Exam 2 - Bovine Lymphosarcoma Flashcards
what is the only form of lymphoma that is related to bovine leukemia virus?
enzootic bovine lymphoma
what are the 5 forms of lymphoma that affect cows?
cutaneous
juvenile
thymic
hemal lymph node enlargement
enzootic bovine lymphoma
what cows are commonly affected by cutaneous lymphoma?
young - under 1-3 years of age
what clinical signs are seen with cutaneous lymphoma in cows?
extreme lymphadenopathy
the prevalence of BLV is higher in _____ cattle than in _______ cattle
dairy higher than beef
T/F: there is no breed or sex predilection for BLV
true
why are some cattle believed to be resistant to BLV infection?
major histocompatibility complex - confers susceptibility or resistance to BLV infection due to differences in allele types
T/F: infections of BLV increase with age
true
how is BLV transmitted? what is the common means of transmission?
relies on transmission of one infected lymphocyte to another bovid through blood
iatrogenic - same instruments used for dehorning/castration, ear taggers, same needles used
rectal palpation - damage to rectal mucosa
reported cases of in utero transmission
biting flies - lower risk of transmission
what cattle are affected by juvenile lymphoma?
extremely rare - seen in animals 2-3 months of age with peripheral lymph node enlargement
T/F: for BLV to be transmitted, it has to be blood to blood because it can’t cross intact mucosa
true
T/F: blood, milk, & colostrum are the main fluids associated with transmitting BLV to other animals
true
T/F: relatively few new infections of BLV rarely occur in cattle older than 3-5 years
true
if only 2-5% of cattle with BLV develop solid clinical tumors, what is the ‘loss’ associated with increased prevalence within a herd?
direct loss - death/culling, reproductive inefficiencies, & decreased milk production
indirect loss - loss of revenue from decreased export of breeding animals, loss of eradication & control, & decreased sales of semen & embryos
T/F: AI is a cause of BLV transmission even if no injury to the mucosa occurs
false - has to be blood to blood transmission
how is bovine enzootic lymphoma diagnosed in adult cattle?
ELISA for the gp-51 antigen on serum or whole blood - presence of antibodies to this antigen is positive for the virus (once infected always infected)
how are calves diagnosed with bovine enzootic lymphosarcoma?
if under 3 months of age, test should be run on whole blood due to the potential of interference from maternal antibodies & then they should be checked again at weaning
T/F: clinical signs of enzootic bovine lymphoma depends on the organs involved
true
what organs are commonly involved in enzootic bovine lymphosarcoma?
right atrium, lymphadenopathy, abomasum, spinal column lymphatics & associated lymph nodes, uterus, & retro-bulbar
what age of cows are typically affected by enzootic bovine lymphosarcoma?
3-5 year old cows
T/F: for bovine enzootic lymphoma, infection rates increase with age & relatively few new infections happen after 3-5 years of age
true
T/F: 70% of cattle that test positive for BLV show no clinical signs
true
does a negative BLV test rule out neoplasia?
yes - look at other causes for clinical signs you are seeing
what clinical signs may be seen in a cow that has BLV and a tumor on the right atrium?
right sided heart failure - brisket edema, jugular pulse/distension, +/- murmur
