Elanco Animal Health, maker of Advocate, is highlighting a new study which found that in a group of dogs naturally infected by Angiostronglyus vasorum, 36.1% were clinically asymptomatic and apparently healthy.

This, says the company, suggests that infection could be more common among seemingly healthy dogs than vets or owners realise, which may mean there is a greater risk of perioperative bleeding caused by the coagulopathies associated with A. vasorum2 than previously thought.

Elanco says another recent study indicates that there may be a bigger environmental risk for dogs than previously thought, too.

In the study, by Robbins et al, L3 larvae of A. vasorum and Crenosoma vulpis arising from the gastropod intermediate host were found to be immediately infective to dogs and remain so for up to eight weeks, meaning that dogs may only need to lick the molluscs’ slime to be at risk of infection.

Elanco says this new data means A.vasorum should be added to many differential diagnosis lists, and that pre-operative testing could also be wise.

Jenny Helm, BVMS Cert SAM Dip-ECVIM CA FHEA MRCVS, European Specialist in Small Animal Internal Medicine, said: “Owners need to be aware that healthy dogs could be silently carrying and spreading the disease and that asymptomatic carriers could develop clinical signs at any time.

"They need to be aware that dogs don’t necessarily have to eat slugs and snails to become infected, as recent evidence suggest that other routes of transmission are possible.”
To improve data on the prevalence of lungworm, Elanco has developed a version of its lungworm map specifically for veterinary surgeons, where you are invited to upload your cases (including asymptomatic positive cases: www.lungwormmap-vet.co.uk.

For those practices which want to run lungworm awareness campaigns in their area, Elanco has a how-to guide, posters and artwork available to download at www.myelanco.co.uk.


  1. Colombo, M., Traversa, D., Grillotti, E., Pezzuto, C., De Tommaso, C., Pampurini, F., Schaper, R., Drake, J., Crisi, P.E., Russi, I. and Ripamonti, M., 2021. Highly Variable Clinical Pictures in Dogs Naturally Infected with Angiostrongylus vasorum. Pathogens, 10(11), p.1372.
  2. ESCCAP (2021). Worm Control in Dogs and Cats [ESCCAP Guideline 01 Sixth Edition]. Available https://www.esccap.org/uploads/docs/oc1bt50t_0778_ESCCAP_GL1_v15_1p.pdf  (last accessed 18th May).
  3. Robbins, W., et al. (2021) ‘Infectivity of gastropod-shed third-stage larvae of Angiostrongylus vasorum and Crenosoma vulpis to dogs.’ Parasites Vectors 14:307)

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