Lab 3.7 Flashcards
SCENARIO: called to poultry farm
-increased mortality rate
-yellow-green diarrhea
-drooping wings
-circular movements
-vaccinated against newcastle through water at 1-day of age
-dead young cormorants found nearby
NECROPSY: no gross lesions, some with hemorrhages in subcutaneous tissues, muscles, GI
What is your differential diagnosis?
- Newcastle disease (Avian paramyxovirus 1)
- Highly pathogenic avian influenza (Fowl plague/Orthomyxoviridae)
- Laryngotracheitis (Gallid herpesvirus 1) (hemorrhages in the upper respiratory tract)
- Marek`s disease (Gallid herpesvirus 2)
- Infectious bronchitis (Coronavirus)
classic signs of newcastle disease:
Haemorrhagic necrosis in the intestinal, respiratory tracts and visceral organs, associated with neurological and GI clinical signs could mean Newcastle Disease!
what avian species are susceptible to newcastle disease?
- All avian species have demonstrated some level of susceptibility (chicken and cormorants!)
How does the virulence of Newcastle disease virus influence the pathogenesis of the disease?
Four pathotypes:
1) Asymptomatic
2) Lentogenic: subclinical to mild respiratory
Virulent pathotypes:
3) Mesogenic: respiratory or neurological
4) Velogenic: most pathogenic
4.1 Velogenic neurotropic: respiratory and neurological
4.2 Velogenic viscerotropic: hemorrhagic intestinal
some clinical signs of virulent newcastle disease
- Respiratory signs
- Surviving birds may have neurological damage
- Greenish, dark watery diarrhea
How do we test for newcastle disease?
RT-PCR
what samples do we send in to test for newcastle disease?
- Samples: cloacal / choanal swab, respiratory swab, tissues
What methods can we use to determine the virulence/pathotype of Newcastle disease?
1) Sequencing: at least 3 arginine or lysine residues of the fusion protein
2) Intracerebral index pathogenicity (1-day old chicks)
Modes of introduction of NDV between flocks
-Moving live infected birds (including vaccinated birds), and infected poultry products
-Moving people and equipment
-Airborne spread
-Contaminated poultry feed
-Contaminated water
-Vaccines
Which captive birds can get Newcastle disease virus? which common bird should we be careful of?
Everyone… watch out for psittacines who can excrete virus for at least one year
What will you recommend to a farm to eradicate Newcastle disease?
- Depopulation of all remaining animalsL
- Cleaning and disinfection
> APMV-1 may survive in contaminated, uncleaned poultry houses for up to 16 days after depopulation - Strict quarantine of new animals
are people at risk for Newcastle disease? who? what symptoms?
-conjunctivitis
-laboratory workers, vaccination teams, people in poultry processing plants
- The human disease has not been reported in people who are rearing poultry or consume poultry products
- Person-to-person spread has not been reported
SCENARIO: puppy adopted from shelter
* A week later:
> coughing
> discharge from his eyes and nose
> mild diarrhea
Another week later:
- head pressing, stumbling and twitching
- repetitive chewing movements of the jaw
Within the next week several dogs at the shelter developed respiratory signs and some looked very sick.
What is your differential diagnosis?
- Canine distemper (Paramyxoviridae/Morbilivirus)
- Rabies (Rhabdoviridae/Lissavirus)
You’ve got an unvaccinated dog (for rabies virus) with an acute development of neurological signs…. who do you need to call and why?
- call your local CFIA veterinarian
- you can’t rule out rabies!
Canine Distemper Virus common body system affected
- respiratory, GI and neurological
- Disease of the immune system and infects mostly leukocytes (immunosuppression)
Long-term consequences of Canine Distemper
> if dogs manage to survive acute infection:
- foot pad hyperplasia
- enamel hypoplasia
- Can also see permanent neurological damage
post mortem findings for canine distemper
- multifocal to coalescing bronchopneumonia, encephalitis and myelitis
- Characteristic inclusion bodies were in H/E-stained brain, lung, stomach, urinary bladder
what laboratory tests can be done for canine distemper?
- PCR PANEL for canine respiratory disease
What animals are at risk of CDV?
A lot:
- Mustelidae: One of the most important viral diseases in ferrets, also weasels, mink, skunk, badger, marten, otter
* Canidae: Dingo, fox, coyote, jackal, wolf
* Procyonidae: Raccoon, coati
* Ailuridae: red panda
* Ursidae: Bears, panda
* Viverridae: civet, mongoose
* Large Felidae: Lions, leopards, cheetahs, tigers (not in small Felidae)
* Rodents: Marmots
* Rhesus monkeys
* Pinnipeds
how is canine distemper transmitted?
- droplet infection, direct contact
with another infected animal
treatment for CDV
supportive (antibiotics, fluid therapy)
Prognosis for CDV
- Mortality rate: depends to a large extent on the immune status of the infected dog
- High mortality in non-immune puppies
- Often die from generalized disease +/- secondary infections L
vaccine options for CDV
Modified-live vaccine
* Usually given as a combination vaccine→ DAPP
(Distemper, Adenovirus, Parvovirus, Parainfluenza) or DHPP (Distemper, Hepatitis, Parvovirus, Parainfluenza)
Inactivated vaccines for pregnant bitches (reduced risk of abortion)
How can a shelter prevent infections/outbreaks of CDV
- Most disinfectants, including phenols and quaternary ammonium compounds should be sufficient to get rid of the virus (Morbilivirus - enveloped virus)
- In the future, could test dogs for infectious diseases as they enter the shelter or impose a quarantine on any new animals entering the shelter
