APPROACH TO CANINE INFECTIOUS DISEASES

2 PRIMARY METHODS FOR DIAGNOSING

INFECTIOUS DISEASES

• Detection of the organism

• Detection of antibodies against the organism

• CPV, aka ___________

• Targets rapidly dividing cells in the _______

• <2 weeks – ______________

• Liver, kidney, heart, vessel, bone marrow, intestine, lungs

• 3 – 8 weeks – _______

• Death after 5 months – from __________

• Parvoviral enteritis

• intestine

• generalized; virus-induced necrosis in tissues rapidly dividing cells

• myocarditis

• myocardial scarring and conduction failure

PATHOPHYSIOLOGY of CPV

• Viral entry → oropharynx & lymphoid

organs → Viremia → Tissue tropism

(radiomimetic) → Viral shedding

• Intestinal damage (crypts)

• Bacterial colonization

• Endotoxic shock

> Hypothermia

> DIC

> Jaundice

GROSS PATHOLOGY

• Lymphoid depletion and thymic

involution

• Mesenteric lymphadenomegaly

• Coagulative lymphadenitis

• Flaccid, segmentally reddened

intestine with serositis (generally

limited to small intestine)

• Intestinal contents: brown to red

brown and fluid with fibrinous

exudate (with or without

hemorrhage)

CPV

HISTOPATHOLOGY

• Villous atrophy secondary to crypt

cell destruction

• Necrotic crypt epithelial cells

• Basophilic intranuclear inclusion

bodies in enterocytes and

lymphocytes (early infection)

CPV

HISTOPATHOLOGY

• Thickened alveolar walls +

inflammatory cells →

interstitial

pneumonia/pulmonary

edema & congestion

• Lymphocytic myocarditis,

recruitment of macrophages

admixed with neutrophils

• Hepatic congestion with

engorged vascular and

sinusoids dilatation

CPV

PATHOLOGICAL SEQUELA of CPV

• Dehydration

• Sepsis

• Acidosis/electrolyte imbalances

ISOLATED BACTERIA FROM FECES (Zheng, Y. et al,

2018)

• Shigella

• Peptoclostridium

• Peptostreptococcus

• Streptococcus

• Fusobacterium

TREATMENT

• Supportive

• Fluids

• Multivitamins

• Symptomatic

• Antiemetic

• Anti-hemorrhagic

• Antimicrobials

RECOMMENDED TREATMENT for CPV

• Crystalloid + Colloid (if with signs of oncotic compromise)

• LRS as primary fluid of choice

• Canine shock dose of 80-90 mL/kg – split in consecutive boluses of 15 – 20 mL/kg given over 15 minutes until improvement of the perfusion

is achieved

• >20 mEq/L potassium hydrochloride (should not exceed 0.5

mEq/kg/h)

• Antibiotics

• Ampicillin, Cefoxitin, Enrofloxacin

• Aminoglycoside (if well-hydrated)

CONTROL AND PREVENTION

• Immunization with MLV CPV2 at ____ weeks of age (for protection)

• Immunization with MLV CPV2 for adults (hyperimmunization of adults → minimized viral shedding)

• Disinfection

• 6

• Subacute systemic disease

with high mortality in dogs

and other carnivores

worldwide

• Single stranded RNA virus,

family Paramyxoviridae

• Outbreaks in shelter facilities

• High morbidity and mortality

• Rapid spread

CANINE DISTEMPER VIRUS

TRANSMISSION

• Oronasal exposure

• Aerosol via coughing and sneezing

• Viral shedding (days 4 to 7)

• Hematogenous spread --> epithelial cells and CNS tissues

• Contagious up to 3 months

CANINE DISTEMPER VIRUS

PATHOGENESIS of CANINE DISTEMPER VIRUS

• Replication in macrophages and

monocytes:

• -

• -

• -

• Multisystemic infection of the

epithelial cells

• Peak virion reproduction _____ days post

infection

• Viremia → Systemic spread of virus to

different organs

• -

• -

• -

• Tonsils

• URT epithelium

• Regional lymph nodes

• 4

• Fever

• Lymphocytic apoptosis → Lymphopenia

• Immunosuppression

CNS PATHOLOGY

• Viral injury & inflammatory

cytokines

• Macrophage activation and

release of inflammatory

cytokines

• Destruction and demyelination of

CNS cells

CANINE DISTEMPER VIRUS

CLINICAL SIGNS

• Asymptomatic to mild (older, with

partial immunity)

• Fever

• Lethargy

• Anorexia

• Dehydration

• Hyperkeratosis

• Serous to mucopurulent oculonasal

discharge

• Viral pneumonia with secondary

bacterial infection

• Vomiting & mucoid to hemorrhagic

diarrhea

• Neurologic sign

CANINE DISTEMPER VIRUS

DIAGNOSIS

• No pathognomonic signs (difficult to diagnose based on symptoms)

• Poor vaccination history

• CBC – lymphopenia as most consistent abnormality

• Biochemical profile

• Cerebrospinal fluid

• ELISA

• RT-PCR

• Necropsy & histopathology

• Culture & SensitivitY

CANINE DISTEMPER VIRUS

TREATMENT FOR CDV

• Supportive

• Parenteral fluids (vomiting & severe diarrhea)

• Antibiotics (bacterial bronchopneumonia and other infection)

• Doxycycline

• Broad-spectrum bactericidal

• Steroid

• Dexamethasone (to control CNS edema)

• Anticonvulsant

• Diazepam (0.25 to 1 mg/kg IV PRN)

• Phenobarbital (2.2 to 8 mg/kg PO BID)

• Levetiracetam (20 mg/kg PO TID)

• Cause of infectious canine hepatitis

• Non-enveloped, double stranded DNA

• Protected with vaccination

CANINE ADENOVIRUS TYPE 1

TRANSMISSION

• Oronasal exposure (body secretions, excretions & environmental

fomites)

• Not airborne

• Viral shedding during acute infection

• Urine as most important source of infection

CANINE ADENOVIRUS TYPE 1

PATHOGENESIS

• Lymphoid tissues of tonsils and regional lymph nodes

• Viremia (3 to 4 days post-infection)

• Infection of other tissues

• Cytopathic effect (liver, eyes, kidney)

• Vascular damage and hemorrhage (from endothelial infection)

• Hepatic necrosis (depends on the level of antiviral antibody)

CANINE ADENOVIRUS TYPE 1

CLINICAL SIGNS

• Corneal edema and anterior uveitis

• Fever, depression, lethargy

• Abdominal discomfort

• Mucus membrane pallor

• Inflammation of the tonsil

• Pharynx with tonsillar and cervical

lymph node enlargement

• Ascites & hepatomegaly

• Laryngitis, tracheitis, pneumonia,

coughing, vomiting & diarrhea

CANINE ADENOVIRUS TYPE 1

OTHER CLINICAL SIGNS

• Petechial and ecchymotic hemorrhages & epistaxis (from coagulation

abnormalities)

• Icterus (uncommon)

• Neurologic signs secondary to hepatic encephalopathy or CNS

infection

• Supported by elevation in serum bile acid and ammonia

CANINE ADENOVIRUS TYPE 1

DIAGNOSIS

• Presenting signs

• Evidence of hepatic disease with poor vaccination history

• CBC

• Thrombocytopenia and bleeding disorder (in the setting of DIC)

• PCR

• Blood chemistry profile

• Elevated ALP, ALT

• Bleeding profile

• Prolonged aPTT and PT

CANINE ADENOVIRUS TYPE 1

TREATMENT OF CAV TYPE 1

• Supportive care

• Liver tonic (i.e. Liv 52, Samylin®, S-adenosylmethionine [Denamarin®])

• Management of clinical signs and complications

• Intravenous fluid

• Blood transfusion

• To address complications of hemorrhage and DIC

• Lactulose

• To address neurologic signs → reduction of concentrations of encephalotoxins

Longest-known infectious diseases in human history

• Has 7 serotypes (6 are transmitted by bats)

• Humans and nearly all animals are susceptible

• 100% fatal if clinical signs appeared

RABIES

TRANSMISSION

• dogs as the main reservoir host

• Mainly predominant in areas of Africa,

Asia, and Central and South America

• Transmission is mainly through

infected saliva

• Replicates in muscles, and ascend via

PNS/CNS

• Shedding: Saliva

RABIES

RABIES

CLINICAL SIGNS

•______

• 2-3 months but may vary from 1 week

to 1 year (6 months on the average)

• _________-

• Starts with the first appearance of

symptoms

• When the virus enters the CNS and

begins to cause damage

• Occurs usually from 2 to 10 days (on the

average) post-inoculation

• Incubation Period

• Prodromal Period

CLINICAL MANIFESTATIONS IN HUMANS

• Acute Neurologic Period

• Duration is 2 to 10 days that may ensue death due to irreversible neuronal

damages

• Occurs in 2 forms: Furious and Paralytic

• _______- hyperactivity, excitable behavior, hydrophobia, aerophobia; death

secondary to cardiorespiratory arrest

• _______ - 20% of the total number of human cases; paralytic muscles

(begins at the site of bite/scratch); progression from comatose to death

• Furious

• Paralytic

DIAGNOSIS

• ANIMALS

• Post-mortem

examination

•___________

• Gold standard

• Brain tissue tested with

fluorescent labelled

antirabies Ab

• Ab directed at

nucleoprotein componenT

• Direct fluorescent

  antibody test

RABIES POST-EXPOSURE PROPHYLAXIS MODALITIES

• ss RNA, Paramyoviridae family

• Most commonly associated with CIRD

• Acute Respiratory Signs

  • Part of core or specific kennel cough vaccine

Canine Parainfluenza Virus (CPiV)

• non-enveloped ds DNA, Adenoviridae family

• seldom isolated from dogs with CIRD in Europe (possibly due to vaccination)

  • Confirmatory test:_____

Canine Adenovirus 2 (CAV-2)
PCR

• enveloped ds dna, Herpesviridiae

• higher prevelance in kenneled dogs vs household

• with secondary role in CIRD

  • activated by more virulent respiratory pathogens

Canine Herpesvirus 1 (CHV-1)

• once considered as a component of CIRD

• but now a multi-systemic morbilivirus causing fatal disease

  • incidence reduced in areas with widely practiced vaccination

CDV

• ss RNA betacoronavirus genus of Coronaviridae

• closely related to bovine coronavirus and human coronavirus

• genetically and serologically distinct from canine coronavirus (enteric)

  • 2nd most prevelent in CIRD

Canine Respiratory Coronavirus (CRCoV)

• ss RNA, orthomyxoviridae family, H3N8

• closely related to equine influenze virus H3N8

• 2007, South korea, avian influenza H3N2 associated with outbreaks of respiratory disease in kenneled dogs

• development of more pathogenic H3N1 CIV

  • Risk: Genetic drift and genetic shift

Canine Influenza Virus (CIV)

• gram negative, aerobic coccobacillus

• normal inhabitant of canine URT

• secondary pathogen

• 80% of dogs with acute respiratory distress

  • most common: Co infection with CPiV

Bordetella bronchioseptica

• gram-positive coccus

• sporadic disease in kenneled and racing dogs

• Beta hemolytic (complete hemolysis), Lancefield group C bacterium

• Chronic nasal discharge rhinitis

  • Acute hemorrhagic, fibrinosuppurative and sometimes fatal bronchopneumonia

Streptococcus equi subsp. Zooepidemicus

Clinical signs

• cough

• decrease in appetite

• anorexia

  • usually BA and afebrile on presentation

DIagnosis

• HIstory

• physical exam

  • tracheal sensitivity

• Diagnostic tests

  • can be deferred or excluded if mild

  • CBC/electrolytes

    • left shift neutrophilia

  • radiograph

  • culture sensitivity

    • PCR

Treatment for respiratory ds.

• Antitussive

  • HYdrocodone - 0.25 mg/kg PO TID - QID PRN

• Expectorant

  • Guaifenesin 3-5 mg/kg PO TID -QID PRN

• Antihistamine

  • Dipenhydramine 2 mg/kg PO BID PRN

• Antibiotic

  • Doxycycline 5-10 mg/kg PO BID 14-21 days

  • Amoxiclav - 13.75 - 20 mg/kg PO BID 7-21 days

  • TMPS for Bordetella

  • Fluoroquinolones for Mycoplasma

Treatment for respiratory ds. Critical care

• Steroids/ anti-inflammatory

• Opioid

  • Morphine 0.3 mg/kg IV PRN

  • Indicated for ARDS (acute respiratory distress syndrome)

• Supportive

  • fluid support

  • oxygen

  • multivitamins