Streptococcus spp

S suis^c

S equisimilis

S dysgalactiae

S zooepidemicus

Suckling: 3

W-F:^b 3, 4

Adult: 2

S suis is a common primary cause of joint infections, serositis, meningitis, sepsis, and pneumonia, with considerable strain variation in virulence. Other streptococci are usually opportunistic and less impactful at the herd level. All are often endemic within herd subpopulations. Diagnosis is by culture and histological examination of affected tissues. S zooepidemicus can be sporadic, with severe mortality.

Glaesserella parasuis^c

Suckling: 2

W-F: 3, 4

Adult: 2

Acute sepsis, polyserositis, meningitis, arthritis. Variation in virulence and immunogenicity. Severe outbreaks in naive pigs. Diagnosis is by culture or PCR assay of joint fluid or fibrin, with histological examination.

Mycoplasma hyorhinis^c

Suckling: 1, 2

W-F: 3, 4

Adult: 1

Usually endemic, often silent. Change in herd immunity and risk factors results in polyserositis and joint disease. Common in pigs 3–8 weeks old. Diagnosis is by PCR assay or culture of joint fluids or fibrin, with histological examination.

Actinobacillus spp

A suis^c

Suckling: 1, 2

W-F: 2, 3, 4

Adult: 1, 2

Common in swine but usually silent. Risk factors exacerbate disease expression. Occurs as sepsis, pneumonia, serositis, arthritis. Diagnosis is by culture or PCR assay of fibrin or joint fluid, with histological examination.

Mycoplasma hyosynoviae^c

Suckling: 1

W-F: 3, 4

Adult: 2

Usually endemic. Long associated with hind limb arthritis at 10–26 weeks. Production practices and noninfectious risk factors alter expression. Diagnosis is by culture or PCR assay of joint fluid, with histological examination.

Erysipelothrix rhusiopathiae^c

Suckling: 1

W-F: 1, 4

Adult: 1, 4

Sepsis, arthritis, endocarditis. Outbreaks from improper vaccination of sows and growing pigs, contaminated environment, biosecurity. Diamond skin disease. Diagnosis is by culture or PCR assay of joint, spleen, skin.

Trueperella pyogenes

Suckling: 3

W-F: 3

Adult: 2

Ubiquitous opportunist. Pyogenic (abscesses) common. Colonizes localized tissue damage from many insult types. Control focuses on primary insults and risk factors. Diagnosis is by gross lesions and culture.

Staphylococcus spp

S hyicus

Suckling: 4

W-F: 4

Adult: 1

Endemic opportunist. S hyicus causes exudative epidermitis (greasy pig disease) with sepsis and joint infection. Diagnosis is by culture and histological examination of skin lesions, synovium, joint fluid, lesions.

Escherichia coli

Suckling: 3

W-F: 0

Adult: 0

Not typical colibacillosis strains. Opportunist in neonates. Risk higher in gilt litters, inadequate maternal immunity, poor hygiene. Diagnosis is by culture of joint fluid, with histological examination.

Miscellaneous other bacterial species

Suckling: 3

W-F: 1

Adult: 1

Many bacteria isolated from joints or sepsis. Can be late-stage contaminants or sporadic (eg, Klebsiella, Salmonella). Diagnosis is by culture, histological examination, and ruling out other risk factors.