Infectious Disease: Profiles of Common Shelter Diseases

Infectious Disease: Profiles of Common Shelter Diseases

This section contains one page information sheets with BASIC information about these commonly seen pathogens including, the clinical significance of each agent, the diagnostic options available to shelters, as well as tips on preventing these commonly seen pathogens in the shelter environment.

Campylobacter spp.

Agent: / Campylobacter spp. especially jejuni, sometimes coli. Gram negative, microareophilic, curved rod. Some strain variation in pathogenicity. Non-pathogenic species also exist.
Susceptible domestic species / Cats, dogs, ferrets, rabbits, livestock, poultry, many others
Zoonotic? / Yes; most human cases acquired from undercooked meant but transmission from pets may also occur.
Prevalence / Estimates from 1-6% of pet and shelter cats in several recent surveys in the U.S. Up to 40-50% in some studies. Many studies have shown no association with diarrhea, but other sources have reported higher frequency in diarrheic animals.
Risk factors / Age (< 6 months), stress including surgery,
Clinical signs and significance / Usually asymptomatic. Disease more frequently documented in dogs than cats: watery mucoid diarrhea, +/- blood. Systemic signs may be seen (fever, leukocytosis, inappetance, vomiting). Disease usually lasts 3-7 days, occasionally may be chronic or intermittent. Uncommon sole cause of disease in cats, especially > 6 months old; look for concurrent infections or other problems.
Diagnostic aids: / Stained smear: Insert moistened cotton swab 3-4 cm into rectum. Roll gently on slide. Air dry. Stain with diffquick. Neutrophils suggest bacterial infection (Salmonella or Campy). Gull forms suggest Campylobacter spp. / Culture: Notify lab if campylobacter is suspected. Microareophilic culture required. Lab may suggest special transport media to enhance culture viability. Transport fresh promptly to lab to maximize results. Campylobacter is somewhat fragile; false negative results can occur if sample handling is compromised.
Test comments / Non-pathogenic Campylobacter species may be seen on slide; lab may report results as culture negative in that case. Assorted spirochetes can look like gull forms.
Excreted in : / Feces
Mode of transmission: / Fecal-oral, food and water borne, fomites
Disinfection / Routine disinfection is adequate
Incubation / ~ 3-5 days
Post-recovery shedding / Indefinite in untreated
Carrier state? / Yes
Specific treatment / Macrolides (erythromycin or azithromycin) usually drug of choice, tx for 3 weeks recommended. Resistance is common to penicillins and trimethoprim. Culture and sensitivity may be required in persistent infections.

Canine distemper (CDV)

Disease name: / Canine distemper
Agent: / Morbillivirus (family Paramyxoviridae; enveloped RNA)
Susceptible domestic species / Dogs, ferrets
Zoonotic? / No (suspected links to multiple sclerosis have not been supported by research)
Diagnostic tests: / IFA for viral antigen or inclusion bodies in cells from conjunctival scrape, urine sediment, buffy coat / PCR of nasal or ocular discharge / Serum IgM or rising serum IgG / CSF antibody detection
Test sensitivity / Fair to poor in acute disease, lousy in subacute or chronic disease / Fair during acute respiratory phase of disease / Good / Good in acute encephalitic disease, otherwise poor
Test specificity / Very good / Good ? false positive possible 1-2 weeks after vaccine / Good except false positive may occur within 3 weeks of vaccination / Good ? antibody ratio can rule out blood contamination from traumatic collection
Test comments / Lymphopenia and thrombocytopenia are common acutely. There is no really satisfactory test for diagnosing distemper ante-mortem.
Vaccine available? / Yes
Vaccine efficacy / Good. Vaccine provides rapid protection against infection; puppies exposed 4 hours after vaccination were protected in one study. Recombinant vaccine provides better protection in the face of maternal antibodies (puppies less than 16 weeks).
Excreted in : / All body excretions (feces, urine, etc), but most abundant in respiratory secretions
Mode of transmission: / Highly contagious. Aerosol, droplet, direct contact spread most common. Fomite transmission over short time/distance.
Disinfection / Routine disinfection is adequate. Susceptible to heat, drying and most common disinfectants
Incubation / Fever spike 3-6 days post-infection, clinical signs 1-4 weeks post-infection (longer incubation more common), CNS signs may appear up to 3 months later with or without preceding signs
Post-recovery shedding / Up to 90 days, but usually < 60 days
Carrier state? / No, but mild and inapparent infection common and important in propagation.. Old dog encephalitis may represent recrudescence of latent disease, but dogs are not infectious in the interim.

Canine influenza

Disease name: / Canine influenza
Agent: / Enveloped RNA virus
Susceptible domestic species / Dogs, horses
Zoonotic? / No
Diagnostic tests: / Serology / E.g. Cornell Animal Health Diagnostic Center
Obtain samples 1 week after onset of signs, second sample 2-3 weeks later. 4X rise in titer indicates recent infection. Single positive serum sample indicates past exposure at unknown time.
Flu-A antigen ELISA / Becton-Diskinson

Most sensitive in first 2-3 days of clinical signs. False negatives uncommon. Test kits come on batches of 20, cost comes out to ~ $25/ test.
PCR / E.g. Idexx (
Most sensitive before onset of signs in recently exposed dogs
False negatives common after onset of signs
Excreted in : / Primarily oropharyngeal secretions (mucous, saliva)
Mode of transmission: / Direct, fomite and AEROSOL
Ideally infected dogs should be kept in an area with separate ventilation. At minimum, infected dogs should be separated from other dogs by at least 30 feet.
Disinfection / Persists < 1 week in the environment. Inactivated by most commonly used disinfectants such as alcohol, bleach, quaternary ammonium compounds, and potassium peroxymonosulfate (e.g. Trifectant ?).
Incubation / Onset of signs 2-4 days post infection. Onset of shedding 2-5 days post infection. Note that maximum shedding may occur prior to development of clinical signs.
Post-recovery shedding / Shedding resolves within 7 days post infection.
Carrier state? / No

Canine Kennel Cough (Canine ITB)

Disease name: / Kennel Cough (canine URI)
Agent: / Bordetella bronchiseptica, canine parinfluenza virus (CpiV, enveloped RNA paramyxovirus), canine adenovirus 2 (CAV-2, unenveloped DNA Virus), others
Susceptible domestic species / Dogs, cats
/ Less common for cats to suffer clinical disease, but they may be carriers.. In some cases Bordetella infection may contribute to URI or pneumonia in young kittens.
Zoonotic? / Yes ? rare ? most common in immunocompromised people or those with preexisting respiratory disease
Diagnostic tests: / Culture or PCR of ocular, nasal or oropharyngeal swab for Bordetella. PCR for adenovirus, parainfluenza virus available from some labs.
Test sensitivity (false negatives) / Good ? improved by careful sample handling
Test specificity (false positives) / Good ? however, Bordetella may be isolated from healthy dogs. Specificity of culture is improved by culturing transtracheal or endotracheal wash fluid rather than oral or nasal swabs.
Test comments / Diagnosis almost always made based on clinical signs, r/o of canine distemper in severe cases
Vaccine available? / Yes ? for Bordetella, CpiV, and CAV-2
Vaccine efficacy / Moderate: does not completely prevent infection but reduces severity of signs. MLV IN vaccine may cause mild signs including green nasal discharge that can trigger distemper worries.
Excreted in : / Primarily ocular, nasal and oral secretions
Mode of transmission: / Highly contagious. Transmitted by aerosolized microdroplets, fomites over moderate time/distance, direct contact.
Disinfection / Routine disinfection adequate for all but CAV-2, which requires bleach 1:32 or potassium peroxymonosulfate to fully inactivate Ю / CAV-2 probably a minor player in most cases of kennel cough
Incubation / 3-10 days
Post-recovery shedding / Bordetella may be shed up to 3 months. Viral agents shed < 2 weeks Ю / Infectious risk is greatly reduced when dogs no longer have discharge or coughing.
Carrier state? / No. Cats may have subclinical infections and transmit disease to dogs.

Canine Parvovirus (CPV/parvo)

Disease name: / Parvo (canine parvoviral enteritis)
Agent: / Canine parvovirus (unenveloped DNA virus)
Susceptible domestic species / Dogs, cats (feline infection with CPV strains uncommonly reported in U.S., but is possible [1])
Zoonotic? / No
Diagnostic aids: / ELISA test for fecal antigen / CBC: leukopenia-lymphopenia / In-house necropsy: enteritis, thickening of distal duodenum and jejunum
Test sensitivity (false negatives) / Good in first 5-7 days of disease (estimates range from 69% - 95.8%[2-5]) / Moderate ? more common in severe disease / Good during acute disease
Test specificity (false positives) / Very good (estimates range from 93%-100% - caution in recent vaccinates [2-5]) / Moderate ? may also be seen with Canine Distemper, others / Moderate ? mild cases indistinguishable from enteritis of other causes
Test comments / False positive possible (though uncommon) 5-12 days after MLV vaccine. Usually weak if present. / Histopathology performed by commercial lab is gold standard
Vaccine available? / Yes; modified live subcutanous
Vaccine efficacy / Excellent in dogs >16 weeks (maternal antibody interference possible in dogs < 12-16 weeks)
Excreted in : / Feces ?shedding often precedes clinical signs by a couple of days L
Mode of transmission: / Readily spread due to extreme environmental resistance ? direct contact, fomites, mechanically spread by rodents and insects, can be aerosolized by high pressure sprayers
Disinfection / THOROUGH cleaning followed by bleach 1:32 or potassium peroxymonosulfate. No way to fully decontaminate unbleachable materials/organic matter such as grass or dirt yards. May persist for months or years, especially in dark, cool environments.
Incubation / 3 -14 days (usually 4 -7 days, occasionally up to 21 days)
Post-recovery shedding / Usually <2 weeks
Carrier state? / No, but mild or inapparent infection is common, especially in adults

1.Ikeda, Y., et al., Feline host range of canine parvovirus: Recent emergence of new antigenic types in cats. Emerging Infectious Diseases, 2002. 8(4): p. 341-6.
2.Hoskins, J.D., T. Mirza, and H.W. Taylor, Evaluation of a fecal antigen test for the diagnosis of canine parvovirus. J Am Coll Vet Intern Med, 1996. 10: p. 159.
3.Esfandiari, J. and B. Klingeborn, A comparative study of a new rapid and one-step test for the detection of parvovirus in feces from dogs, cats and mink. J Vet Med B Infect Dis Vet Public Health, 2000. 47(2): p. 145-53.
4.Drane, D.P., R.C. Hamilton, and J.C. Cox, Evaluation of a novel diagnostic test for canine parvovirus. Vet Microbiol, 1994. 41(3): p. 293-302.
5.Veijalainen, P.M., et al., Latex agglutination test for detecting feline panleukopenia virus, canine parvovirus, and parvoviruses of fur animals. J Clin Microbiol, 1986. 23(3): p. 556-9.

Coccidia (Isospora spp.).

Agent: / Coccidia (Isospora spp) Some strain variation in pathogenicity
Susceptible domestic species / Isospora species are species-specific. Feline isospora do not infect dogs and vice versa.
Zoonotic? / No
Prevalence / Estimates from < 5% to > 60% depending on population sampled. No significant association with diarrhea reported.
Risk factors / Age (kittens and puppies), co-infections, stress including transportation, change in ownership, weaning
Clinical signs and significance / Most often subclinical. Difficult to recreate disease in SPF kittens > 4 weeks of age. May cause diarrhea +/- weight loss, dehydration, mucous or blood. Death occurs rarely.
Diagnostic aids: / Fecal floatation.
Test comments / Consider signs, history, signalment, and number of oocysts when assessing significance of oocysts in feces. Clinical signs may precede shedding, leading to false negative floatation results acutely. Coprophagy may lead to presence of oocysts from other species.
Excreted in : / Feces
Mode of transmission: / Fecal-oral, very effectively spread by fomites
Disinfection / Resistant to many disinfectants. High heat cleaning/scalding water or 10% ammonia solution are reportedly effective. Frequent litter box changes are helpful, as it takes 8-36 hours to become infectious in feces.
Incubation / Prepatent period 3-11 days
Post-recovery shedding / 1-9 weeks
Carrier state? / Yes
Specific treatment / Sulfadimethoxine, trimethoprim-sulfa, amprolium.
New treatments are available. For more information visit our vet only section.

Feline calicivirus (FCV)

Disease name: / Feline URI: calicivirus
Agent: / Feline calicivirus (unenvelopedRNA virus)
Susceptible domestic species / Cats
Zoonotic? / No
Clinical signs and significance / Commonly isolated from clinically normal cats. Causes URI: Fever, oral or nasal ulceration (particularly suggestive of calici), sneezing, conjunctivitis (less common than with herpes). Acute or chronic gingivitis, stomatitis, faucitis. Some strains cause limping, Polyarthritis. Pneumonia especially in young kittens. Virulent systemic disease associated with systemic vascular compromise, edema, high fever, death especially in adult cats.
Diagnostic tests: / Viral culture on ocular, nasal or oropharyngeal swabs or serum. / PCR on ocular, nasal or oropharyngeal swabs
Test sensitivity
(false negatives) / Good during acute disease if sample handled correctly. Sensitivity drops off quickly over course of illness. / Similar to viral culture. RNA virus is fragile, easier than herpes to destroy through rough sample handling.
Test specificity (false positives) / Good (but see comments). Vaccination can cause positive results, including long term positive results. / Good (depending on quality control at lab), same considerations as for culture.
Test comments / Many cats are chronic carriers, positive results are common in apparently healthy cats. Positive results from serum (as opposed to oronasal or conjunctival swabs) are more suggestive of infection causing signs of disease.
Vaccine available? / Yes: modified live intranasal, and modified live or killed parenteral.
Vaccine efficacy / Moderate for protection against severe disease, does not prevent infection, may cause mild, contagious disease. Vaccine resistant strains exist. Additional benefit may be gained by giving both IN and parenteral vaccine in shelter.
Excreted in : / All body excretions, especially oronasal secretions.
Mode of transmission: / Highly contagious, moderately environmentally persistent. Spread by direct contact, fomite spread over significant time/distance, droplet spread over distances < five feet
Disinfection / Not reliably killed by quaternary ammonium or many other disinfects, including many alcohol hand sanitizers. Inactivated by bleach or potassium peroxymonosulfate (Trifectant/Virkon) applied to clean surface free of organic matter. Can persist in environment up to 4 weeks if not killed by disinfection.
Incubation / Usually 1-5 days
Post-recovery shedding / Extended. Most shed > 30 days after recovery, and some cats shed life long.
Specific treatment / None proven. Feline interferon (not currently available in the U.S.), bovine lactoferrin, antisense RNA and others have been proposed.
Carrier state? / Yes ? chronic infection is common and shedding tends to be constant rather than stress-associated. Likelihood of transmission from asymptomatic carriers is significantly less than from acutely infected cats, but is possible and may serve to maintain a severe strain of FCV in a population

Feline herpesvirus (FHV - Rhinotraccheitis)

Disease name: / Feline URI: herpes, aka feline viral rhinotracheitis
Agent: / Herpesvirus (enveloped DNA virus)
Susceptible domestic species / Cats
Zoonotic? / No
Clinical signs and significance / May be isolated from asymptomatic cats, especially in multiple cat environments. Causes URI: Sneezing, ocular and nasal discharge, conjunctivitis, keratitis, blepharospasm, fever, anorexia, rarely oral ulceration.Ocular ulceration is particularly suggestive of herpes. Wide range of ocular signs, including chronic conjunctivitis, anterior uveitis, symblepharon, eosinophilic keratitis, corneal sequestrum. Can cause chronic rhinitis/sinusitis, implicated with calicivirus in chronic lymphoplasmacytic gingivostomatitis.
Diagnostic tests: / Viral culture on ocular, nasal or oropharyngeal swabs / PCR on ocular, nasal or oropharyngeal swabs
Test sensitivity
(false negatives) / Good during acute disease if sample handled correctly. Sample will be over-run by calici if concurrently infected. / Good during acute disease. Various PCR techniques exist, some more sensitive than others.
Test specificity (false positives) / Good. Intranasal vaccine can cause positive results soon after vaccination. / Good (depending on quality control at lab)
Test comments / Many cats are chronic carriers; positive test only indicates infection, not that infection is causing clinical signs. Positive results may also be caused by vaccine induced acute or chronic infection.
Vaccine available? / Yes: modified live intranasal, and modified live or killed parenteral.
Vaccine efficacy / Moderate for protection against severe disease, does not prevent infection, may cause mild, contagious disease. Additional benefit may be gained by giving both IN and parenteral vaccine in shelter.
Excreted in : / Primarily in nasal, ocular and oral secretions
Mode of transmission: / Direct contact, fomite spread over short time/distance, droplet spread over distances < five feet
Disinfection / Routine disinfection adequate. Survives no more than 18 hours in the environment (long enough to be transported on unwashed hands or scrub tops, however!)
Incubation / Usually 2-6 days; recrudescent disease usually observed within ~ 7 days after a stressful event.
Post-recovery shedding / 2-3 weeks; see carrier state
Carrier state? / Yes indeed, > 80% of infected cats remain chronic carriers and intermittently shed with stress
Specific treatment / Lysine 500 mgs per adult cat PO BID may help reduce frequency and severity of recurrence. Give as powder, sprinkle on food. Probably more effective as long term preventive than acute treatment.
Topical (for ocular herpes): trifluridine, idoxuridine, or vidarabine (in order from most to least effective AND most to least irritating). At least 5 times a day for 3 weeks.

Feline Immunodeficiency Virus (FIV, sometimes called Feline AIDS)

Disease name: / FIV (sometimes called feline AIDS)
Agent: / Feline Immunodeficiency virus (enveloped RNA retrovirus)
Susceptible domestic species / Cats
Zoonotic? / NO
Diagnostic tests: / ELISA serum test for antibody / Western blot serum test for antibody
Test sensitivity (false negatives) / Good (must be performed 60 days after last known exposure to allow time for seroconversion) / Moderate
Test specificity (false positives) / Good, but false positive common in low prevalence populations ? if possible, positive test should be confirmed by another test.. False positives due to maternal antibodies in kittens < 6 months old or prior vaccination / Good. Thought to be more specific than ELISA, but recent study by Julie Levy suggests ELISA is more specific.
Test comments / There is no currently available test which distinguishes natural infection from vaccination for FIV. More information on retrovirus testing can be found at The American Association of Feline Practitioners Guidelines site
Vaccine available? / Yes
Vaccine efficacy / ~ 80% in manufacturer study; may be less effective in field conditions.
More information on vaccine is available at
Excreted in : / Primarily saliva, genital fluids
Mode of transmission: / Not highly contagious. Transmitted primarily through biting and mating.
Disinfection / Routine disinfection adequate.
Incubation / Antiviral antibodies first detected 2-4 weeks post infection; clinical signs usually develop within 3-6 years post-infection
Post-recovery shedding / N/A
Carrier state? / Cats may be viremic and appear healthy for extended periods, but are infectious to other cats

Feline Infectious Peritonitis (FIP)