A unilateral case of orchitis in a male broiler breeder was caused by Staphylococcus aureus, while a bilateral case of epididymo-orchitis in another male broiler breeder was caused by Escherichia coli. Microscopic examination found heterophilic interstitial-intratubular orchitis and epididymitis in both cases, with intralesional bacterial colonies. The infections were believed to have occurred via the ascending route in both cases. This report describes two cases of bacterial orchitis/epididymo-orchitis in broiler breeders and identifies novel causes.

1. LRH: R. Monleon and H. J. Barnes
RRH: Orchitis in broiler breeders
Case Report --
Bacterial Orchitis and Epididymo-orchitis in Broiler Breeders
R. Monleon and H. J. BarnesA
Poultry Health Management, Department of Population Health & Pathobiology, College
of Veterinary Medicine, North Carolina State University,
4700 Hillsborough St., Raleigh, NC 27606, U.S.A.
For submission to: Avian Diseases
A
Corresponding Author. Dr. H. John Barnes, Poultry Health Management, Department
of Population Health & Pathobiology, College of Veterinary Medicine, North Carolina
State University, 4700 Hillsborough Street, Raleigh, NC 27606.
Tel: (919) 513-6273. Fax: (919) 513-6383. Email: john_barnes@ncsu.edu

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SUMMARY. A unilateral case of orchitis due to Staphylococcus aureus and a bilateral
case of epididymo-orchitis due Escherichia coli are described. Male broiler breeders from
two different farms were collected and a unilateral orchitis and a bilateral epididymo-
orchitis were identified at necropsy. Bacteriology samples recovered S. aureus and E. coli
respectively. Microscopically, heterophilic interstitial-intratubular orchitis with
intralesional bacterial colonies was observed in both cases. Bacterial heterophilic
interstitial-intratubular epididymitis was observed in Case 2. Infection most likely
occurred via the ascending route.
RESUMEN. Un caso de orquitis unilateral por Staphylococcus aureus, y una epididimo-
orquitis bilateral por Escherichia coli son descritos. Machos progenitores de dos granjas
distintas fueron tomados y necropsiados, una orquitis unilateral y una epididimo-orquitis
bilateral fueron identificadas. En las muestras bacteriologicas S. aureus e E. coli fueron
identificados respectivamente. Microscopicamente, orquitis intersticial-intratubular
heterophilica con colonias bacterianas en la lesion fueron observadas en ambos casos.
Epididimitis intersticial-intratubular heterophilica bacterianas fue observada en el Caso 2.
La via ascendente fue considerada la ruta mas probable de infeccion.

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Keywords: orchitis, epididymo-orchitis, Staphylococcus aureus, Escherichia coli,
infertility
Abbreviations: O/E/EpO = Orchitis / Epididymitis / Epididymo-orchitis

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Broiler breeder infertility is a major concern in the poultry industry that can result
in severe economic significance. Orchitis, epididymitis and epididymo-orchitis
(O/E/EpO) cause fertility performance impairment in male breeders, thus decreasing their
productivity. In poultry, these infections have previously been associated with
Salmonella spp. (12, 13), and Escherichia coli (5, 11). Likewise, in other species,
O/E/EpO have been associated with many different agents such as Brucella ovis,
Histophilus ovsi, Arcanobacterium pyogenes, and Actinobacillus seminis in sheep (1, 4),
Brucella abortus, Actinomyces pyogenes, Mycobacterium tuberculosis in bulls (1),
Staphylococcus aureus, Escherichia coli and Proteus spp. in camels (16), and Chlamydia
trachomatis, Escherichia coli, Staphylococcus spp., and Neisseria gonorrhoeae, among
others, in humans (6, 7, 10). The amount of literature available regarding these
conditions in poultry is scarce. In the present study, two cases of orchitis are described, a
unilateral infection caused by S. aureus, and a bilateral case of epididymo-orchitis due to
E. coli.
CASE HISTORY
Case 1. During a male fertility check in which 10 male broiler breeders with
characteristics of infertility from were taken for necropsy examination from a normal
fertility house of 62 week-old broiler breeders, a bird with an abnormal testicle was
discovered.
Case 2. A male broiler breeder with abnormal testicles was found in a 28 week-
old broiler breeder flock that was experiencing increased mortality. The rooster was

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among the birds found dead on the morning the flock was visited. It was the only male
with testicular lesions among 7 dead males that were examined.
RESULTS
Necropsy and gross pathology. Birds that were either culled in Case 1 or found
dead in Case 2 were examined for gross lesions. Upon necropsy of the 10 affected birds
in Case 1, 8 (80%) had no gross lesions, 1 (10%) had small testicles, and 1 (10%) had
unilateral orchitis. The affected testis was irregularly shaped, edematous, swollen,
yellowish in color, have fibrin on the surface, and displayed prominent vessels (Figure 1).
No other gross lesions were noted in the bird. In Case 2, 7 birds were necropsied: 3
(43%) had hip degeneration, 3 (43%) had a blocked larynx (choke), and 1 (14%) had
bilateral orchitis. The affected testes were irregular, edematous, swollen with extended
depressed areas, prominent vessels and multiple petechiae were present on the tunica
albuginea (Figure 2). On cut section, they exhibited characteristic deep dark depressed
multifocal areas. The bird was thin, dehydrated, and lacked normal body fat stores. The
cloaca was distended, and skin between the cloaca and ventral abdomen was ulcerated.
Internally, inflammatory lesions were not identified in any tissues other than the testicles.
Bacteriology. Swabs were aseptically used to obtain samples for aerobic
bacteriology from affected testicles in both cases. Heavy growth of S. aureus was
recovered in Case 1. Escherichia coli was identified from both the testes and epididymis
in Case 2.

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Histopathology. Microscopic examination of the affected testis in Case 1
revealed intratubular-interstitial orchitis. A multicentric distribution of necrotic foci was
observed (Figure 3), with approximately 30% of the seminiferous tubules lumina filled
with fibrin, degenerated spermatozoa, heterophils, epithelial debris, macrophages, and
bacterial colonies. The least affected tubules displayed a pink eosinophilic stain material,
consistent with fibrin. Fibrin, immature granulation tissue and collagenous connective
tissue infiltrated by heterophils, lymphocytes, plasma cells, macrophages and
multinucleated giant cells were present in the interstitial tissue between necrotic foci
(Figure 4). A positive blue-staining reaction of intralesional colonies resembling grape-
like clusters were apparent when sections were stained with Gram stain (Figure 5). The
epididymis was not available for histopathology.
Microscopic examination of the affected testes and epididymis in Case 2 revealed
intratubular-interstitial epididymo-orchitis in which a multicentric coalescing distribution
of lesions resulted in inflammation and necrosis of approximately 80% of the
seminiferous tubules (Figure 6). Lumina of affected tubules were filled with fibrin,
degenerated spermatozoa, heterophils, epithelial debris, macrophages, and colonies of
rod-shaped bacteria. Fibrin, immature granulation tissue, and collagenous connective
tissue infiltrated by heterophils, lymphocytes, plasma cells, and macrophages were
present in the interstitial tissue between necrotic foci. No multinucleated giant cells were
observed. The epididymis also displayed multicentric necrotic foci (Figure 7) filled with
fibrin, degenerated spermatozoa, heterophils, epithelial debris, macrophages, and
colonies of rod-shaped bacteria (Figure 8).

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DISCUSSION
Infertility in male broiler breeders is a serious concern in the poultry industry due
to severe economic losses associated with decreased fertility and productivity. Orchitis,
epididymitis, and epididymo-orchitis are among the leading causes of infertility. Many
cases begin as epididymitis, and progress to epididymo-orchitis (14). The milder forms
will at minimum cause aspermatogenesis, whereas the most severe can potentially
increase mortality due to fatal septicemia. (14)
Both in animals and humans, epididymitis and epididymo-orchitis occur more
commonly than only orchitis (8, 9). Epididymo-orchitis is generally observed as a
unilateral disease (1, 7); however a bilateral case of epididymo-orchitis is presented in
this study. Infectious O/E/EpO can result from two possible routes: hematogenous or
ascending. Orchitis without involvement of the epididymis most often arises by
hematogenous infection (1, 8, 9), whereas epididymitis and epididymo-orchitis, in which
organisms travel along and invade the different components of the genital tract, are most
commonly considered ascending infections (1, 8, 14, 15).
We believe that both cases described in this study occurred via the ascending
route. Despite the lack of epididymis in Case 1, the unilateral nature of the disease makes
the hematogenous route unlikely. Availability of the epididymis and evidence of
epididymo-orchitis would have been helpful to corroborate an ascending infection.
In Case 2, ulceration of the abdominal skin and a distention of the cloaca were
observed during necropsy, suggesting an underlying condition affecting the cloaca that
could have predisposed microorganisms to colonize and ascend the ductus deferens.

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Involvement of the epididymis in the same process as the testicle also supports the
likelihood that the orchitis resulted from coliforms located in the cloaca.
Infectious orchitis and epididymo-orchitis are poorly described diseases in poultry
literature, with only a few references available (5, 11, 12, 13). These publications
reported E. coli and Salmonella spp. as the causative agents of the disease. We could not
locate references to S. aureus, as a cause of orchitis in poultry. Pyogranulomatous orchitis
due to E. coli has been described previously (5), but not as a bilateral epididymo-orchitis.
Both microorganisms are commonly found in poultry environments, and have pathogenic
capacity (2, 3). This study shows that common environmental organisms can cause
O/E/EpO in male broiler breeders via the ascending route.
Prevalence of O/P/EpO in the studied males seemed to be low; 10% in Case 1 and
14% in Case 2. However, further studies should be conducted in order to understand the
occurrence of O/E/EpO and its role in reproductive performance.
In summary, a case of infectious orchitis and a case epididymo-orchitis, both of
which most likely occurred via an ascending route of infection, are presented in this
paper. A novel isolation of Staphylococcus aureus as a testicular pathogen in poultry,
and an ascending bilateral epididymo-orchitis due to E. coli were identified. Despite low
prevalence of disease, sufficient evidence has been presented to recommend considering
infectious O/E/EpO in the differential diagnoses of male broiler breeder fertility problem.
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ACKNOWLEDGMENTS
The authors would like to thank Dr. Michael Martin for his involvement in this work, and
Miss C. Germain for her editorial assistance.

11. Figure legends.
Figure 1. Case 1, 62-wk broiler breeder, orchitis. Testicle is irregularly shaped,
edematous, swollen, yellowish color with prominent vessels and fibrin on the surface.
The opposite testicle was normal. .
Figure 2. Case 2, 28-wk broiler breeder, epididymo-orchitis. Irregular, edematous,
swollen testes with extended depressed areas, prominent vessels, and multiple petechiae
on the tunica albuginea.
Figure 3. Case 1, 62-wk broiler breeder, orchitis. Intratubular-interstitial orchitis.
Multicentric necrotic foci. H&E. Bar = 0.5 mm.
Figure 4. Case 1, 62-wk broiler breeder, orchitis. Seminiferous tubules filled with fibrin,
degenerated spermatozoa, heterophils, epithelial debris, macrophages, and colonies of
bacteria. H&E. Bar = 100 µm.
Figure 5. Case 1, 62-wk broiler breeder, orchitis. Positive blue staining reaction of
intralesional bacterial colonies. Gram. Bar = 25 µm.
Figure 6. Case 2, 28-wk broiler breeder. Intratubular-interstitial orchitis. Multicentric
coalescing necrotic foci. H&E. Bar = 0.5 mm
Figure 7. Case 2, 28-wk broiler breeder. Epididymitis. Multicentric necrotic foci. H&E.
Bar = 0.5 mm
Figure 8. Case 2, 28-wk broiler breeder. Epididymitis. Foci filled with fibrin, degenerated
spermatozoa, heterophils, epithelial debris, macrophages, and colonies of rod-shaped
bacteria. H&E. Bar = 25 µm.