Clinical Cases - Serology Flashcards
Interpret: BVD herd testing
- Antigen ELISA = negative
- Virus neutralization = 1:64
previous infection & now has antibodies
Interpret: BVD herd testing
- Antigen ELISA = positive
- Virus neutralization = 1:8
early infection, maternal antibodies, or persistently infected
convalescent Ab titers 2 weeks later can confirm recent infection if there is a >4-fold increase
Interpret: BVD herd testing
- Antigen ELISA = positive
- Virus neutralization = negative
acute exposure; antibodies have not formed/appeared yet
antibodies for BVD take ~2-3weeks
Interpret: BVD herd testing
- Antigen ELISA = negative
- Virus neutralization = 1:128
Vaccinated
How to ID calves that are PI with BVD in herd?
Ear notch all positive calves (at birth) to differentiate PI from transient infection
ear notch by IHC (PCR cannot discriminate PI from transient)
A “PI” calf is the result of a pregnant cow or heifer getting infected with the BVD virus between 42-125 days of gestation. The adult cow or heifer will experience a “transient BVD infection” which is often mild, or she may show no symptoms at all. However, the virus will also cross the placenta, infecting her unborn calf. When this calf is born, it is “persistently infected” or “PI” and is a “carrier” and “spreader” of the virus for its lifetime.
A BVD-PI calf is born with the BVD virus and sheds virus everywhere it goes for its entire life. Identification and removal of PI calves is critical to stop survival of the virus.
An owner would like distemper and parvo virus titers performed on her 4 y/o dog.
1. Distemper: IgG IFA = 1:50
2. Parvo: IgG IFA = 1:200
What do these results mean if the cutoff for this assay is ≥1:100?
- Distempter needs to be boosted
- Parvo titer is good
Only Distempter, adenovirus, and parvo have known protective titers
IgG = most abundant, smallest, sticks to/neutralizes pathogens; can cross placenta
A 3mo La Mancha doe’s competitive ELISA test result for small ruminant lentivirus (CAE/OPP) is positive. Interpret + plan.
Most likely detecting maternal antibodies
- to r/o current infection, perform Ag test now (may get false negative if early), then perform convalescent titer in 14 days w/ doe in quarantine until results come back.
What type of immunity do antibody titers measure? What type is essential to consider for viral pathogens?
Antibody titers measure humoral immunity; cell-mediated immunity is very important in viral pathogens.
A dog presents for hepatic failure and acute renal failure. Last lepto vax was 4 years ago. You perform leptospira microagglutination test and these are the results:
1. Pomona = 1:200
2. Hardjo = 1:100
3. Icterohaemirrhagiae = 1:400
4. Grippotyphosa = 1:200
5. Canicola = 1:400
6. Bratislava = 1:1600
7. Autumnalis = 1:100
Why serovar is he likely infected with any why?
Bratislava - high Ab titer even tho last vaccine was 4 years ago indicates active infection.
If aggressive and appropriate medical therapy is administered, including hemodialysis when indicated, the prognosis for dogs with leptospirosis is good. The rate for survival to hospital discharge is approximately 80%.40 For dogs with mild to moderate disease that is treated conservatively and for dogs with severe azotemia treated with hemodialysis,40 the short-term prognosis is also good. However, the prognosis for dogs that need hemodialysis but do not receive it is grave. If severe pulmonary hemorrhage syndrome develops, the prognosis becomes worse and survival rates drop to 40% to 50%.15 Some leptospirosis patients will have lasting chronic renal changes and will need long-term monitoring and care for chronic kidney disease.
https://todaysveterinarypractice.com/infectious-disease/diagnosis-and-treatment-of-leptospirosis-in-dogs/
Hemodialysis (HD) is a form of blood purification. It is used to treat animals with kidney disease or intoxications. A venous catheter is placed in the jugular vein of the animal to allow for repeat treatments if necessary. During hemodialysis blood is pumped through a machine and cleared by a special filter (called artificial kidney or dialyzer). This allows for removal of toxic waste products accumulating due to kidney disease or failure, or for direct removal of ingested toxins from the patient’s blood. Hemodialysis is not a painful procedure and does not require the patient to be anesthetized. Dogs or cats typically rest comfortably while receiving treatment. https://vet.purdue.edu/hospital/small-animal/services/hemodialysis.php#:~:text=It%20is%20used%20to%20treat,called%20artificial%20kidney%20or%20dialyzer).
