ISSN 2398-2977      

Aspergillosis

pequis

Introduction

  • Cause: infection with Aspergillus spp.
  • Sinonasal (more common), guttural pouch or pulmonary (rare: related to immunosuppression?).
  • Sinonasal form either invasive (protracted treatment) or non-invasive (often unnoticed).
  • Signs: malodorous purulent/mucopurulent unilateral nasal discharge; signs consistent with lower respiratory tract disease; epistaxis, nasal discharge and various neurologic signs.
  • Diagnosis: radiology, ultrasonography, mycology, endoscopy.
  • Treatment: surgery, topical or systemic fungicidal treatment.
  • Prognosis: sinonasal form may require treatment for months; pulmonary form has hopeless prognosis; guttural pouch form has a guarded prognosis and life-threatening hemorrhage is common.

Pathogenesis

Etiology

  • Aspergillus spp Aspergillus spp.
  • Aspergillus spp are common in the equine environment, especially in moldy feed and bedding.
  • Aspergillus spp are opportunistic pathogens and often cause disease in horses that are immunosuppressed from debilitating disease or that have been treated with immunosuppressive drugs.

Predisposing factors

General

  • Pulmonary form: immunosuppression, eg
    • Treatment of a pre-existing condition with either antibiotics or corticosteroids.
    • Concurrent presence of debilitating disease, eg neoplasia or pituitary pars intermedia dysfunction (PPID).

Specific

  • Exposure to massive numbers of spores from moldy feeds and bedding.
  • Sino-nasal form: secondary to nasal trauma or to intra nasal/sinus surgery, eg excision of ethmoid hematoma Ethmoid: hematoma, sinus cysts Paranasal sinus: cyst.
  • Pulmonary form: opportunistic infection by fungi associated with translocation of organisms across an inflamed gastrointestinal tract, ie enterocolitis, eg following infection with Salmonella Intestine: salmonellosis or inhalation of an overwhelming number of spores resulting in fungal proliferation and invasion of the small airways.
  • Guttural pouch form: an underlying lesion of the arterial wall such as an aneurysmal dilatation has been suggested as a predisposing factor.

Pathophysiology

Sinonasal form
  • Etiology of fungal rhinitis is not known.
  • Predisposing factors could be immunosuppression or disruption of the mucosal layer owing to trauma, inflammation or infection which potentially could allow fungal invasion.
Pulmonary form
  • Acute Aspergillus bronchopneumonia due to fungal invasion and proliferation in small airways.
  • Angioinvasive pulmonary aspergillosis due to fungal infiltration of large blood vessels.

Either Pulmonary form: inhalation of massive number of spores.
Or Acute enterocolitis → mycotic invasion from gut → embolic mycotic pulmonary aspergillosis (often find multiple organ involvement, eg kidney and brain).

Guttural pouch form
  • Inhaled aspergillus spores → colonize wall of arterial vessel in the guttural pouch.
  • Growth of mycotic plaque and erosion of arterial wall → spontaneous hemorrhage → epistaxis or catastrophic hemorrhage → death.
  • More rarely, mycotic plaque impinges major nerve, eg vagus (sympathetic trunk), glossopharyngeal, hypoglossal, facial nerve → Horner's syndrome, pharyngeal paralysis and facial paralysis.

Timecourse

  • Pulmonary form may be asymptomatic with sudden death.
  • Invasive nasal form may persist, cause sequestration of nasal bones/cartilage and require treatment for several months.
  • Guttural pouch may be asymptomatic with sudden fatal hemorrhage.

Diagnosis

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Arnauld des Lions J, Guillot J, Legrand E, Bisseaud O & Jensens H E (2000) Aspergillosis involving the frontal sinus in a horse. Equine Vet J 12 (5), 248-250 VetMedResource.
  • Guillot J et al (1999) Comparative study of serological tests for the diagnosis of equine aspergillosis. Vet Rec 145 (12), 348-349 PubMed.
  • Johnson P J, Moore L A, Mrad D R, Turk J R & Wilson D A (1999) Sudden death of two horses associated with pulmonary aspergillosis. Vet Rec 145 (1), 16-20 PubMed.
  • Tremaine W H, Clarke C J & Dixon P M (1999) Histopathological findings in equine sinonasal disorders. Equine Vet J 31 (4), 296-303 PubMed.
  • Blomme E, Del Piero F, La Perle K M D & Wilkins P A (1998) Aspergillosis in horses: a review. Equine Vet Educ 10 (2), 86-93 VetMedResource.
  • McGorum B C, Dixon P M & Lawson G H M (1997) A review of 10 cases of mycotic rhinitis. Equine Vet Educ 4 (1), 8-12 WileyOnline.

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!

 
 
 
 

To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code