As its alternative name suggests, the lungworm parasite was not always a disease common among cats and dogs in the UK. The first case of ‘French Heartworm’ appeared in 1975. In the 40 years since, the parasite has established hotspots in the UK’s more southerly counties, with cases reported as far north as Paisley in Scotland.
UK veterinary laboratories reported more than 80 cases of lungworm, including 6 fatalities in the first half of 2017. Infection with the nematode worm species, Angiostrongylus vasorum, has many symptoms including coughing and shortness of breath, an aversion to exercise, weight loss, vomiting, abdominal and back pain, nervous disorders, unusual bleeding, heart failure, and sudden death.
The life cycle of A.vasorum makes it difficult to eradicate. The adult parasite lives in the small arteries of the lungs and in the right-side heart chambers producing eggs that hatch into larvae. Larvae penetrate into the lungs and make their way into the back of the throat where they are swallowed to enter the animal’s digestive system. Finally, the lungworm larvae are passed out with animal’s faeces.
Slugs, snails and even frogs are the usual suspects
Slugs, snails and even frogs are the usual suspects in the spread of lungworm, though exactly how is not altogether clear. The established theory is that the larger slug species, which will eat dog and fox faeces, become intermediate hosts for the maturing lungworm larvae. When domestic cats and dogs eat infected molluscs, anything else that ate them, or lick infected slug and snail slime off their paws, the cycle of infection is complete.
Research estimates the presence of lungworm in UK foxes has risen from about 7% in 2008 to just over 18% today. The highest incidence is in the south-east where up to 50% of foxes are thought to be infected. This might not be entirely the foxes’ fault. A high urban fox population – feeding on readily available discarded food, would also be in much closer contact with fouling from domestic animals.
Links to climate change
The increase in infection rates might be linked to climate change with milder, wetter winters boosting the population of larvae-carrying slugs and snails.
Lungworm is not infectious to people, although other diseases that can infect your pet also pose a risk to human health. Perhaps the most significant of these is the tick-borne Lymes Disease. Like lungworm, the spread of Lymes in the UK might be linked to changes in the climate and the growth in travel to and from countries where such diseases are endemic.
Keeping your pet safe from lungworm and other parasites
Whatever the reason for the increase in infection rates, prevention is better than cure, and early diagnosis with veterinary diagnostic tests is vital to effective treatment. A word with your vet is the best way to find out all you need to keep your pet safe from lungworm and other parasites including fleas, ticks, heartworm, roundworm and tapeworms.