Page 721 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

696 CHAPTER 3

VetBooks.ir Management progressing to a more acute form characterised
by skin ulceration and ulceration and abscess for-
Sporadic reports of successful resolution have
included long-term antimicrobial administration.
an insidious onset and slowly progressive respira-
Antimicrobial therapy should target the causative mation throughout the respiratory tract. There is
organism identified through culture and antimicro- tory disease with typical URT infection clinical
bial sensitivity testing. Empirical therapy should be signs (nasal discharge and lymphadenopathy), but
based on the suspected aetiological agent and known often with nasal mucosal ulceration. This mild
efficacy in the treatment of abscesses. Surgical drain- and chronic disease may continue for several
age of the abscess improves the response to antibi- months, but a more acute disease, possibly trig-
otic therapy but is difficult and generally limited to gered by stress or intercurrent illness, develops. In
those at the thoracic inlet. the acute form there is pyrexia, depression, cough-
ing, weight loss and clinical signs of pneumonia
Prognosis (tachypnoea and dyspnoea) due to abscessation
The prognosis is variable depending on the location and ulceration along the URT and in the lungs.
of the abscess within the mediastinum. Some horses Cutaneous ulcerative lesions (‘farcy’) also develop
may respond to long-term antimicrobial therapy, but along the limbs, especially the medial thigh and
the overall prognosis is guarded. hock, which discharge a yellow-brown pus con-
taining granules. There is often marked lymphatic
GLANDERS AND MELIOIDOSIS cording.

Definition/overview Differential diagnosis
Glanders (farcy) is regarded as one of the most Other causes of URT and LRT infectious disease
serious contagious diseases of Equidae. It is caused should be considered.
by infection with Burkbolderia mallei. The dis-
ease has been eradicated from many parts of the Diagnosis
world, but it is endemic in the Middle East, Africa, The initial clinical signs are non-specific and horses
India, Southeast Asia, China and Mongolia. It is may appear healthy during the chronic form of the
absent in the USA and the UK, where it is a noti- disease. The later, acute form, with LRT signs,
fiable disease. Most countries have strict import nasal ulceration and skin ulceration over the medial
regulations (testing and/or quarantine) to con- hindlimbs, is more characteristic. Post-mortem
trol the spread of B. mallei infection. Glanders examination reveals variable-sized abscesses con-
is a respiratory disease that also has skin (farcy) taining brown/yellow granular pus throughout the
manifestations, and it is a significant zoono- respiratory tract and in other organs, including the
sis in endemically infected countries. Disease in liver and spleen. Isolation of the organism confirms
horses is usually initially chronic, and affected the diagnosis.
horses almost always die from acute-onset pneu-
monia following a long debilitating illness. Management
Disease in donkeys and mules is usually acute, Glanders and melioidosis respond poorly to treat-
with rapid death from pneumonia. Melioidosis is ment and the prognosis is poor. An intradermal skin
a similar disease caused by the related bacterium test using bacterial antigen (the Mallein test) is used
B. pseudomallei and occurs in the Far East and to identify carriers or horses that have been exposed
northern Australia. to the organism and have antibody. The disease is
a zoonosis and infection-control precautions must
Clinical presentation be followed when handling tissues that might be
Glanders and melioidosis are generally chronic infected. Further information is available from vari-
diseases, with initial respiratory disease ous governmental sources.