Infectious diseases of dogs Flashcards
What is the causative agent of Rubarth’s disease
Canine adenovirus 1
Infectious canine hepatitis virus characteristics
= from canine adenovirus 1
Non enveloped dsDNA; survives well in environment
How does infection with canine adenovirus 1 work
Mainly puppies before vaccination
Naso/oropharyngeal infection; penetrates epithelium –> lymphatic spread to hepatocytes/kidney/spleen/eye
Clinical signs of canine infectious hepatitis
Lethargy, anorexia, abdominal pain, hepatomegaly, jaundice, vomiting, haematemesis/chezia
May see BLUE EYE in first week of infection
Pathological findings with infectious canine hepatitis PM
Protein rich fluid in peritoneum, swollen pale liver, ecchymotic haemorrhages on serosa
Histologically: hepatocytes have owl eye includion bodies, necrosis in liver
+ blue eye = antibody-antigen response; POSITIVE sign for recovery
Can get dissemination into brain
Canine distemper virus
= enveloped RNS virus; causes multisystem disease
Paramyxovirus
Get infection of URT lymphoid tissue, spread via lymphatics –> viraemia
THEN affects respiratry, GI, CNS and skin
What are the signs of classical distemper
Prexia, anorexa, conjunctiviity, oculo-nasal diacharge, cough, leukopenia
What is chronic distemper
Where a good immune response is mounted
See ocular signs
CNS effects; progressive ataxia, paralysis
Hyperkeratotic epithelial tissue = HARD PAD
Enamel hypoplasia if while developing dentition
Which virus is responsible for ‘hard pad’ due to proliferation of epithelial tissue
Distemper virus; chornic form
What viruses are covered by DHPPi vaccination
Distemper virus
Hepatitis; via canine adenovirus
Parainfluenza virus
Parvovirus
Canine parovirus
= non-enveloped ssDNA virus; stable in environment
Seen esp in puppies
Faeco-oral transmission; get replication in oropharyngeal lymphoid tissue -> viraemia -> infects rapidly dividing cells
Clinical signs of canine parvovirus
Fever, lethargy, abdominal pain, emesis
THEN profuse haemorrhagic diarrhoea
IF neonates/in utero infections: can get myocarditis; see death or congestive heart failure
What strains does the L4 vaccine contain
L icterohaemorrhagiae, L canicola, L grippotyphosa, L australis
What do leptospira pathogens look like
= thin, spiral, motile bacteria
How does leptospira infection work
Urine contact; organisms penetrate abraded skin or intact MMs
–> Rapid multiplication in blood stream
–> Spread to kidneys and liver
Release haemolysin toxin; so see intravascular haemolysis and icterus
+ petechial haemorrhages from bacteraemia
Where is the reservoir of lectospira in the host
Proximal convoluted tubules
What blood parameters give leptospira suspicion
Thrombocytopenia, raised liver and kidney parameters
Normal blood glucose BUT GLUCOSE IN URINE
Treatment of leptospira
Doxycycline
Ampicillin/penicillin
Pathology seen with leptospira infection
Icterus, enlarged liver and spleen, ecchymotic haemorhages
On histology: dissociation of hepatocytes so don’t see portal triads etc; relative lack f inflammation
Which dogs are especially at risk of leptospirosis
Male, large breed, entire dogs with wildlife access i.e outdoor
What are the infectious agents in kennel cough
Bordetella bronchiseptica
Canine parainfluenza virus
Also: CDV, CAV-2, CHV-1
Clinical signs of infectious canine tracheobronchitis
Dry hacking cough, pharyngeal retch, serous nasal discharge
Often think there is ‘something in their throat’
Difference in how herpes viruses affect dogs and cats
In dogs, virus can become systemic
What class of herpesvirus affects dogs
Alpha
e.g CHV-1
Causative agent in tetanus
Clostridium tetani = gram +ve spore forming anaerobe
Clinical signs of tetanus
Stiff gait, dorsally curved tail, erect ears, difficulty standing or lying
Pathogenesis of tetanus
Spores enter penetrating wounds and convert to vegetative state; start making toxins which ascend nerves and prevent release of inhibitory neurotransmitters by interneurons
-> Get spastic paralysis
See signs 3-18 days after wound contamination
What causes Lyme disease and what are the signs in dogs
Spirochaete B burgdorferi; spread by Ixodes ricinis ticks
Dogs mainly asymptomatic
If in doubt in dogs what are we treating bacterial infections with
doxycycline
How does angiostrongylus vasorum infection in dogs work
Adults live in pulmonary arteries; get coughing and activation of coagulation system
COMBINATION: RESPIRATORY SIGNS AND ABNORMAL BLEEDING
Treatment for angiostrongylus vasorum in dogs
Fenbendazole
Could use advocate (moxidectin)
What type of virus causes rabies
Enveloped RNA virus
= lyssavirus
What genotype is classical rabies vs bat rabies
Classical = 1
Bat rabies = 2-7
Diagnosis of rabies
Fluorescent antibody staining of the brain used to be used but false -ves
real-time PCR best
Pathogenesis of rabies
Inoculation via bite wound; migration to the CNS via nerves, CNS multiplication then viral dissemination
Furious form: excitement pyrexia, aggression
Dumb form: timid, affectionate, dysphagia
Both progress to paralysis and death
Other sign - hydrophobia due to pain on swallowing; so saliva drools out
What is the minimum age a puppy can be given. rabies vaccination
12 weeks; then takes 3 weeks before effective enough to import puppy
Survival of rabies virus
Can surivive in deep freezing
BUT readily inactivated by disinfectants
Histopath of rabies
No gross lesions
On histopath see non-suppurative polioencephalomyelitis
Negri bodies = intra-cytoplasmic inclusinos
