Mycoplasma hyorhinis

Mycoplasma hyorhinis
Phylum	Firmicutes
Class	Mollicutes
Order	Mycoplasmatales
Family	Mycoplasmataceae
Genus	Mycoplasma

Also Known As: Mycoplasma arthritis — Mycoplasma septicaemia — Mycoplasmal polyserositis

Introduction

Mycoplasma hyorhinis is a common bacterial commensal of pig’s respiratory tracts and an occasional cause of polyarthritis and polyserositis in young pigs.

M. hyorhinis is commonly associated with other pathogens, exacerbating and facilitating disease, especially Mycoplasma hyopneumoniae, the principal cause of Enzootic Pneumonia - Pigs, Actinobacillus pleuropneumoniae and Arcanobacterium pyogenes.

M. hyorhinis is also implicated in many severe cases of Porcine Reproductive and Respiratory Syndrome.

Pathogenesis

Clinical Disease is most common in young pigs under 10 weeks old.

Antigens persist in the tissues, especially the joints, long after infection has resolved, stimulating auto-immune mechanisms which further damage the joints, causing damage which may be permanent.

Disease

The main presentation is as a chronic progressive polyserositis in pigs under 10 weeks old. Lameness and swollen joints are common and congenital arthrogryposis may be seen in young stock.

Fever usually accompanies clinical signs and animals often have a rough, dull, staring hair coat. Laboured breathing and tachycardia are non-specific cardiorespiratory signs.

Aural discharge with a foul odour represents otitis and may result in deafness. Otitis media may cause a head tilt and vestibular signs.

Dysphagia and vomiting/regurgitation are less common but significant. Other neurological and ocular signs may be also present .

Serofibrinous pleurisy, pericarditis and peritonitis are pathological features of M. hyorhinis.

Diagnosis

Joint fluid, synovial membranes and samples from the pleura, pericardium and peritoneum can be used for culture of M. hyorhinis.

Immunofluorescent Antibody Testing (IFAT) is also possible. Complement Fixation and Haemagglutination can be performed for serological diagnosis but are not widely available.

Antibodies can be detected in serum and synovial fluid, but not until 6 weeks post-infection.

Treatment

A variety of antibiotics are effective, including tetracycline, tiamulin, enrofloxacin, tylosin and lincomycin.

Mycoplasma hyorhinis Learning Resources
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References

Animal Health & Production Compendium, Mycoplasma hyorhinis datasheet, accessed 15/06/2011 @ http://www.cabi.org/ahpc/