WHAT DO YOU NEED TO KNOW ABOUT FELINE
WHAT DO YOU NEED TO KNOW ABOUT FELINE INFECTIOUS DISEASES? FANAN SUKSAWAT DVM, MS, PH. D
FELINE INFECTIOUS DISEASES Causative agents FVR FCV P C Fe. LV FIP FIV Chlamydophila Coronavirus Parvovirus Cat flu Calicivirus Herpesvirus Feline leukemia virus Feline immunodeficiency virus
FELINE INFECTIOUS DISEASES Causative agents Chlamydophila spp. Bartonella spp. Toxoplasma gondii Cryptococcus spp.
Scope of this talk Characteristics of each disease Diagnosis Vaccination Potential interferon application
FELINE PARVOVIRAL INFECTION FELINE PANLEUKOPENIA Syn: feline distemper, feline infectious enteritis, cat fever and cat typhoid
FELINE PARVOVIRUS, PANLEUKOPENIA characteristics diarrhea DIC Cerebellar hypoplasia feline ataxia syndrome
Less prevalent nowadays • Widely vaccinated • Virus adjust to cats • CPV to cats. . Ab crossprotect to FPV
FELINE PANLEUKOPENIA diagnosis • clinical signs, and the presence of leukopenia • Leukopenia (severe: 50 -3000 at D 4 -D 6, mild: 3000 -7000 cells/ul( • Thrombocytopenia CPV Kit • 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.
Vaccination Age > 2 m <2 m. Adult Booster Type of vaccine 3 m and yearly MLV 3 -4 wks after till killed* 3 m. and yearly 1 time and MLV, killed yearly pregnanted cat * MLV in <2 m of age no MLV and killed vac
FELINE CORONAVIRUS INFECTION Feline Infectious Peritonitis, FIP
More prevalent • farm raised • indoor raised • inbred
FIP characteristics • • • effusion systemic serositis fibrin on internal organ’s surface granuloma peritonitis
http: //www. vetmed. wsu. edu/courses_vm 546/Co ntent_Links/Df. Dx/Cat%20 Case%204/systemic_d iseases. htm Wet FIP Dry FIP
Wet acute 4 -8 wks, C’ fixation increases permeability Dry chronic, months to years, CMI
FIP diagnosis Good clinical skills- signs history environment Serology 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 FCo. V 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 FCo. V antibodies alone is NOT diagnostic of FIP, if the other parameters of the profile do not indicate a diagnosis of FIP
Rivalta’s test 1. Mix 8 ml of distilled water with one drop of 98% acetic acid 2. 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. . total protein> 35 g/l. . <5000 nucleated cells effusion color: clear straw viscous froth when shaken may clot when refrigerated
Cytology effusive FIP generally < 3 x 109 nucleated cells/L in the effusion Neutrophils macrophages 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 wet FIP • • • FCo. V seropositive total protein of the effusion >35 g/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 FCo. V in the macrophages in the effusion
Conclusions Dry FIP • high FCo. V antibody titre • be hyperglobulinaemic and have a reduced albumin: globulin ratio • high AGP, lymphopenia, PCV < 30%, nonregenerative anemia and possibly a neutrophilia • lost weight and ocular signs such as iritis, retinal vessel cuffing, keratic precipitates, aqueous or vitreous flare
Vaccination • • Non-core Primucell® -type 2 attenuated virus intranasal > 4 m old. . booster 3 -4 wks later and annually • can be used in Fe. LV cat • safe in pregnanted cats • Primucell doesn’t cause ADE
FELINE LEUKEMIA VIRUS (Fe. LV) characteristics leukemia non-regenerative anemia fadding kitten syndrome infection after birth-thymus atrophy-immunosuppression anorexia
Fe. LV diagnosis • Serology detect Fe. LV core protein p 27 Ag ELISA immunochromatographic assays (ICGAs( direct FA test recheck 90 days after exposure/previous test Free soluble Ag in serum and plasma, tear saliva? Ag in cytoplasm
In some insituations Ab can’t be detected • Abortive infection • Fe. LV induced malignant cell clone but not permanently in genome and destroyed earlier • Fe. LV 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 for. Fe. LV
• Fe. LV status of all cats should be known • Testing and identifying positive cats is the mainstay of managing this disease • All new kittens and adult cats should be tested before introduction into any house • Kittens can be tested at any age • Fe. LV vaccine does not interfere with the Fe. LV test • 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 Fe. LV-positive cats against Fe. LV is of no benefit whatsoever • FIV infection should be vaccinated against Fe. LV 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, FIV characteristics • Immunodeficiency • Stomatitis • Tumor
Signs at terminal stage
AC stage ARC stage FIV AID stage
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
FIV diagnosis Serology is Mainstay Ab: ELISA, Rapid immunomigration-type assay best confirm with westernblot Using serum better than whole blood *Ab from vaccine interfere when vaccinated with different subtype false positive. . _early stage of the disease- Ab from mother-recheck 6 -8 weeks after * * false negative. . late stage of disease
FIV interpretation 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
FIV diagnosis • 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
Vaccination • 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%20 Recommendations. htm
CAT FLU • • Herpesvirus Calicivirus Reovirus Cowpox Bordetella bronchiseptica Chlamydophila felis Mycoplasma
CAT FLU characteristics Ulcer in oral cavity Sneezing conjunctivitis
PREDISPOSING FACTOR • Crowded environment
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
Feline Calicivirus FCV characteristics Oral ulcer
FELINE HERPESVIRUS&CALICIVIRUS Diagnosis • Clinical signs oral ulceration: FCV hypersalivation, marked sneezing, severe respiratory&conjunctival sign: FHV • Viral isolation in feline cell culture • Serology ELISA, no good because Ab from vaccine interfere interpretation Immunofluorescence staining • PCR
• 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 2 SP (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 • Serology direct 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 810 weeks of age with a second injection 3 -4 weeks later
BORDETTELLA BRONCHISEPTICA diagnosis 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 anemia Icterous
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 Remedy False positive Stain precipitate Use fresh-filtered stains Drying artifacts Make thin smears, dry rapidly Howell-Jolly bodies Siderotic inclusions False negative Transient parasitemia Excess amount or exposure time to EDTA None Positive with Prussian blue stain PCR New bl. specimen, fresh smears, heparin or no anticoagulants
BARTONELLOSIS characteristics • • • not specific lymphadenopathy endocarditis rhinitis more studies are needed
BARTONELLOSIS diagnosis • • Clinical signs Isolation* IFA EIA Western. Blot 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 Ig. G Slide IFA test for the detection and semi-quantitation of human serum Ig. G antibodies to Bartonella henselae and Bartonella quintana
CRYPTOCOCCOSIS characteristics • sneezing • epistaxis • granulomatous rhinitis
CRYPTOCOCCOSIS diagnosis • 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 (Diff. Quik Giemsa Wright) new methylene blue, Gram stain Viewed at X 10 India ink (not recommended, lymphocyte and fat droplet cause confusion( CSF specimens best done by being cytocentrifuged then stained with Diff. Quik
CRYPTOCOCCOSIS diagnosis • Serology (Commercial kits 90 -100% sensitivity, 97 -100% specificity) • Tissue biopsy (impression smear, KOH preparation) • PCR • Mycology
CONCLUSION FPV: 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 Fe. LV: Fe. LV vaccine does not interfere with the Fe. LV test The ELISA (Enzyme linked immunosorbant assay) test is the preferred screening test FIV: *Ab from vaccine interfere false positive. . _early stage of the disease- Ab from mother-recheck 6 -8 weeks after false negative. . late stage of disease FCV: oral ulceration FHV: marked sneezing, severe respiratory&conjunctival sign, hypersalivation Chlamydophila felis: Marked conjunctivitis
TOXOPLASMOSIS characteristics • pneumonia • encephalitis • stillbirths
TOXOPLASMOSIS diagnosis • Serology Sabin-Felman dye test (human( IFA Agglutination tests Indirect hemagglutination Latex agglutination Modified Agglutination tests ELISA
TOXOPLASMOSIS diagnosis • 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 Ig. G • antibodies
TOXOPLASMOSIS Diagnosis • Cytology tissues, body fluids (peritoneal&thoracic fluids) during acute illness Rarely found in blood, CSF fine-needle aspirates, transtracheal or bronchoalveolar washings
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 cats not 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 “flulike” 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
Feline IFN- • Fe. LV • 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 topically in the feline eye for herpes conjunctivitis • Gingivitis&stomatitis • Tumor
FIP FIV Fe. LV FCV FHV Human IFN-α Feline IFN- Contradicated May be Ineffective May be Improved (antiviral or 2 nd infection? 5 d 3 t 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
Side effects of interferon • 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
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