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Flashcards in Spirurids Deck (35):
1

___ are tissue parasites transmitted by bloodsucking insects, microfilaria accumulate either in blood or connective tissue.

Filarial worms

2

What is the intermediate host of D. immitis?

Mosquito
(only form of transmission)

3

What is the primary definitive host of D. immitis?

Canids

4

What percentage of mosquitos may be D. immitis positive?

2-20%

5

What percentage of mosquitos may be D. immitis positive near a positive animal?

30-70%

6

Where can D. immitis be found within the body?

Pulmonary arteries

7

Based on the eggs released, what are the D. immitis females?

Viviparous

8

Where does the larva change from L1 into L3?

In malpighian tubules of the mosquito

9

How long does it takes these to go from a microfilaria to an infectious L3 inside the misquito during transmission season?

10-14 days

10

After becoming L3s in the misquito, to where do they migrate within the body?

Mouthpart

11

Explain the process of the mosquito bite and the larva entering the host.

L3 exit labrum when mosquito feeds and enter the bite wound. L3 --> L4 takes 3-4 days. L4 --> L5 takes 45-65 days. Immature adults (L5) migrate within muscle cells to blood vessels. From there they enter pulmonary arteries. L5 --> Adulte = 6-9 months (prepatent period)

12

How long does it take the the L3 to develop into L4 in the host?

3-4 days

13

What does the heartworm test detect?

Antigen produced by ADULT females

14

What can the ELISA antigen test be used for?

Semi-quantitative data

15

What are 3 cases where an animal would come up with a FALSE NEGATIVE?

1. All male infection
2. Infection with low # of females
3. Infection with immature females

16

What are some causes of an occult heatworm infection?

1. Infection with only females
2. Use of HW preventatives that kill the microfilaria
3. Maturing adult females present
4. Immune-mediated clearance of microfilaria

17

What is the GOAL of HW treatment?

Eliminate all life cycle stages of HW with minimal post treatment complications

18

How might you eliminate adults?

1. Melarsomine
2. Surgical removal

19

Which life stage do you eliminate first?

Microfilaria
Follow up with adults

20

What are the 3 things you should assess prior to treating HW adults?

1. Activity level
2. Physical exam, chest radiographs, blood work
3. Worm burden

21

What do macrocyclic lactones treat?
What does melarsomine treat?

1. L3s and L4s
2. Adults only

22

How do you treat a HW positive dog before treating with melarsamine?

Killing the Wohlbachia bacteria helps in treatment
Treat with doxycycline + IVM

23

If you get rid of Wolbachia, what is lost in the embyro?

Asymmetry - will not develop properly

24

What restriction do Melarsomine treatment dogs require?

Exercise restriction

25

Explain the Melarsomine treatment.

Three injections
1 dose
2 doses 30 days later 24 hours apart

26

At what point should an antigen test be negative after treatment?

6 months later

27

How often do you perform an antigen test?

Annually

28

Start puppies on prophylaxis no later than ___ weeks old.

8

29

In older puppies (

1. 6 months
2. 1st dose

30

Differ the HW disease in cats from that in the dog.

1. Cats more resistant
2. Fewer L3 mature to adults
3. Mature more slowly
4. Shorter adult life span
5. Fewer adult worms in the heart (antigen test will not work as well)
6. Less worms required for disease

31

What does the antibody test confirmed?

An infection has occurred

32

Why does the antigen test have a high incidence of false negatives?

Fewer worms present

33

Does the AHS recommend giving a feline the adulticide melarsamine? Why or why not?

NO - this is potentially toxic to the cat and will NOT increase survival

34

What is the prevention protocol for feline HW?

Monthly oral or topical macrolides

35

Which exotic animal is susceptible to HW? Is there a test for this infection? Can it be prevented?

Ferrets
Yes - antigen test
Yes