Canine viral diseases 1 - Nicole Flashcards
how does herpesvirus infect adult dogs?
infection through venereal or respiratory epithelial cells
how does herpesvirus infect neonate dogs?
ingestion or inhalation (birth canal, contact, fomites)
how does herpesvirus infect fetal dogs?
through the placenta
once a dog has been infected with herpesvirus, what happens? (adult, neonate, fetus)
adult & neonate >2 weeks old - localized infection & replication, then latency
Fetus & neonate <1 week old - leukocyte-associated viremia and generalized infection
Once the adult & neonate > 2 weeks old have been infected with herpesvirus, and localized infection & replication have happened, what is the outcome?
virus will not be cleared from body and will persist in respiratory and genital tracts & replicate in endothelial cells and have latency
after a neonate <1 week old or fetus are infected with herpesvirus, and leukocyte-associated viremia + generalized infection has taken place, what then?
diffuse necrotizing vasculitis, mutlifocal hemorrhagic necrosis of many organs, including CNS
THEN
- animal recovers OR
- neonatal illness/death // fetal abortion/ stillbirth / infertility
herpesvirus clinical presentation adults
often subclinical and latency follows. It may also be associated with mild rhinitis / vesicular vaginitis /posthitis
where are the sites of herpesvirus latency
the trigeminal and lumbosacral ganglia are the sites of latency
herpesvirus presentation in pregnant animals
early fetal loss, late-term abortion, stillbirth, or the birth of compromised neonates
what gross lesion is pathognomonic of canine herpesvirus-1 infection?
presence of petechiae in the renal cortex of the newborn
herpesvirus - radiating hemorrhages from the renal pelvis are present in the
kidneys & may also have tubular necrosis
herpesvirus-infected epithelial cells contain
round eosinophilic, intranuclear inclusion bodies surrounded by a clear halo and marginated chromatin
herpesvirus effects on liver
multifocal necrosis and hemorrhages
herpesvirus - viral antigen and similar lesions observable in which organs
vascular endothelium, liver, adrenal glands, lungs, spleen, kidneys, and lymph nodes
lung lesions from herpesvirus
small coalescing pale foci - necrotizing interstitial pneumonitis
pulmonary parenchyma appearance herpesvirus
focally effaced by fibrin exudate and necrotic cell debris
herpesvirus-infected epithelial cells contain
round, eosinophilic, intranuclear inclusion bodies surrounded by a clear halo and marginated chromatin
ocular form of herpesvirus
diffuse corneal oedema and mature cataracts
can you isolate herpesvirus in the CNS?
yes in cerebellum and cerebrum
diagnosis herpesvirus
-lesions in affected neonates are pathognomonic
- virus can be isolated from fresh lung, liver, kidney, and spleen by cell culture techniques
-histological demonstration of intra-nuclear inclusion bodies
-virus neutralization assay is available at OVC
control of herpesvirus
no vaccine is available
- colostrum (maternal antibody) protects the pup from disease
- removing puppies from affected mother by c-section and rearing in isolation has prevented deaths under experimental conditions - but if virus has crossed the placenta already might not work
infectious canine hepatitis family & causative agent
adenoviridae & canine adenovirus 1 (CAV-1)
CAV-2 infection is part of the complex that causes
infectious canine tracheobronchitis (kennel cough)
CAV-1 virus description
-naked double stranded DNA virus
-replicates in nucleus & forms intranuclear inclusions
Adenoviridae pentons make up
the apices and possess projecting fibers that mediate the attachment of the virus to cellular receptors
can adenoviruses infect many different species?
yes
is CAV-1 stable in the environment?
yes but is susceptible to iodine, phenol, and sodium hydroxide and heating for 5 minutes between 50-60°C
CAV-1 causes clinical disease in
dogs, foxes, coyotes, and other canids and bears
is subclinical disease common for CAV-1
yes, widespread serological response in wild canids
most common age for Infectious canine hepatitis
within a year of age - however, unvaccinated dogs may get the clinical disease at any time
transmission of infectious canine hepatitis
contact with fomites
-oronasal exposure
-ectoparasites are shown to harbour the virus and may be involved
-aerosol transmission unlikely
does canine infectious hepatitis have an acute or chronic phase?
both
acute canine infectious hepatitis - virus excretion
virus excretion in saliva, feces, respiratory mucus-during the acute phase (5-10 days)
which type of hypersensitivity does canine infectious hepatitis cause?
local type 3 hypersensitivity - immune complex formation
canine infectious hepatitis - chronic - how long do animals excrete the virus
virus excretion in urine for 6-9 months, start 10-14 days of infection
mechanisms of kidney damage during canine adenovirus 1 * WILL PROBABLY BE A QUESTION*
1 - cytopathic effect due to viral replication
2 - antibody production/immune complex formation
canine adenovirus 1 - cytopathic effect due to viral replication explained
virus can replicate in cells which causes damage to the cells and affects hepatocytes, renal tubule cells, and vascular endothelial cells
can the brain get affected by infectious canine hepatitis?
yes - it has endothelial cells that can be targets for viral replication or antibody complex deposition
canine adenovirus 1 - how do circulating antibody complexes damage the kidneys
circulating complexes can deposit in ANY endothelial cells and can then deposit in renal glomeruli causing glomerulonephritis
canine adenovirus 1 - how do circulating antibody complexes cause local damage in eyes
antibody complexes deposit in cornea, causing opacity and anterior uveitis
signs of canine adenovirus-1
slight fever, lethargy, mucous membrane congestion, tender abdomen, jaundice, vomiting
where can canine adenovirus 1 cause hemorrhage?
lungs, thickened gall bladder, lymph nodes, enteritis, oral mucosa, neurologic
other lesions caused by canine adenovirus 1
petechial and echimotic hemorrhages in all serous surfaces
diagnosis of canine adenovirus 1
clinical signs, hematological findings, and liver enzyme changes are suggestive of infectious canine hepatitis (main way)
- can also do ante mortem confirmation by serology, virus isolation, and molecular techniques or post mortem histopathology
source of infection of infectious canine hepatitis-
virus in environment is very resistant (not enveloped) and reservoir in wild carnivores (sub clinical) and ectoparasites
control of infectious canine hepatitis - maternal immunity
pups are protected 5-7 wks but by 14-16 weeks wanes completely
control of infectious canine hepatitis - vaccination
killed vaccines - safe & need frequent administration (annual) - CAV-1
-modified live viral vaccine (given every 3-5 years) - CAV-1
if given the CAV-1 modified live viral vaccine, what can develop in dogs?
vaccine virus can localize in the kidney - mild subclinical interstitial nephritis and virus is shed in urine, they can also develop blue eye (see other flashcard)
do modern vaccines against infectious canine hepatitis contain CAV-1 or CAV-2?
CAV-1 or CAV-2, but not both. However, either one protects against both hepatitis and cough
can different vaccines for canine infectious hepatitis cause different side effects?
yes - different for CAV-1 vs CAV-2 vaccines AND by route administered
typical modified live vaccine route for canine infectious hepatitis
IM/subq
IM/subq modified live side effects for CAV-1 and CAV-2 vaccines
CAV-1 - uveitis (0.4%) & urinary shedding
CAV-2 - none
does an intraocular CAV-1 or CAV-2 modified live vaccine cause any side effects?
yes - uveitis in 100% of cases for both
does intranasal CAV-1 or CAV-2 modified live vaccine cause any side effects
none in CAV-1 and mild resp disease in CAV-2
does IV CAV-1 or CAV-2 modified live vaccine cause any side effects
CAV-1 - fever, uveitis, urinary shedding
CAV-2 - fever, mild resp, tonsilitis
Does CAV-2 virus protect against kennel cough too?
yes
is canine infectious tracheobronchitis a multifactorial disease?
yes - can have viral & bacterial causes
canine infectious tracheobronchitis viral etiology
canine parainfluenza virus (CPiV) - most common
CAV-2
Canine distemper virus
canine infectious tracheobronchitis bacterial etiology
bordatella bronchisepta may act as primary pathogen & most common
others may cause secondary infections after viral injury
risk factors for canine infectious tracheobronchitis
-dogs housed in high density
-mixing of dogs from diff origins and age
-contact with sick animals
-stress
- B. bronchosepta host range
-pre-existing subclinical airway diseases
-housing with poor hygiene
how long do animals shed canine infectious tracheobronchitis
viral agents excreted for about 2 weeks and bacterial agents for >3 months
transmission of canine infectious tracheobronchitis
virus is shed in ocular and resp secretions
-aerosolized micro-droplets, direct contact, and on contaminated fomites
canine infectious tracheobronchitis viral shedding
one slide said for about two weeks and another slide said for 8-10 days so not sure which one is right
two forms of canine infectious tracheobronchitis
- uncomplicated
- complicated
uncomplicated form canine infectious tracheobronchitis - signs
harsh dry cough, watery nasal discharge, pharyngitis, and tonsillitis (not systemically ill)
site of viral replication canine infectious tracheobronchitis
respiratory epithelium, & destroys these cells
how long does uncomplicated canine infectious tracheobronchitis last
body mounts immune response and mild disease passes in 1-2 weeks, severe disease passes in 3-4 weeks
how to help treat uncomplicated canine infectious tracheobronchitis
reduce stress and exercise to minimize irritation to the airways
complicated form canine infectious tracheobronchitis - who does this occur in
young unvaccinated puppies, immunocompromised, and elderly animals
in complicated form, can the body generate immune response?
canine infectious tracheobronchitis
body unable to generate appropriate antibody response –> viremia –> secondary bacterial infections –> lethargy, severe fever, and inappetence
do complicated canine infectious tracheobronchitis dogs require treatment
yes
canine infectious tracheobronchitis clinical findings
dry hacking cough sometimes followed by retching and gagging - loud honking sound
- cough can be induced by gentle palpation of larynx or trachea
control of canine infectious tracheobronchitis
vaccination <3
canine infectious tracheobronchitis - what kind of vaccine is used?
modified live virus vaccines against distemper, CPiV, and CAV-2, which also provides protection against CAV-1
canine infectious tracheobronchitis vaccine schedule
initial vaccination should be given at 6-8 weeks and repeated twice at 3-4 week intervals until animal is 14-16 wks old
-revaccinate annually
when risk of Bordatella bronchioseptica is significant, what’s the ideal vaccine
use of a live, avirulent, intranasal vaccine is preferable to parenteral products containing inactivated bacteria or bacterial extracts
combination vaccine of avirulent B. bronchioseptica and a modified live parainfluenza vaccine is available for intranasal use - schedule
- one inoculation is administered to puppies >3 weeks old
combination vaccine of avirulent B. bronchioseptica and a modified live parainfluenza vaccine - side effects
very efficacious BUT mild resp signs
vaccine virus excretion for about 4 days
combination vaccine of avirulent B. bronchioseptica and a modified live parainfluenza vaccine
- who is this recommended for
higher risk animals
can dogs get influenza
ya boiiii
which influenza mutated to affect dogs too
H3N8 equine influenza virus mutated to produce canine influenza virus
2 main target cells of canine influenza
alveolar macrophages + resp epithelium (ciliary membrane)
how many subtypes of canine influenza are there
2 - H3N8 & H3N2
are both subtypes of canine influenza well established in popn?
yes in North America
- both have vaccines against them
what happens to respiratory tract after being infected with canine influenza?
causes clumping of cilia which means there’s a hard time clearing mucus, bacteria
mucus production is not affected
why is canine influenza attacking alveolar macrophages significant?
affects macrophage functions & decreasing numbers of macrophages allows secondary bacterial infections
can human H1N1 infect dogs
yes, but is transmitted inefficiently between dogs
H5N1 (HPAI) - is it in dogs?
2023 April - first domestic dog case in Canada (ON) after chewing on a dead goose
- showed resp signs then died
another dog in Thailand in 2006
canine influenza - clinical signs
not reliable - coughing, sneezing, and nasal discharge
how to detect canine influenza
virus isolation, immunoassays to detect virus antigen, RT-PCR to detect virus nucleic acid, and serology for antibodies - deep or pharyngeal swabs
vaccines available for canine influenza
monovalent or bivalent vaccines are available for both H3N8 and H3N2 canine influenza
does vaccination for canine influenza help
vaccination may not all together prevent an infection but it may reduce the severity and duration of clinical illness
you may see intranuclear eosinophilic inclusions in a section of liver in
herpesvirus
you may see intranuclear basophilic inclusions in a section of liver in
adenovirus
