Persistent Viruses (Exam 5) Flashcards
Persistent infections occur and last for long periods when the primary infection is not cleared by:
adaptive immune response
Persistent infection bypasses _________ immunity and then ________ response cannot clear the virus.
innate
adaptive
List 3 types of persistent infections.
- latent infection
- chronic infection
- slow infection
Match the type of persistent infection with the description:
- life-long, long incubation period with rapid progression of clinical disease
- initial infection and virus released from host; serve as persistent carriers
- life-long maintenance of viral genome with periods of non-productive state and reactivation.
- slow infection
- chronic infection
- latent infection
Which two persistent infections discussed occur due to a virus within Family Retroviridae & Genus Lentivirus?
Feline Immunodeficiency Virus (FIV)
Equine Infectious Anemia Virus (EIAV)
(T/F) Lentiviruses are oncogenic.
False! (non-oncogenic)
Lentiviruses are (enveloped/nonenveloped) (negative/positive) sense (ss/ds) (DNA/RNA) viruses.
enveloped (+) ssRNA
Lentiviruses use __________ where a provirus is inserted into the host genome.
reverse transcriptase
Lentiviruses undergo antigenic (shift/drift) where mutations accumulate and affect antibody recognition.
drift
Lentiviruses cause persistent, lifelong infection of ________ (cell type).
phagocytes (monocytes, macrophages, DCs, microglia)
Feline Immunodeficiency Virus infects and kills _______ cells.
CD4+ T cells
Which type of hypersensitivity do lentiviruses cause?
Type III (immune complexes)
How are lentiviruses in general transmitted?
body fluid (blood, milk)
What is the official test for diagnosis of Lentiviruses?
Agar Gel Immunodiffusion test (AGID)
Once a Lentivirus infects phagocytes and the provirus is inserted, latency occurs in precursors cells such as _________ and _______.
monocytes
lymphocytes
List 3 common sequelae / lesions from Lentivirus infection.
- chronic granulomatous inflammation
- macrophage/lymphocyte lysis
- immunosuppresion
Feline Immunodeficiency Virus (FIV) has ______ protein properties which determine cell tropism.
Env
Mutations of Env protein can lead to new FIV ________ which can impede vaccine development.
subtypes (variants)
There are currently ___ subtypes of FIV.
6 (A-F)
(T/F) ALL cats can become infected with FIV.
True (more common in free-roaming males)
List 3 possible routes of FIV transmission.
- bite wounds (contaminated blood/saliva)
- transplacental (milk)
- venereal (possible)
What is the primary tropism for FIV?
CD4+ T cells
Due to FIV’s tropism for CD4+ T cells, this leads to a progressive _______ deficiency.
immune
While there is a large antibody response to FIV, infected cats need ________ immunity to suppress viremia, so this is the limiting factor.
cell-mediated
List the 3 phases of Clinical Disease of FIV.
- short acute phase
- prolonged asymptomatic phase
- terminal phase (Feline Acquired Immunodeficiency Syndrome)
(T/F) F-AIDS is ultimately fatal and presents with non-specific signs.
True
List 4 possible non-specific signs of F-AIDS during the terminal phase of FIV.
- recurrent rhinitis / sinusitis
- progressive weight loss
- diarrhea
- recurring fever
In addition to the non-specific signs of FIV, what 3 disease types can develop?
- Neoplasia
- Ocular disease
- Neurologic syndromes
What in-office test is seen as the “gold standard” for FIV diagnosis?
Western-Blot
FIV in-office diagnostic tests detect (antigen/antibody) to _____ capsid protein & _____ envelope protein.
antibody
p24
gp41
(T/F) PCR is a common diagnostic method for FIV.
False (too much antigenic variation)
There are NO _______ vaccines for FIV prevention and the _______ vaccine is NOT recommended.
MLV
killed
Which horse Lentivirus is a reportable disease in Missouri?
Equine Infectious Anemia Virus
(T/F) Equine Infectious Anemia Virus causes immunodeficiency in horses.
False (DOES NOT attack immune system)
All equidae are affected by Equine Infectious Anemia Virus.
_________ are resistant to clinical disease but can transmit it to horses.
_________ develop a similar disease to horses.
donkeys
mules
What is the main pathogenic mechanism for EIAV?
intravascular hemolysis
Equine Infectious Anemia Virus inserts a provirus in ________, causing a permanent infection.
macrophages
(T/F) Antigenic shift is common in EIAV.
False (antigenic drift)
EIAV replicates in macrophages. From there, two outcomes are possible:
- provirus inserted –> permanent infection
- macrophage lysis –> viremia
When EIAV causes viremia, _______ cells via cell-mediated response can clear the virus OR ________ generation occurs leading to Type ____ & ___ Hypersensitivities.
cytotoxic T cells
antibody
II & III
When EIAV generates antibody production leading to Type II & III Hypersensitivities, this causes 3 clinical signs:
- fever
- anemia
- thrombocytopenia
Equine Infectious Anemia Virus is transmitted by contaminated ________.
blood
(T/F) EIAV can be transmitted by mechanical vectors (tabanids) so it is considered an arbovirus.
False (different from arbovirus)
In addition to contaminated blood transmission, EIAV can be transmitted ________ or _______.
vertically
iatrogenically
List the 3 forms of Equine Infectious Anemia.
- acute
- chronic
- inapparent carrier
Acute Equine Infectious Anemia can relapse, causing ________ infection.
chronic
Acute EIA leads to ________ in 2-3 weeks.
death
If horses with chronic EIA survive, they become:
inapparent carriers
The majority of horses infected with EIA develop which form?
inapparent carrier (NO signs of disease)
List 3 methods of EIA diagnosis.
- serology
- AGID
- RT-PCR
What is the main EIA AGID diagnostic test used considered the official test for USDA & OI?
Coggins Test
(T/F) EIA vaccine is a core vaccine for horses.
False (NO vaccine available)
(T/F) EIAV positive horses are usually euthanized.
True
List the 2 small ruminant lentiviruses that affect sheep or goats.
Caprine Arthritis Encephalitis Virus (CAEV)
Ovine Progressive Pneumonia Virus
Caprine Arthritis Encephalitis Virus is a(n) (oncogenic/non-oncogenic) lentivirus.
non-oncogenic
List 2 modes of transmission of CAEV in kids. Which is primary mode?
- ingestion (colostrum) *primary
- vertical (direct contact w/ blood/secretions)
Older goats become infected with CAEV horizontally via:
direct contact (fecal-oral)
After ingestion, CAEV infects and replicates in _______, NOT ______.
monocytes/macrophages
lymphocytes
(T/F) Caprine Arthritis Encephalitis Virus causes immunodeficiency.
False
CAEV is a __________ disease causing Type ___ Hypersensitivity.
lymphoproliferative
III
List the 3 clinical signs that occur in adults with CAEV.
- arthritis
- interstitial pneumonia
- indurate mastitis (“hard bag”)
What clinical sign is seen in kids with CAEV?
leukoencephalomyelitis
List 3 ways to diagnose CAEV.
AGID
histopath
PCR
(T/F) There is NO vaccine available for CAEV.
True
Which virus is a “slow” lentivirus in sheep?
Ovine Progressive Pneumonia Virus
Ovine Progressive Pneumonia Virus is also called _______ ______ virus. ______ means “wasting/shrinking” in the brain while ______ means dyspnea in the lungs.
Visna/Maedi
visna
maedi
List 3 ways OPPV is transmitted and which is the primary route.
- inhalation
- ingestion (colostrum) *primary
- vertical (in-utero)
OPPV chronically infect ________, causing lymphoproliferation but NO immunosuppression.
monocytes/macrophages
Match the 4 clinical signs/syndromes that occur with Ovine Progressive Pneumonia Virus with its descriptions:
- listlessness, poor BC, emaciation
- emaciation –> dyspnea
- hindlimb weakness –> paralysis
- enlarged, firm udder
- Thin Ewe Syndrome
- Maedi
- Visna
- Hard Bag
AGID serologic test can be used to detect OPPV by detecting ______ viral protein.
gp135
(T/F) There are NO treatments and NO vaccines available for Ovine Progressive Pneumonia Virus.
True
Which virus is endemic in standardbred horses and within the Arterivirus genus?
Equine Viral Arteritis Virus
Equine Viral Arteritis Virus is (zoonotic/non-zoonotic) and (reportable/non-reportable) in Missouri.
non-zoonotic
reportable
Equine Viral Arteritis Virus is a (ss/ds) (+/-) sense (DNA/RNA) virus.
ss (+) sense RNA virus
Equine Viral Arteritis Virus infects _________, causing a persistent, often asymptomatic infection.
macrophages
Equine Viral Arteritis can be transmitted in 3 ways. List them. Which is most frequent?
- venereal (semen)
- respiratory *most frequent
- congenital
Most commonly, healthy adult horses infected with Equine Viral Arteritis Virus develop _______ or ______ Respiratory Disease.
inapparent or mild
What is the most important clinical sign of Equine Arteritis Virus?
abortion
If foals become infected congenitally with Equine Arteritis Virus, they develop:
interstitial pneumonia
(T/F) Stallions do not shed Equine Viral Arteritis Virus.
False (persistent carriers)
The main lesion seen with Equine Arteritis Virus is infection of endothelial cells –> vasculitis causing:
edema (subcutaneous, eyelids, scrotal)
What is the official OIE diagnostic test for Equine Arteritis Virus?
viral isolation (in semen)
Control of Equine Arteritis Virus is centered around:
carrier stallions