Large Animal Retroviridae (Exam 2)

Question 1

What diseases are associated with bovine leukemia virus?

Answer 1

Enzootic bovine leukosis
Persistent leukosis (PL), 30% of infected cattle, >12000 lymphocytes/ul
Lymphoma/lymphosarcoma (LS), 0.1 to 5%
Inapparent infection, >60% of infected cattle

Question 2

What is the host range of bovine leukemia virus?

Answer 2

Bovidae (sheep experimentally)

Question 3

What is the susceptibility of bovine leukemia virus?

Answer 3

Highly heritable
Independent genes associated with susceptibility to PL vs LS disease

Question 4

How is bovine leukemia virus transmitted?

Answer 4

Horizontal: iatrogenic via transfer if blod from PL/LS cattle, iv needles, dehorning equipment, OB sleeves
Oral: feeding unpasteurized colostrum, milk to calves <21 days of age
Vertical: low (4%) transfer across the placenta from PL and LS cows to fetus

Question 5

What is the tropism of bovine leukemia virus?

Answer 5

Highly cell-associated with B lymphocytes

Question 6

How is bovine leukemia virus prevented/controlled?

Answer 6

Test and cull: low prevalence/high genetic value
Test and separate: facility dependent, reduce new infections
Test and management: to prevent new infections
No test

Question 7

What are the clinical considerations for bovine leukemia virus?

Answer 7

Many dairy cows are culled prior to developing clinical disease
Physical exam on cows that are thin, unthrifty, have chronic GI signs (diarrhea, recurring abdominal pain), have enlarged lymph nodes
Increased emphasis on testing in cattle for purposes of export

Question 8

What are the important lenitviruses?

Answer 8

Caprine arthritis encephalitis virus (CAEV)
Ovine progressive pneumonia virus (OPPV)
Equine infectious anemia virus (EIAV)
Feline immunodeficiency virus (FIV)

Question 9

What are common features of lentiviruses?

Answer 9

Long incubation period
Long period to seroconversion
Persistent infection in most inoculated animals
Occult location of infectious viruses in the infected animal
Tropism for cells of the immune system

Question 10

What diseases are caused by caprine arthritis encephalitis virus?

Answer 10

Encephalitis
Chronic arthritis
Hard-bag, lymphocytic mastitis
Progressive pneumonia

Question 11

What is the host range of caprine arthritis encephalitis virus?

Answer 11

Goats, sheep

Question 12

What is the geographic distribution of caprine arthritis encephalitis virus?

Answer 12

Worldwide

Question 13

How is caprine arthritis encephalitis virus transmitted?

Answer 13

Vertical: unpasteurized colostrum, milk, transplacental fro doe to kids
Iatrogenic: blood contaminated needles, fomites, equipment, needles
Horizontal: contact with saliva, respiratory aerosols

Question 14

How is caprine arthritis encephalitis virus prevented/controlled?

Answer 14

Test and cull: serology screen, PCR on individuals
Separation of kids from dam at birth, pasteurization of colostrum, milk

Question 15

How does encephalitis present with caprine arthritis encephalitis virus?

Answer 15

Kids 2-4 months of age
Progressive leukoencepahlomyelitis
Ascending paralyisis
Weight loss
Trembling
Febrile
Alert
Paralysis, paddling, torticollis

Question 16

How does arthritis present with caprine arthritis encephalitis virus

Answer 16

Adult goats >1 yr of age
Enlarged, swollen, painful carpal joints most commonly affected
Hocks, stifles, shoulder, fetlocks, vertebral
Fluid filled tendon sheaths
Progressively contracted/flexed joints
Proliferative synovitis

Question 17

What diseases are associated with ovine progressive pneumonia virus?

Answer 17

Progressive pneumonia (Maedi)
Wasting (Visna), demyelinating leukoencephalomyelitis
“Hard-bag”

Question 18

What is the host range of ovine progressive pneumonia virus?

Answer 18

Sheeps, goats

Question 19

How is ovine progressive pneumonia virus transmitted?

Answer 19

Ingestion: unpasteurized colostrum, milk)
Inhalation: contact with saliva, aerosolized respiratory secretions
Sexual: semen
Iatrogenic: contaminated needles, surgical instruments, equipment

Question 20

How is ovine progressive pneumonia virus prevented/controlled?

Answer 20

Test and cull: serology screening
Separation of lambs at birth, pasteurization of colostrum, milk

Question 21

What are other retroviral diseases of sheep?

Answer 21

Ovine pulmonary adenomatosis virus/Jaagsiekte sheep retrovirus
Enzootic nasal tumors

Question 22

What diseases are associated with equine infectious anemia?

Answer 22

Acute: swamp fever
Chronic relapsing carriers

Question 23

What is the host range of equine infectious anemia?

Answer 23

Horses, mules, donkeys

Question 24

What is the geographic distribution of equine infectious anemia?

Answer 24

Worldwide, present in feral horses in the US

Question 25

How is equine infectious anemia transmitted?

Answer 25

Iatrogenic: via administration of equine blood contaminated traansfusions, needles
Mechanical: via biting insects
Transplacental: mare to foals

Question 26

How is equine infectious anemia prevented/controlled?

Answer 26

Serologic testing of horses, market, sale, show, inter-state transport: Coggins test, ELISA
Carriers are destroyed or quarantined in insect-proof barns permanently

Question 27

What is the acute clinical presentation of equine infectious anemia?

Answer 27

Fever
Anorexia, depression, weakness
Severe anemia
Thrombocytopenia
Jaundice
Petechial hemorrhages on mucosae
Dependent edema
Weight loss
Mortality in horses

Question 28

What is the chronic clinical presentation of equine infectious anemia?

Answer 28

Following recovery from acute phase
Lifelong persistent infection
Recurrent episodes of fever, anemia, cachexia, ventral edema
Subclinical in between periods of fever
Viremia serves as a source of virus
Weight loss, failure to thrive

Question 29

What is the pathogenesis of equine infectious anemia?

Answer 29

Tropism for macrophages
Viremia
Vigorous immune response does not clear the virus
Immune-mediated lysis of RBCs involving complement leads to anemia
Vasculitis, immune complex disease
Glomerulonephritis, immune complex deposition