Endoparasites

Question 1

The ascarid group (type of roundworm) causes what?

Answer 1

toxocara canis, toxocara cati or toxocara leonina

Question 2

Describe the lifecycle of toxocara canis

Answer 2

1. Infective eggs may be ingested by your pets directly from the environment, a paratenic host (carrier, eg flea), or humans (only get to larvae before passing on) 2. The paratenic host is eaten and egg containing larvae are released into the small intestine. 3. Larvae are released from the infective eggs and turn into adults in the dogs intestine

Question 3

Describe toxocara canis in a pregnant bitch

Answer 3

After a dog is 6/7 mths of age, larvae usually migrate from intestine to muscle where they remain dormant. Some of the larvae reactivate when high levels of progesterone occur. From day 42 of pregnancy these reactivated larvae can cross the placenta. The larvae pass through liver/lungs get coughed up and swallow, and by 3 wks post part, have developed to adults. These can be passed to the pups through milk.

Question 4

The toxocara species are zoonotic, what do they cause?

Answer 4

Occular larval migrans, which causes damage to the retina, giving reduced vision. It also causes visceral larval migrans. These tend to affect children more because of their poor hygiene

Question 5

Lungworm is another type of roundworm (Angiostrongylus vasorum)..describe the lifecycle

Answer 5

1. Dog eats snail/slug infected with lungworm larvae 2. Larvae mature into adults and live in the right ventricle of the heart and in the pulmonary artery 3. Male/female adult worm mate and lay eggs in the circulation. It lodges in lung capillaries, hatches and goes into lung alveoli. They’re coughed up, swallowed and passed into faeces. Cycle Repeats

Question 6

What are lungworm symptoms?

Answer 6

1. decreased ability to clot blood 2. seizures due to haemorrhaging into the brain 3. Heart failure caused by blocked blood flow.

Question 7

What family do tapeworms belong to?

Answer 7

Cestodes

Question 8

Where does reproduction occur in the tapeworm?

Answer 8

In the segmented part of it called a proglottid, in the case of dipylidium caninum they can lay up to 15 eggs.

Question 9

Lifecycle of the dipylidium caninum (most common tapeworm in Ireland/uk) with flea as the intermidiate host

Answer 9

1. Mature segments with 15/16 eggs detatch from the tapeworm and are shed into the faeces. 2. Once in environment, the segments dry out, burst and release eggs. 3. Flea larvae eats swallow eggs, grows into adult flea and tapeworm larva released from eggs. 4. If swallowed larva travels to intestines. 5. in intestine, larva attatches its head to intestinal mucosa and turns into adult. 6. The mature egg filled segments shed away and are released into the faeces.

Question 10

Lifecyle of giardia intestinalis (protozoa)

Answer 10

Giardia is passed directly animal to animal. 1. Giardia cysts are passed in the faeces and get into water/soil 2. Cats/dogs become infected by drinking it. 3. In the SI of host, giardia cysts turn into a trophozite which feeds and replicates itself. 4. Giardia cysts are then formed and passed in faces

Question 11

Is giardia intestinalis zoonotic?

Answer 11

Yes, it can cause diarrhoea, stomach cramps and loss of appetite in humans.