Difference between revisions of "Encephalitozoon cuniculi"
Jump to navigation
Jump to search
(9 intermediate revisions by 4 users not shown) | |||
Line 1: | Line 1: | ||
− | {{ | + | {{unfinished}} |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | == | + | ==Taxonomy== |
− | + | *Phylum Microspora; no mitochondria polar tube polar cap | |
+ | *Class Microsporida | ||
+ | *Order Microsporidia | ||
+ | *May be more related to fungi than to protozoa (Wasson and Peper 2000) | ||
+ | *Obligate intracellular protozoan parasite | ||
+ | *52% normal healthy domestic pet rabbits arte infected (Keeble and Shaw 2006) | ||
+ | *Ubiquitous in other species too | ||
− | + | ==The life cycle== | |
+ | The life cycle of this coccidian is 3 – 4 weeks in total: | ||
+ | *Inhaled, ingested or transplacental – rabbits of 4 – 6 weeks appear most vulnerable | ||
+ | *In utero infections => invasion of foetal lens => => => => => => multiplication and euption of spores later in the rabbit’s life => cataracts, lens rupture and phacoclastic [[Uveitis – Rabbit|uveitis]] | ||
+ | *Invasion of the mucosa per polar tube | ||
+ | *Spiroplasm extruded and multiplication occurs in vacuole | ||
+ | *Distribution by reticulo-endothelial cells => invasion of organs with high blood flow | ||
+ | *Invasion of target organs | ||
+ | *Intracellular multiplication, cell rupture (=> inflammation) and invasion of neighbouring cells or passage to circulation in 3-4 weeks | ||
+ | *Shedding in urine 35 days after initial infection. | ||
− | + | ==Presentations of ''Encephalitozoon cuniculi'' in pet rabbits== | |
+ | *Granulomatous nephritis or interstitial infiltration of lymphocytes and plasma cells | ||
+ | **Usually asymptomatic | ||
+ | **Possibly haematuria | ||
+ | **Incontinence could be neurological in origin | ||
+ | **Treat with benzimidazoles and antibiotics | ||
+ | *Pyogranulomatous phacoclastic [[Uveitis – Rabbit|uveitis]] | ||
+ | **See treatment under [[Iridal Abscesses – Rabbit|iridal abscesses]] | ||
+ | **Use topical ophthalmic preparations, parenteral oxytetracycline and a benzimidazole | ||
+ | *Neurological manifestation of ''E. cuniculi'' infection: granulomatous encephalitis | ||
+ | **Sometimes perivascular infiltration with lymphocytes and plasma | ||
+ | **All areas of the brain | ||
+ | **[[Head Tilt – Rabbit|Torticollis]] | ||
+ | **Treatment | ||
+ | ***Initial short-acting corticosteroids, parenteral oxytetracycline and benzimidazoles awaiting lab results | ||
+ | ***Vestibular agents | ||
− | == | + | ==Transmission of ''Encephalitozoon cuniculi''== |
− | + | *Shedding in urine | |
+ | *Oral and tracheal access | ||
+ | *Neonates can be infected but can also receive immunity from dam. | ||
+ | *Ecto- and endo-parasites? May aid in transmission | ||
+ | *Provision of recently cut short grass gathered from the wild | ||
− | + | ==Pathology== | |
+ | *Principal target organs are kidney, brain, spinal cord | ||
+ | *Other target organs include liver and heart | ||
+ | *Rupture of host cell => invasion of neighbouring cells => chronic, granulomatous inflammation. | ||
+ | *In utero infections => invasion of foetal lens => => => => => => multiplication and eruption of spores later in the rabbit’s life => cataracts, lens rupture and phacoclastic [[Uveitis – Rabbit|uveitis]] | ||
− | + | ==Survival of ''Encephalitozoon cuniculi'' in the environment== | |
− | + | *Survives in extreme cold or heat | |
− | == | + | *At average temperature and in dry conditions it survives 4 weeks |
− | + | *Easily killed by routine disinfection | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
==Diagnosis== | ==Diagnosis== | ||
− | + | *Urine microscopy (35 days after initial infection) | |
− | + | *Serology – antibodies develop soon after infection but clinical signs take much longer (several weeks) | |
− | + | *Antibodies demonstrated 2 weeks before organisms can be demonstrated intracellularly and 4 weeks before histopathological changes are demonstrated in kidney or organisms demonstrated in urine (Harcourt Brown 2002) | |
− | + | *PCR | |
− | + | *CSF analysis | |
− | + | **Procedure: | |
− | + | ***Propofol and intubation | |
− | + | ***Head flexed 90º to spine | |
− | + | ***38mm 22G spinal needle in cisterna magna | |
+ | ***700-1000μl sample. | ||
+ | ***Vestibular signs are accentuated for up to 8hrs post sampling. | ||
+ | **Findings | ||
+ | ***Lymphomonocytic pleocytosis 15 cells/μl (n=1.5 /μl) | ||
+ | ***Increased protein 0.79g/μl (n= 0.24g/μl) | ||
+ | ***Unfortunately other viral, protozoan or immune-mediated encephalitis may induce similar lymphomonocytic pleocytosis | ||
− | + | ==Interpretation of ''Encephalitozoon'' antibody tests (Keeble 2007)== | |
− | |||
− | ==Interpretation of ''Encephalitozoon'' | ||
===Single positive result in healthy rabbit=== | ===Single positive result in healthy rabbit=== | ||
− | + | *Recent infection prior to development of clinical signs | |
− | + | *Chronically infected with no clinical signs | |
− | + | *Previously infected and recovered | |
− | + | *Antibody levels can persist for many years in symptomless animals | |
===Single positive result in rabbit with clinical signs of encephalitozoonosis=== | ===Single positive result in rabbit with clinical signs of encephalitozoonosis=== | ||
− | + | *Could be active Encephalitozoon cuniculi infection (or other infection causing signs) | |
===Single negative result in healthy rabbit=== | ===Single negative result in healthy rabbit=== | ||
− | + | *Could be free from infection | |
− | + | *Could be infected less than 2 weeks ago | |
− | + | *Retest in four weeks | |
− | |||
===Single negative result in rabbit with clinical signs of encephalitozoonosis=== | ===Single negative result in rabbit with clinical signs of encephalitozoonosis=== | ||
− | + | *Rules out ''Encephalitozoon cuniculi'' infection as the cause of clinical signs | |
+ | *Advise further tests | ||
+ | **renal biopsy | ||
+ | **CSF analysis | ||
+ | **mononulear pleocytosis and elevated protein | ||
+ | **MRI/CT scans | ||
− | + | ===To establish an ''Encephalitozoon''-free colony=== | |
+ | *Test fortnightly for two months or until all animals are negative for a month, whichever is longer | ||
+ | *Sacrifice any positive cases | ||
− | ==Treatment== | + | ===Treatment=== |
− | + | *Albendazole q 24 hrs - ?teratogenic (Pollock 2006) | |
− | + | *Fenbendazole q 24 hrs | |
− | + | *Oxytetracycline SC q 72hrs. | |
− | + | *Three possible therapies – my cocktail is albendazole and oxytetracycline as shown above. | |
− | + | *Vestibular-calming agents | |
− | + | *Environmental disinfection | |
− | + | *Corticosteroids | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
==References== | ==References== | ||
− | + | [[Category:Neurological_Disorders_-_Rabbit]] | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | [[Category: | ||
− | |||
− | |||
− |
Revision as of 01:17, 11 August 2010
This article is still under construction. |
Taxonomy
- Phylum Microspora; no mitochondria polar tube polar cap
- Class Microsporida
- Order Microsporidia
- May be more related to fungi than to protozoa (Wasson and Peper 2000)
- Obligate intracellular protozoan parasite
- 52% normal healthy domestic pet rabbits arte infected (Keeble and Shaw 2006)
- Ubiquitous in other species too
The life cycle
The life cycle of this coccidian is 3 – 4 weeks in total:
- Inhaled, ingested or transplacental – rabbits of 4 – 6 weeks appear most vulnerable
- In utero infections => invasion of foetal lens => => => => => => multiplication and euption of spores later in the rabbit’s life => cataracts, lens rupture and phacoclastic uveitis
- Invasion of the mucosa per polar tube
- Spiroplasm extruded and multiplication occurs in vacuole
- Distribution by reticulo-endothelial cells => invasion of organs with high blood flow
- Invasion of target organs
- Intracellular multiplication, cell rupture (=> inflammation) and invasion of neighbouring cells or passage to circulation in 3-4 weeks
- Shedding in urine 35 days after initial infection.
Presentations of Encephalitozoon cuniculi in pet rabbits
- Granulomatous nephritis or interstitial infiltration of lymphocytes and plasma cells
- Usually asymptomatic
- Possibly haematuria
- Incontinence could be neurological in origin
- Treat with benzimidazoles and antibiotics
- Pyogranulomatous phacoclastic uveitis
- See treatment under iridal abscesses
- Use topical ophthalmic preparations, parenteral oxytetracycline and a benzimidazole
- Neurological manifestation of E. cuniculi infection: granulomatous encephalitis
- Sometimes perivascular infiltration with lymphocytes and plasma
- All areas of the brain
- Torticollis
- Treatment
- Initial short-acting corticosteroids, parenteral oxytetracycline and benzimidazoles awaiting lab results
- Vestibular agents
Transmission of Encephalitozoon cuniculi
- Shedding in urine
- Oral and tracheal access
- Neonates can be infected but can also receive immunity from dam.
- Ecto- and endo-parasites? May aid in transmission
- Provision of recently cut short grass gathered from the wild
Pathology
- Principal target organs are kidney, brain, spinal cord
- Other target organs include liver and heart
- Rupture of host cell => invasion of neighbouring cells => chronic, granulomatous inflammation.
- In utero infections => invasion of foetal lens => => => => => => multiplication and eruption of spores later in the rabbit’s life => cataracts, lens rupture and phacoclastic uveitis
Survival of Encephalitozoon cuniculi in the environment
- Survives in extreme cold or heat
- At average temperature and in dry conditions it survives 4 weeks
- Easily killed by routine disinfection
Diagnosis
- Urine microscopy (35 days after initial infection)
- Serology – antibodies develop soon after infection but clinical signs take much longer (several weeks)
- Antibodies demonstrated 2 weeks before organisms can be demonstrated intracellularly and 4 weeks before histopathological changes are demonstrated in kidney or organisms demonstrated in urine (Harcourt Brown 2002)
- PCR
- CSF analysis
- Procedure:
- Propofol and intubation
- Head flexed 90º to spine
- 38mm 22G spinal needle in cisterna magna
- 700-1000μl sample.
- Vestibular signs are accentuated for up to 8hrs post sampling.
- Findings
- Lymphomonocytic pleocytosis 15 cells/μl (n=1.5 /μl)
- Increased protein 0.79g/μl (n= 0.24g/μl)
- Unfortunately other viral, protozoan or immune-mediated encephalitis may induce similar lymphomonocytic pleocytosis
- Procedure:
Interpretation of Encephalitozoon antibody tests (Keeble 2007)
Single positive result in healthy rabbit
- Recent infection prior to development of clinical signs
- Chronically infected with no clinical signs
- Previously infected and recovered
- Antibody levels can persist for many years in symptomless animals
Single positive result in rabbit with clinical signs of encephalitozoonosis
- Could be active Encephalitozoon cuniculi infection (or other infection causing signs)
Single negative result in healthy rabbit
- Could be free from infection
- Could be infected less than 2 weeks ago
- Retest in four weeks
Single negative result in rabbit with clinical signs of encephalitozoonosis
- Rules out Encephalitozoon cuniculi infection as the cause of clinical signs
- Advise further tests
- renal biopsy
- CSF analysis
- mononulear pleocytosis and elevated protein
- MRI/CT scans
To establish an Encephalitozoon-free colony
- Test fortnightly for two months or until all animals are negative for a month, whichever is longer
- Sacrifice any positive cases
Treatment
- Albendazole q 24 hrs - ?teratogenic (Pollock 2006)
- Fenbendazole q 24 hrs
- Oxytetracycline SC q 72hrs.
- Three possible therapies – my cocktail is albendazole and oxytetracycline as shown above.
- Vestibular-calming agents
- Environmental disinfection
- Corticosteroids