Copyright 1995, Sarah Hartwell

This tick-borne disease can affect humans, dogs and cats and is currently something of a phenomenon in the US, where it is reinforcing the indoor-only style of cat ownership. Although relatively rare in the UK, the hotter summers are seeing an increase in Lyme disease and according to Which Way to Health Magazine it is frequently overlooked by doctors (and vets) who are unfamiliar with its symptoms. Although Lyme disease itself has been around for centuries, it was only in 1975 that it gained its name after an outbreak of human Lyme disease in Old Lyme, Connecticut.

Lyme disease is caused by corkscrew-shaped Borrelia bacteria which are carried inside Ixodes ticks. Ixodes ticks are typically found in grassland or woodland and commonly feed on deer, sheep, horses and rodents though they also attach themselves to cats, dogs and humans. Gorged ticks drop from their hosts and remain in surrounding vegetation between meals. When hungry, they climb aboard suitable hosts which brush through the vegetation.

In America, the disease has become a problem in some regions although it is probably being overdiagnosed and some cat owners are becoming almost paranoid about it. Due to its prevalence in areas of abandoned farmland, Lyme disease is well documented in American pet magazines and journals. In Britain, it is less well known despite an article in on human Lyme Disease in the "Which Way To Health" magazine.

In cats, symptoms suggestive of Lyme disease are:

Some owners have described Lyme-infected cats as being in a "zombielike trance". Often, Lyme disease is only diagnosed because the owner notices a tick or a tick bite on the cat; otherwise the symptoms are ambiguous and can be mistaken for other illnesses. Studies of cats deliberately infected with Lyme disease showed that some show no symptoms at all! According to American researchers, infected ticks do not start to transmit the bacteria until they have been sucking a host's blood for 10-12 hours which is why it is important to remove ticks as soon as possible.

In humans, early symptoms include:

Later symptoms include:

Chronic effects have been reported - and denied - in America where the disease is more widespread and apparently more severe than in Britain. Very few tick bites lead to to serious complications and Lyme disease in both cats and humans can be treated with antibiotics, treatment being most effective in the early stages.

Pet owners cannot get Lyme disease directly from their pets; it is only transmitted by the ticks which remain in vegetation between meals.

In the US, feline Lyme disease is treated with antibiotics such as amoxicillin, tetracycline and doxycycline; which are quickly effective if treatment is started early. Cats which have had Lyme disease may still become reinfected through subsequent tick-bites. In the US, where the disease is more problematical, there is a vaccine available (with mixed results) for dogs, but none available for cats.

American vets recommend keeping cats indoors as the best way to avoid Lyme disease. Failing that, a tick-collar formulated for use by cats is recommended; many flea collars do not repel ticks and dog's tick collars may be toxic to cats. A daily tick check for free-roaming cats is advisable as is regular spraying with a parasite-spray containing permethrin.

If you live in an area where Lyme disease is likely, check your cat regularly for ticks. Ticks can be carefully removed with tweezers used with a twisting motion. Be careful not to jerk a tick from the skin as its buried mouthparts may be left behind and cause an abscess. Although many people use a drop of alcohol to loosen the tick's grasp, or smother it with petroleum jelly, these methods can cause the tick to regurgitate saliva (which might contain the Borrelia organism) into the bite wound. If your cat does develop worrying symptoms later, remember to tell your vet that it has been bitten by a tick.

The main guidelines used by US cat owners in Lyme-affected areas are:

Even if the answer to all of these is yes, it is still not conclusive proof that Lyme disease is causing the illness since cats in some areas have high antibody levels due to past exposure to Borrelia; but American vets believe it is worthwhile having a blood test done any time Lyme disease is suspected even if this serves only to rule out Borrelia infection as the cause of the cat's symptoms.

Although Lyme disease does not appear to pose a major threat to cats, who seem more resistant to it than humans or dogs, its most dangerous feature is that it may go unrecognised and undiagnosed.