ABSTRACT: This is an article on the most common blood and tick-borne parasites found in dogs and cats in the United Kingdom. It will hopefully make veterinary nurses aware of the clinical signs and nursing care that is needed and also the methods of prevention of the different diseases that these parasites cause. There is also a small section on blood borne parasites which are less common because they are found outside the United Kingdom, but that are increasingly important as they may become more common in practice as a consequence of more pets travelling to and from different countries.

Lyme disease

Lyme disease is caused by the bacterium Borrelia burgdoferi. It is zoonotic, as it affects several species including man. The disease spreads because its host, the tick, requires several different hosts during its life cycle, and thus acts as a vector for the disease if one of these hosts is infected.

Most infected animals show no clinical signs. However, if these are present, they can include pyrexia, depression, acute- onset lameness and painful joints. Diagnosis can prove difficult, with osteoarthritis being a differential diagnosis. The incubation period can vary from several weeks to years, so the animal may be infected for a long time before showing clinical signs.

It is very important to use an appropriate acaricide, such as fipronil (Frontline, Merial) and selamectin (Stronghold, Pfizer), and to ensure that the recommended dosage regimen is followed. Owners should be advised to remove any ticks seen on their pets as soon as possible.

There are many methods for doing this. The simple green plastic ‘tick hook’ is one the cheapest and easiest (Figure 1). It should be slid under the tick and gently twisted around until the tick falls off. It is most important to ensure that the buried head and mouthparts are removed fully as these can cause a problem if left in.

Figure 1: A tick hook. Image courtesy of Ian Wright

A blood sample sent to an external laboratory may be used to diagnose Lyme disease. Although research is being carried out, there is no vaccination at present to prevent the disease – although a vaccine was launched in the USA but then withdrawn.

On positive diagnosis, treatment includes removal of any ticks from the animal, and antibiotics and analgesics are often required. Doxycycline is effective and treatment may need to be given for up to 30 days. If the animal is in pain a non¬steroidal anti-inflammatory (NSAID) agent, such as carprofen, is also helpful. Hospitalisation of the patient is not normally necessary.

Lyme disease can damage renal function, so urine testing should be carried out as a routine part of diagnosis. Clinical cases are uncommon but, it is useful to be aware of the symptoms – not least because of an apparent increase in the number of animals that have ticks, being presented in veterinary practice (Figure 2).

Figure 2: The tick. Ixodes ricinus. Image courtesy of lan Wright

Mycoplasma haemofelis [Haemabartonella felis)

Mycoplasma haemofelis is the most common blood borne parasite seen in cats in the UK. The vector is unknown but it is thought to be fleas, most likely Ctenocephalides felis. Other routes of infection for the disease are thought to be transplacental, via the queens milk or via fighting injuries, such as cat bites.

Cats that are immune suppressed – FeLV positive cases, for instance – can be affected. Damage to the erythrocyte structure, eventually leads to their destruction leading to anaemia. Other symptoms may include pale mucous membranes, inappetence, weight loss, tachypnoea, tachycardia, spenomegaly, weakness and pyrexia although some cats may be symptomatic.

A routine haematology screen will demonstrate a high reticulocyte (immature red blood cell) count indicating a regenerative anaemia. As red blood cells are destroyed, the bone marrow produces more precursory forms of erythrocytes, which are released into the blood stream before they are fully mature in order to try to maintain normal levels.

Additionally the parasites will be visible on the surface of the cells when viewing a Wright-Giemsa-stained peripheral blood smear.

Treatment options include doxycycline for at least two or three weeks and corticosteroids may also be useful. Intravenous fluids – usually compound sodium lactate (Hartmanns solution) – should be used if dehydration, resulting from inappetance, is evident.

In cases of severe anaemia, a whole-blood transfusion will be required. The patient will usually be hospitalised until a significant improvement is seen. Repeat blood samples should be carried out to check that the anaemia is resolving. However, in anaemic patients remember to only take the volume of blood that is required for testing.

One of the most important aspects of the nursing care in cases of anaemia is to encourage eating, including assisted feeding, if necessary.

The main vector for the parasite is the flea and prevention of the spread of this disease should focus on the use of an appropriate flea treatment, such as fipronil (Frontline, Merial), which should be applied as directed.

Affected cats remain carriers for life.1 The author has seen one case of Mycoplasma haemofelis in practice that recovered well, after a long course of doxycycline, repeat blood testing and intensive nursing care.

It is also likely that with the Pet Travel Scheme (PETS) and increased numbers of animals travelling between different countries, other less common diseases may also become more prevalent in the UK. Two common blood borne parasites that are not native to the UK are Babesia spp. and Leishmania spp.

Babesia spp. also cause anaemia and usually affect dogs, although cats can also become infected. It is most prevalent in Europe and is another tick-transmitted infection. Clinical signs usually include pyrexia and anaemia, but death can occur quickly so treatment is not always possible. If diagnosed early, treatment with imidocarb dipropionate (Imizol, Intervet/Schering-Plough) is necessary.

Leishmania spp. are intracellular protozoans. They are most prevalent in southern Europe and transmitted by sand flies. Leishmaniasis is also most commonly seen in dogs.

Infected animals may not show any clinical signs for years. However, where present, they can include weight loss, lethargy and anaemia. These clinical signs are dependent upon the actual organs infected. The presence of a non¬healing wound may lead to suspicion of Leishmaniasis.

Extra care must be taken when handling infected animals because of its zoonotic potential. When animals are abroad, an appropriate insect repellent should be used to prevent the sand flies biting.

As for acaricides, a combination of imidacloprid and permethrin (Advantix, Bayer) and a collar containing deltamethrin (Scalibor, Intervet/ Schering-Plough) are both licensed for use in dogs, but not cats.

Veterinary nurses in practice need to be aware not just of the common diseases but also of the less common ones as well. Extra care will need to be taken, with animals that travel on a pet passport or have been abroad previously.

The current regulations on the use of acaricides can be found at www.defra.co.uk. The most important thing to remember is that the appropriat
e use of acaricides and rapid tick removal can help to prevent most of these diseases, as prevention is always better than cure. 


Victoria Stanhope BSc (Hons) RVN

Victoria Stanhope-qualified from Myerscough College in 2008 with a BSc (Hons) in Veterinary Nursing. She is currently working as head veterinary nurse in a small animal practice in Fleetwood.

To cite this article use either

DOI 10.1111/|j.2045-0648.2011.00121 x or Veterinary Nursing Journal Vol 26 pp 435-436


1. ASPINALL, V [2006] The Complete Textbook of Veterinary Nursing Oxford Butterworth Heinemann Elsevier


• VOL 26 • December 2011 • Veterinary Nursing Journal