Feline Disease Flashcards
What are feline coronaviruses?
FCoVs are large enveloped RNA viruses. Replication of RNA genomes are prone to mistakes, resulting in mutations.
How does increasing potential of FCoV strains cause disease?
Low virulence strains = no disease
Low-medium virulence strains = enteritis
Highly virulent strains = FIP
What are the viral factors of FCoV?
FIP spike protein mutations allow increases replication within monocytes and macrophages.
What are the host factors of FCoV?
Immune response (humoral response with many antibodies produced are most at risk of FIP, T cell depletion) causes increased risk of FIP. Genetics/breed, age 6-24 months, male
What are the environmental factors of FCoV?
Level of stress, degree of FCoV exposure leads to increased risk of FIP
Is FCoV serology likely to be useful in the diagnosis of FIP?
No, it tells us a cat has been infected in the past
How is feline coronavirus transmitted?
- Shedding within 1 week of oral infection
- Faecal-oral – sharing litter trays, grooming
- Kittens acquire maternal derived immunity in colostrum from their mum/queen
What are the 2 possible outcomes of FCoV?
Transient FCoV infection – shed in faeces for a few months then eliminated, then susceptible to reinfection with FCoV as immunity is only short term.
Development of FIP – viral, host and environmental factors leading to mutations and FIP.
Distinguish effusive and non-effusive FIP.
Effusive/wet FIP = vasculitis and non-specific exudates
Non-effusive/dry FIP = pyogranulomatous lesions in tissue
What is effusive FIP?
- Acute disease
- Effusions are more abdominal than pleural or both
- Look for evidence of abdominal masses – visceral/omental adhesions mesenteric lymph nodes increased
What are the clinical signs of effusive FIP?
Fever
Anorexia
Lethargy
Weight loss
Jaundice
Abdominal effusion = abdominal distension
Pleural effusion = dyspnoea, tachypnoea
Pericardial effusion
Scrotal swelling
What are the symptomsof non-effusive FIP?
- Fever
- Anorexia
- Lethargy
- Weight loss
- Jaundice
- Ocular signs – iritis, corneal oedema, dyscornia/anisocoria, loss of vision, hyphaema/RBC in the eye, hypopyon/WBC in the eye, keratic precipitates, aqueous flare, perivascular cuffing, chorioretinitis
- Neurological signs – ataxia, head tilt in some cases, hyperaesthesia, nystagmus, seizures
How is FIP diagnosed?
- Need a histopathology of affected tissue with immunostaining of FCoV antigen – immunohistochemistry
- Effusion or FNA cytology with immunostaining of FCoV antigen also useful
- Biopsies
What does FIP show up in haematology?
- Lymphopenia – not specific
- Neutrophilia and/or mild left shift
- Anaemia
How does FIP show up in biochemistry?
- Hyperproteinaemia
- Decreased albumin:globulin ratio
- Large increase in a1 acid glycoprotein AGP = acute phase protein
- Hyperbilirubinaemia but liver enzymes are normal
How is the effusions of FIP analysed?
- Often viscous, yellow
- Protein > 35 g/l
- Globulins > 50% decreased albumin:globulin ratio
- Poor cellularity
- Immunostaining for FCoV antigen
What about RT-PCRs that target specific mutations in FCoV spike protein gene?
Not more specific than RT-PCR as spike protein gene mutations likely show the presence of systemic FCoV compared to a FCoV definitely causing FIP & many different types of mutation are likely to be involved
What is the advice for FCoV in multicat households?
- Minimise stress, decrease overcrowding, decrease other diseases
- Keep cats in small stable groups of less than 3-4 per group
- Good hygiene
- Kitten management – do not re-home too early if possible, minimise stress after rehoming
- Ideally stop all breeding and quarantine household for 6-12 months
- Stop using breeding cats that have repeated FIP problems – especially males
How are the retroviruses, feline leukaemia virus and feline immunodeficiency virus, differ in virus detection?
FeLV - P27 core protein is the antigen detected in most test kits in practices
FIV - amount of virus is very low in cat’s blood so need to detect antibodies in the blood instead, transmembrane glycoproteins
How do FeLV and FIV differ in prevalence?
FeLV - increased in sick cats, 3% shelter cats
FIV - increased in sick cats, 11.4% shelter cats
How do FeLV and FIV differ in signalment and risk factors?
FeLV - adults, outdoor cats, females and males (entire), think, MSK disease
FIV - adults, male (entire), feral cats
What happens if FLV has an abortive exposure?
Immune system generates antibodies and immune response expels virus
What happens if FeLV has affect before mounted immune response?
Regressive infections without transient viraemia, this can occur at different times in infection, cats are PCR positive but not infected, has provirus in some host cells
What is FeLV transient viraemia?
P27 protein/antigen in the blood so there is viraemia so positive test results
What happens if FeLV infects bone marrow?
Can still get immune response but bone marrow can be infected at 4 weeks and increases likelihood of progressive infection developing
What is progressive infection of FeLV?
The worst outcome - persistent viraemia, inadequate immune response, get sick.
What is the main difference between FeLV and FIV infections?
Cats can recover from FeLV infection
Cat don’t recover from FIV infection
List disease syndromes associated with FeLV infection.
Neoplasia
Bone marrow disease
Chronic/recurrent/opportunistic infections suggesting immunosuppression
Chronic gingivostomatitis
Neurological signs
Reproductive disorders
Fading kitten syndrome
Immune-mediated haemolytic anaemia
List the disease syndromes associated with FIV infection.
Chronic gingivostomatitis
Chronic or recurrent infections
Uveitis
Neoplasia
Bone marrow disease
Glomerulonephritis
Neurological disease
Possible role in enteropathies, cardiomyopathy/myocarditis, chronic kidney disease?
How can ELISA and immunochromatography be used to test for FeLV?
Detects free p27 antigen – viraemia
But viraemia could be transient = regressive infection or persistent – progressive infection so retest after 4 weeks or use alternative test
How can immunofluorescence test for FeLV?
Detects p27 antigen within neutrophils and platelets = bone marrow associated-viraemia
How can PCR be used to test for FeLV?
- Usually detects FeLV DNA provirus
- Remain positive with regressive infection and progressive infection
- Although initially proviral loads are similar with both regressive and progressive infections, after a few weeks proviral loads decreases in regressive infection
How is FIV tested for?
- FIV ELISA or RIM – in-house and commercially, detect just 1 or 2 types of FIV antibody
- FIV immunofluorescence (IF)
- FIV Western blotting – done in commercial labs only, detect many types of FIV antibody
- FIV PCR – usually detects FIV DNA provirus
When is it helpful to send a sample for FeLV or FIV testing to an outside lab?
Unexpected results or equivocal result
How are false positives in healthy cat population a concern?
- Prevalence of FeLV and FIV in healthy cat populations is low
- If FeLV prevalence is 1% then 1 in 100 cats will be truly FeLV +ve
- If an ELISA has a specificity of 99% then 1 in 100 cats will be a false FeLV +ve
- So 2 +ve results are generated per 100 cats: 50% of the +ve results are false +ves - positive predictive value 50%
How are false negatives in sick cat population less of a problem than healthy cat false positives?
- Prevalence of FeLV and FIV in sick cat populations is higher
- If FeLV prevalence is 9% then 9 in 100 cats will be truly FeLV +ve
- If an ELISA has a specificity of 99% then 1 in 100 cats will be a false FeLV +ve
- So 10 +ve results are generated per 100 cats: only 10% of the +ve results are false +ves - positive predictive value 90%
What are the advantages and disadvantages of AZT used to treated FIV?
+ Helpful for stomatitis/gingivitis and neurological signs
- Can cause anaemia so monitor haematology
- Resistance can occur after years of treatment
What is the advantage of using recombinant interferon to treat FIV?
Improvement in FIV infected cats with more severe clinical signs
What is an issue with using chemo or radiotherapy to treat FeLV?
Prognosis worse long term if FeLV +ve as FeLV has more of a limiting effect on lifespan
What supportive treatments can be used for FeLV and FIV infections?
Treat secondary infections
Dentistry
Nutrition
Cautious use of steroids is okay if immune-mediated disease
What are the preventative measures against FeLV and FIV infections?
- 6-12 monthly clinical examinations – weight, lymph nodes, mouth, eyes, clinical signs
- Keep indoors and neuter
- Good hygiene, stress management, regular dentals
- Regular ectoparasite and endoparasite prevention based on exposure
- Vaccinate for FHV, FCV and FPV
- Prevent hunting and do not feed raw meat
What is marboflaxacin C and its uses?
Fluoroquinolone – good for G-ve aerobes, okay for G+ve aerobes, n/e on anaerobes
What is cephalexin C and its uses?
1st generation cephalosporin – good for G+ve aerobes, okay for most G-ve aerobes, some anaerobes
What is doxycycline S and its uses?
Tetracycline – good for G+ve aerobes and ‘atypical bacteria’ e.g. Chlamydia, Bordetella, Mycoplasma, Rickettsiae
What is amoxycillin-clavulanate C and its uses?
Penicillin – good for G-ve aerobes, okay for G+ve aerobes, v. good for anaerobes, okay for Chlamydia
What is clindamycin S and its uses?
Lincosamide – good for G+ve and anaerobes
Why do you think a 5 month cat has mildly elevated calcium and phosphate concentrations?
Age related (5 months) – bone growth so elevated
What are the signs of cat flu/upper respiratory tract disease?
- Ocular discharge – conjunctivitis, possibly corneal ulcers
- Nasal discharge – rhinitis
- Coughing
- Sneezing
- Oral ulceration/drooling
- Inappetence
- Depression
- Pyrexia
How is acute and chronic URT disease defined?
Acute is less than 10 days in duration. Chronic more than 10 days.
Compare and contrast feline herpes and calicivirus in terms of survival.
FHV - labile, max 18 hours, damp conditions only
FCV - fairly labile, 7-10 days, but up to a month
How do FHV and FCV compare upon disinfection?
Inactivated by 1:32 dilution of bleach in water for 10 mins contact time. FCV more resistant
How are FHV and FCV transmitted to cause URT disease?
Nasal, oral and conjunctival routes and infect the respiratory mucosa. Oropharynx is the primary site of replication
How do cats become infected with FHV or FCV?
- Contact with clinical case is common
- Contact with asymptomatic carrier is common
- Contact with fomites is less common but FCV
How are FHV carriers characterised?
By latency. Predominantly in nervous tissue. - Cannot identify carriers during latency as not shedding. Reactivation from stress, corticosteroids or spontaneous. Shed for 1-2 weeks
How are FCV carriers characterised?
Shedding of virus is persistent with no latency, persists in upper respiratory tract tissue and tonsils
What are the clinical signs of FHV/FCV 1 week after infection?
- Nasal signs – discharge
- Ocular signs
- Oral signs – drooling
- Systemic signs – behaviour changes, reluctance to be handled
What is limping syndrome?
Uncommon presentation/complication of FCV. Acute transient lameness with fever natural infection or after vaccination
What can an immune mediated reaction to FCV result in?
Feline chronic gingivostomatitis
What is virulent systemic FCV disease?
Newly recognised FCV strains, causing the additional signs:
- Facial/paw oedema
- Ulcerative
- Dermatitis
- Alopecia
- Icterus
- Pancreatitis
- Nasal/GIT haemorrhage
How are FHV and FCV diagnosed?
Conjunctival and oral swabs – virus isolation or PCR (PCR more sensitive)
What supportive treatment can be given to cats suffering FHV/FCV URT disease?
- Fluid therapy
- Good nursing care
- Mucolytics to break up purulent ocular/nasal discharge
- Nebulisation to keep cilia working in respiratory tract
- Ocular lubrication
- NSAIDs if not contraindicated (hydrated and renal function normal) – Metacam/meloxicam
- Antibiotics only if secondary infection an issue
How should vaccination against URT diseases be done in outdoor and indoor cats?
1st dose 8-9 weeks of age, 2nd dose 3-4 weeks later. Ideally a 3rd dose at 16 weeks of age.
How should vaccination against URT disease be done in high risk cats?
1st dose at 4 weeks of age (ideally 6 weeks), then every 3-4 weeks until 16 weeks of age.
When should cats receive a booster vaccination for URT diseases?
Every 1-3 years depending on risk
What is bordatella bronchiseptica?
- Gram negative bacteria
- Part of canine infectious respiratory disease complex
- Infection common I cats but disease is rare
What is the epidemiology of bordatella bronchiseptica in cats?
- Shed in nasal and oral secretions of infected cats
- Spread by direct and indirect contact with discharge
What is the pathogenesis of bordatella bronchiseptica?
Colonises ciliated epithelium and causes destruction of cilia
What are the clinical signs of bordatella bronchiseptica?
- Coughing, sneezing, pyrexia, ocular discharge
- Severe pneumonia with dyspnoea, cyanosis and death
How is bordatella bronchiseptica treated?
Doxycycline antibiotic and supportive care
What is chlamydia in cats?
- Most common cause of conjunctivitis in cats
- Gram negative, obligate intracellular bacteria, only lives a few days outside of host
What is the pathogenesis of chlamydia in cats?
- Source of infection is ocular secretions
- Usually ocular pathogen and targets conjunctival mucosa
- Incubation is 2-5 days
How long it shedding period for chlamydia in cats?
18 months
What are the clinical signs of feline chlamydia?
- Conjunctivitis
- Conjunctival hyperaemia
- Ocular discharge
- Blepharospasm
- Chemosis
- Mild pyrexia
What clinical signs would indicate it is unlikely to be chlamydia felis alone causing disease?
- Unilateral (3-4 days) then bilateral; if remains unilateral unlikely to be C. felis
- If corneal ulceration present, unlikely to be C.felis alone
How is feline chlamydia treated?
Doxycycline. Can also use amoxycillin/clavulanate in pregnant queens and kittens.
What is toxoplasma gondii?
- Intracellular protozoa
- All warm blooded animals and people can be intermediate hosts
- Only cats are the definitive hosts
- Infection is common in cats but disease is rare
How is toxoplasma gondii transmitted in cats?
- Ingestion of cysts in tissues of intermediate host – raw diet or prey
- Kittens infected from queen – transplacental or milk
Name the 3 infectious forms of toxoplasma gondii.
Tachyzoites – rapidly multiplying form
Bradyzoites – slow multiplying form that appears in tissue cysts
Sporozoites – reproductively active form and is released into oocysts in cat faeces
What are the clinical signs of toxoplasma gondii?
Anterior-posterior uveitis
Chorioretinitis
Hyperaesthesia
Seizures
Ataxia
Muscle inflammation and pain
Dyspnoea
Pneumonia in kittens
Anorexia
Depression
Pyrexia
Icterus
Pancreatitis
Weight loss
Diarrhoea
Effusions
How can toxoplama gondii be treated?
- Clindamycin – 4-6 weeks, longer if neurological
- Ocular treatment if uveitis – topical glucocorticoids to prevent glaucoma and lens luxation
What are haemoplasmas?
Epicellular bacteria that attach to the surface of RBCs
What is the pathogenesis of haemoplasmosis?
Haemoplasmas can cause anaemia via haemolysis. M. haemofelis pathogenic in immunocompetent cats whereas other haemoplasma species usually need immunocompromisation or splenectomy of host.
What is the epidemiology of haemplasmosis?
Older male outdoor cat
FeLV/FIV positive
Blood transfusion
Fighting/fleas
What are the clinical signs of haemoplasmosis?
Pallor – anaemia
Lethargy
Anorexia
Weight loss
Depression
Pyrexia
Dehydration
Splenomegaly
Icterus uncommon
How is haemoplasmosis treated and managed in cats?
- Doxycycline 1st line – at least 3 weeks of treatment ideally
- Fluoroquinolones 2nd line
- Monitor response to treatment using quantitative PCR
- Supportive care – address dehydration, blood transfusion?
- Consider flea and tick control
