L12: BLV And Anaplasma (Donovan)

Question 1

3 forms of “SPORADIC” Bovine LSA**

Answer 1

1) Calf/Juvenile form
- generalized lymphadenopathy in calves and young heifers
2) Thymic/Adolescent form
- thymic involvement in 6-24 mo. Heifers
3) Cutaneous form
- multiple cutaneous lesions in young cattle (

Question 2

Forms of Bovine LSA

Answer 2

Sporadic
Multicentric
Cardiac
Abomasal
Uterine
Other (eyes, spinal cord)

Question 3

Multicentric LSA: CS

Answer 3

• enlarged peripheral LN, esp. Internal iliac and/or subaortic
• dyspnea and/or bloat if thoracic LN involved
• enlarged internal LN

Question 4

CS of Cardiac LSA

Answer 4

-occasionally see CHF due to lesion in RA/RV

+/- murmur

Question 5

CS of abomasal LSA

Answer 5

Wt. loss
Melena
Outflow obstruction
"Papple-shaped" abdomen
(Abomasum can no longer secrete acid)

Question 6

CS of uterine LS

Answer 6

Palpable masses in the uterus

+/- abortion

Question 7

Retrobulbar LSA –>

Answer 7

Exophthalmos

Question 8

LSA in spinal cord –>

Answer 8

• acute downer cow

- posterior paresis/paralysis

Question 9

Epidemiology of bovine LSA: animal causes

Answer 9

• genetic susceptibility to viral infection (not well defined)
• genetic susceptibility to develop tumors (BoLA haplotype): many Holsteins carry this!

Question 10

Epidemiology of bovine LSA: infectious causes

Answer 10

BLV

Question 11

Epidemiology of bovine LSA: environmental causes

Answer 11

Nutrition?
Concurrent infection?
Other stressors? (Ie. Stress of calving)

Question 12

T/F: animal MUST have genetic susceptibility for tumor production to occur

Answer 12

T

-LSA occurs in about 2% of BLV+ cattle

Question 13

Clin path of bovine LSA

Answer 13

Lymphocytosis +/- anemia

Question 14

Dx of bovine LSA

Answer 14

• AGID to look for Ab
• ELISA to Ag
• Cytology of LN or suspect tissue aspirates

Question 15

Pathology of LSA

Answer 15

• firm, cream-colored “fish flesh” tumors w/o uniform shape

- LN enlarged up to 0.5 meters in diameter

Question 16

Ddx of bovine LSA

Answer 16

• Multicentric abscess (abscess won’t be freely moveable)
• Benign LN hyperplasia
• Abomasal ulcers, upper GI obstruction, peritonitis, vagal indigestion

Cardiac: traumatic pericarditis, endocarditis, altitude sickness
Uterine: adhesions, abscess, mummification, other tumors
Spinal: trauma, hypocalcemia, rabies, cattle grubs
Periocular: SCC, retrobulbar abscess

Question 17

Prevalence of BLV based on geography

Answer 17

More prevalent in the south (most likely due to insect populations)

Question 18

Is BLV found in semen?

Answer 18

Only if bull has inflammation in reproductive tract

Question 19

Colostral half life of gp51 Ab?

Answer 19

26 days

Question 20

Methods of transmission of BLV

Answer 20

• vertical
• colostrum and milk from infected cows
• uterine flush fluids and ova or embryos (unlikely)
• biting/sucking flies (very possible)
• injections
• rectal transmission
• dehorning
• ear tattooing

Question 21

Testing methodologies for BLV

Answer 21

1) AGID gp51 (industry standard)
- detects Ab induced by infection
- seropositive 4-8 wks post-infection (will be FN during this time)
- sensitive and specific
2) RIA gp51 (same as AGID)
3) ELISA (same as AGID, but positive after only 2-4 wks)
- useful for pooled samples

Question 22

Effect of BLV on cow health and productivity

Answer 22

• no link b/w BLV infection and mastitis or repro performance (UF study DID find an association)
• increased culling rate in BLV+ cows

Question 23

1 cause of condemnation of dairy cattle carcasses at slaughter**

Answer 23

BLV infection

Question 24

BLV may be zoonotic? Found in human breast tissue, and may be associated with breast cancer

Answer 24

:)

Question 25

Control of BLV

Answer 25

- test and slaughter (requires 3 tests) - test and segregate (after 2-3 tests) - corrective management (palpation sleeves, single use needles, house replacements away from herd, dehorning practices) - no vaccine

Question 26

CS of anaplasmosis in calf/heifers

Answer 26

- inapparent, asymptomatic | - mild lethargy, partial anorexia for 24-48hrs

Question 27

CS of anaplasmosis in heifers 1-2 yrs old:

Answer 27

- fever - dyspnea - moderate to severe anemia - anorexia - decreased rumen motility - infrequently fatal

Question 28

CS of anaplasmosis in cows > 2yrs old:

Answer 28

-very high fever (or hypothermia) -anorexia and agalactia -dec. rumen motility -pale mm (anemia) -constipation w/ dry, bile-stained (dark), mucus-coated feces -staggering +/- abortion -watery blood that fails to clot -uncommonly death

Question 29

Geographic distr. of anaplasma

Answer 29

Southeast, West/northwest

Question 30

Infectious causes of anaplasmosis

Answer 30

Anaplasma marginale | Anaplasma ovis in sheep (asymptomatic)

Question 31

Environmental causes of Anaplasmosis

Answer 31

Ticks: Dermacentor | Biting flies: Tabanids

Question 32

Transmission of anaplasma

Answer 32

- predominantly vectors: tick, horsefly (esp. In SE)** - iatrogenic (common needles, dehorner, etc.) *calves, young heifers have innate resistance*

Question 33

Pathophys. Of Anaplasmosis

Answer 33

~30 day incubation period # infected RBCs doubles daily for 7-10 days -erythrophagocytosis of infected RBCs, predominantly in SP and LIV -immune system coats RBCs w/ autoAb that enhance phagocytosis of infected AND normal RBCs --> severe anemia -little IV hemolysis, NO hemoglobinuria** -icterus mild if present -survivors are chronic carriers

Question 34

Clin path of anaplasmosis

Answer 34

``` PCV 12-15% --> CS of severe anemia PCV death Icterus index variable Marginal bodies seen in RBCs with stain -difficult to see if in recovery and infected RBCs destroyed and immature RBCs are prevalent ```

Question 35

Dx of anaplasma

Answer 35

Serology: - complement fixation - rapid card agglutination - cELISA * only verify carrier state, not clinical cows** - clinical cows won't have Ab to these tests

Question 36

Pathology of anaplamsa

Answer 36

- enlarged spleen - pale mm, musculature, lungs - distended GB - variable icterus - no hemoglobinuria

Question 37

Ddx of anaplasma

Answer 37

1) Lepto - usually has marked icterus and hemoglobinuria 2) Toxic plants - bracken fern, Senecia 3) Babesia 4) Bacillary hemoglobinuria #3 and 4 are regional problems and not in SE

Question 38

Management of anaplasma

Answer 38

- control ticks/biting flies, iatrogenic blood transmission - abx: long-acting oxytet or chlortetracycline to eliminate carrier state - killed vaccine

Question 39

Vaccination for anaplasma

Answer 39

- killed vax made from erythrocytes of acutely infected cattle - variable efficacy - short duration of immunity - can induce neonatal isoerythrolysis

Question 40

Tx of anaplasma

Answer 40

Anemia: blood transfusion, reduce stress Infection: oxytetracycline

Question 41

Bovine Lymphosarcoma aka Bovine Enzootic Leukemia: signalment

Answer 41

- Adult cattle (>2yrs) | - assoc. with Bovine leukemia virus (BLV)