Epididymitis in Male Animals: Etiology, Pathogenesis, Diagnosis and Control

Epididymitis is the inflammation of the epididymis. It is occasionally observed as an acquired lesion in all species of animals and is caused by or may be secondary to the same factors causing orchitis.

Etiology

Infectious causes of epididymitis include:

• Brucella abortus in bulls, Brucella suis in boars, Brucella canis in dogs, Brucella ovis (Ram Epididymitis Organism / REO) in rams
• Streptococcus zooepidemicus in a stallion
• C. Pyogenes and other miscellaneous organisms such as Streptococci, Staphylococci, Proteus, E. coli, C. pseudotuberculosis, Actinobacillusseminis and Pseudomonas Aeruginosa

Infections may be caused by organisms, such as mycoplasma, invading the epididymis through the vas deferens or by way of the blood or lymph vessels.

Traumatic injuries may also produce an epididymitis.

Inflammation of the epididymis may be caused by accidental passage of either normal or infected urine to the epididymis through the vas deferens.

Canine distemper virus in sexually mature dogs causes an epididymitis.

A Specific Bovine Venereal Epididymitis and Vaginitis (“EPIVAG”) a viral disease is usually characterized by a marked bilateral hardening and swelling of the tail of the epididymis in the bull. There is no cure for affected males but artificial insemination has been an effective control measure to prevent the spread of this venereal diseases.

Besnoitiosis due to Besnoitia besnoiti produces elephantiasis of the scrotal skin and cysts in the scrotum, inguinal canal, testes and epididymis. These cysts may persist and calcify, causing sterility.

A psittacoid, Chlamydia or PLT agent in bulls causes epididymitis, orchitis and seminal vesiculitis.

Brucella ovis (ram epidyimitis organisdm) is a common cause of ram epidymitis and infertility.

Ewes bred to infected rams had a greatly increased number of services per conception and fewer lambs per ewe  than ewes bred to non infected control rams.

Pathogenesis

The infective organism is spread mainly by venereal contact to susceptible rams breeding a ewe recently bred by an infected ram, or by rams penned together mounting each other and having rectal copulation or sodomy between rams.

Ewes play a minor role in the spread of the infection and are relatively resistant to the infection; but occasional abortions due to Brucella ovis are reported.

Rams are readily infected by the conjunctival or rectal instillation of the organism.

Rams may spread the organism for 3 to 4 years while ewes may spread infection for a much shorter period, especially for several days after an occasional abortion.

Following infections the antibody levels rise by the third week and persist for more than a year after the bacteremic stage of the disease.

The organisms localize in the epididymis, seminal vesicles, ampullae, liver, and kidneys.

The organisms cause perivascular lesions with edema and fibrosis in the epididymis resulting in obstruction of the lumen and stasis of the epididymal contents and finally extravasation of semen that because of its high lipid and mycolic acid content results in the formation of the spermatic granulomas resembling tubercular granulomas.

Over 90 percent of these lesions affect the tail of the epididymis but occasionally the body and head of the epididymis may be involved.

If the lesions are unilateral, fertility is normal or only slightly impaired; if they are bilateral sterility is usually present.

It takes 2 to 4 months from the onset of infection to the development of the lesions in the tail of the epididymis that causes it to become 3 to 5 times normal size and fibrotic. Some infected rams fail to develop gross palpable lesions.

Diagnosis

Diagnosis is based on clinical palpating of the epididymis to detect induration, spermatic granulomas and enlargements, especially involving the tail of the epididymis.

The combination of clinical palpation of the testes and the complement fixation test on serum was most effective in locating shedders of Brucella ovis.

A precipitin test for the detection for REO is proved to be simpler to run and more accurate than the C.F. test.

Fluorescent antibody techniques and the indirect hemagglutination test are also promising diagnostic laboratory techniques.

Control

Controlling ram epididymitis in a flock is highly important to maintaining good fertility in the flock.

Before the breeding season all rams that show clinical or serologic evidence of epididymitis should be eliminated.

Various vaccination procedures have been used successfully to protect rams against Brucella ovis.

The combination of the vaccine with other control practices was highly effective in infected flocks of sheep.

Although B. ovis reported to be sensitive to some antibiotics, the treatment of chronic lesions is of doubtful value.