CV parasites Flashcards
What is canine heartworm
Dirofilaria Immitis
What factors affect the distribution of D. Immitis
Requires water temperature to be above 27 degrees for 2 weeks , mosquito breeding
Describe the D. Immitis life cycle
- Mosquito takes L1 from blood of infected patient
- L1-L3 in mosquito
- mosquito bites another uninfected dog and transfers L3 into their blood
- L4/L5/Adult develop in the dogs right heart and pulmonary vessels
What are the clinicl features of a D. immitis infection
- Exercise intolerance
- Hydrothorax
- Hydroperitoneum
- Chronic cough
- Dyspnoea
- Haemoptysis
- Eosinophillia in lung
- Oedema in lung parenchyma
How does D. Immitis cause hypertension
inner lining of the blood vessel gets disrupted and this leads to platelet influx and production of platelet derived growth factor. This increases proliferation of medial smooth muscle cells and fibroblasts. causing blood vessels walls to thicken
Which cells produce histamine
Basophils and Mast cells
What bacteria do D. Immitis carry
Wolbachia
Why do neutrophils respond to DE. immitis
Becaus D. immitis as it carries Wolbachia which is a type of bacteria
How do you diagnose canine heartworm
- Complete blood count to lok for microfilariae in blood X-rays Echocardiogram Tracheal wash ELISA
How do heartworms appear on a echocardiogram
very echogenic
What are the limitations of complete blood count to diagnose D. immitis
some other disease will give similar results
What are the limitations of blood smears in testing for D. Immitis
microfilariae may not be seen if few are present
What are the limitations of echocardiograms when diagnosing D. immitis
May be difficult to interpret
What are the limitations of radiology when diagnosing D. immitis
Signs may be similar to other diseases
What are the limitations of ELISA tests when diagnosing D. Immitis
Only adult female antigens detected
False negatives occur- if immature females present or male only infection
How can D. immitis cause thrombocytes
Worms die, decompose and can break into little bits, particles can get lodged in different areas
What is the best way to deal with a heavy infection of D. immitis so thrombocytes don’t occur
Surgical removal
What are the issues with surgical removal of D. immitis
prognosis and complications from treatment as well as cost need to be discussed with the client
How can you tell the difference between D. reconditum and D. immitis microfilariae
acid phosphate test- only stains 2 spots in D. Immitis
Are cats susceptible to D. immitis
Yes, but not as much as dogs
What is caval syndrome
obstruction of blood flow from the vena cava caused by heavy heartworm infestation
Why is it so hard to diagnose D. immitis in cats
they are amicroflaraemic, ELISA analysis isn’t good because worm count is low and single sex infections occur more
