Hemolymphatic Dz - Nagy Flashcards
what is the most common cancer of cattle?
lymphosarcoma (LSA)
what are the 4 manifestations of LSA in cattle?
- juveline multicentric
- thymic
- cutaneous
- enzzotic bovine leukosis
of the 4 manifestations of LSA, which is caused by a virus?
enzootic bovine leukosis
Juvenile multicentric LSA is:
BLV associated or non BLV associated?
NON BLV accociated
what is the typical age of juvenile multicentric LSA?
- birth to 6 months
is the nature of onset of juvenile multicentric LSA chronic or acute?
acute - sudden onset
what are clinical signs of juvenile multicentric LSA?
- variable: depending on the location of the tumor
liver = jaundice GIT = diarrhea, wasting
how common is a diagnosis of juvenile multicentric LSA?
uncommon - b/c often no necropsy is carried out
T/F
there are many anti cancer drug options in food animal medicine.
false
dexamethosone is one of few - and patient cannot handle prolonged exposure to high doses of steroids
is thymic LSA BLV associated or non BLV associated?
Non BLV associated
what is the typical age of presentation of thymic LSA?
6-24 months
does thymic LSA affect the cervical or intrathoracic thymus?
either one
what are common signs associated with cervical thymic LSA?
- swelling neck
- bloat, if capacity of eructation or swallowing occurs
what are common signs associated with intra thoracic thymic LSA?
- bloat and other lesions suggestive of a mass in the chest
- tachycardia, tachypnea -> bc space occupying lesion in chest impedes heart pump or breathing ability
what is diagnostic for thymic LSA?
- biopsy
what cell line is affected in T cell lymphoma?
T cell lymphoma
what is the prognosis of thymic LSA?
poor — it is fatal
is cutaneous LSA BLV associated or not?
NOT BLV associated
what age is common for cutaneous LSA?
1-3 years
clin signs of cutaneous LSA?
many bumps all over (LSA masses)
diagnosis of cutaneous LSA?
biopsy
can cattle recover from cutaneous LSA?
yes - it is the only form of LSA where the animal may get better
spontaneous remission without recurrence
is enzootic bovine leukosis BLV associated?
YES
what age cattle does enzootic bovine leukosis occur?
4-8 years
what virus is enzootic bovine leukosis associated with?
BLV = bovine leukemia virus
how common is infection with BLV in the US dairy herd?
very common
how common is LSA in US diary herd?
uncommon - much less common than BLV infection
about what % of infected US diary cows do not show any clinical signs
65%
about what % of infected US dairy cows experience persistent lymphocytosis from BLV infection?
30%
how is BLV transmitted?
hematologically primarily - an infected lymphocyte from infected cow to non infected cow
besides BLV, what is another differential for persistent lymphocytosis?
bone marrow problem
why is the 30% of cows with high lymphocyte count a concern on farms?
their lymphocytes are virally infected so the cows act as “typhoid mary cows” and spread the virus with less blood b/c a higher proportion of their cells are infected
what % of cows develop a tumor as a result of BLV?
5%
what is the MC sign associated w LSA?
lymphadenopathy
LSA clin sign: peripheral / central lymphadenopathy
where does it occur? and what signs occur as a result?
- enlarged nodes
- bloat [if intrathoracic esophagus is impinged]
- choke
- intestinal obstruction
- lymphatic obstruction
retrobulbar signs of LSA?
- exopthalmos
- exposure keratitis
- proptosis of globe
“bug eyed” look due to high intraocular pressure
right heart signs of LSA?
can it occur on both sides of the heart?
yes, can occur on both sides of the heart
- muffled heart sounds
- pericardial effusion
- murmur
- arrhythmia
- heart failure
what are some effects of lymphosarcoma in the non gravid uterus?
how can LSA present in the uterus? [focal, diffuse, etc]
- early embryonic death (b/c of poor attachment)
- abortion (b/c of poor attachment)
- infertility
- dystocia (due to mass obstructing parturition)
- mass in uterus
can present as a mass or infiltrates tissue diffusely
how does LSA in the GIT present?
what part of the GIT?
melena
pain
outflow obsruction
Abomasum
what signs does extradural LSA cause?
what part of the spinal cord is it located in?
paresis
ataxia
paralysis
loc: inside the spinal column (bone) but outside of the dura
what internal organs does LSA often affect?
spleen
liver
kidney / ureters
bone marrow
what type of virus is BLV?
what does this mean in terms of the nature of the infection?
retrovirus
once infected, the animal will have it for life
T/F: the cell free phase of the BLV is present in the body of the animal.
FALSE - the cell free phase is NOT found in the body
in what cells is the BLV found?
lymphocytes
dehorning procedures typically do NOT risk BLV spread.
F: dehorning procedures do present an opportunity to transmit blood
disinfect instruments to dec transmission
also: cut then burn for better hemostasis on smaller buds
how can veterinarians reduce the risk of spread of BLV during surgical procedures, blood sampling and rectal examination?
use new materials for each cow - do NOT reuse needles or instruments or palpation sleeves
T/F
tattoo ink is viricidal so tattooing cattle does not pose a risk to BLV transmission
false
ink is NOT viricidal so tattooing can, in theory, transmit BLV
T/F
if a rectal sleeve does not have any blood on it after palpation, it is safe to use on another cow.
false
even in the absence of visible blood, multiple uses of a sleeve will spread the virus
what do studies regarding BLV transmission via colostrum state?
why is this the result?
variable transmission via colostrum
colostrum is a prime source for BLV but it is also packed with antibody (Aby)
colostrum is more infectious if given sub q - when administered orally, how it should be given, it is less infectious
how long does BLV live outside the body?
what does this mean for the transmission of BLV via flies?
45 mins
flies are very infectious and can transmit the BLV from animal to animal
what reproduction methods transmit the virus? what methods are safe?
natural service does transmit virus
AI and ET (embryo transfer) do NOT move the virus
t/f
BLV is more prevalent in pasture vs confined animals
false
it is more prevalent in confined animals
BLV cannot be transmitted in utero
false
BLV is transmitted in utero
what Aby (antibody) tests are available for BLV testing?
AGID
ELISA
Western immunoblot
which Aby test is used MC to test for BLV?
ELISA
what do the results of the ELISA BLV test indicate?
Tells you if you have an aby response
if animal is infected, they will have an aby response w/in 2 weeks and will stay positive for the rest of their lives
what happens to levels of aby in the dam around the time of calving?
as a result, are levels detectable by aby tests?
they fall - aby move from dam and into colostrum
ELISA can detect these lower levels but AGID test cannot
what BLV antigen tests exist?
PCR
Virus isolation
SIA
which antigen test is MC used to detect BLV?
PCR
what does a positive PCR and positive aby test for BLV from a calf indicate?
the calf is positive
what does a pos aby test and a negative PCR test for BLV Indicate?
the calf is negative
assume the pos aby test is due to the colostrum in the young calf
what are the 3 testing modalities available for BLV testing?
- aby (antibody)
- ag (antigen)
- Hematologic assay
what are some reasons to test for BLV?
- animal movement requirements
- assist in Dx of LSA
- herd status info
- voluntary control / eradication program
t/f
the US has worked extensively to eradicate BLV from the US dairy herd
false
US has NOT - voluntary eradication programs exist
many other countries in the world have worked to eradicate themselves of BLV
how is diagnosis of BLV made?
- viral infection
serology [most useful test]
PCR
hematologic assays - cancer
hisology