41. INFECTIOUS CENTRAL NERVOUS DISEASES Flashcards
What diseases does infections cause in the brain:
meningitis, encephalitis, and meningoencephalitis
infectious pathogens:
– Viral
– Bacterial
– Fungal
– Protozoal
in cats:
- FIP, FeLV, toxoplasmosis etc
in dogs:
- distemper, toxoplasmosis, neosporosis, cryptococcosis
viral encephalitis route of infections:
- Inhalation
- Bite
- Ingestion of infected raw meat
- Vector
Causes of viral encephalitis:
- Canine distemper (febris catarrhalis)
- Rabies (lyssa)
- Pseudorabies (Aujeszky disease)
- Tick encephalitis
- Feline Borna disease
Canine distemper is caused by:
- Morbillivirus genus, paramyxovirus
- Remains virulent for several days in dried secretion, spread through urine and nasal secretions.
signs of distemper
- General signs (apathy, fever)
- Gastrointestinal (diarrhoea),
- Respiratory (cough, mucopurulent discharge – nose, eyes)
- Neurologic signs
- Hyperkeratosis (hard pad – paws, nasal planum)
- Polysystemic signs: most often in young dogs with inadequate vaccination, less strong immune system
The two types of distemper
Neuronal and glial cell death (polioencephalomyelopathy)
- Mostly young dogs
- Usually with history of seizures
Demyelination (leukoencephalomyelopathy)
- Mostly adult dogs
- Immune mediated
- Brain stem, cerebellar, vestibular signs
- Myoclonus!
diagnosis of distemper
- PCR (urine)
- Conjunctival / bronchial smear
- inclusion bodies
- IF teszt
Types of rabies
– Urbanic rabies: (from dog-to-dog) very rare in Europe
– Sylvatic rabies: dogs and cats are infected from rabid foxes
Diagnosis of rabies
– Justification postmortem
– IF test: reaction of anti viral antibodies conjugated with fluorescent dye with tissue samples
– Real time RT-PCR
– Virus isolation on cell culture
Pathogen of pseudorabies - aujeskys
- Alphaherpesvirus, porcine herpesvirus – 1, PHV-1
Tick encephalitis pathogen:
flavivirus
Tick encephalitis vector
- Ixodes ricinus (Europe)
Symptoms of tick encephalitis
- fever, apathy or excitement, convulsions, ataxia, paraplegia, disorders of propriocepcion, aggressiveness, sensational disorders, tremor, nystagmus, mydriasis, anisocoria, strabismus, facial paralysis
FELINE INFECTIOUS PERITONITIS (FIP) pathogen:
coronavirus
FIP etiology
- Primarily intracranial and spinal cord structures are affected
- Typically associated with „dry”, pyogranulomatous FIP (noneffusive form of FIP)
- Immune complex vasculitis → inflammation of the ependyma, choroid plexus, meninges
FIP signs:
- Motoric disorders, cerebellar ataxia, tremor, hind leg paralysis
- Menthal state: stupor/dementia or even aggressivness
- Eyes: nystagmus, mydriasis, anisocoria, anterior uveitis, chorioretinitis
Bacterial infection of CNS - route
– Direct invasion (after trauma of the skull or vertebral column)
– local source of infection (sinusitis, otitis, nasal passage)
– hematogenous (dog: endocarditis)
– Bacterial inflammation in the cns is rare
Bacterial infection of CNS - pathogens
– staphylococcus, streptococcus, pateurella m. (mostlyincats), escherichia, klebsiella, actinomyces, nocardia, anaerobes: bacteroides, peptostreptococcus
Bacterial infection - diagnosis
– history, clinical signs, (CT, MRI – abscess, oedema)
– CSF → citology: neutrophil pleiocytosis (toxic and degenerate neutrophils), intracellular bacteria
– CSF → biochemistry: protein, glucose ↑
– CSF → bacterial culture
Treatment of bacteria in the cns
– AB (ampicillin, enrofloxacin, cefotaxime, metronidazol for anaerobes, 10-14 days after resolution of clinical signs)
– Glucocorticoids in antiinflammatory dose (max. 4 days)
LISTERIA MONOCITOGENES
bacteria invades through (oral) mucosal lesions → reach the CNS via the nerves → cranial nerve damage → laryngeal paralysis
doxycyline for treatment
toxoplasma gondii: host
- Cats are definitive hosts.
- In acute infection (young dog/cat)
toxoplasma gondii: symptoms
- Severe in young cats, symptomless in older
- Systemic signs (lethargy, anorexia, dyspnoe – pneumonia, diarrhea)
- Classic sign: hyperextended pelvic limbs, chorioretinitis may be present
- myositis
- Nervous system: encephalitis, myelitis, peripheral neuropathies
shed, Infection, Diagnosis,Therapy of toxoplasma :
shed - Oocysts are shed in acute illness for 2-3 weeks.
Infection: - with cyst containing meat, spored oocyst, intrauterin
Diagnosis - antigen: PCR, antibody (IgG, IgM): IF
Therapy - clindamycin
NEOSPORA CANINUM - host and infection
– Dogs are definitive hosts.
– Dogs can be infected in utero or with infected meat
– Neosporosis is frequently a complication of canine distemper
– Not described in cats
NEOSPORA CANINUM - symptoms
– nervous system: encephalitis, myelitis, peripheral neuropathies
– chorioretinitis
– pneumonia
– myositis
– in chronic cases, older dogs: aggression, depression, other behavioral changes
NEOSPORA CANINUM - diagnosis and therapy
– antigen: PCR, antibody: IF
– clindamycin, potentiated sulphonamids
– A puppy with classic signs of pelvic limb hyperextension and rigidity secondary to Neospora caninum infection.
Etiology of fungal infection of cns
Etiology:
– Inhalation of fungal spores
– local extension from nasal / frontal sinus –
– haematogen spread
pathogens of fungal infection of cns
Fungal organisms that may invade the CNS: Aspergillus, Blastomyces, Coccidioides (USA), Cryptococcus (USA), Histoplasma (USA)
occurence of fungal infection of cns
– mainly as part of systemic mycosis – Slow progression – Fungal elements may be identifiable in urine samples – CSF: mixed cell pleocytosis – In cats concurrent FeLV / FIV common
therapy of fungal infection of cns
- antifungal drugs that cross the blood –brain barrier: fluconazole, flucytosine long term (months- one year)
