Coughing youngstock/ parasitic respiratory disease SDL

Question 1

What causes lungworm in cattle

Answer 1

Dictyocaulus viviparus

Question 2

Describe the lifecycle of lungworm in cattle

Answer 2

Direct, however dispersion also occurs via fungal spores
1. Larva ingested and then migrate to lungs
2. Adults develop in lungs and produce eggs
3. Eggs hatch and L1 larvae are coughed up then swallowed
4. L1 larvae passed in faeces
5. L3 larvae develop in dung pat
6. infective larvae spread onto herbage

Question 3

Describe how lungworm spread when it is in the environment

Answer 3

fungal spores produced by Pilobolus, helps to move it around through the dung pat

Question 4

When do we see lungworm infections

Answer 4

midsummer into autumn

Question 5

How do lungworm larvae get to the lungs

Answer 5

larvae are ingested
activated by bile
they transverse through small intestinal wall
through the lymphatics
through the thoracic duct and then into the lungs

Question 6

How long does it take for larvae to get from the intestines to the lungs

Answer 6

7 days

Question 7

How long is the prepatent phase for lungworm in cattle

Answer 7

1-3 weeks

Question 8

Describe the clinical signs of lungworm

Answer 8

Depends if mild, moderate or severe
widespread coughing
loss of condition
tachypnoea
dysponea
reduced milk yield

Question 8

Describe phase 1 of host immune response against lung worm

Answer 8

immune response is initiated in the mesenteric lymph nodes- short term immunity

Question 9

Decsribe the phase 2 of host immune response against lung worm

Answer 9

secondary immune response evoked, parasites are destroyed and eliminated from the lungs- lasts 2 years

Question 10

Why can we still get clinical signs even when cattle are able to clear the infection

Answer 10

due to large amounts of inflammation and the large number of larvae

Question 11

Describe how to test for lung worm

Answer 11

Baermann’s test
BAL
ELISA
Post mortem

Question 12

Describe how to treat lungworm in cattle

Answer 12

Moxidectin
Doramectin
Ivermectin

Question 13

Describe why treating lungworm temporarily can make the cattle worse

Answer 13

because we can exacerbate the immune repsonse to the worms- when they are dying they release higher numbers of toxins

Question 14

How can we control lungworm

Answer 14

delayed turnout
vaccination
rotational grazing
dose and move

Question 15

What type of vaccine is used against lungworm

Answer 15

2 live attenuated vaccines given orally

Question 16

Why is vaccination against lungworm difficult in cattle

Answer 16

we can’t predict when lungworm cases will rise - if vaccinated cattle get a patent infection at the same time as vaccination, they can be very ill, vaccinated animals can become carriers

Question 17

why is treating cattle at the start of the grazing season not always economically viable

Answer 17

they have to stay on the same field for that whole season otherwise they need to be retreated