Spirurids

Question 1

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

Answer 1

Filarial worms

Question 2

What is the intermediate host of D. immitis?

Answer 2

Mosquito

only form of transmission

Question 3

What is the primary definitive host of D. immitis?

Answer 3

Canids

Question 4

What percentage of mosquitos may be D. immitis positive?

Answer 4

2-20%

Question 5

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

Answer 5

30-70%

Question 6

Where can D. immitis be found within the body?

Answer 6

Pulmonary arteries

Question 7

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

Answer 7

Viviparous

Question 8

Where does the larva change from L1 into L3?

Answer 8

In malpighian tubules of the mosquito

Question 9

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

Answer 9

10-14 days

Question 10

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

Answer 10

Mouthpart

Question 11

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

Answer 11

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)

Question 12

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

Answer 12

3-4 days

Question 13

What does the heartworm test detect?

Answer 13

Antigen produced by ADULT females

Question 14

What can the ELISA antigen test be used for?

Answer 14

Semi-quantitative data

Question 15

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

Answer 15

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

Question 16

What are some causes of an occult heatworm infection?

Answer 16

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

Question 17

What is the GOAL of HW treatment?

Answer 17

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

Question 18

How might you eliminate adults?

Answer 18

1. Melarsomine

2. Surgical removal

Question 19

Which life stage do you eliminate first?

Answer 19

Microfilaria

Follow up with adults

Question 20

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

Answer 20

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

Question 21

What do macrocyclic lactones treat?

What does melarsomine treat?

Answer 21

1. L3s and L4s

2. Adults only

Question 22

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

Answer 22

Killing the Wohlbachia bacteria helps in treatment

Treat with doxycycline + IVM

Question 23

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

Answer 23

Asymmetry - will not develop properly

Question 24

What restriction do Melarsomine treatment dogs require?

Answer 24

Exercise restriction

Question 25

Explain the Melarsomine treatment.

Answer 25

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

Question 26

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

Answer 26

6 months later

Question 27

How often do you perform an antigen test?

Answer 27

Annually

Question 28

Start puppies on prophylaxis no later than ___ weeks old.

Answer 28

8

Question 29

In older puppies (

Answer 29

1. 6 months | 2. 1st dose

Question 30

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

Answer 30

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

Question 31

What does the antibody test confirmed?

Answer 31

An infection has occurred

Question 32

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

Answer 32

Fewer worms present

Question 33

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

Answer 33

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

Question 34

What is the prevention protocol for feline HW?

Answer 34

Monthly oral or topical macrolides

Question 35

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

Answer 35

Ferrets Yes - antigen test Yes