Infectious respiratory diseases Flashcards
CIRD = ?
Describe it.
Canine infectious respiratory disease
complex
- CIRD, kennel cough, infectious tracheobronchitis
- Very common worldwide
- Highly contagious
- Most prevalent in dense dog populations
- Affects larynx, trachea, bronchi, nasal mucosa
CIRD – etiology (5+3)
multifactorial
- Viruses
Canine parainfluenza virus
Canine respiratory coronavirus
Canine adenovirus-2
Canine herpesvirus
Canine influenza virus - Bacteria
Bordetella bronchiseptica
Mycoplasma spp.
Streptococcus equi sp. zooepidemicus
Which of these CIRD pathogens can be vaccinated against?
- Viruses
Canine parainfluenza virus
Canine respiratory coronavirus
Canine adenovirus-2
Canine herpesvirus
Canine influenza virus - Bacteria
Bordetella bronchiseptica
Mycoplasma spp.
Streptococcus equi sp. zooepidemicus
parainfluenza
adenovirus
bordetella
CIRD – clinical signs and findings (4)
- Loud and persistent cough
- Bright, alert, no fever
- Normal respiratory rate and pattern
- No crackles or wheezes on auscultation,
lung sound may be increased
CIRD – diagnostic evaluation
Physical exam, no further testing
Otherwise healthy dog
Cough but in good condition
History of Recent exposure to other dogs
Usually is mild and self-limiting disease (< 10 days).
Complications:
Bacterial pneumonia (especially irish wolfhounds), Bordetella -tracheobronchitis (which can last weeks)
All coughing dogs do not need antibiotic treatment!
CIRD – diagnostic evaluation.
Do further diagnostic testing in which cases?
Febrile, inappetent, lethargic dog
Concurrent illnesses
Immunosuppressive medication
Breed
History of Long-lasting cough
Do Thoracic radiography, blood work,
bronchoscopy, bacterial culture
Describe Bacterial tracheobronchitis.
Occurs in Dogs. Is a Bacterial infection of the airways, but not parenchyma (so not pneumonia). Can be a complication of CIRD.
Most commonly Bordetella bronchiseptica.
You can die of pneumonia but not of tracheobronchitis cause its on the surface of the airways not within the parenchyma.
Bacterial tracheobronchitis presents with (4)
Acute or chronic cough
+ bacterial growth in respiratory sample
+ lack of alveolar infiltrates in thoracic radiographs
+ usually no fever or hematological changes
Treatment of Bacterial tracheobronchitis.
- Treatment
Doxycycline 10-14 days
NB enamel discoloration can occur
Left: normal
Right: bacterial pneumonia with inflammatory cell infiltrate
Describe Bacterial pneumonia
Bacterial infection of airways and
pulmonary parenchyma.
Also called bronchopneumonia
Is more common in Dogs > cats
A potentially severe systemic infection!
50-70 % of cases require hospital treatment
Canine bacterial pneumonia - predisposing factors. (9)
- Viral respiratory infections
- Aspiration
- Ciliary dyskinesia
- Neoplasia
- Trauma, bleeding
- Smoke inhalation
- Pulmonary parasites
- Structural changes
Tracheal collapse, bronchiectasis,
bronchoesophageal fistula - Immune dysfunction
Medications, illnesses, primary dysfunction
Bronchiectasis is…
a long-term condition where the airways of the lungs become widened, leading to a build-up of excess mucus that can make the lungs more vulnerable to infection.
mirrored organ syndrome also called
Situs inversus
Canine bacterial pneumonia - causative bacteria (4)
- Gram negative rods (40-60% of cases)
E. coli, Pasteurella spp., Klebsiella spp. - Gram positive cocci (5-20% of cases)
Streptococcus spp., Staphylococcus spp. - Bordetella bronchiseptica
Significant in puppies and young dogs - Mycoplasma spp.
Commonly a co-infection - Mixed infection in 10-40% of cases
Canine bacterial pneumonia - typical patient
- Large breed dogs
- Less than 5 years of age
- Males overrepresented but we don’t know why
Canine bacterial pneumonia - clinical signs and findings
most typical: tachypnea, lethargy, abnormal auscultation
Next,
* Cough
* Fever
* Respiratory distress
* Anorexia
* Nasal discharge
* Weight loss
Irish Wolfhounds are prone to what respiratory disease?
immune mediated ciliary deficiency / ciliary dyskinesia / Rhinitis/Bronchopneumonia Syndrome
a rare congenital defect where the ciliary throughout the body do not function properly.
This can cause respiratory issues such as coughing, nasal congestion and exercise intolerance.
Canine bacterial pneumonia
- typical blood work (4+2)
Hematology
Left shift (too many immature in circulation)
Neutrophilia
Leukocytosis
Leukopenia
Hypoxemia common
Elevated C-reactive protein (CRP)
Canine bacterial pneumonia - thoracic radiography findings.
- Most important single diagnostic measure.
- Typical findings
Alveolar pattern
Usually several lung lobes affected
Cranial and ventral lobes, both sides - Take 2-3 views! (VD + 2 x lat)
patchy alveolar pattern
only 10% of dogs have this type of change in bacterial pneumonia
Canine bacterial pneumonia - respiratory sample
- Sampling, yes or no?
Antibiotic selection according to susceptibility
Bacterial culture takes time
Samples do not always grow
Bronchoalveolar lavage vs. transtracheal wash
Consider sampling at least in recurrent infections - Neutrophilic inflammation
Possibly intracellular bacteria
Canine bacterial pneumonia - antibiotic treatment.
Antibiotics
Mild pneumonia
Doxycycline (not when liver disease! cause elevation of liver values) / TMS / amoxicillin-clavulanate po
Pneumonia in a dog less than 1 year of age
Doxycycline
Severe pneumonia
Ampicillin + enrofloxacin iv
Treatment length? Is debatable.
Conventional treatment Continue 1-2 weeks after resolution of radiographic findings so up to ~4-6 weeks.
Or CRP-guided therapy
Continue 5-7 days after CRP normalization
~3 weeks
Canine bacterial pneumonia
- treatment other than AB.
Supplemental oxygen
Fluid therapy iv!
Gastric acid blockers if severely hypoxemic
Couppage q 4-6 h
No NSAIDs! (not if they have endotoxemic shock, too much for the kidneys)
Canine bacterial pneumonia
- what NOT to give as treatment
No cough suppressants
No NSAIDs
No conventional-dose furosemide
Describe Feline bacterial pneumonia
- Less common than in dogs
- Less well documented
- No breed predisposition
- Likely underdiagnosed? Can be tricky to diagnose!
Feline bacterial pneumonia - signs and findings.
- Clinical signs
Depression, anorexia, cough, respiratory distress, tachypnea, weight loss, nasal discharge, fever - Clinical findings
Abnormal auscultation
Wheezes, crackles, increased or decreased lung sounds
Dyspnea, tachypnea, abnormal respiratory pattern
Feline bacterial pneumonia can be chronic and mimic inflammatory airway disease!
Feline bacterial pneumonia - diagnosis
- Hematology can be normal
Leukocytosis
Leukopenia and left shift uncommon
SAA can be elevated in acute cases but also can be normal. But you should do SAA anyway.
- Thoracic radiography (min. 2 views!)
Any pattern is possible!
Often alveolar changes
Interstitial, bronchial pattern
Can be normal - Respiratory sample? Can be challenging in cats.
Feline bacterial pneumonia - etiology
- Predisposing cause?
Viral upper respiratory tract infection
Retrovirus infection (FIV,FeLV)
Immunosuppressive medication
Foreign body
Aspiration
Environmental conditions
Feline bacterial pneumonia - possible bacteria (5)
- Mycoplasma spp.
- Pasteurella spp.
- Bordetella bronchiseptica
- Streptococcus spp., Staphylococcus spp.
- E. coli
Feline bacterial pneumonia - treatment
- Antibiotics
Ideally selected on basis of bacterial culture and antibiotic sensitivity testing
Choice Depending on the severity of the disease
Mild disease – PO treatment
Doxycycline, amoxicillin-clavulanate +/-
enro/pradofloxacin
Severe pneumonia, sepsis – iv treatment
Ampicillin iv + enrofloxacin iv
+ Supportive treatment
Aspiration pneumonia
- Inhalation of materials to the lower respiratory tract.
- Chemical damage leading to Inflammation and edema leading to
Secondary bacterial infection - More common in dogs than in cats
Diagnosis of Aspiration pneumonia
Anamnesis, physical exam, radiography
Xray: Cranioventral parts of cranial and middle lung lobes. Right middle lung lobe typical.
Treatment of Aspiration pneumonia
Supportive treatment such as in bacterial pneumonia
Amoxicillin-clavulanate
FURTD = ?
Agents? (5)
Feline upper respiratory tract disease
- Worldwide distribution despite vaccinations
- Problem in multi-cat households
- Young, old, otherwise sick cats
- Causative agents
Feline calicivirus
Feline herpesvirus
Bordetella bronchiseptica
Chlamydia felis
(Mycoplasma felis?)
FURTD – epidemiology
Transmission
Direct contact
Through fomites
Aerosol
herpes & calici viruses (can also include chlamydia bact.)
Clinically recovered carrier cats:
Fe herpes virus leads to a lifelong latent infection which can be reactivated
Feline calici virus carriers shed virus continuously
FURTD – clinical signs
Nasal and ocular discharge, conjunctivitis should self-resolve in 1-2 weeks unless complications.
Calicivirus
Oral ulceration
Hypervirulent strains
Herpesvirus
Ulcerative keratitis, sometimes coughing and systemic disease
Image: left is calici, right is herpes
FURTD – clinical signs of Chlamydia felis (bacteria)
More an ocular than a respiratory pathogen!
Acute and chronic conjunctivitis,
ocular ulceration uncommon.
How to differentiate herpes and calici?
Calicivirus causes ulcers in the mouth.
Herpesvirus causes ulcers in the eyes.
FURTD - diagnosis
In practice, Based on Typical clinical signs and course of disease.
Usually self-limiting in a week
- What is the causative agent?
Important in cat shelter/cattery
outbreaks. Use RT-PCR.
Sample by Nasal swab or swab from conjunctival sack or oropharynx. False negative and false positive results can occur.
FURTD - treatment
- Supportive therapy
- Antibiotics only in more severe cases
Consider if you could have Bordetella? Mycoplasma?
Choose Doxycycline, amoxicillin clavulanate, pradofloxacin but not all of these have efficacy against mycoplasma. - Antiviral treatment in severe or chronic herpes infections (famciclovir/famvir)
- Oral L-lysine for herpes infection can be tried (flumax).
- Prevention by vaccination and management measures.
Name Respiratory parasites
- Non-lungworms
Pulmonary migration of intestinal worms
e.g. Toxocara, Ancylostoma
Usually few symptoms - Lungworms
Final destination the airways, pulmonary
parenchyma or both
e.g. crenosoma vulpis, filaroides osleri/oslerus osleri, capillaria aerophila, aelurostrongylus abstrusus (cat lungworm) etc.
Resp parasite Infection can easily be confused with other respiratory disease!
Diagnosis of Respiratory parasites
Baermann sedimentation and
flotation from feces. Due to Intermittent shedding, 3-day sample! (even when its respiratory parasites - you need both baerman and flotation)
Blood test also possible for specifically Angiostrongylus vasorum (french heartworm) (Immunochromatography, ELISA, PCR) and dirofilaria with 4Dx.
Describe Crenosoma vulpis (only dogs)
Indirect transmission after ingesting a snail or slug.
Matures in the bronchi and bronchioles
Subclinical infection, cough, nasal discharge
Larvae in fecal or BAL Baermann test so order both flotation and baermann.
Treat with Fenbendazole 50mg/kg daily 3 days, moxidectin, ivermectin, milbemycin oxime
In chronically coughing dogs, what parasite should you rule out first?
crenosoma vulpis / french heartworm
Describe Oslerus osleri (Filaroides osleri)
Direct transmission
Causes Granulomatous nodules to distal trachea and proximal bronchi
Subclinical infection, cough, respiratory distress, pneumothorax
Nodules at carina
Fenbendazole, moxidectin?, ivermectin?
Describe Eucoleus aerophilus (Capillaria aerophila) (in both dogs and cats)
Transmission from Ingesting eggs or earthworms
Infects airway mucosa and becomes embedded
Subclinical infection, chronic cough, respiratory distress. Can cause Eosinophilic bronchitis.
Fecal flotation better than Baermann in this case. But false negatives can occur so deworm anyway.
Fenbedazole 50mg/kg daily 10-14 days, ivermectin, maybe moxidectin too. NB long AB course
Describe Aelurostrongylus abstrusus (affects cats)
Common feline lungworm
Transmission by Ingestion of an intermediate host (snail, slug) or a bird or rodent which has ingested it.
Adult worms reside in terminal bronchioles and alveolar ducts.
Cough, wheezing, respiratory distress,
even death
Mimics asthma!
Larvae in feces (Baermann) or BAL
Fenbendazole 50mg/kg daily 10-14 days,
ivermectin, selamectin NB long AB course
Describe Filaroides hirthi and milksi (dogs)
A type of filaroides, canine lungworm
Feco-oral transmission
Reside in the alveolar space and terminal
bronchioles
Subclinical infection, cough, respiratory distress,
even death
Larvae in feces (Baermann) or BAL
Fenbendazole 50mg/kg 10-14 days, ivermectin
Describe Paragonimus kellicotti (dogs and cats)
Lung fluke
Indirect infection after eating crayfish
Migration from intestines into pleural space
and pulmonary parenchyma
Subclinical infection, cough, respiratory distress, pneumothorax
Eggs in feces or BAL (sedimentation)
Praziquantel 25 mg/kg q 8h for 3 days,
fenbendazole
Describe Angiostrongylus vasorum (dogs)
French heart worm
Indirect infection after eating snails, slugs, frogs etc.
Mature parasites reside in pulmonary artery, right heart and pulmonary arterioles
Causes cardiopulmonary symptoms, systemic bleeding
Anemia, eosinophilia, thrombocytopenia, hypercalcemia
Fecal Baermann sedimentation, BAL, ELISA from blood
Fenbendazole 25-50 mg/kg daily for 10-20 days, ivermectin, milbemycin oxime, imidacloprid/moxidectin spot-on, levamisole
Angiostrongylus vasorum vs. Dirofilaria immitis
predilection site?
size?
transmission?
migration?
Both parasites reside in the right heart and pulmonary arteries. Dirofilaria can grow up to 30 cm and Angiostrongylus only up to 1 inch.
Differences in Transmission:
Av: Eating slug, snail, frog containing infective larvae
Di: Transmitted by a bite of a mosquito containing infective larvae
Migration:
Av travels through the gut wall – liver – liver vasculature to right heart and pulmonary arteries, L1 penetrate bronchial and alveolar walls, are coughed up and ingested and passed out in feces.
Di travels in SC tissue and ends up pulmonary arteries and right heart.
Differences in Diagnosis of dirofilaria vs angiostrongylus.
Av: Fecal Baermann, BAL, ELISA from blood
Di: IDEXX Snapp 4Dx ELISA for adult heart worm and modified Knott’s test or PCR for microfilaria
Differences in treatment of dirofilaria vs angiostrongylus.
Av: Fenbendazole 25-50 mg/kg daily for 10-20 days, ivermectin, milbemycin oxime, imidacloprid/moxidectin spot-on, levamisole
Di: From the American heart worm association:
Monthly administration of macrocyclic lactones (e.g., ivermectin, milbemycin) to kill microfilariae and inhibit the maturation of new larvae.
Administering doxycycline (10 mg/kg twice daily for 4 weeks) to target Wolbachia bacteria, an endosymbiont crucial to the survival of heartworms. Reducing Wolbachia weakens heartworms and reduces inflammatory responses.
Adulticide Therapy: a three-dose protocol using melarsomine dihydrochloride. First injection is followed one month later by two more injections given 24 hours apart. This regimen is preferred over the two-dose protocol due to its greater safety and efficacy.
