Fox Lungworm. Why are we not diagnosing it?
Mid August, and summer is officially over in Cornwall. Truro town is full of holidaymakers, the roads are horrendously busy and the indoor soft play centres are brimmed to bursting. But for the rain, everyone would be on the beach. Instead, everyone is reminiscing about the sunny, hot July’s and August’s of the 70s and 80s and contemplating how to do battle in our drowned backyards with increasing numbers of our old friend, the garden slug.
Slugs have a hard time in my household. My wife’s recently flowered border plants have been decimated by them on numerous occasions. She’s tried beer traps, animal friendly iron pellets (I’ve even caught her welly clad furnishing a torch at midnight trying to manually extract the blighters from the borders before chucking them over the garden fence) but it seems the only thing that works are metaldehyde pellets. I don’t like using them myself, having seen dogs die from ingestion of slugbait, but we all know who rules TruroVet’s household with an iron rod. So Metaldehyde it is.
Slugs are also the intermediary host of Angiostrongylus vasorum, French heartworm, also known as Fox lungworm. The lungworm parasite is carried by slugs and snails. Problems may arise when dogs purposefully or accidentally eat these common garden pests when rummaging through undergrowth, eating grass, drinking from puddles or outdoor water bowls, or pick them up from their toys.
Foxes can also become infected with the lungworm, and have been implicated in the spread of the parasite across the country. The adult of this particular lungworm lives in the heart and major blood vessels supplying the lungs, where it can cause a host of problems. Left untreated, the infection can often be fatal. The clinical signs vary from the dog coughing to developing spontaneous blood clotting disorders.A diagnosis can only be made definitively by sending faecal stools for analysis or by performing a tracheal wash. In both cases, one might expect to see evidence of the worm larvae under the microscope.
This condition was first noted approximately 20 years or so ago, initially seen only in certain pockets of areas in the UK, notably, South Wales, Cornwall and Surrey.
The german pharmaceutical giant, Bayer produces a very effective topical spot on preventative and treatment. Last year, the Bayer rep for the S-W visited our clinic and made a very convincing argument for using this product as a routine, by producing a map of Cornwall which demonstrated so called hot spot areas of Angiostrongylus. She also stated that 2 other practices in Truro were seeing cases of Angiostrongylus on a weekly basis. On closer questioning, it transpired that these cases (both in Truro and the map hot spots) had not been confirmed definitively by faecal/tracheal wash examination and were only suspected!!
Now I practiced in Surrey for 3 years and saw several cases of Angiostrongylus,one of these memorably presented with stroke type symptoms secondary to an intracranial bleed, and was only diagnosed by MRI scan and post mortem.
We have a busy 3 vet practice in central Truro. All of us are aware of the threat of Angiostrongylus, know the clinical signs to watch out for, do NOT use the Bayer product as a matter of routine, but have NEVER seen a case.
So the question we need to ask ourselves is:- How common is Angiostrongylus? Are we missing the cases? or a cynic might suggest there has been a huge marketing ruse to scaremonger the public and clinicians into promoting a certain product?
Let me know what you think?
Until next time…….