Exam 1 Flashcards
Which 2 viral families have a circular genome?
Circoviridae
Papillomaviridae
All _____ viruses are enveloped
helical
The two types of capsid symmetry?
Icosahedral
Helical
Which type of viruses are readily inactivated by lipid solvents and detergents?
Enveloped
4 criteria for species delineation?
1) type and nature of genome
2) mode and site of replication
3) structure of virion
4) sequencing of viral genome
Of the DNA viruses we’ve studied, which do NOT replicate in the nucleus?
Asfaviridae
Poxiviridae
Circoviridae
Retroviruses must bring which two enzymes with them in order to support replication?
Reverse transcriptase
Integrase
Can replicate only under defined permissive conditions
conditional-lethal mutants
Can infect host species different from those of parent viruses
Host-range mutants
____ require the presence of a complementing helper virus for replication
defective interfering particles
The exchange or transfer of genetic material between different but closely related viruses infecting the same cell
Genetic recombination
This occurs when the RNA polymerase switches between template strands during synthesis of complementary negative-sense strand
Template switching (copy-choice) recombination
This can occur randomly in RNA viruses with segmented genomes
Reassortment
Intramolecular recombination, copy-choice recombination, and reassortment can all lead to?
Genetic reactivation
______ & ______ do not result in a change in the genome (i.e. changes don’t last past 1 replication)
phenotypic mixing and complementation
When comparing phenotypic mixing and complementation, which does NOT require a defective virus?
Phenotypic mixing
Of the viruses we’ve studied, which can be associated with cell fusion (syncytia)?
Lentiviruses (sub family of retrovirus)
Herpesviruses
Binding of RBCs to the surface of infected cells; example virus that causes this?
Hemadsorption
African swine fever virus
If hemagglutination does not occur in a well, what two things could that mean?
1) the patient doesn’t have the virus
2) patient has Abs that bind that virus
These types of infections have a short clinical course and large amounts of the virus are shed over a short period of time
Acute infection
How do
1) retroviruses
2) herpesviruses
establish latent infections?
1) via provirus
2) episome
The severity of disease exhibited by infected hosts
virulence
ability of a pathogen to invade and establish replication within the host
infectivity
What is the incubation period
the time that lapses between infection and presentation of clinical signs
Why is Acyclovir so effective in herpes-infected cells?
Because it targets thymidine kinase, which is only expressed by infected cells
Poxviridae are _______ viruses?
DNA, enveloped
Which family of viruses is associated with intracellular enveloped viruses (IEVs)?
Poxvirus
You go to a barn to look at a milking cow that appears to have leisons on her teats. The owner claims they have had a rat problem recently, and you notice similar lesions on the face of the barn cat. Your top Dx? Is this a FAD?
Cowpox
Yes
You’re called in to look at cows that have recently started showing oral lesions, but are healthy otherwise. What is your Dx? Advice to the owner?
Bovine papular stomatitis
No need to treat, should resolve in a few weeks; is zoonotic, so be careful
This disease primarily affects YOUNG sheep and is characterized by ulcerative lesions around the muzzle
Orf virus
T/F: If a lamb gets orf, it means it didn’t get adequate Abs in the colostrum
False; colostrum Abs are not protective (requires CMI)
Though not found in the US, these poxviruses are considered the most important because they cause high mortality and significant economic loss
Sheeppox and goatpox
You are called to examine a herd of box taurus cattle. They have skin nodules on the head and neck. Physical exam reveals a fever, lacrimation, and nasal discharge. You also notice a large number of biting insects in the area. Top Dx?
Lumpy skin disease
Is lumpy skin disease considered foreign?
Yes
Which disease in swine is usually subclinical and is trasferred via pig louse?
Swinepox
You are called to examine a flock of chickens that have proliferative skin lesions; what histopath finding would confirm your Dx?
Finding intracytoplasmic inclusions (Fowlpox)
You examine a group of rabbits that have benign cutaneous fibromas. Your top Dx?
Myoxoma virus
How Myoxoma virus differ in its impact on Eurpoean rabbits?
Lethal
The virus can cause ulcerative lesions on the feet, tail, and snout of mice
Ectromelia virus (mousepox)
Because herpesviruses are _________, they don’t survive well in the environment and require close contact for transmission
enveloped
Except for _____ & ______, herpesviruses tend to be very species specific
ovine herpes virus 2
Pseudorabies
Two main disease types associated with herpes infection
respiratory & reproductive (abortion)
When examining a cow with lumpy skin, these two viruses should be on the top of the list
Lumpy skin disease virus
Bovine-herpes virus 2
Though not associated with clinical disease in sheep, this virus can be deadly to cattle and buffalo
Ovine herpesvirus 2
This herpesvirus is characterized by a broad host range but is not zoonotic
Pseudorabies virus
In pigs, these diseases are associated with abortions, mummified fetuses, and still births
Pseudorabies
Porcine parvo virus
Which strains of equine herpesvirus are associated with rhinopneumonitis and abortion?
1 & 4
Equine herpes virus 2 associated with what disease?
Keratoconjuctivitis
Equine herpes virus 3 associated with what disease?
Coital exanthema (won’t stand to be bred)
You examine a litter of puppies. You notice a few of the puppies have low body temperature and are being kept separate from the rest of the litter. Likely Dx?
Canine herpesvirus (fading puppy syndrome)
This virus is responsible for ~40% of respiratory infections in cats
Feline Herpes virus 1 (feline viral rhinotracheitis)
You are examining a flock of backyard chickens that have signs of respiratory disease (coughing, moist rales, oculonasal discharge). The owner reports several of the chickens have already died. Dx?
Avian herpesvirus 1 (infectious laryngotracheitis)
This herpesvirus can survive for months in dust/litter, breaking the rule that close contact is required for its transmission
Gallid herpesvirus 2 (Marek’s disease)
This virus causes lymphoproliferative disease in chickens and is more likely to infect young, female birds (genetic susceptibility)
Gallid herpesvirus 2
Which disease is more fatal: Marek’s disease or ILT?
ILT (70%)
The only enveloped, DNA arbovirus we have covered?
African swine fever virus
Unlike most enveloped viruses, this virus is stable in the environment and can persist for months in meat
African swine fever virus
Papillomaviridae is a _______ virus
non-enveloped, DNA (circular!)
This viral family can cause proliferative lesions (warts) in young animals that usually regress on their own in weeks to months
Papillomaviridae
Equine sarcoids are thought (controversially) to be associated with disease from
Bovine papillomarvirus 1
These types of tumors in dogs ARE NOT assoicated with a virus and respond well to chemotherapeutic agents
Transmissible venereal tumors (TVT)
Highly infectious virus of psittacine birds; can cause acute generalized disease in young budgerigars
avian polyomavirus
Adenoviridae family are ______ viruses
non-enveloped, DNA
Which strain of adenovirus is associated with infectious canine hepatitis?
CAV-1
Why do we use CAV-2 in our vaccines?
MLV with CAV-1 causes blue eye (severe corneal edema); vaccination with CAV-2 protects from infectious hepatitis even though it doesn’t cause it
This virus is associated with inclusion body hepatitis and egg drop syndrome in chickens;
Avian adenoviruses
This virus is a common cause of fetal death and mummification in pregnant GILTS
porcine parvovirus
Concerning porcine parvovirus, infection at these days leads to what consequence?
1) 10-30 days
2) 30-70 days
3) 70-terms
1) death and resorption
2) death and mummification
3) usually survive in utero (born weak)
Best way to control porcine parvo?
expose gilts prior to breeding
Disease of mink and ferrets (primarily with pale coat colors) that caused B lymphocyte stimulation
Aleutian mink disease
You are examining CHICKS that have aplastic anemia and generalized lymphoid atrophy…top Dx?
Chicken anemia virus (circoviridae)
Which strain of porcine circovirus is considered pathogenic?
PCV 2
1 is non-pathogenic
What 2 diseases can be seen with PCV-2
Post-weaning multisystemic wasting syndrome (PMWS)
Porcine dermatitis and nephropathy syndrome (PDNS)
You are examining a cockatoo that has feather loss, abnormal mature features, and his beak is shiny and overgrown; histopath reveals intracytoplasmic inclusion bodies.. likely Dx?
Psittacine beak and feather disease
circovirus
3 important things found in retrovirus capsule?
Reverse transcriptase
Integrase
Protease
Which 4 retroviruses are in the subfamily lentivirus?
FIV, EIA, maedi/visna virus, caprine arthritis-encephalitis virus
Lentiviruses have a _____ incubation period
long
Which means is not effective for killing retroviruses?
UV light (due to diploid genome)
The most common and most economically important neoplastic condition of birds 5-9 months of age
lymphoid leucosis (caused by avian leucosis virus)
An avian virus that has incorporated a cellular oncogene, is replication competent, and capable of rapid cell transformation
Rous sarcoma virus
Compared to Marek’s disease, birds affected with ALV tend to be ______ and lack ______?
Older; lack thickening of peripheral nerves
Which subgroup of FeLV is found in all infected cats?
A
FeLV subgroups:
Which results in higher risk for tumors?
Which is not transmitted but results in rapid, fatal anemia?
B–tumors
C–fatal anemia
Which subgroup of FeLV leads to immunodeficiency?
T (insertion from soluble cofactor)
What rule of retroviruses does FeLV not follow?
Once infected always infected (cats infected after 4 months of age are usually able to clear the virus)
When testing for FeLV, it’s important to check for ______ not ______
Check for ANTIGEN, not antibodies (Abs don’t tell you if there’s an active infection or if there was previous exposure)
Causes persistent lymphocytosis and development of lymphosarcoma in infected animals; cattle are usually infected between 6months and 3 years of age
Bovine leukemia virus
This virus replicates in the lungs of sheep and the tumors slowly replace normal lung tissue and produce excess surfactant–>death by asphyxia
Ovine pulmonary adenocarcinoma
Wheelbarrow test can be used to diagnose?
Ovine pulmonary adenocarcinoma
4 phases of FIV
acute phase
asymptomatic phase
phase of vague clinical signs
Terminal phase (immunodeficiency)
“Trojan horse” mechanism of equine infectious anemia?
will infect monocytes but viral expression only occurs after they differentiate into macrophages in a tissue
Primary mode of transmission of equine infectious anemia?
blood feeding insects
Causes a life-long infection in sheep associated with labored breathing and wasting, but infection is usually subclinical
Maedi/visna virus (ovine progressive pneumonia)
Best way to prevent lamb infection with maedi/visna virus?
Don’t allow them to take colostrum from affected ewes
This disease presents with slowly progressive onset of arthritis, swelling of affected joints (variable lameness), weight loss, and chronic mastitis.
Caprine arthritis-encephalitis
Best way to prevent kid exposure to Caprine arthritis-encephalitis
fed heat-treated colostrum & pasteurized milk
