Our pets are constantly under attack by a wide range of nasty little critters. In this blog, we’ll take a brief spin through the most important parasites, and then look at how to kill them!
Fleas are probably the parasite that most often causes problems. There are several different species, but the Cat Flea Ctenocephalides felis) is the most common. The adults live on your pets (and sometimes you too!) drinking blood, causing itching, and spreading diseases (like tapeworms in dogs and cats, or Myxomatosis in rabbits). Some animals become allergic to flea saliva, resulting in a severe skin disease called Flea Allergy Dermatitis every time even a single flea takes a bite! Sadly, all animals are potentially vulnerable to fleas – there’s no truth in the myth that certain breeds are resistant.
However, controlling a flea infestation is very difficult – at any one time, only 5% of the flea population exists as adults, hopping around and sucking blood. The remainder are eggs, larvae (flea maggots, living in the soft furnishings, carpets and dust), and pupae (chrysalises containing hibernating adults).
There are a wide variety of worms we need to worry about in the UK (although fortunately there are fewer species than in continental Europe). First are the roundworms, such as Toxocara canis (in dogs) and Toxocara cati (in cats). The adults of these species live inside the gut, passing out eggs in the faeces. The eggs can survive for a long time (possibly several years) before infecting a new dog or cat and starting the cycle again. Many of these worms can infect people, and the larvae crawl through our internal organs, possibly invading the brain, liver and eyes. Some of them are also passed on in live prey caught by cats, dead animals scavenged by dogs, and even contracted by a puppy or kitten from their mother. A heavy roundworm infestation often causes weight loss, and sometimes vomiting and diarrhoea. In puppies and kittens, the result is often a serious failure to thrive.
Tapeworms on the other hand are a bit more sneaky – they are ALWAYS spread by an intermediate host (e.g. fleas and lice for Dipylidium caninum; mice or rats, birds, even cattle, sheep and humans for Taenia and the dangerous Echinococcus species) and infect the dog or cat when they eat this animal. Many of them can be spread to humans too. The main symptoms of a tapeworm infestation is an itchy bottom – because segments of the worm break off and crawl out of the anus to lay their eggs. These segments look like grains of rice and commonly cause itching, scooting and licking! Really heavy infestations may also result in weight loss (although this is rare), and in younger animals, a twisted gut (which requires emergency surgery).
The last type of worms we worry about are the lungworms. Lungworms in cats (Aelurostrongylus abstrusus) are usually just an annoyance, causing coughing; however, the dog version (Angiostrongylus vasorum) is potentially fatal, and can cause difficulty breathing, abnormal bleeding, collapse and death. These worms are spread by slugs and snails, in their slime, and are present across the UK.
Ticks are another group of blood-suckers, but unlike fleas they aren’t insects (they’re actually more closely related to spiders). They typically live in longer vegetation and climb to the top to wait for a passing meal – dog, cat, rabbit, sheep, human, whatever! Then they anchor themselves to the skin and suck blood. The trouble is that after about 24-48 hours, they become greedy, and start backwashing saliva into the bloodstream. This is when they become dangerous – they can spread a number of nasty diseases, including Lyme Disease and Babesiosis. If a tick is carelessly removed, its head may stay inside the skin, resulting in a nasty infection or abscess.
So how do we kill them?
Sadly, there’s no one treatment that kills everything.
Fleas in particular are difficult to control, not because they’re hard to kill (even really old drugs like fipronil are still relatively effective) but because you have to break the life-cycle by killing the eggs and larvae (the pupae are basically immune to anything we can treat them with – but we can trick them into hatching early by vacuuming, and once hatched, they are vulnerable!). So, you need to kill the adults (there are a range of spot-ons and prescription tablets that are very effective); PLUS environmental control (some spot-ons contain medications that will prevent eggs from hatching properly, or that kill larvae; other options include insecticidal sprays for the house and car). Some of the tablets for dogs will kill ticks too!
Roundworms and tapeworms can be killed with many worming tablets, but do beware of some over-the-counter pet shop and supermarket products, they are much less effective than the vet-only (NFA-VPS and POM-V) versions, and often only kill certain types of tapeworm. There is also a prescription-only tablet now that will kill all types of worm – tapeworms, roundworms and even lungworms. There are also a number of spot-ons that will kill roundworms, although many do not do tapeworms as well.
There are some combination prescription-only spot ons available now that will kill roundworms, fleas and lungworms – but not ticks or tapeworms.
There are also repellant products that will “chase away” ticks from dogs (do not use in cats – they’re toxic!), and flies from rabbits. For tick prevention in cats, there are spot-ons, and we don’t usually worry about ticks in rabbits.
We do recommend worming rabbits periodically – not, ironically, because worms are a particular problem for them, but because they prevent another nasty parasite, Encephalitazoon cunuculi which attacks the brain and kidneys.
Confused? Don’t worry – That’s why it’s important to speak to our vets to arrange a programme of flea, tick and worm treatment that will cover all the bases!