pulmonary parasites

Question 1

describe the life cycle of dictyocaulus spp.

Answer 1

• adult lungworms live in the trachea and brinchi causing parasitic bronchitis
• deposition of eggs/newly hatched larvae may lead to parasitic pneumonia
• usually seen in cattle on permanent pastures used for seasonal grazing in the UK and europe
• cattle exposed to D. viviparus develope rapid immunity
• hypobiosis (dormancy) of larval stage has been demonstrated in adult cattle
• L3 larvae may overwinter on pasture in enough numbers to cuase disease the following sprinf but conditions need to be favourable

Question 2

how do you diagnose lungworm disease

Answer 2

• baermann apparatus used to detect L1 larvae in feces
• ELISA
• post mortem

Question 3

what is the difference between lungworm disease and respiratory signs attributed to the passage of some nematode larvae through the lungs

Answer 3

Lungworm Disease:
Common symptoms of lungworm disease include coughing, wheezing, difficulty breathing, exercise intolerance, and in severe cases, respiratory distress and even death. The disease is caused by the worms’ presence and activity within the respiratory system, which can lead to inflammation, damage to lung tissue, and interference with the normal functioning of the respiratory system.

Respiratory Signs from Nematode Larvae Passage:
This concept refers to the temporary respiratory signs and symptoms that animals may exhibit when they are exposed to nematode larvae that migrate through their respiratory system. Nematode larvae from certain parasitic species have a unique lifecycle that involves passing through the lungs of their host animals during their migration to reach their final destination in the body. As these larvae move through the respiratory passages, they can cause irritation, inflammation, and coughing as the host’s body attempts to clear them from the airways. However, these signs are typically temporary and subside once the larvae complete their migration and move on to their intended location in the body.

Question 4

list the species of lungworms found in ruminants and equids

Answer 4

cattle and deer: dictyocaulus viviparus
sheep and goats: dictyocaulus filaria OR protostrongylus rufescens/mullerius capilars
donkeys and horses: dictyocaulus arnfieldi

Question 5

what are the clinical signs of dictyocaulus viviparus

Answer 5

mild infection:
- intermittent coughing, more pronounced on exercise
- resp rate often normal (30/min)
- lung auscultation often normal, sometimes occasional squeaks

moderate infection:
- frequent coughing even at rest
- tachypnoea (40-60/min
- diaphragmatic lobes give pronounced squeaks and crackles on auscultation

severe infection:
- deep, harsh couch
- severe tachypnoea (more than 80/min)
- diaphragmatic lobes give pronounced squeaks and crackles on auscultation
- respiratory distress
- gasping for air with head and neck outstretched
- salivation
- loss of appetite
- fever

Question 6

why have cases of lungworm increased

Answer 6

preventative treatment with anthelmintics instead of vaccination (for cattle) compromises immune systems ability to fight infection on own (anthelmintic resistance)

Question 7

describe the lifecycle of angiostrongylus vasorum

Answer 7

1. L1 penetrates capillaries and alveolar wall
2. L1 coughed up and swallowed
3. L1 in feces
4. L1-L3 develop in slug/snail (indirect)
5. dog eats slug/snail
6. stomach/intestines
7. L5 mesenteric lymph nodes
8. migration via lymphatics to Hp vein/liver
9. vena cava
10. Right ventricle
11. adult developes in pulmonary artery
12. eggs laid in pulmonary artery

Question 8

what radiographic indicators help diagnose lungworm in dogs

Answer 8

in ventro-dorso viewa shift of heart axis to the left suggests right ventricular enlargement

Question 9

how do you diagnose aelurostrongylus abstrusus in cats

Answer 9

• larvae in feces
• larvae in BAL fluid
• radiograph of lung shows hazy heart/lung