Glossary Links Lab Manual PDF

Case Study 2 ('04): Heartworm in dogs

Let's assume that it is May 15th, 2005.  The blood sample you were provided in lab today came from an asymptomatic 18-month-old collie dog named Fiona whose family relocated to the Philadelphia area in December of 2004 from Mobile, Alabama.  They adopted Fiona from a farmer in a rural Alabama county near Mobile just before their move.  The owners impress you as being very conscientious about Fiona's care.  They are aware of the benefits of chemoprophylaxis against heartworm infection, but they have not been giving Fiona prophylactic medication since moving to Philadelphia and they do not know Fiona's previous history with respect to heartworm prevention.  The circumstances in which the dog lived prior to adoption did not inspire confidence in the level of veterinary care she had received.

Questions:

1. What does your diagnostic testing in lab today reveal about Fiona's infection status?

Click here for the answer:

 

2. What is the species identity of the parasite with which Fiona is infected?

Click here for the answer:

3. Which of the tests you performed allows you to make this diagnosis unambiguously?

Click here for the answer:

 

4. Which of the tests confirms the presence of adult female heartworms?

Click here for the answer:

5. Does the fact that Fiona is asymptomatic contradict your diagnosis?

Click here for the answer:

 

 

6. What is the latest calendar date on which Fiona could have been inoculated with the infective heartworm larvae and still be positive on the Ag and Knott tests on May 15th, 2005.

Click here for the answer:

 

7. As Fiona's new veterinarian, what options do you have in terms of treating her for the adult heartworms if she is infected?  What are some of the precautions you should take in administering adulticidal treatment in any dog?

Click here for the answer:

 

 

8. Once the immediate problem of the adult heartworms has been addressed, what FDA approved medications could you prescribe to prevent re-infection over the coming summer in Philadelphia (list all the generic compounds (not brand names) used for this)?  Give the recommended dosing interval for each of these.

Click here for the answer:

 

 

 

 

 

9. Does the fact that Fiona is a rough-coated collie limit your options with regard to choice of prophylactic medications, assuming that you will adhere strictly to the label instructions about dosage for any drug you prescribe?

Click here for the answer:

 

10. We have said that Fiona's owners seem to be conscientious.  However, viewing the problem strictly from the standpoint of the risk of new infection, were they misguided in not seeing that the dog was given prophylactic medication after moving to Philadelphia in December?

Click here for the answer:

 

11. Aside from preventing new infection, could any of the medications licensed as preventives have had an effect on the intensity of her adult worm infection if given beginning in December (explain)?

Click here for the answer:

 

12. Does having circulating microfilaria prohibit you from immediately starting an infected dog on a course of prophylactic medication? Answer this question for each of the drugs that you mentioned in Question 8.

Click here for the answer:

 

 

 

 

     

 


Copyright © 2006 - University of Pennsylvania School of Veterinary Medicine, All rights reserved.
Faculty: Dr. Thomas Nolan
Students: Molly Church V'09, Diana Knight V'08, Douglas Gilson V'05, Chris Dykhouse V'04, Kimberly Mah V'00

Comments or Questions contact Dr. Tom Nolan at: