Dictyocaulus viviparus – Severe risk of Lungworm in Unvaccinated Bovines
A lungworm is a nematode that can affect many species of animals, including species such as: sheep, cattle, deer, goats and horses. Each species typically has a paired species of lungworm that it is susceptible to. The bovine lungworm called (Dictyocaulus viviparus) is the most common cause of lungworm in cattle.
The location occupied by a lungworm will vary dependent on the host species and parasite species; lungworms may reside in both the bronchi and bronchioles of the lungs and rarely the heart. When they inevitably lay eggs, they are coughed up and swallowed into the Gastro-intestinal tract, where they develop into the first stage of larvae (L1).
These larvae are then excreted by cattle onto pastures in faeces, wherein they develop into motile larvae (L2) that are able to escape by themselves or make use of sporulating Pilobilus sp. fungi to facilitate an airborne escape; larvae reach the infective larval stage (L3) within only 4-6 days (L1-L3). They are then either consumed from the pasture or taken up on Pilobilus sp., perpetuating the cycle. Spread throughout a herd is quick for this species as the incubation period is short and they do not require an intermediate host. Outbreaks are associated with wet summer weather, which June has been full of! Due to this, ensure you are observant of your cattle and watch out for signs of lungworm (listed below).
Infection with lungworm can lead to a condition seen in cattle known as ‘husk’ or parasitic bronchitis. Signs of lungworm in cattle include: dry coughing, increased breathing rate/difficulty, rapid weight loss/body condition and in severe infections – sudden death. If you suspect lungworm due to these signs, we strongly advise you to call your vet.
See our overview to find out how to protect your herd against lungworm.
Alternatively if you require, we can test for lungworm at RRL. See more.
Examples of lungworm
There are a variety of lungworm species – read some of the below articles to learn more:
Lungworm in sheep – Dictyocaulus Filaria
Lungworm in cats – Aelurostrongylus abstrusus
Lungworm in dogs – Angiostrongylus vasorum + Crenosoma vulpis
References:
https://www.nadis.org.uk/parasite-forecast/
https://www.nadis.org.uk/webinars/preventing-lungworm-in-cattle/
McLeonard C, van Dijk J. Controlling lungworm disease (husk) in dairy cattleIn Practice 2017;39:408-419.
McNulty, S., Strübe, C., Rosa, B. et al. Dictyocaulus viviparus genome, variome and transcriptome elucidate lungworm biology and support future intervention. Sci Rep 6, 20316 (2016).