Lungworm

Question 1

What species of lungworm causes disease in cattle?

Answer 1

Dictyacaulus viviparus

Question 2

Which species of lungworm cause disease in sheep?

Answer 2

Dictyocaulus filaria and Muellerius capillaris

Question 3

Describe the lifecycle of Dictyocaulus

Answer 3

1. Adults in bronchi and trachea lay eggs
2. Eggs coughed up, swallowed
3. Eggs hatch during passage through gut
4. L1 passed in faeces and develops to L3 on pasture
5. L3 ingested by host
6. Larvae penetrate gut wall and migrate to the lungs via the lymphatics
7. Larvae ascend up the respiratory tree where they develop into adults

Question 4

What occurs during the PPP of Dictyocaulus?

Answer 4

1-3 wks

Migrating larvae cause broncholitis and eosinophilic exudate which blocks the airways and causes alveolar collapse

Question 5

What occurs during the patent period of Dictyocaulus?

Answer 5

4-8 wks

Mature worms cause bronchitis and parasitic pneumonia

Question 6

What occurs during the post patent period of Dictyocaulus?

Answer 6

8-12 wks

Majority of worms expelled. Interstitial emphysema, pulmonary oedema and secondary bacterial infection

Question 7

How does the lifecycle of Muelleris capillaris differ from that of Dictyocaulus?

Answer 7

L1 penetrate snails and then develop to L3 which can take weeks to months

Question 8

What are the clinical signs seen in cattle?

Answer 8

Cough, tachypnoea, decreased growth rate in calves, reduced milk yield, mild respiratory signs

Question 9

What are the clinical signs associated with Dictyocaulus in sheep?

Answer 9

Coughing, weight loss.

Less severe than in cattle.

Question 10

What are the clinical signs associated with Muelleris capillaris?

Answer 10

Asymptomatic, general weakness, mild respiratory signs

Question 11

How is lungworm diagnosed in cattle?

Answer 11

Seasonal incidence, previous grazing hx, CS, Baerrman FEC (larvae), PM, milk/blood ELISA, gross exam of larvae on poo

Question 12

How is lungworm diagnosed in sheep?

Answer 12

Grazing hx, CS, faecal examination, PM

Question 13

How can lungworm be controlled in cattle?

Answer 13

Vaccination with Huskvac
FGS calves > 2 months old vaccinate @ 6 and 2 wks pre-turnout
Adults 2 wks pre-turnout
Immunity is maintained as long as there is exposure to lungworm

Question 14

How can lungworm be controlled in sheep?

Answer 14

Difficult as outbreaks are unpredictable
PGE control measures usually sufficient
Remove and treat affected sheep from the flock

Question 15

How is lungworm treated in cattle and sheep?

Answer 15

ML - Moxidectin (Cydectin), Doramectin (Dectomax), Eprinomectin (Eprinex), Ivermectin (Ivomec)
BZD - Albendazole (Ovispec), Fenbendazole (Panacur)
Levamisol (Levacide)