Dictyocaulus spp

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Adults Dictyocaulus spp in the lung of a 3 year old cow

Dictyocaulus spp are a parasitic lungworm of cattle that cause bronchitis and pneumonia in cattle worldwide. It is one of the most important parasites in grazing cattle, and outbreaks result not only in clinical disease but also economic losses.

A number of Dictyocaulus species are known to infect cattle, including:

  • Dictyocaulus viviparus

Adult females in the bronchi lay larvated eggs that hatch either in the bronchi.

Clinical signs

Weight loss, intermittent afrebrile cough and failure to thrive are common signs in early stages of the disease. In the prepatent phase, D. viviparus causes blockage of bronchioles, resulting in obstruction of the airways and collapse of alveoli distal to the block. Sudden deaths have been reported due to severe interstitial emphysema. In dairy herds, milk yield noticeably drops in affected cattle.

In chronic cases, a nonsuppurative, eosinophilic, granulomatous pneumonia is observed, complicated by interstitial emphysema, pulmonary edema, and secondary bacterial infection.


Diagnosis is based on isolation of nematode eggs in feces or ELISA detection of antigens in bovine milk[1] or serum samples[2].


In acute cases, broad-spectrum antibiotics are recommended to minimise secondary bacterial infections.

Treatment is effective using various anthelmintic preparations. These include the benzimidazoles (fenbendazole, oxfendazole, and albendazole) and macrocyclic lactones (ivermectin, doramectin, eprinomectin, and moxidectin). Levamisole is used in cattle but treatment may need to be repeated 2 weeks later because it is less effective against larvae during the early stages.

Vaccination strategies are also indicated for lungworm-naïve animals when introduced into an adult herd[3].

Single mass-treatment before the grazing season may be useful to break a series of annual lungworm outbreaks. However, it is not a secure method to prevent parasitic bronchitis for more than one year[4].


  1. Ploeger HW et al (2012) The value of a bulk-tank milk ELISA and individual serological and faecal examination for diagnosing (sub)clinical Dictyocaulus viviparus infection in dairy cows. Vet Parasitol 184(2-4):168-179
  2. Goździk K et al (2012) Optimization of in-house ELISA based on recombinant major sperm protein (rMSP) of Dictyocaulus viviparus for the detection of lungworm infection in cattle. Res Vet Sci 93(2):813-818
  3. Holzhauer M et al (2011) Lungworm outbreaks in adult dairy cows: estimating economic losses and lessons to be learned. Vet Rec 169(19):494
  4. Ploeger HW & Holzhauer (2012) Failure to eradicate the lungworm Dictyocaulus viviparus on dairy farms by a single mass-treatment before turnout. Vet Parasitol 185(2-4):335-338