Ectoparasites

Fleas

The most common ectoparasite complaint in UK cats and dogs is flea infestation, the majority of fleas seen being cat fleas. Fleas spend their adult life on the cat or dog, jumping from one host to another to feed on blood. Within 2 days of feeding females start to lay eggs, 20-30 a day, eggs develop into larvae at a variable rate depending on environmental conditions. Larvae feed on debris in carpets and bedding, then mature into pupae which seek warm dark areas to complete development into adult fleas. Flea development can be as rapid as 14 days during prime conditions, typically in the warmth of the summer or the indoor warmth of a centrally heated house in autumn/winter.

For many pets a low number of fleas may go unnoticed by an owner but typically the adult fleas on the pet represent only 5% of the population, 95% being the eggs and larvae being in the environment. With the high reproductive rate and short lifecycle heavy infestations can be quick to develop. Simple flea infestations may present as an increase in a pet scratching, but for flea sensitive pets, those allergic to flea saliva, significant self-trauma can lead to major hair loss, body sores and the potential for secondary skin infections. Heavy flea infestations, particularly in puppies and kittens can lead to anaemia. Fleas can also transmit a number of different diseases between pets. In cats fleas can transmit a parasite Mycoplasma haemofelis which can lead to immune destruction of red cells and subsequent anaemia; and Bartonella, a parasite which often causes no symptoms in cats but can cause serious illness in humans (cat scratch disease). Ingestion of fleas can result in infection of Dipilydium species of tapeworm in both dogs and cats. In rabbits myxomatosis and viral haemorrhagic disease (VHD) can both be transmitted by fleas.

Flea control must include both pet and environmental management. Table 2 summarises the antiparasitic products we stock at Holmer Vet Surgery. Please speak to one of our vets about the treatment most suitable for you and your pet. There are many other products available on the market and if you, as a client, have a particular interest in a product we do not routinely stock we will be happy to discuss this with you. For environmental management vacuuming carpets and upholstery at least three times a week has been shown to stimulate larval maturation, as adult fleas hatch they will be exposed to and killed by the treatment on your pet. Alternatively we can supply you with an environmental spray, particularly for severe infestations, which kills all stages of the flea lifecycle.

Ticks

The most common tick found in the UK is the hard tick Ixodes ricinus which is mainly found in woodlands, with immature ticks found on small rodents and birds, adults on larger animals including deer, sheep and dogs, and less commonly cats. The hedgehog tick can also affect dogs and cats. Hungry ticks position themselves in the vegetation to attach to passing animals. Ticks bite the host feeding for several days sucking blood and passing saliva into the host which aids their continued attachment, as well as having anticoagulant and anti-inflammatory properties to facilitate continued feeding.  Peak activity for ticks tends to be in Spring and Autumn.

Apart from local inflammation with potential local infection the main concern about ticks is the diseases they can transmit. In the UK ticks can transmit Lymes disease, a condition which can also affect humans, that can cause flu like symptoms, muscle, joint, heart and nervous system disorders. Ticks can transmit myxomatosis and VHD in rabbits. Foreign ticks which have been detected in the UK, brought in by travelled pets, can transmit potentially life-threatening diseases including: Babesia, a parasite which affects red cells and can cause anaemia, and Ehrlichia which affects white cells and can cause fever, swollen glands, anaemia, respiratory and occasionally neurological issues.

Mites

The two most common mites seen in dogs in practice are Sarcoptes Scabiei (the fox mange mite) and demodex.
Sarcoptes is an infectious mite with zoonotic potential, which means it can also affect humans. Sarcoptes mites are contracted by direct and indirect contact with an infected dog or fox. The mites burrow under the skin causing severe irritation, dogs will often develop scaling lesions especially on the tips of the ears, nose and front legs, as the condition progresses the whole body can become affected with significant hair loss. Sarcoptes rarely affects cats.

Demodex is a mite that naturally lives, in low numbers in the hair follicles of dogs and cat, passed on from their mothers in the first few days of life. In the majority of cases the demodex do not cause a problem, but if an animal, for some reason, has a reduced immunity the mites can multiply and lead to clinical signs. Demodicosis can present as a juvenile form seen in young dogs typically aged between 3-4months, either localised or generalised. Puppies with localised demodicosis tend to have small patches of inflamed skin around the face, head and feet, the degree of pruritis (itch) is variable. Generalised juvenile demodicosis may initially look like the localised form but progresses so that the skin is more generally affected, lumps can develop within the skin and the condition is typically itchy and painful. Adult demodicosis is usually seen as a generalised form in dogs over 4 years of age, these animals who have previously had no issue with the mite tend to have developed an underlying systemic illness which lowers their immune system, making them susceptible to the demodex over populating. Adult onset demodicosis is generally more severe than the juvenile form.

Cheyletiella, also known as walking dandruff, is a common surface mite seen in rabbits and occasionally seen in dogs and cats. Affected animals have a mild level of pruritis and dandruff in their coat. The mite is acquired by direct contact with an infected animal and is highly contagious, including to humans (zoonosis).

Otodectes cyanosis is more commonly known as the ear mite. Otodectes is a surface mite which is transmitted by direct contact with another infected animal. Otodectes is more commonly found in young animals, it causes local irritation seen as head shaking or ear scratching, and in response to the ear mites the pet often produces a large amount of dark wax. Sometimes the ear mites will cause irritation near the base of the tail, which is more likely to be seen in cats who curl up to sleep.