Defense & Barriers 2: Ruminant Retroviruses Flashcards
RETROVIRUSES…
how do they infect hosts?
once infected, how long does it last?
clinical signs?
how is it transmitted?
how do they infect hosts?
–> uses REVERSE TRANSCRIPTASE to infect host by PRODUCING VIRAL DNA from HOST DNA GENOME and INSERTS THIS VIRAL DNA INTO HOST GENOME
once infected…
–> ANTIBODIES/INFECTION ARE FOR LIFE
clinical signs?
–> Can or cannot have clinical signs, MIGHT TAKE A LONG TIME TO DEVELOP
transmission? = via BLOOD/SECRETIONS containing specific WBCs
ONCORNAVIRUS…
classification?
behavior?
example? (one disease, 3 species)
classification?
–> ONCOGENIC RNA RETROVIRUS
behavior?
–> Reproduces LIKE A TUMOR
example?
–> BOVINE/FELINE/AVIAN LEUKOSIS VIRUS
LENTIVIRUS…
classification?
behavior? (2)
2 examples?
classification?
–> LONG INCUBATION RETROVIRUS
behavior?
1. Has LONG INCUBATION
2. DEVELOPMENT OF NON-TUMOR RELATED CLINICAL SIGNS
2 examples?
1. HIV
2. OVINE PROGRESSIVE PNEUMONIA
BOVINE LEUKOSIS VIRUS…
AKA “Name?”
classification?
action?
prevalence? (3, 3 subs for last and mention something about the SPECIFIC industry)
AKA “ENZOOTIC BOVINE LYMPHOSARCOMA”
classification? = ONCOGENIC RETROVIRUS
action?
–> INFECTS LYMPHOCYTES and INACTIVATES P53, which leads to initiation or progression of BLV-INDUCED tumors
prevalence?
1. This is the MOST COMMON NEOPLASTIC DISEASE IN DAIRY AND BEEF CATTLE
2. VERY COMMON IN US
3. MORE COMMON IN DAIRY INDUSTRY because of INCREASED MANAGEMENT that allows for infected blood to enter…
–> More tattooing
–> More preventative vaccines given
–> More tagging/branding
BOVINE LEUKOSIS VIRUS…
most common finding?
WHY are cows often asymptomatic?
another common finding? + what 2 things can it lead to?
an UNCOMMON finding?
MOST are…
–> ASYMPTOMATIC with HIGH SHEDDING RATE, can look normal despite being positive
Why? = FOOD ANIMALS DON’T LIVE LONG, so we could just NOT HAVE WAITED LONG ENOUGH to see signs
another common finding?
–> PERSISTENT LYMPHOCYTOSIS that can lead to…
1. COMPROMISED IMMUNITY
2. DECREASED PERFORMANCE
UNCOMMON findings..
–> DEVELOP MALIGNANT B-CELL LYMPHOMA
what is a CHARACTERISTIC finding for BLV?
how is it diagnosed?
DEVELOPMENT OF MALIGNANT B CELL LYMPHOMA
Diagnosed via NEOPLASTIC CELLS present in BIOPSY OR ASPIRATE
TRANSMISSION of BLV…
what SPECIFICALLY causes infection?
how can the pathogen access the cow? (3)
BLV can be transmitted via ___ & ____ routes
VERTICAL transmission? (2)
HORIZONTAL transmission? (2)
SPECIFICALLY causes infection?
–> Via LYMPHOCYTES in the BLOOD getting into cows by ONLY JUST A FEW DROPS
Usually blood able to access cow via…
1. FLIES = mouth parts can SLASH SKIN of cows/cause bleeding
2. TOOLS = Surgical, Dehorning equipment, Needles
3. PALPATION PER RECTUM
can be transmitted via HORIZONTAL & VERTICAL routes
VERTICAL transmission?
1. COLOSTRUM/MILK
–> MILK is more likely to have HIGHER LEVEL OF BLOOD/TRANSMIT BLV from LEAKY VESSELS
2. IN-UTERO
–> Usually NOT SEEN unless DAM HAS VERY HIGH VIRAL LOAD (persistent lymphocytosis)
HORIZONTAL transmission?
1. DIRECT CONTACT
–> Mucous contact, grooming, licking more common when CALVES HOUSED TOGETHER
2. SEMEN during INSEMINATION
–> If male has SEMINAL VASCICULITIS, more likely to have BLOOD IN EJACULATE and transmit BLV
BLV treatment?
NONE AVAILABLE, AGGRESSIVE CULLING OR SEGREGATION
BLV economic losses…
how does DISEASE cause DECREASED PRODUCTIVITY? (trick, 2)
where are FINANCES LOST? (2)
DZ causing DECREASED PRODUCTIVITY?
1. So far, this hasn’t been proven!
2. But, the longer they have BLV, likely to succumb to other SECONDARY diseases
finances LOST?
1. IMPORT RESTRICTIONS on regions that have high rates of BLV INFECTIONS
2. we CANNOT SELL ANIMALS THAT HAVE BLV IN SOME COUNTRIES
BLV diagnosis…
when do we KNOW that infection is present?
what 2 tests are used to measure this?
what is the EXCEPTION?
KNOW infection is present?
–> ANTIBODIES in SERUM or MILK = INFECTION PRESENT
Measured via…
1. Serum AGID or ELISA
2. Milk ELISA
EXCEPTION = UNINFECTED calves can still have Ab from COLOSTRUM up to 6 MONTHS OF AGE UNTIL THEY DISAPPEAR
–> Need to wait until 6 mos old to TEST for BLV
NAME 4 LNs we expect to find LSA or LYMPHADENOPATHY in BLV patients
- ILIAC
- PRE-FEMORAL
- PRE-SCAPULAR
- POPLITEAL
how can BLV cause ABOMASAL DISEASES?
what 5 clinical signs can form as a result?
BLV + ABOMASAL DZ?
–> PYLORIC region of stomach has A LOT of LYMPHOID-ASSOCIATED TISSUE that can be AFFECTED BY TUMORS
5 clinical signs that form as a result?
1. Obstruction
2. Fluid in intestine
3. Hemorrhage
4. Melena
5. Hypochloremia
3 METASTATIC SITES for BLV? & explain WHERE
- CARDIAC, usually RIGHT-SIDED disease
- Signs?
–> Heart failure
–> Edema
–> Muffled heart sounds - UTERUS
–> Can have BONY STRUCTURE that RESEMBLES FETAL STRUCTURE/BONE in UTERUS - RETROBULBAR
–> METASTATIC LNs can reside BEHIND GLOBE of eye
CONTROL of BLV? (2)
TEST, SEPARATE & ERADICATE
but if not, THAT’S OK! –> <5% SHOW CLINICAL MANIFESTATIONS, just accept it
2 ways to PREVENT/DELAY BLV infection in young calves?
- FREEZE COLOSTRUM at 145F for 30 minutes to KILL VIRUS while PRESERVING Abs
- SEPARATE CALVES from COWS
