Path cardioresp: canine infectious resp

Indications for antimicrobial treatment of URT infection

if persists for 10 days

if concurrent fever, lethargy and anorexia

infective agents involved in kennel cough

vanine parainfluenza virus (very common)

canine adenovirus 2

canine herpesvirus 1

Bordetella bronchiseptica

Mycoplasma cynos

Full name for kennel cough

infectious canine tracheobronchitis

Canine infectious respiratory disease complex

Clinical signs and onset/offset of kennel cough

symptoms appear 3-7 days after exposure

Coughing (dry or productive)

Retching (especially during exercise or on lead)

Nasal ± ocular discharge

Sneezing

Usually recovers in 1-3 weeks

Pathogenesis of kennel cough

Virus or Bordetella infect respiratory epithelium.

Pathogen toxins cause cell damage

Damage to ciliated cells inhibits ciliary clearance

Risk of secondary infections in some cases

Symptoms of canine parainfluenza virus

Mild respiratory disease

More severe if combined with Bordetella

Symptoms of canine adenovirus 1 and 2

1 = hepatitis , also reported in resp disease

2 = respiratory disease

not commonly associated with kennel cough

Causative agent

Canine herpesvirus 1

Symptoms of canine herpesvirus 1

fatal systemic disease in puppies <2 weeks “fading puppy syndrome”

<35.5 Celsius

Mild tracheobronchitis in adults (kennel cough)

Multifocal necrotising hepatitis with eosinophilic intranuclear inclusion bodies

necrotising nephritis

Treatment options for Bordetella bronchiseptica

doxycycline

amoxicillin with clavulanic acid

Symptoms of canine respiratory coronavirus

Mild respiratory disease

Newley discovered virus in 2010 involved in kennel cough

canine pneumovirus. Often co-infects with another virus. 93% dogs have antibodies from past exposure.

What strain is canine influenza

H3N2

Symptoms of canine influenza virus (greyhound kennels)

mild respiratory disease (fever, cough)

Haemorrhagic pneumonia

What disease does this dog have

Canine distemper

Symptoms of canine distemper

Nasal and ocular discharge

Cough

Diarrhoea

Vomiting

Depression

Anorexia

Pathogenesis of canine distemper

Virus enters via respiratory tract

Spreads to tonsils and local lymph nodes

Infection of monocytes/macrophages = viraemia and systemic dissemination

some dogs develop good immune response after 2-3 weeks and develop milder form of disease

Dogs with insufficient immune response get viral infection of respiratory, gastrointestinal and genitourinary epithelium, and central nervous system

Virus causes immunosuppression, secondary bacterial infections

4 causes of pneumonia in dogs (LRT infection)

Viral infection

Aspiration of liquid

Inhalation of foreign bodies

Bacterial infection (rare to be primary)

4 causes of pyothorax in dogs (LRT infection)

penetrating wound to chest wall

Rupture of oesophagus or traches due to foreign body

Migration of foreign bodies

Pneumonia (rare), more likely to be consequential

Example lower respiratory pathogens in dogs

Bordetella bronchiseptica

Pasteurella multocida

Streptococcus equi subsp. zooepidermicus, streptococcus canis

Describe the lesion.

cranio-ventral consolidation : suppurative bronchopneumonia.

Describe the pathology and state causative agent

Severe suppurative pneumonia and pleuritis - pyothorax

Associated with cat bite wounds

Pasteurella multocida

Causative agent

Streptococcus equii subsp. zooepidermicus

Clinical signs of Streptococcus subsp. zooepidermicus antemortum and postmortum

antemortum: pyrexia, haemorrhagic nasal discharge, sudden death

Postmortem: severe necro-haemorrhagic and fibrino-suppurative bronchopneumonia

Description, possible causative agents and their features

Pyogranulomatous thoracic infection. Copious red-brown exudate in pleural cavity, contains sulphur granules.

Actinobacteria(gram positive, forms branching filaments: Actinomycetes viscosus - commenal oral- and Nocardia spp (asteroides) - found in soil. Both have same clinical appearance

Causative agent and describe the lesions

Aspergillus fumigatus

Progressive destruction of nasal turbinates by chronic pyogranulomatious (and eosinophilic) inflammation.
Possible yellow mycotic exudate in caudal nasal cavity

Best medium for Aspergillus growth

Sabouraud Dextrose agar (low ph of 5.5 and antibiotics to stop bacterial growth) Grows in 2-3 days.

Describe the two types of aspergillosis infections in dogs

Nasal: invasive sinusitis with persistent sanguino-purulent(blood/pus) nasal discharge (usually unilateral)

Systemic: affects immunosuppressed animals. Signs depend on the locations affected. Difficult treatment, poor prognosis.

What is this pneumonia/lung lesion

Bronchopneumonia caused by aspiration pneumonia. Necrosis present if there are toxin-producing bacteria

Whats this

Lobar pneumonia. Common appearance in cats and dogs

Whats this? causes

Interstitial pneumonia

Haematogenous damage = diffuse distribution

5 acute and 3 chronic causes of interstitial pneumonia

Acute = Infectious (distemper), inhaled chemicals, ingested toxins, systemic conditions (uraemia), hypersensitivity reactions (lungworm)

Chronic = infections (jaagsiekte in sheep), inhaled dust, hypersensitivity reactions (Farmers lung/Saccharopolyspora rectivigula)

What is this and its causes (what it occurs secondary to-3)

Embolic pneumonia.

pulmonary abscesses resulting from septic emboli in the pulmonary vessels.
Secondary to endocarditis, hepatic abscessation and phlebitis

Whats this and causative agent (and how to detect)

Granulomatous pneumonia

Mycobacteria - Ziehl-Neelsen stains red due to acid fast

Fungi/aspergillosis