Synonyms

Dictyocauliasis, verminous bronchitis

Name of the disease in English

Lungworm infestation-Verminous pneumonia-Verminous bronchitis

The disease in brief

The disease is caused by the presence in the trachea and large bronchi of worms of the species Dictyocaulus viviparus. This parasite is widespread in temperate climates and its development is favored by humidity. It is thus very present in regions without summer drought; its frequency in drier regions is less regular, this partly explaining the immunity breaks favoring the attack of adults.

The disease affects young non-immune cattle, adults who have lost their immunity due to lack of contact with the parasite, adults subjected to high infestation pressure due to contamination of pastures by non-immune animals (immunity exceeded). Immune animals host parasites in winter in hypobiosis at the origin of the restart of the cycle in spring. The cycle is similar to digestive strongyles but: the eggs hatch in the bronchi and it is a larva that is eliminated in the faeces; the evolution in the external environment is more dependent on humidity conditions and is less predictable; the contamination pressure inducing clinical expression is lower.

Clinic & diagnosis

In infested regions, between spring and autumn, a cough in cattle in pasture, collective, without fever, is a suspicion of dictyocaulosis. If these cattle are made to run, they cough and quickly stop running. This suspicion remains even if the cattle have been dewormed in the previous days.

The parasite causes the formation of muco-verminous plugs (parasites + mucus) developing into near-obstruction of the bronchi and worsening of clinical signs.

Typical sign of the disease

No description

Pictures

See below

Diagnostic formulas

No description

Differential diagnosis

-RS18.1 virus bronchitis

Confirm a suspicion?

Collect droppings and search for larvae without delay using the Baermann method; larvae survive for less than 24 hours.

Prognosis and treatment

Treatment can be initiated with benzimidazole, levamisole or a lactone. The prognosis is good for early infestations and in the absence of serious lung lesions.

Prevention

In infested regions, prevention of dictyocaulosis is part of prevention of parasitic risks in pastures. Since infestation is inevitable, it must be done without damage and to build immunity for the following years. The first year in pasture (sometimes the 2nd) is essential. 

Care must be taken when crossing animals of different ages; non-immune animals (of any age) can be responsible for significant contamination of plots, causing problems in immune animals whose immunity may be exceeded.

In areas where the parasite is less common, care should be taken when purchasing animals that may introduce the parasite into a non-immune herd.

References

Veterinary Medicine-Pocket companion -9th Edition BLOOD DC-page 489