Big lungworm
| Big lungworm | ||||||||||||
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Larval stages |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Dictyocaulus viviparus | ||||||||||||
| ( Bloch , 1782) |
The large lungworm ( Dictyocaulus viviparus ) lives as an adult worm in the bronchi and trachea of cattle . The thread-like, white worms belong to the nematode tribe . They die after about two months, but can also survive for up to six months.
The host is usually infected through food.
Life cycle
The female lays large numbers of embryonated eggs in the bronchioli and bronchi. The first larval stage of the parasite then develops in the windpipe . These migrate to the throat and are partially coughed up. The greater part is swallowed and excreted with the faeces.
The next phase of the larva follows outside the body. The larvae leave the dung heap or are washed out by rain. Depending on the temperature, the larvae develop into the third phase.
The host animal ingests the larvae when they eat infected grass. The larvae migrate through the wall of the small intestine via the lymphatic system to the mesenteric lymph nodes and then via the breast duct ( ductus thoracicus ) and the anterior vena cava cranialis into the right heart and into the capillary area of the lungs. The larvae pierce the air sacs (alveoli) and occur as larvae of Phase 4 in the bronchioles and bronchi, where they develop 21 to 25 days after infection to sexually mature worms.
Course of disease
Dictyocaulosis or lungworm disease runs without clinical symptoms in the first seven days. This sometimes leads to attacks of fever, superficial coughing and breathing noises due to the damage to the lungs. After a short recovery phase, edema and - due to secondary infections - febrile pneumonia appear on the 20th day . Young animals often die in this phase.
The adult worms in the lungs and the inflammation cause breathing problems. In order to be able to breathe better, the animal adopts a gentle posture. Cough, lack of appetite and nasal discharge are side effects.
After surviving the infection, the animal can acquire a certain immunity.
diagnosis
- Baermann / Wetzel test
- Dissection of the affected animal
prevention
Lungworm infection can be prevented. These include the following methods.
- vaccination
- Medication
- Pasture management
Further representatives of the genus
The genus Dictyocaulus also includes:
- Dictyocaulus filaria (parasite of sheep and goats)
- Dictyocaulus arnfieldi (parasite of horses and donkeys)