Target Practice
CIRCOVIRUSES
Target lymphocytes and other rapidly dividing cells
Rotavirus infection
Non-bloody diarrhea in young animals
Less severe & shorter duration (3-4days) than parvovirus infection (5-7 days)
PCR (+) PCR (-)
VetScan (+) 30 0
VetScan (-) 2 29
Calculate specificity of the VetScan for FeLV
29/29= 100%
Direct fluorescent assays
Vs
Indirect fluorescent assays
Direct: Detect viral antigen in patient tissue, using a labeled primary antibody form a kit
Indirect: Detects antiviral antibodies in the patient serum, using fixed viral antigen on a slide and labeled secondary antibody from the test kit
Rotaviruses
Villus TIPS
Circovirus infection
Relate to decreased immune function, secondary infections are often present and more severe than normal
Pathogenesis for Orbiviruses
Bluetongue, Epizootic Hemorrhagic Disease, African horse sickness Pathogenesis:
Exposure to BIOLOGICAL vector (culicoides midges) ➡️ 1 degree viremia (bone marrow) ➡️ Secondary viremia (endothelial cells)➡️ Edema, hemorrhage, thrombosis
FeLV
PCR (+) PCR (-)
VetScan (+) 30 0
VetScan (-) 2 29
Calculate the sensitivity of the VetScan test FeLV
30/32= 94%
A 10 yr old quarter horse presents with ulcerative lesions in the oral cavity. FAD is ruled out.
You ultimately want to distinguish EHD from Blue Tongue—what is your choice diagnostic?
RT-PCR
Parvoviruses
Intestinal crypts; bone marrow, LN, spleen
Birnaviruses
Enlarged bursa of fabricius
Eccymotic hemorrhage
Pathogenesis for Rabies
ACHr at peripheral nerves ➡️ Ascending fibers ➡️ Spinal column ➡️ CNS ➡️ Peripheral excretory organs
⭐️ Centripetal phase = periphery to CNS
⭐️ Centrifugal phase = CNS to peripheral excretory organs
FeLV
PCR (+) PCR (-)
VetScan (+) 30 0
VetScan (-) 2 29
Calculate the prevalence of FeLV based on the Vetscan test
30/61=49%
FeLV vs. FIV Snap tests
FeLV (p27 antigen) FIV (p24 capsid & p15 matrix)
Paramyxoviruses
Target upper respiratory tract mucosa
Paramyxoviruses
Respiratory disease
CNS manifestations
Pathogenesis for Equine infectious anemia
Virus infects monocytes and macrophages ➡️ Upregulation of proinflammatory cytokines (IL-1, IL6, TNF-a) ➡️ thrombocytopenia, splenomegaly, hepatomegaly, increased phagocytosis + lysis of RBC’s
Toxoplasma
PCR(+) PCR (-)
Latex Ag (+) 33 9
Latex Ag (-) 3 16
Calculate sensitivity & specificity of the LAT for Toxoplasma
Sensitivity: 33/36= 91.7%
Specificity: 16/25= 64%
(AGID) detects ANTIBODIES to p26 capsid protein
Retroviruses
*name the target of each retrovirus discussed
1. FeLV = Lymphatic system
2. FIV = CD4+ T Lymphocytes (binds CD134 CXCR4)
3. Equine infectious anemia= monocytes + macrophages
4. Mareks disease virus= T-Cells
5. Avian Leukosis Virus= B-Cells
6. Jaagsieke Sheep Retrovirus= Type II pneumocytes + bronchiolar club cells
7. Bovine Leukemia Virus = B cells
8. Maedi-Visna Virus= Mononuclear WBC
9. Caprine Arthritis-Encephalitis Virus= Monocytes/macrophages
Avian Leukosis Virus
Leukosis (lymphoid most common)
Decreased Egg production
Enlarged bursa, liver, pale wattles, osteopetrosis
Diffuse or nodular tumors (NOT in nervous tissue)
Avian Influenza Pathogenesis
Hemagglutinin facilitates viral attachment & fushion to host cellular membrane, cleaved by proteases found only in specific tissues
LPAI = cleaves by intestinal proteases
HPAI= Liver, lung, kidneys, brain
FIV
PCR (+) PCR (-)
VetScan (+) 23 0
VetScan (-) 1 37
Calculate sensitivity, specificity, and prevalence of FIV
Sensitivity: 23/24 = 95.8%
Specificity: 37/37= 100%
Prevalence: 23/61 = 37.7%
Only diagnostic for Jaagsiekte Sheep Retrovirus
PCR