Feline Infectious Diease Flashcards

0
Q

What are the characteristics of FeLV?

A

Replicates in many tissues and is non-cytopathic

Labile, enveloped ssRNA virus that uses reverse transcriptase and integrates into host DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What group of viruses does FeLV belong to?

A

Retroviridae Oncovirinae Gammaretrovirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the three fates of a cell infected with FeLV?

A

Immune system destroys infected cell
Infection of cell with or without virus production
Transformation into a neoplastic cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the structure of FeLV?

A

RNA and reverse transcriptase inside a p27 icosahedral capsid surrounded by matrix and an envelope with p15E and gp70 envelope proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is p27?

A

Gag protein which is the basis for most diagnostic tests and is produced in infected cells and can circulate free in plasma or excreted in tears or saliva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is p15E?

A

Spike protein that leads to immunosuppression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is gp70?

A

Knob and defines viral subgroup (A,B,C) and is important for inducing antiviral neutralising antibodies as they are subgroup specific
Target for vaccine production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is FeLV subgroup A characteristics?

A

Present in almost all infected cats and is only transmitted cat to cat
Provides basis for production of other subgroups and is the least pathogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the characteristics of FeLV subgroup B?

A

Recombination of A with endogenous FeLV proviral sequences and is oncogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the characteristics of FeLV subgroup C?

A

Arises from the mutation of A and causes non-regenerative anaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the prevalence of FeLV in UK cat population?

A

1-2% in healthy cats

20% in symptomatic cats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is FeLV transmitted?

A

Source of infection is persistently infected cats with virus shed in saliva, nasal secretions, faeces, urine and milk
Short survival time in the environment lasting only hours
Transmitted by intimate prolonged contact e.g. sharing food/water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the risk factors for FeLV infection?

A

Greater risk in males than females
Young cats between 1-6
Multicat households especially outdoor cats
Susceptibility highest in young kittens under 4-5 months of age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the four possible results of infection with FeLV?

A

Persistent viraemia
Transient viraemia
Latent infection
Localised infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to persistently viraemic cats infected with FeLV?

A

Majority of cats developing FeLV associated disease within 3-5 years of infection
Don’t develop virus neutralising antibody
Show signs of neoplastic or non-neoplastic disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens to cats with FeLV transient viraemia?

A

Virus is completely eliminated usually after about 3 months with high titres of neutralising antibody measures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens to cats with latent FeLV infection?

A

Virus persists but doesn’t replicate so is undetected and difficult to diagnose requiring bone marrow/PCR and occurs in 30% of infected cats resulting in remaining latent, becoming persistent or eliminating after 30 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens to cats with a localised FeLV infection?

A

Uncommon with the virus sequestered in certain tissues such as mammary gland, bladder or eyes and may give discordant test results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the clinical signs of FeLV infection?

A

Many cats are asymptomatic with those showing signs varied and non-specific depending on organ system and secondary disease but include inappetance, weight loss, wasting, persistent diarrhoea, poor coat condition, lymphadenopathy, persistent fever, pale MM, ocular disease, gingivitis, stomatitis, skin/bladder/URT infection, seizures, behavioural changes, other neurological disorders, abortion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why do secondary infections occur with FeLV?

A

Immunosuppression and depletion or interference with function of lymphocytes and/or neutrophils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which haematological disorders can be found with FeLV?

A

Bone marrow suppression due to viral infection of haematopoietic stem cells and stromal cells resulting in non-regenerative anaemia, aplastic anaemia, regenerative anaemia, thrombocytopaenia or granulocytopaenia
Myelodysplasia leading to myelodysplasitc syndrome
Leukaemia of any/all cell lines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How many more times likely is lymphoma in FeLV positive cats?

A

60 times and is expected to develop in 25% of FeLV positive cats within two years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What kind of lymphoma affects cats with FeLV?

A

Mediastinal (thymic) and multicentral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is Feline Oncoronavirus Cell Membrane Antigen (FOCMA)? What can it be used for?

A

Present on membrane of malignant cells but absent on all other body cells so anti-FOCMA antibodies can be used to complement lyse tumour cells leading to immune surveillance against tumour development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why does immune-mediated disease occur with FeLV?

A

Overactive or dysregulated response to virus and includes IMHA, glomerulonephritis, uveitis and polyarthritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What reproductive diseases can FeLV cause?

A

Infertility causes foetal death and resorption in middle trimester
Abortion is less common
Transmission of virus transplacentally and via colostrum in both viraemic and latently infected queens can result in Fading Kitten Syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What skeletal abnormalities can occur with FeLV?

A

Osteochondromatosis = benign proliferative disease of bone resulting in multiple cartilaginous extoses of flat bones
Chronic progressive polyarthritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What neurological diseases are associated with FeLV infection?

A

Neuropathies are infrequent and need to be distinguished from CNS lymphoma
Clinical signs of aniscoria, urinary incontinence, vague pain or spinal hyperaesthesia, posterior paresis
Acute demyelinating myelopathies are also seen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How are cats diagnosed with FeLV?

A

Immunoassay such as ELISA for p27
IFA to detect p27 in leukocytes and platelets (confirmatory)
PCR to detect viral nucleic acid (confirmatory)
Viral culture (gold standard)
Antibody test doesn’t diagnose but indicates exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What does a positive antigen test for FeLV mean?

A

Transient/persistent viraemia however a positive IFA indicates persistent viraemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What can a negative test result for FeLV mean?

A

Unexposed, eliminated previous infection, early infection retest in 9-12 weeks, latent infection, localised infection or false negative (unlikely)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What can discordant results from an FeLV test mean?

A

Positive antigen and negative IFA or viral isolation indicates early infection, in recovery, false positive, detection of incomplete virus, localised infection or greater sensitivity of antigen test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the treatment for FeLV in cats?

A

If systemically well then general preventative health care

If sick then supportive care, treat secondary illness and confine indoors

33
Q

What viral family does Feline Immunodeficiency Virus (FIV) belong to?

A

Retroviridae Lentivirus

34
Q

What are the characteristics of FIV?

A

RNA virus with five subtypes that uses reverse transcriptase and is similar to HIV but there is no risk of transmission to people

35
Q

What is the prevalence of FIV in the UK cat population?

A

3-6% in healthy cats and 15-19% in sick cats

36
Q

Which cats are most commonly infected with FIV?

A

Free-roaming, aggressive male cats

37
Q

How is FIV transmitted?

A

Primarily through bite wounds but less commonly vertically and sexually

38
Q

What are the five phases of pathogenesis of FIV?

A
Acute phase
Asymptomatic carrier
Persistent generalised lymphadenopathy
AIDS-related complex
AIDS
39
Q

What occurs during the acute phase of FIV infection?

A

Lasts several days to weeks with transient mild illness
Early replication in lymphoid tissues and salivary glands with later spread to mononuclear cells in non-lymphoid organs (lung/kidney/GIT)
Neutropenia and lymphopenia possible

40
Q

What occurs during the asymptomatic carrier phase of FIV infection?

A

Healthy appearance but immune deficits with low level of circulating virus after host immune response
CBC normal but CD4+:CD8+ T cell ratio decreased or inverted

41
Q

What occurs during persistent generalised lymphadenopathy phase of FIV infection?

A

Anorexia, weight loss, PUO, lymphadenopathy
Lasts 6 months - several years
Leukopaenia, anaemia and CD4+:CD8+ T cell ratio inverted

42
Q

What occurs during AIDS-related complex phase of FIV infection?

A

Secondary bacterial infections and less commonly neurological signs or neoplasia
Lasts 6 months to 1-2 years
CBC shows anaemia, leukopenia/leukocytosis, inverted CD4+:CD8+ ratio

43
Q

What occurs during AIDS phase of FIV infection?

A

Survival is a few weeks to months
Cats infected with opportunistic infections, neurological disease and neoplasia
CBC shows leukopenia, anaemia and CD4+:CD8+ T cell ratio inverted

44
Q

What are some common clinical findings with FIV infection?

A

Stomatitis, neoplasia, ocular inflammation, anaemia, leukopaenia, opportunistic infections and renal insufficiency

45
Q

How is FIV diagnosed in cats?

A

CBC showing neutropenia, anaemia and thrombocytopaenia, polyclonal gammopathy, antibody test of core p24 or envelope gp41, IFA, Western blot, PCR, viral isolation only available in research centres

46
Q

What does a positive test result indicate about FIV infection?

A

Persistent infection, false positive or weak positive

If positive queen then test kittens until > 6 months old

47
Q

What does a negative test result indicate when testing for FIV?

A

Not infected, antibodies not detected, test error, no antibody response or early infection so retest in 60 days

48
Q

What is the treatment for FIV?

A

Supportive antibiotics, cautious glucocorticoid use, lactoferrin
Antiviral therapy called Zidovudine

50
Q

What are the methods for prevention of FIV?

A

Prevent exposure, virus readily killed by disinfectants and dies within a few hours in environment, social contact has low risk of transmission, don’t breed from FIV positive queens and hand raise kittens, vaccination possible in USA

51
Q

What is the classification of FCoV?

A

Feline coronavirus previously classified as feline enteric coronavirus (FECV) and feline infectious peritonitis virus (FIPV) now thought to be biotypes of same virus

52
Q

What are the characteristics of FCoV?

A

Enveloped ssRNA virus, large, pleomorphic, undergoes mutation
Replicates in the cytoplasm and newly synthesised virons acquire envelopes from membranes of ER and Golgi

53
Q

What are the two types of FCoV?

A

Two types: I = wholly feline, II = recombination with canine coronavirus

54
Q

What are the specific characteristics of FECV?

A

Present in large proportion of the healthy cat population
Undergoes oronasal transmission
Virus replicates in enterocytes with clinical signs of mild/inapparent vomiting, diarrhoea, URT signs

55
Q

What are the specific characteristics of FIPV?

A

FCoV may undergo mutation into FIPV and infects macrophages resulting in systemic infection
FIP is clinical disease resulting from ineffective immune response

56
Q

What is the pathophysiology of FCoV?

A

Immune complex disease characterised by vasculitis, complement activation and excessive cytokine production,

57
Q

How does the process of FCoV infection result in increased vascular permeability?

A

Viral antigen and anti-viral antibodies complement bind forming complement fixation leading to the release of vasoactive amines and endothelial cell retraction

58
Q

What are the different body responses and their outcomes?

A

Strong cell-mediated response = protection
Partial cell-mediated response = non-effusive disease
Poor cell-mediated response = effusive disease

59
Q

What are the early signs of FCoV infection?

A

Pyrexia, inappetance, anorexia, weight loss, diarrhoea, listlessness, dehydration and jaundice

60
Q

What are the clinical signs of effusive FIP?

A

Abdominal, pleural or pericardial effusion (60-75% cases)

61
Q

What organs does the non-effusive form of FIP affect?

A

Predisposition for eye, brain and CNS, kidney, liver and localised regions of intestine

62
Q

What is diagnosis of FIP based on?

A

History, clinical signs, physical exam, laboratory and imaging findings

63
Q

What can a CBC in a cat with FIP show?

A

Lymphopenia, neutrophilia with mild left shift, mild non-regenerative anaemia but can also be normal

64
Q

What can biochemistry from a cat with FIP show?

A

Hyperglobulinaemia, hyperbilirubinaemia, usually not azotaemic but can also be normal

65
Q

What can fluid analysis from a cat with FIP show?

A

Clear, straw to yellow colour, viscous, may be frothy when shaken, high protein content and may clot in the tube, variable cellularity

66
Q

What does an IFA or ELISA test show when testing for FIP?

A

Prior exposure to FCoV not presence of FIP

Doesn’t distinguish between FCoV or FIPV

67
Q

What other tests can be used to try and diagnose FIP?

A

CSF, direct FA and immunohistochemistry, RT-PCR, alpha-1 acid glycoprotein, histopathology of light plaques on serosal surfaces and adhesions of omentum and mesentry

68
Q

What are the treatment options and prognosis?

A

Supportive care, immune modulators, glucocorticoids +/- chlorambucil, asprin and oral polypranyl immunostimulant
Grave prognosis as no cure

69
Q

Is vaccination possible and how effective is it?

A

Effective cell-mediated response but poor antibody response

Available in USA

70
Q

What causes Feline Infectious Anaemia (FIA)?

A

Haemotropic mycoplasms which are small epicellular parasites with no cell wall and tetracycline-sensitivity

71
Q

What are the different mycoplasms that cause FIA?

A

Mycoplasma haemofelis is more pathogenic form

Mycoplasma haemominutum is less pathogenic form

72
Q

What is the pathogenesis of FIA?

A

Mycoplasmas attach to RBCs causing immune-mediated destruction and immunosuppression leads to concurrent diseases being enhanced
If recover from infection can be chronically infected for variable time

73
Q

What transmits mycoplasmas involved in FIA?

A

Fleas, blood transfusion, in utero? nursing? fighting? orally?

74
Q

In which animals is FIA more common in?

A

Young entire males often latently with stress/concurrent illness causing acute disease

75
Q

What are the clinical findings of a cat with FIA?

A

Rapid decrease in PCV which rises as organisms disappear, direct damage to RBCs but can also be immune-mediated so may be Coombs test positive

76
Q

What does an acute FIA patient present with?

A

Lethargy, inappetance, anorexia, fever 39-41C, anaemia, splenomegaly, icterus

77
Q

What does a chronic FIA patient present with?

A

Normal to subnormal temperature, weakness, depression, weight loss, emaciation, icterus and splenomegaly less likely

78
Q

What does the CBC of a cat with FIA look like?

A

Regenerative anaemia but can be pre-regenerative

79
Q

How do you diagnose FIA?

A

Fresh blood smear (only 50% acute cases, differentiate from Howell-Jolly bodies/basophilic stippline and stain precipitates)
Acidine orange stain, IFA
PCR = most sensitive test

80
Q

What is the treatment for FIA?

A

Doxycycline 5-10mg/kg orally BID for 14-21 days
Flea control
Supportive care such as blood transfusion or immunosuppressive therapy

81
Q

What is the prognosis for FIA?

A

No treatment = 1/3 with uncomplicated acute disease die
Regeneration > destruction and immune response = recovery
Carrier state possible