13. Retroviral infectoius diseases, enzootic bovine leucosis

Question 1

What are retroviral infectious diseases?

Answer 1

• Viral infections caused by family Retroviridae.
• RNA viruses

Question 2

Retroviral infectious diseases are diseases like?

Answer 2

*Enzootic bovine leucosis = bovine leukemia –> formation of lymphosarcoma
* Feline leukemia –> formation of lymphosarcoma
* Avian leukosis = avian leukemia –> formation of lymphosarcoma
* Maedi visna (sheep and goat) –> RT and CNS. OIE listed
* Equine infectious anemia (Equids) –> anemia. OIE listed

Question 3

What are important fact to mention about enzootic bovine leucosis

Answer 3

Contagious, permanent infection

Question 4

What are the agent responsible for enzootic bovine leukosis?

Answer 4

Bovine leukemia virus - BLV. Oncogenic virus

Question 5

What does the enzootic bovine leukosis cause in host?

Answer 5

A permanent infection that can cause lymphosarcoma or death.

Question 6

How is enzootic bovine leukosis transmitted?

Answer 6

• Horizontal - Blood, equipment, needle
• Vertical - Transplacental or colostrum

Question 7

What are clinical signs of enzootic bovine leukosis

Answer 7

• Permanent infection - will not recover- always shedding or die
• 3 outcomes of the disease:
  a) Persistent infection with no C.S - asymptomatic
  b) Persistent infection with lymphocytosis - benign
  c) Lymphosarcoma- malignant
• General signs- include weight loss, fever, tachycardia, dyspnea

Question 8

How can enzootic bovine leucosis be diagnosed?

Answer 8

• Clinical examination - palpate swollen LN, lymphosarcoma
• Serological test - lymphocytosis (increased nr of lymphocytes in blood), RT - PCR for detection of Ag

Question 9

How can enzootic bovine leucosis be treated?

Answer 9

NO treatment.
Slaughter of infected animals

Question 10

How can enzootic bovine leucosis be prevented?

Answer 10

• By early detection and elimination of infected individuals.
• Regularly testing and retesting.
• No vaccine