicine.
12.
13.
Kennedy, P.C., Frazier, L.M., and McGowan, B. Epididymitis in Cornell Vet. -46: 303-319 (1956). Rams. Pathology and Bacteriology. Swift, B.L., and Maki, L.R. Immunologic Studies on Three Ram Cornell Vet. -58: 659-665 (1968). Epididymitis Bacterins.
MARCH
1982VOL.17NO.3
347