Difference between revisions of "Aspergillosis"

Revision as of 17:00, 18 August 2010

Description

Apergillosis is a disease of the respiratory system caused by several Aspergillus spp.. Aspergillus fumigatus is the most frequently reported species in domestic animals but Aspergillus tereus has also been implicated. The pathogen is a ubiquitous saprophyte and is found worldwide. Commonly affected species include birds, dogs, cats, horses and cattle but the disease has been reported in many other wild and domestic species. The pathogenesis of the disease remains largely unknown but is thought to be related to the formation of haemorrhagic lesions and enzymatic breakdown of tissue by elastase.

Clinical signs and features

Birds

In avian species the disease manifests as a diffuse infection of the air sacs. Two forms of the disease have been reported; a diffuse pneumonic form and a nodular form involving the lungs. Clinical signs include dyspnoea, diarrhoes, listlessness, pyrexia, loss of appetite and loss of condition. Seizures and torticollis may occasionally occur if infection disseminates to the brain.

Aspergillus in a swan
^{Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath}

Cattle

Aspergillosis has a number of clinical manifestations in the cow including mastitis, placentitis, ocular infections and mycotic pneumonia. Abortion in the second or third trimester of pregnancy has also been described. Cases of diarrhoea in calves have also been reported. Clinical signs include Lesions are usually up to 2mm in diameter and contain asteroid bodies with a germinated spore in the centre. Acute infection causes miliary lesions and chronic infections causes granulomatous and calcified lesions.

Horses

In the horse, Aspergillus most commonly affects the guttural pouches but infection may also lead to abortion, keratomycosis and rarely pulmonary aspergillosis. Guttural pouch mycosis is characterised by epistaxis as a result of fungal erosion of the internal carotid artery. Other clinical signs include nasal discharge and dysphagia. Mycotic plaques are usually located on the caudodorsal aspect of the medial guttural pouch.

Dogs

Aspergillosis is a common cause of nasal disease in dogs. Cases occur most commonly in young to middle aged male dogs, but animals of all age and of both sexes may be affected. Doliocephalic breeds are thought to be overrepresented. Clinical signs are those seens with any chronic nasal disease and include sneezing, unilateral or bilateral serosanguinous nasal discharge, ulceration of the nares, nasal pain and epistaxis. The disease is usually localised to the paranasal sinuses and nasal cavity but a disseminated form with granulomas and infarcts has been reported in dogs, particularly German Shephards. The disease often involves multiple organ systems including the spleen and kidneys. Clinical signs include lethargy, anorexia, haematuria, urinary incontinence and haematuria. The vertebrae are frequently affected and osteomyelitis and discospondlylitis are common features.

Aspergillus in vivo
^{Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath}

Diagnosis

In dogs, radiology is often peformed in the diagnostic work up of an animal with suspected Aspergillosis. Open-mouth ventro-dorsal views often reveal generalised radiolucency and lysis of the turbinate bones. Rhinoscopy may be used to directly visualise the lesions, revealing characteristic white-green fungal plaques. Fungal culture can be used to demonstrate the organism but should not be used as the sole means of diagnosis due to the possibility of false . Aspergillus grows on Sabauraud's Dextrose and Blood agar. White colonies form intitially which turn green, then dark green, flat and velvety

Microscopically:
- Conidiophores with large terminal vesicles (only visible in the lungs and air sacs where there is access to oxygen)
  - Vesicle shape varies depending on the species
- Is a common contaminant so repeated tests should be done for a definitive diagnosis

Pathology:
- Aspergillus fumigatus causes rhinitis, respiratory tract inflammation and sinusitis
- Sometimes appears on lesions of ethmoidal haematoma

Treatment

In dogs, the treatment of choice is topical application of the anti-fungal agent Clotrimazole. It is admnistered via indwelling catheters placed through a trephine hole in the frontal sinus.

References

Carter, G. R., Wise, D. J. (2004) Essentials of Veterinary Bacteriology and Mycology Wiley-Blackwell

Aspergillus sporing heads
^{Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath}
Aspergillus mycelium stained with blue/black Quink
^{Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath}
Mycotic Abortion caused by Aspergillus
^{Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath}
Mycotic Abortion caused by Aspergillus
^{Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath}
Mycotic Abortion caused by Aspergillus
^{Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath}
Nasal Aspergillus
^{Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath}

Aspergillus fumigatus

Aspergillus hyphae in cattle lung
^{(Image sourced from Bristol Biomed Image Archive with permission)}
Nasal aspergillosis
^{(Image sourced from Bristol Biomed Image Archive with permission)}

Test yourself with the Systemic Mycoses Flashcards

Aspergillosis Flashcards

@@ Line 1: / Line 1: @@
-{{OpenPagesTop}}
+{{unfinished}}
-Also known as: '''''Brooder Pneumonia in young birds'''''
-== Introduction ==
+==Description==
-Apergillosis is a disease of the respiratory system caused by several ''[[Aspergillus spp.]]''. ''Aspergillus fumigatus'' is the most frequently encountered species in domestic animals but ''Aspergillus tereus'' and ''Aspergillus flavus'' have also been reported. ''Aspergillus'' is a ubiquitous saprophyte and is found worldwide. It is also a component of normal hair, skin and mucosal flora in both humans and animals. Commonly affected species include birds, dogs, cats, horses and cattle but the disease has been reported in many other wild and domestic species.
-== Pathogenesis ==
+Apergillosis is a disease of the respiratory system caused by several ''[[Aspergillus spp.]]''. ''Aspergillus fumigatus'' is the most frequently reported species in domestic animals but ''[[Aspergillus tereus]]'' has also been implicated. The pathogen is a ubiquitous saprophyte and is found worldwide. Commonly affected species include birds, dogs, cats, horses and cattle but the disease has been reported in many other wild and domestic species. The pathogenesis of the disease remains largely unknown but is thought to be related to the formation of haemorrhagic lesions and enzymatic breakdown of tissue by elastase.
-In '''dogs''', spores are inhaled from the environment leading to fungal colonisation of the nasal cavities. Following their deposition in tissue and recognition by phagocytes, an inflammatory response is triggered. Haemolytic and dermonecrotic toxins as well as fungal protease and elastase are released leading to tissue damage.
-In '''horses''', the pathogenesis of [[Guttural Pouch Mycosis|'''guttural pouch mycosis''']] is largely unknown but is thought to relate to damage to the mucosal layer of the pouches by trauma or infection. This enables opportunistic ''Aspergillus'' fungi to invade and colonise the damaged tissue.
+==Clinical signs and features==
+===Birds===
+In avian species the disease manifests as a diffuse infection of the air sacs. Two forms of the disease have been reported; a diffuse pneumonic form and a nodular form involving the lungs. Clinical signs include dyspnoea, diarrhoes, listlessness, pyrexia, loss of appetite and loss of condition. Seizures and torticollis may occasionally occur if infection disseminates to the brain.
-== Clinical Signs ==
+{| align="right"
-=== Dogs ===
+|<gallery>Image:Aspergillus swan.jpg|<center><p>'''Aspergillus in a swan'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center></gallery>
-Aspergillosis is a common cause of nasal disease in dogs. Cases occur most commonly in young to middle-aged male dogs, but there is no apparent age or sex predilection. A higher prevalence of disease has been reported in '''doliocephalic breeds''' and '''outdoor/farm dogs'''. Clinical signs are those seen with any chronic nasal disease and include sneezing, unilateral or bilateral serosanguinous nasal discharge, ulceration of the nares, nasal pain and epistaxis. Neurological signs may be displayed if there is involvement of the cribriform plate.
+|}
-The disease is usually localised to the paranasal sinuses and nasal cavity but a disseminated form with granulomas and infarcts has been reported, particularly in German Shepherds. This form of disease often involves multiple organ systems including the spleen and kidneys. Clinical signs include lethargy, anorexia, urinary incontinence and haematuria. The vertebrae are frequently affected and osteomyelitis and discospondlylitis are common features. Dermatological signs of disseminated aspergillosis include abscesses, draining tracts, oral ulcers and cutaneous nodules.
+===Cattle===
+Aspergillosis has a number of clinical manifestations in the cow including mastitis, placentitis, ocular infections and mycotic pneumonia. Abortion in the second or third trimester of pregnancy has also been described. Cases of diarrhoea in calves have also been reported.
+Clinical signs include
+Lesions are usually up to 2mm in diameter and contain asteroid bodies with a germinated spore in the centre. Acute infection causes miliary lesions and chronic infections causes granulomatous and calcified lesions.
-=== Horses ===
+===Horses===
-In the horse, ''Aspergillus'' most commonly affects the guttural pouches but infection may also lead to abortion, keratomycosis and rarely pulmonary aspergillosis. There is no age, sex or breed predisposition for guttural pouch mycosis and both left and right pouches are affected with equal frequency. Guttural pouch mycosis is characterised by spontaneous epistaxis (often in a resting horse) as a result of fungal erosion of the internal carotid artery. Other clinical signs include nasal discharge and dysphagia. Mycotic plaques are usually located on the caudodorsal aspect of the medial guttural pouch.
+In the horse, Aspergillus most commonly affects the guttural pouches but infection may also lead to abortion, keratomycosis and rarely pulmonary aspergillosis. Guttural pouch mycosis is characterised by epistaxis as a result of fungal erosion of the internal carotid artery. Other clinical signs include nasal discharge and dysphagia. Mycotic plaques are usually located on the caudodorsal aspect of the medial guttural pouch.
-=== Cattle ===
-Aspergillosis has a number of clinical manifestations in the cow including mastitis, placentitis, diarrhoea, ocular infection and mycotic pneumonia. Abortion in the second or third trimester of pregnancy has also been described. In the case of pulmonic disease, clinical signs may include pyrexia, cough, dyspnoea and tachypnoea but may be limited to vague signs such as weight loss or signs of mild respiratory disease. In aborting cattle, the foetus and placenta are retained and foetal lesions such as bronchopneumonia and dermatitis may be seen. Mastitic cows may display depression, weight loss and pyrexia with purulent mammary secretions and a hot, swollen udder.
-=== Birds ===
-Three forms of the disease have been reported in avian species; a diffuse infection of the air sacs; a diffuse pneumonic form and a nodular form involving the lungs. In chicks and poults the disease is known as ''''brooder pneumonia'''' and may affect many birds in a flock. It is a very common disease, especially in pet birds due to the poor environments in which the birds are kept, combined with the anatomy of their respiratory system. Animals become infected due to inhalation of spores from contaminated feed or litter. These spores remain lodged in the respiratory system without causing clinical disease until the bird is stressed. Disease normally occurs in the syrinx or the air sacs. Clinical signs include dyspnoea, diarrhoea, listlessness, pyrexia, loss of appetite and loss of condition. Seizures and torticollis may occasionally occur if infection disseminates to the brain. Eggs may also be infected, with the fungal infection growing in the air cell of the membrane within the egg. Embryos may die before hatching or be weak and dyspnoeic after hatching. Occasionally, nervous system problems or diarrhoea are found in birds that survive to hatch.
-== Diagnosis ==
+===Dogs===
-=== Dogs ===
+Aspergillosis is a common cause of nasal disease in dogs. Cases occur most commonly in young to middle aged male dogs, but animals of all age and of both sexes may be affected. Doliocephalic breeds are thought to be overrepresented.  Clinical signs are those seens with any chronic nasal disease and include sneezing, unilateral or bilateral serosanguinous nasal discharge, ulceration of the nares, nasal pain and epistaxis.
-'''Radiology''' is often performed in the diagnostic work up of an animal with suspected Aspergillosis. It should always be performed prior to other procedures such as rhinoscopy and biopsy in order to prevent haemorrhage that may obscure subtle radiographic findings. Open-mouth ventro-dorsal views often reveal generalised radiolucency and lysis of the turbinate bones. Additionally, '''cytological examination of aspirates''' often reveals presence of fungal hyphae with granulomatous to suppurative inflammation and necrosis. '''Rhinoscopy''' may also be used to directly visualise the lesions, revealing characteristic white-green fungal plaques and destruction of the nasal turbinates. It also allows collection of material for '''fungal culture'''. This may be achieved using Sabouraud's dextrose agar in order to demonstrate the organism but should not be used as the sole means of diagnosis due to the ubiquitous nature of ''Aspergillus'' in the environment. White colonies form initially which turn dark green, flat and velvet-like in appearance. '''Serological''' findings such as immunoelectophoresis, [[ELISA testing|ELISA]] and agar gel [[Immunodiffusion|diffusion]] may provide additional diagnostic information.
+The disease is usually localised to the paranasal sinuses and nasal cavity but a disseminated form with granulomas and infarcts has been reported in dogs, particularly German Shephards. The disease often involves multiple organ systems including the spleen and kidneys. Clinical signs include lethargy, anorexia, haematuria, urinary incontinence and haematuria. The vertebrae are frequently affected and osteomyelitis and discospondlylitis are common features.
-=== Horses ===
+{| align="right"
-Diagnosis is obtained following '''endoscopic examination''' of the guttural pouches and observation of white-yellow-black mycotic plaques on the mucosal surface of the guttural pouches. Care must be taken whilst performing endoscopy due to the risk of dislodgement of a thrombus on the affected artery.
+|<gallery>Image:Aspergillus in vivo.jpg|<center><p>'''Aspergillus in vivo'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center></gallery>
+|}
-=== Birds ===
+==Diagnosis==
-'''Endoscopy''' allows visualisation of the fungus and is the fastest and simplest way to obtain a tentative diagnosis. '''Culture''' of the lesions is required for definitive diagnosis. Post-mortem findings include bronchial or tracheal plugs, air cell plaques or small yellow nodules in the lungs. When ''Aspergillus'' infection is suspected in the embryo positive culture of lesions on the air cell membrane, lungs, air sacs or air passages is required for definitive diagnosis.
+In dogs, radiology is often peformed in the diagnostic work up of an animal with suspected Aspergillosis. Open-mouth ventro-dorsal views often reveal generalised radiolucency and lysis of the turbinate bones. Rhinoscopy may be used to directly visualise the lesions, revealing characteristic white-green fungal plaques. Fungal culture can be used to demonstrate the organism but should not be used as the sole means of diagnosis due to the possibility of false . Aspergillus grows on Sabauraud's Dextrose and Blood agar. White colonies form intitially which turn green, then dark green, flat and velvety
-== Treatment ==
-=== Dogs ===
-Several different treatment options are available.
-Ketoconazole can be administered '''orally''' for 6-8 weeks. Itraconazole has also been used. This can be effective in up to 50% of cases.
+*Microscopically:
+**Conidiophores with large terminal vesicles (only visible in the [[Lungs - Anatomy & Physiology|lungs]] and air sacs where there is access to oxygen)
+***Vesicle shape varies depending on the species
+**Is a common contaminant so repeated tests should be done for a definitive diagnosis
-Another non-invasive option includes '''infusion''' of enilconazole or clotrimazole into the '''external nares''' whilst occluding the nasopharynx. The animal is first placed in dorsal recumbency, then switched to ventral recumbency and any fluid is allowed to drain from the nose. This technique may not be effective and may lead to aspiration pneumonia or oesophagitis from leakage of the agent.
-The treatment of choice is topical application of the anti-fungal agent Clotrimazole. It is administered for one hour under general anaesthetic via indwelling '''catheters placed in the frontal sinus'''. Several treatments may be required. For cases that are non-responsive to Clotrimazole, treatment with Enilconazole may be attempted but this is associated with a higher complication rate.
-=== Horses ===
+*Pathology:
-Trans-arterial coil embolisation under fluoroscopic guidance is performed in order to cause internal occlusion of the affected arteries. Following arterial occlusion the mycotic plaques usually resolve without necessitating further treatment.
+**''Aspergillus fumigatus'' causes [[Nasal Cavity Inflammatory - Pathology#Infectious causes of rhinitis|rhinitis]], [[Respiratory Fungal Infections - Pathology#|respiratory tract inflammation]] and [[Paranasal Sinuses Inflammatory - Pathology#Infectious causes of sinusitis|sinusitis]]
+**Sometimes appears on [[Nasal Cavity Hyperplastic and Neoplastic - Pathology#Progressive ethmoidal haematoma|lesions of ethmoidal haematoma]]
-=== Cattle ===
-Antifungal agents are currently unlicensed and management of the disease usually relies on preventative measures such as ensuring clean bedding and good husbandry.
-=== Birds ===
+==Treatment==
-Birds should be treated with both anti-fungal drugs and F10 disinfectant, delivered via nebulisation. This treatment should continue for a minimum of 6 weeks up to a period of 6 months, therefore cost considerations may need to be discussed with the owners. Following the cessation of treatment, repeat endoscopy should be performed to ensure the disease has resolved. Aspergillosis of the syrinx may present as an emergency due to obstruction of the airway. This requires surgical removal of the fungal growths. An air sac tube may be placed to stabilise the bird prior to the planned surgery, and endoscopy should be performed on the lungs and air sacs to assess the spread of the fungus and provide a prognosis (poor with further spread) before surgery is performed. A low dust level, high quality feed and frequent F10 fogging can help to prevent the disease. There is currently no recommended treatment for eggs infected with aspergillosis, therefore efforts should be concentrated on prevention. This is especially important in air-forced incubators, where aspergillosis can be a serious problem. Incubators and hatchers should be cleaned and fumigated between batches of eggs, and an 'all in, all out' system should be in operation. UV sterilization of eggs prior to incubation and sanitizing dips or washes may be used to reduce the chances of infection. Eggs should be examined for cracks and weighed at regular intervals, and dead eggs should be removed immediately as infection of viable eggs by dead ''Aspergillus''-infected eggs can occur. Also, eggs from damp or wet nests should not be incubated.
+In dogs, the treatment of choice is topical application of the anti-fungal agent Clotrimazole. It is admnistered via indwelling catheters placed through a trephine hole in the frontal sinus.
-{{Learning
+==References==
-|flashcards = [[Systemic Mycoses - Flashcards#Aspergillosis|Aspergillosis Flashcards]]
-[[Cytology Q&A 12]]
-[[Small Animal Soft Tissue Surgery Q&A 11]]
-|literature search = [http://www.cabdirect.org/search.html?q=title:(Aspergillosis)+AND+od:(cats) Aspergillosis in cats publications]<br>[http://www.cabdirect.org/search.html?q=title:(Aspergillosis)+AND+od:(horses) Aspergillosis in horses publications]<br>[http://www.cabdirect.org/search.html?q=title:(Aspergillosis)+AND+od:(cattle) Aspergillosis in cattle publications]<br>[http://www.cabdirect.org/search.html?q=title:(Aspergillosis)+AND+od:(birds) Aspergillosis in birds publications]<br>[http://www.cabdirect.org/search.html?q=title:(Aspergillosis)+AND+od:(sheep) Aspergillosis in sheep publications]<br>[http://www.cabdirect.org/search.html?q=title:(Aspergillosis)+AND+od:(goats) Aspergillosis in goats publications]<br>[http://www.cabdirect.org/search.html?q=title:(Aspergillosis)+AND+od:(pigs) Aspergillosis in pigs publications]<br><br><br>
-|full text = [http://www.cabi.org/cabdirect/FullTextPDF/2007/20073017469.pdf '''Aspergillosis: a sapromycotic zoonosis.''' Mahendra Pal; Pratibha Dave; Intas Pharmaceuticals Ltd, Ahmedabad, India, Intas Polivet, 2006, 7, 2, pp 421-428, 44 ref.]
-|Vetstream = [https://www.vetstream.com/felis/Content/Disease/dis02452 Aspergillosis - Felis]
-}}
+* Carter, G. R., Wise, D. J. (2004) '''Essentials of Veterinary Bacteriology and Mycology''' ''Wiley-Blackwell''
 <gallery>
@@ Line 72: / Line 61: @@
 Image:Mycotic abortion asper 3.jpg|<center><p>'''Mycotic Abortion caused by Aspergillus'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center>
 Image:Nasal Aspergillus.jpg|<center><p>'''Nasal Aspergillus'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center>
-Image:Aspergillus in vivo.jpg|<center><p>'''''Aspergillus'' in vivo'''</p><sup>Copyright Professor Andrew Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center>
-Image:Aspergillus swan.jpg|<center><p>'''''Aspergillus'' in a swan'''</p><sup>Copyright Professor Andrew N. Rycroft, BSc, PHD, C. Biol.F.I.Biol., FRCPath</sup></center>
 </gallery>
-== References  ==
+===''Aspergillus fumigatus''===
-*Barr, S. C., Bowman, D. D. (2006) '''The 5-minute Veterinary Consult Clinical Companion: canine and feline infectious diseases and parasitology''' ''Wiley-Blackwell''
-*Brown, SA & Rosenthal KL (1997) '''Self-Assessment Colour Review Small Mammals''' ''Manson Publishing Ltd''
+<gallery>
-*Carter, G. R., Wise, D. J. (2004) '''Essentials of Veterinary Bacteriology and Mycology''' ''Wiley-Blackwell''
-*Ettinger, S. J. (2000) '''Pocket Companion to Textbook of Veterinary Internal Medicine''' ''Elsevier Health Sciences''
+Image:Aspergillus pneumonia of cattle.jpg|<center><p>'''Aspergillus hyphae in cattle lung'''</p><sup> (Image sourced from Bristol Biomed Image Archive with permission)
-*Muller, G. H., Scott, D. W., Kirk, R. W., Miller, W. H., Griffin, C. E. (2001) '''Muller and Kirk's Small Animal Dermatology''' ''Elsevier Health Sciences''
+Image:Aspergillosis in nasal cavity.jpg|<center><p>'''Nasal aspergillosis'''</p><sup> (Image sourced from Bristol Biomed Image Archive with permission)
-*Stanford, M (2009) '''Respiratory Disease in Birds''' RVC Intergrated BVetMed Course, ''Royal Veterinary College''
+</gallery>
+==Test yourself with the Systemic Mycoses Flashcards==
-{{review}}
+[[Systemic_Mycoses_-_WikiBugs#Aspergillosis|Aspergillosis Flashcards]]
-{{OpenPages}}
-[[Category:Respiratory_Fungal_Infections]] [[Category:Respiratory_Diseases_-_Dog]] [[Category:Respiratory_Diseases_-_Birds]] [[Category:Expert_Review]][[Category:Respiratory_Diseases_-_Cattle]] [[Category:Respiratory_Diseases_-_Horse]]
+[[Category:To_Do_-_SophieIgnarski]]
-[[Category:Expert Review]]
+[[Category:Respiratory Fungal Infections]]