what do you need to know about feline infectious diseases? fanan suksawat dvm, ms, ph.d

WHAT DO YOU NEED TO KNOW ABOUT FELINE INFECTIOUS DISEA

SES?

FANAN SUKSAWAT DVM, MS, PH.D

FVR FCV P C FeLV FIP FIV

Herpesvirus

Calicivirus

Parvovirus

Chlamydophila

Feline leukemia virus

CoronavirusFeline immuno-deficiency virus

FELINE INFECTIOUS DISEASES

Cat flu

Causative agents

Chlamydophila spp.

Bartonella spp.

Toxoplasma gondii Cryptococcus spp.

FELINE INFECTIOUS DISEASESCausative agents

Scope of this talk

Characteristics of each disease

Diagnosis

Vaccination

Potential interferon application

Syn: feline distemper, feline infectious enteritis, cat fever and cat typhoid

FELINE PARVOVIRAL INFECTIONFELINE PANLEUKOPENIA

FELINE PARVOVIRUS, PANLEUKOPENIA characteristics

Cerebellar hypoplasia

diarrhea

DIC

feline ataxia syndrome

Less prevalent nowadays

• Widely vaccinated

• Virus adjust to cats

• CPV to cats..Ab crossprotect to FPV

diagnosis

• clinical signs, and the presence of leukopenia

• Leukopenia (severe: 50-3000 at D4-D6, mild: 3000-7000 cells/ul)

• Thrombocytopenia

• confirmed by

necropsy examination

virus isolation

identification of the virus infected tissues

Serology (Ag, serum, feces, 24-48 hrs after infection)

serological tests do not differentiate between infection- and vaccination-induced ab.

FELINE PANLEUKOPENIA

CPV Kit

Vaccination

* MLV in <2 m of age

Age Booster Type of vaccine

> 2 m

<2 m.

Adult

pregnanted cat

3 m and yearly

3-4 wks after till 3 m. and yearly

1 time and yearly

MLV

killed*

MLV, killed

no MLV and killed vac

FELINE CORONAVIRUS INFECTIONFeline Infectious Peritonitis, FIP

More prevalent

• farm raised

• indoor raised

• inbred

FIPcharacteristics

• effusion

• systemic serositis

• fibrin on internal organ’s surface

• granuloma

• peritonitis

Wet FIP Dry FIP

http://www.vetmed.wsu.edu/courses_vm546/Content_Links/DfDx/Cat%20Case%204/systemic_diseases.htm

Wet acute 4-8 wks, C’ fixation increases permeability

Dry chronic, months to

years, CMI

FIPdiagnosis

Good c linical skills- sssss sssssrs

environmentSerology IS NOT THE BEST!

Biopsy Immunohistochemical immunofluorescent staining of gut

biopsy

- RT PCR good but negative doesn’t mean FIP ruled out

WHY SEROLOGY IS NOT THE BEST IN FIP?

• Either healthy and sick cats with disease other than FIP have FCoV antibodies

• Effusive FIP cats have low titers or negative.. Ab bind to lots of viral Ag in effusion not many left to bind with Ag in the test

• The presence of FCoV antibodies alone is NOT diagnostic of FIP, if the other parameters of the profile do not indicate a diagnosis of FIP

Rivalta’s test1. Mix 8 ml of distilled water with one drop of 98% acetic acid2. Carefully place one drop of the pleural or abdominal fluid on the surface

+ if the drop adheres to the surface and hangs like a jellyfish...85% positive predictive value for FIP

- If the drop mixes with the solution and falls to the bottom…nearly 100% negative predictive value

Lab results

• A:G of < 0.4 indicates FIP is quite likely

• A:G of >0.8 rules out FIP

• A:G of between 0.4-0.8 is inconclusive consider other parameters

Lab results

modified transudate.. 3totalprotein>5 / .. sssssss< 5 0 0 0ss sssss

ssssssss sssss: clear straw viscous froth when shaken may clot when refrigerated

Cytology

effusive FIPgenerally < 3 x 109 nucleated cells/L in the effusion

Neutrophilsmacrophages predominate

Cytology of pleural effusions is useful for differentiation of thymic lymphosarcomas

GP level

• alpha one acid glycoprotein (AGP) is an acute phase protein which has been shown to be very useful in distinguishing FIP from other clinically similar conditions

• In FIP, AGP levels are usually > 1500 µg/ml) (normal range 500 µg/ml) )

Conclusions

• FCoV seropositive• total protein of the effusion >35g/l• A:G < 0.4 (or at least less than 0.8)• AGP >1500 µg/ml) • cytology should reveal few nucleated cells which

are mainly neutrophils and macrophages• Rivalta test should be positive• Diagnosis can be confirmed by detecting FCoV

in the macrophages in the effusion

wet FIP

Dry FIP

• high FCoV antibody titre• be hyperglobulinaemic and have a reduced

albumin:globulin ratio• high AGP, lymphopenia, PCV < 30%, non-

regenerative anemia and possibly a neutrophilia• lost weight and ocular signs such as iritis, retinal

vessel cuffing, keratic precipitates, aqueous or vitreous flare

Conclusions

• Non-core• Primucell® -type 2 attenuated virus• intranasal• > 4 m old..booster 3-4 wks later and

annually • can be used in FeLV cat• safe in pregnanted cats• Primucell doesn’t cause ADE

Vaccination

FELINE LEUKEMIA VIRUS (FeLV)characteristics

leukemia

non-regenerative anemia

fadding kitten syndrome infection after birth-thymus atrophy-immunosuppression anorexia

i

FeLVdiagnosis

detect FeLV core protein p27 Ag

ELISA

immunochromatographic assays (ICGAs)

direct FA test

ssss sssss sss9 0 osure/previous test

Free soluble Ag in serum and plasma, tear saliva?

Ag in cytoplasm

•Serology

In some insituations Ab can’t be detected

• Abortive infection• FeLV induced malignant cell clone but not

permanently in genome and destroyed earlier• FeLV infected cells that the body can’t detected• Ab cannot be detected in B cell lymphoma but T

cell lymphoma• 70-94% of cats with mesenteric lymphoma can

not detected Ab• Therefore, use Ag testing forFeLV

• FeLV status of all cats should be known • Testing and identifying positive cats is the mains

tay of managing this disease • All new kittens and adult cats should be tested b

efore introduction into any house • Kittens can be tested at any age • FeLV vaccine does not interfere with the FeLV te

st• ELISA test is the preferred screening test

• Viral isolation

• PCR..strain specific when retrovirus mutation but good to detect latent infection

Vaccination

• all cats at a potential risk of exposure should be vaccinated at the age of 8 or 9 weeks and repeat at 12 weeks

• Annually booster• >older than 3-4 yrs, booster 2-3 years

interval• Use killed vaccine because MLV can

cause disease

Vaccination of immunocompromised cats

• The vaccination of FeLV-positive cats against FeLV is of no benefit whatsoever

• FIV infection should be vaccinated against FeLV infection, but only if they are at risk

• As the immune response in immunocompromised cats is decreased, more frequent boosters may be considered (in asymptomatic cats)

FELINE IMMUNODEFICIENCY VIRUS, FIVcharacteristics

• Immunodeficiency

• Stomatitis

• Tumor

Signs at terminal stage

AC stage

ARC stage

ARC stage AID stageFIV

Dermatological

Chronic abscesses

Chronic gingivitis

Chronic stomatitis

Periodontitis

Pustular dermatitis

http://www.whitecourtvet.com/material/FIVcats.htm

Gastrointestinal

Chronic diarrhea

Weight loss

Immunological Anemia

Leukopenia

Lymph node hypoplasia

Lymph adenopathy

Lymphosarcoma

Neurological

Behavioral changes

Dementia (mental deterioration)

Facial twitching

Peripheral neuropathies

Psychomotor abnormalities

Seizures

Ocular

Cataracts

Conjunctivitis

Glaucoma

Keratitis

Reproductive

Spontaneous abortions and stillbirths

Upper Respiratory

Chronic rhinitis

FIVdiagnosis

Ab - : ELISA, Rapid immunomigration type assay

best confirm with westernblot

Using s erum better than whole blood

* Ab from vaccine interfere when vaccinated wit h different subtype

* sssss ssssssssssssssss sssss ss sss sssssss- Ab from mother- - recheck 6 8 weeks after

* false negative .. late stage of disease

Serology is Mainstay

FIVinterpretation of serology results

• After vaccination, 2-3 weeks, Ab. detected and last for 4 years

• After infection, 8, 10 weeks to 6 months to have Ab.

• Mistake: Cats vaccinated with one type of virus, get infected with the other but interpreted as false positive

maternal immunity• Be aware of interpretation serology results in

cats younger than 6 months old,, detect at age of >6 month

FIVdiagnosis

• FIV Antibody test

• Viral isolation

• PCR, false negative from strain specific

• AAFP recommends testing all cats being introduced into a household to prevent exposing any existing cats to the virus

Misdiagnosis of FIV in uninfected cats may lead to the

inappropriate euthanasia of vaccinated cats or kittens from

vaccinated mother

• Fel-O-Vax vaccine, killed vaccine

• 5 clades of FIV virus

• The virus in the vaccine is not the virus that is commonly causing FIV

• Fibrosarcoma risk

• For FIV cat, used killed vaccine for other disease protection

http://www.newvaccinationprotocols.com/Cat%20Recommendations.htm

Vaccination

CAT FLU

• Herpesvirus • Calicivirus• Reovirus• Cowpox• Bordetella bronchiseptica• Chlamydophila felis• Mycoplasma

CAT FLUcharacteristics

Ulcer in oral cavitySneezingconjunctivitis

PREDISPOSING FACTOR• Crowded environment

зњѥєѝѤєёѤьыҙі ѣўњҕѥкѠѥдѥі ъѥкзј ѧьѧддѤэѯнѪѸѠлѫј нѨёеѠкі ѣээъѥкѯчѧьўѥѕѲлѲьѰєњ

Ѡѥдѥі FHV-1 FCVa Bb ChF Lethargy Sneezing Conjunctivitis Hypersalivation Ocular discharge Nasal discharge Oral ulceration Keratitis Coughing Pneumonia Lameness

+++ +++ ++ ++

+++ +++ (+) +

(+) (+) -

+ + + -c + +

+++ - -

(+) +

+ ++ - -

(+) ++ - -

++ + -

+ +

+++b -

+++ + - - -

+/- -

FHV-1, feline herpesvirus; FCV, feline calicivirus; Bb, Bordetella bronchiseptica; chF, Chlamydophila felis; +++, єѥд; ++, юѥьдј ѥк; +, ѠѕҕѥкѠҕѠь; (+), ѳєҕёээҕѠѕ; +/-, ѳєҕѰѝчкѠѥдѥі -, ѳєҕёэ; a, єѨзњѥєѰшдшҕѥкіѣўњҕѥкѝѯшіь; b, ёэѳчҖшј Ѡчѯњј ѥ, c, ўѥдєѨѰяј ўј ѫєѲьюѥдъѼѥѲўҖіѠэюѥдєѨдѥіѯюҍѕдѰмѣ ъѨѷєѥ: Greene, CE, 2006.

- FELINE HERPESVIRUS (FHV 1, FVR)

FELINE HERPESVIRUS

Characteristics: conjunctivitis

FELINE HERPESVIRUS

diagnosis

• Herpesvirus infection is suspected anytime a cat has an eye problem that does not respond to antibiotics, drooling

• PCR

FCV

Feline Calicivirus

characteristicsOral ulcer

FELINE HERPESVIRUS&CALICIVIRUS

• Clinical signsoral ulceration: FCVhypersalivation, marked sneezing, severe respiratory&conjunctival sign: FHV

• Viral isolation in feline cell culture• Serology

ELISA, no good because Ab from vaccine interfere interpretationImmunofluorescence staining

• PCR

Diagnosis

• all kittens should be vaccinated against FCV

CHLAMYDOPHILA FELIS characteristics

marked persistent conjunctivitis

CHLAMYDOPHILA FELIS diagnosis

• Cultivation is definitive diagnostic test from conjunctival&nasal swabs (rectal&vaginal swabs) using cotton swabs not Dacron swabs then placed immediately in Chlamydia transport medium such as 2SP (0.2 M sucrose, 0.02 M phosphate)

• Do not use viral transport medium containing antibiotics (will inactivated the organisms if not cultured within 24 hrs, keep at 4 C)

CHLAMYDOPHILA FELIS diagnosis

• Cytology: Giemsa staining can detect in early infection, melanin granules in cytoplasm of conjunctival epith. can yield false positive

• Serologydirect FA test using MABs or ELISA cross-reaction with the same genus ELISA - lower specificity and sensitivity

• PCR

CHLAMYDOPHILA FELIS Vaccination

• Both killed and MLV based on whole Chlamydia organism are available as part of multivalent vaccine preparations

• Vaccines are effective in protecting against disease but not against infection

• Vaccination should be considered for cats at risk of exposure to infection, particularly in multicat environments, and if there has been a previous history of Chl infection

• Vaccination of kittens generally begins at 8-10 weeks of age with a second injection 3-4 weeks later

BORDETTELLA BRONCHISEPTICAdiagnosis

B.bronchiseptica isolation

from oropharyngeal&nasal swabs or from tracheal wash, placed into charcoal Amies transport medium before plating to selective medium

BORDETTELLA BRONCHISEPTICA

vaccination

live vaccine is licensed for use as a single vaccination with annual boosters

MYCOPLASMA spp.

characteristics

Hemolytic anemiaIcterous

MYCOPLASMA spp. diagnosis

• Clinical signs• Blood smear • films must be performed before therapy

Blood smears must be performed as soon as possible after collected: detach from RBC so soon in EDTA

Do not use new methylene blue wet preparation

• PCR

Cytologic inaccuracies for detection of hemotrophic Mycoplasmas in cats

Reasons

False positive

Stain precipitate

Drying artifacts

Howell-Jolly bodies

Siderotic inclusions

False negative Transient parasitemia

Excess amount or exposure time to EDTA

Remedy

Use fresh-filtered stains

Make thin smears, dry rapidly

None

Positive with Prussian blue stain

PCR

New bl. specimen, fresh smears, heparin or no anticoagulants

BARTONELLOSIScharacteristics

• not specific• lymphadenopathy• endocarditis• rhinitis• more studies are needed

BARTONELLOSISdiagnosis

• Clinical signs• Isolation*• IFA EIA WesternBlot• PCR

Isolation

• Blood in plastic EDTA tube or lysis centrifugation blood culture

• Sheep or rabbit blood agar• Due to often false negative, not

recommended for screening

Bartonella IFA IgG Slide

IFA test for the detection and semi-quantitation of human serum IgG

antibodies to Bartonella henselae and Bartonella

quintana

CRYPTOCOCCOSIScharacteristics

• sneezing

• epistaxis

• granulomatous rhinitis

CRYPTOCOCCOSISdiagnosis

• Cytology (60% positive of infected cats)

from deep nasal swabs, needle aspiration pleural fluid, bronchoalveolar larvage specimens and CSF, crushed preparation of biopsy samples

Romanovsky stains (DiffQuik Giemsa Wright) new methylene blue, Gram stain

Viewed at X10

India ink (not recommended, lymphocyte and fat droplet cause confusion)

CSF specimens best done by being cytocentrifuged then stained with DiffQuik

CRYPTOCOCCOSIS diagnosis

• Serology

(Commercial kits 90-100% sensitivity, 97-100% specificity)

• Tissue biopsy (impression smear, KOH preparation)

• PCR• Mycology

CONCLUSIONFPV: Serology (Ag, serum, feces, 24-48 hrs after infection)

FIP: Either healthy and sick cats with disease other than FIP can get seropositive result, Effusive FIP cats have low titers or negative.. Ab bind to lots of viral Ag in effusion not many left to bind with Ag in the test

FeLV: FeLV vaccine does not interfere with the FeLV test The ELISA (Enzyme linked immunosorbant assay) test is the preferred screening test

FIV: *Ab from vaccine interferefalse positive.._early stage of the disease- Ab from mother-recheck

6-8 weeks afterfalse negative.. late stage of disease

FCV: oral ulceration FHV: marked sneezing, severe respiratory&conjunctival sign,

hypersalivationChlamydophila felis: Marked conjunctivitis

TOXOPLASMOSIScharacteristics

• pneumonia

• encephalitis

• stillbirths

TOXOPLASMOSISdiagnosis

• Serology

Sabin-Felman dye test (human)

IFA

Agglutination tests

Indirect hemagglutination

Latex agglutination

Modified Agglutination tests

ELISA

TOXOPLASMOSISdiagnosis

• Commercial kits are available

• However, the sensitivity and specificity of these kits may vary widely from one commercial brand to another

• This is of concern because serology results can influence decisions on continuation or termination of pregnancies

•Test serum for presence of Toxoplasma-specific IgG antibodies

TOXOPLASMOSIS

• Cytology

tissues, body fluids (peritoneal&thoracic fluids) during acute illness

Rarely found in blood, CSF fine-needle aspirates, transtracheal or bronchoalveolar washings

Diagnosis

TOXOPLASMOSIS

• Fecal examination

Oocytes found so low (1%) cat shed oocyte 1-2 weeks after exposure

•PCR

Interferon application in Vet. Med.

• Interferons (IFNs): proteins made and released by lymphocytes in response to the presence of pathogens—such as viruses, bacteria, or parasites—or tumor cells

• allow communication between cells to trigger the

protective defenses of the immune system that eradicate pathogens or tumors

• IFNs belong to the large class of glycoproteins known as cytokines

• activate immune cells, such as natural killer cells and macrophages

• increase recognition of infection or tumor cells by up-regulating antigen presentation to T lymphocytes

• increase the ability of uninfected host cells to resist new infection by virus

Types of interferon

• Based on the type of receptor through which they signal, human interferons have been classified into three major types, I II III

Interferon application in Vet. Med.

• Human IFN-α viral replication in some infected catsnot licensed for use in cats, but some clinical studies found increased activity, increased appetite, improvement of blood abnormalities, increased clearance of virus and prolonged survival

• Feline IFN-

In Cats

low-dose interferon protocol as immunomodulator

has not been associated with side effects possibly unpleasant salty taste

high dose protocol as antivirus

may be associated with fever, joint pain, and “flu-like” symptoms

Human IFN-α

Low dose protocol

• Viral Upper Respiratory Infections  

• Feline plasma cell stomatitis 

• Feline eosinophilic granulomas  

• FIP •   • FIV

Human IFN-α

High dose protocol 10,000 unit

•  FIP

• canine viral papillomas

Human IFN-α

• as foreign proteins, they stimulate the pet’s immune system to react against them

Hypersensitivity

• After 3-7 weeks on the high dose protocols, antibodies against interferon may make it ineffective

• FeLV• FIV• FIP good for 1/3 of FIP cats

• non-effusive FIP orally given 30 i.u. / day• effusive FIP >30 i.u. IM / day

• Cat flu

• Gingivitis&stomatitis

• Tumor

topically in the feline eye for herpes conjunctivitis

Feline IFN-

Human IFN-α Feline IFN-

FIP

FIV

FeLV

FCV

FHV

Contradicated

May be

yes

Ineffective

May be

Improved (antiviral or 2nd infection? 5d 3t

Inhibit viral rep

yes

Side effects of interferon• Death, suicide

• Psychiatric

• Cardiovascular myocardial infarction, septal, age undetermined, cardiomyopathy, severe depression of left ventricular systolic function

• Renal nephrotic syndrome, interstitial nephritis

• Hematologic

autoimmune thrombocytopenia, epistaxis

• Neuroloqic left-sided facial paralysis associated with neutropenia and thrombocytopenia, oculomotor nerve paralysis, diplopia, hearing loss

• Dermatologic psoriasis aggravated, generalized urticaria

• Autoimmune SLE-like syndrome

Side effects of interferon

• Ophthalmic

retinal ischemia, decreased visual acuity, cotton wool spots, retinal vein thrombosis, vision disorder

• Endocrine autoimmune thyroiditis, myalgia,asthenia

Side effects of interferon