Vasculitides

Question 1

Malignant Catarrhal Fever: Ovine Herpesvirus-2

Answer 1

Gammaherpesvirus
Cervids, bovines
Sheep are asymptomatic carriers
Virus replicates in Type II pneumocytes, transmitted via nasal and ocular secretions/airborne
Causes lymphoproliferative necrotizing vasculitis.
Viral infection detected in leukocytes, vascular endothelial cells, smooth muscle of tunica media, fibroblasts of tunica adventitia

Question 2

Epizootic Hemorrhagic Disease Virus/
Bluetongue Virus (Orbivirus)

Answer 2

Sheep, Cows, Deer
Transmitted by Culicoides midges
Lower morbidity in cattle
Virus infects erythrocytes and endothelial cells
Endo damage > microthrombi > clotting factors and platelets used up > DIC
Fibrinoid necrosis of arterioles and venules
Ischemic necrosis of tissues downstream of necrotic vessels

Question 3

Equine Viral Arteritis

Answer 3

Induces hemorrhage, edema, and abortions (b/c blood supply to fetus becomes compromised)
Fever, anorexia, hindlimb and abd edema. But many asymptomatic
Transmitted in resp secretions, semen, fomites.
Virus found in endothelium, tunica media, and pericytes. Induces fibrinoid necrosis of vessels.

Question 4

African Swine Fever

Answer 4

Asfarviridae
Tick-transmitted
Induces apoptosis of T,B, and endothelial cells.
Hemorrhagic fever w/ cutaneous hyperemia, sudden death.
Necropsy: marked splenomegaly, degeneration of vascular endos and extensive thrombosis and hemorrhage.
Fibrinoid necrosis and thrombosis, hemorrhage everwhere

Question 5

Swine Erysipelas
“Diamond Skin Disease”

Answer 5

Anaerobic, gram +, bacteria
Erysipelothrix rhusiopathiae
Healthy pigs are carriers
Pregnant sows and younger pigs most susceptible.
Anorexia, fever, cyanosis, abortions.
Vegetative valvular endocarditis.
Septicemia and bacterial emboli cause systemic vasculitis, thrombosis, ischemia, and infarction.