Infectious Diseases - Dogs Flashcards
What is parvovirus?
A virus causing severe haemorrhagic vomiting and/or diarrhoea with leukopenia
How is canine parvovirus transmitted?
Faeco-oral spread - large quantities shed in diarrhoea
How can parvovirus particles be inactivated?
Formalin and hypochlorite disinfectants (bleach-based)
What is the pathogenesis of canine parvovirus?
Infects rapidly dividing tissue (neonatal myocardium, intestinal crypts, bone marrow) and causes ulcerations
What are the clinical signs of canine parvovirus?
Intestinal - haemorrhagic diarrhoea +/- vomiting - depressed, anorexic, abdominal pain
Bone marrow - neutropenia
Risk of sepsis - pyrexia, CVS compromise
How is canine parvovirus diagnosed?
Clinical suspicions should lead to faecal parvovirus antigen ELISA test
May be anaemic/hypoproteinaemic
Electrolyte imbalances
Post-mortem (various tissues)
What is the treatment for canine parvovirus?
Aggressive fluid therapy - IV crystalloids
Monitor electrolytes and glucose
NG tube trickle feeding (once vomiting controlled)
Anti-emetics (Maropitant, metoclopramide)
Antibiotics (amoxicillin clavulanate IV)
What nursing considerations should be made when caring for a parvovirus puppy?
Dedicated nurse/nurse last
Ensure comfortable (reduce diarrhoea/salivation scalds)
Ensure warm and euhydrated/euvolaemic
Notify if pyrexic/hypothermic
Early nutrition essential to recovery
How can canine parvovirus infection be prevented?
Vaccination
Recovery from natural infection gives life-long protection (not ideal)
Can cats get parvovirus?
Yes - feline panleukopenia, feline infectious enteritis
Closely related to canine PV
What is the typical presentation of a dog with leptospirosis?
Acute or chronic hepatic and/or renal insult
Is leptospirosis zoonotic?
Yes
How is leptospirosis transmitted?
Environmental contamination with infected urine - cannot replicate outside host
Infection when contaminated urine contacts mucous membranes/compromised skin
What are the 2 phases of pathogenesis involving leptospirosis?
Replicates within the bloodstream (leptospiraemia)
Renal infection and shedding in urine (leptospiruria)
What is the incubation period for leptospirosis?
Approx 1 week - varies between animals
What is the clinical presentation of leptospirosis infection?
Typically acute
Hepatic injury +/- jaundice
Renal injury +/- failure
Lethargy, pyrexia, inappetence, vomiting, diarrhoea
Signs related to affected organ system(s)
What might you find upon examination of a dog with leptospirosis?
Dog is lethargic, dull, frequently pyrexic
+/- jaundice, petechial haemorrhages, mild generalised lymphadenomegaly
What laboratory findings might be seen with leptospirosis infection?
Varies considerably between patients
Thrombocytopenia common
Raised liver enzymes (hepatic injury)
Azotemia (renal injury) - anuria/polyuria possible, monitor UOP
How is leptospirosis diagnosed?
Demonstration of serologic conversion (antibodies in blood)
Organism identification via PCR
How is leptospirosis treated?
If suspected, start treating BEFORE confirmed diagnosis
Doxycycline (2 weeks)
Amoxicillin clavulanate
Supportive treatment for affected organs
What is the prognosis for leptospirosis infection?
> 50% full recovery
Others turn into chronic disease which is ultimately fatal despite treatment
What nursing care considerations should you take with leptospirosis?
Careful hygiene, barrier nursing
Disinfect appropriately (chlorine/phenol based)
Appropriate cage signage
Designated urination area - roughly monitor UOP (do not handle - zoonotic)
Consider location of phlebotomy if thrombocytopenic
What considerations should be taken to avoid zoonotic infections of leptospirosis?
Avoid contact with bodily fluids (urine and blood esp)
What is canine distemper virus?
Virus causing multi-systemic disease, including respiratory, GI, neurological and dermatological disease
What type of virus is canine distemper virus?
Enveloped RNA morbillivirus
How is canine distemper virus inactivated?
Rapidly via heat, drying, disinfectants
Survives <1 day in environment
What is the pathogenesis of canine distemper?
Replicates in tonsils/lymphoid tissues of upper respiratory tract
Invades and travels in monocytes and disseminates to entire reticuloendothelial system
How is canine distemper transmitted?
Transmitted via oro-nasal secretions - direct contact or large-particle aerosol
What is the clinical presentation of acute canine distemper infection?
Highly variable - can be sub-clinical or rapidly progressive and fatal
Pyrexia, lethargy, vomiting +/- diarrhoea
Cough, naso-ocular discharge
Neurological signs
Secondary infections common
What are the common neurological signs of canine distemper?
Seizures, ataxia, myoclonus
‘Old dog encephalitis’
What clinical signs can be seen with chronic distemper infection?
Ocular - various inflammatory manifestations +/- blindness
Dental - enamel and dentin hypoplasia
Dermatological - foot pad and nasal planum hyperkeratosis
How is canine distemper diagnosed?
Lymphopenia common
Identification of organism via cytology, ELISA/PCR, post-mortem
Serology (antibody detection)
What is the management for canine distemper?
Isolate/barrier nurse
Supportive nursing and management of secondary infections
Vitamin A?
are anti-virals available for canine distemper?
not currently
How can canine distemper infection be prevented?
Recovery from natural infection gives life-long immunity
Immunity requires cell-mediated immunity and antibodies
What are the 2 types of canine adenovirus?
CAV-1 - infectious canine hepatitis
CAV-2 - respiratory pathogen, causes mild disease, part of the kennel cough complex
What type of adenovirus do we vaccinate dogs with?
Modified live CAV-2
Why don’t we vaccinate dogs with CAV-1?
Vaccination with CAV-1 can lead to glomerulopathy and corneal oedema (‘blue eye’) - CAV-2 gives protection against both types
How long does CAV-1 survive in the environment? How is it inactivated?
Survives at room temperature for months but readily inactivated by disinfectants
How is CAV-1 transmitted?
Shed in saliva/urine/faeces for months post-infection
Direct dog-dog contact or via fomites
What is the pathogenesis of CAV-1?
First picked up by oro-nasopharynx/conjunctiva –> tonsillar replication –> lymphatic spread –> lymph nodes and bloodstream
Cell injury and lysis causes widespread tissue damage
What is the incubation period for CAV-1?
4-9 days (average, can vary)
What are the 4 classifications of CAV-1 infection?
Mild/subclinical (vaccinated dogs)
Per-acute (circulatory collapse and death in 1-2 days)
Acute (severe disease, 1-2 weeks)
Sub-acute (hepatic failure)
What are the clinical signs of CAV-1 infection?
Hepatic injury
Petechial haemorrhages +/- GI haemorrhage
Conjunctivitis +/- uveitis and oedema
Pyrexia, lethargy, inappetence, V+/D+, tachypnoea
Glomerular/tubular damage
How is CAV-1 infection diagnosed?
Leukopenia/neutropenia +/- pancytopenia
Serology - rising titre
Virus identification through PCR
Characteristic intranuclear inclusion bodies
What is the treatment for CAV-1 infection?
No specific treatment - supportive nursing (barrier)
Fluid/nutritional support
Anti-emetics and analgesia if required
Ophthalmic care
How is canine herpesvirus transmitted?
Latent infection of neural ganglia –> reactivation/shedding at times of stress
Typically venereal transmission
Why are signs of canine herpesvirus usually only apparent in puppies?
Canine herpesvirus only replicates <37°C - puppies have lower internal body temperature than adults
Why is it important to have pregnant bitches vaccinated against herpesvirus?
Exposure of pregnant bitch in last trimester leads to abortions/neonatal deaths (up to 100% of litter)
Which respiratory pathogens are considered part of the canine kennel cough complex?
Bordetella bronchiseptica
Canine parainfluenza virus
CAV-2
What is the lay term for infectious tracheobronchitis?
kennel cough
What are the clinical indications of kennel cough?
Self-liming acute URT cough, harsh and hacking
Concurrent oculo-nasal signs
Progression to pneumonia (not common)
How is kennel cough transmitted?
Highly contagious aerosol, direct and fomite transmission
How should kennel cough be treated if there are no other significant clinical findings?
Usually self limiting - don’t walk on collar, keep well away from other dogs
+/- NSAIDs
+/- Cough suppressants (only if non-productive coughing)
How should kennel cough be treated if there are also lower respiratory/systemic signs?
Antibiotics - doxycycline
Radiography
What are the symptoms of bacterial enterocolitis?
Haemorrhagic vomiting +/- diarrhoea
Pyrexia
Sepsis
+/- abdominal pain
Why is diagnosis of bacterial enterocolitis often a challenge?
Most culprit bacteria can be isolated from faeces of healthy dogs - challenge is proving causality
What are the risk factors for bacterial enterocolitis?
Raw fed
Young dogs
Unsanitary/crowded environments
How is bacterial enterocolitis diagnosed?
Consider faecal culture but remember to evaluate for parvovirus as signs can be very similar
How would you diagnose and treat campylobacter spp.?
If faecal culture positive, speciate with PCR (C. jejuni related to disease in dogs)
First line treatment is erythromycin (not licensed)
How would you diagnose and treat a salmonella spp. infection?
Faecal and/or blood culture and PCR
Treat with antibiotics (fluoroquinolones) but only if systemically unwell
How would you diagnose a Escherichia coli. infection?
Positive faecal culture
Can then evaluate for pathogenicity genes but this still does not prove causality - may be commensal
How would you treat an Escherichia coli infection?
Antimicrobials
How would you diagnose a Clostridium perfringens infection?
Test for clostridium perfringens enterotoxin (CPE) in faeces (ELISA)
Identify CPE gene via PCR
How would you treat a Clostridium perfringens infection?
Ampicillin or metronidazole
Only treat if systemically ill (haemorrhagic gastroenteritis, pyrexia, inflammatory leukogram)
What is acute haemorrhagic diarrhoea syndrome?
Syndrome of acute haemorrhagic diarrhoea and marked haemoconcentration (+/- vomiting)
Which bacteria most commonly causes AHDS?
Increasing evidence for C. perfringens NetF in pathogenesis (causes pore in enterocytes)
What is the clinical presentation of AHDS?
Acute onset haemorrhagic vomiting +/- diarrhoea
Abdominal pain
Obtundation
Hypovolaemic shock
Marked haemoconcentration
How would you diagnose AHDS?
Consistent clinical signs
Marked elevation in PCV (>60%) without commensurate increase in proteins
Exclusion of other causes (parvo, dietary toxins, pacreatitis, hypoadrenocorticism)
How would you treat a case of AHDS?
IV crystalloids (boluses and CRI)
Amoxicillin clavulanate (not indicated unless systemically unwell)
How would you diagnose a Clostridium difficile infection?
Faecal culture and/or common antigen test
ELISA for toxins
How would you treat a Clostridium difficile infection?
Metronidazole (where clinically indicated)
If antibiotic-induced, stop antibiotics
With which overall symptoms should you consider the cause to be a bacterial pathogen?
Acute haemorrhagic vomiting and/or diarrhoea
With signs of sepsis, pyrexia, inflammatory leukogram
What nursing considerations should you take with a bacterial enterocolitis infection?
Barrier nursing
Fluid balance - euvolaemia, euhydration
Consider abdominal pain, nausea, appetite, and severity of haemorrhagic component
