Exotic Diseases In Cats

This month’s newsletter focuses on exotic diseases in cats, that can be brought into the UK from abroad.

As there are several diseases to be aware of, this article is longer than some of our previous ones, but we feel awareness of these is crucial to keep risks to a minimum, especially during the warmer months when travel is generally more extensive and disease bearing insects are more prevalent. 

There are several infectious diseases that cats can bring into the UK. As pet travel has become more common, we have seen a significant increase in the number of pet cats being imported from abroad, to be rehomed in the UK. Animals that come from other countries have specific health concerns due to the presence of diseases that are not currently found in the UK. 

The term ‘exotic’ refers to diseases that do not occur under normal circumstances in the UK. These exotic diseases may be difficult to test for and testing before importation is often not a requirement for most of these diseases, especially in cats. A 2018 study reported that 40% of UK vets have seen cases of rare or new diseases associated with imported pets, in the previous year. The exotic diseases that cats can carry and transmit include rabies, babesiosis, ehrlichiosis, leishmaniasis, heartworm and the Echinococcus multilocularis tapeworm. 

This also means that cats who travel from the UK to other countries for short periods are at some risk of contracting infections; cats who have been born, or lived for some time, in a foreign country are significantly more likely to become infected. The longer the cat is abroad the higher the chance of contact with infectious diseases. This is due to increased opportunity for exposure; some diseases are passed from mother to kitten and many street cats will never have received parasite control (unlike owned cats that travel). 

Some foreign diseases can make an infected cat very poorly, even months or years after exposure. Since most of these diseases are rare or not found in the UK, vets have less experience of recognising the clinical signs and it can be challenging to make a diagnosis. For some conditions, the medications needed to treat them can be difficult to obtain in the UK and can be very costly. Some foreign diseases can be passed between cats, so the imported cat is a risk to other cats. 

Our existing cat population has little to no immunity against these rare exotic diseases, so if they become widespread in the UK, the consequences for pet cats could be devastating. Less commonly, some foreign diseases are zoonotic and can spread from animals to people. This poses a potentially serious public health risk, especially to people with a weak immune system. 

Following the guidelines of the PETS travel scheme for rabies vaccination and tapeworm treatment when travelling with your cat and before importing a new cat into the UK, can help prevent these diseases from entering. 

In 2012, the pet travel rules on tick control were relaxed. However, it is still highly recommended that cats are protected from tick attachment prior to travel and there are several approved products that are licensed and safe for use with cats. 

It is important to remember never to use spot on treatments or collars licensed for dogs, on cats. Cats are very sensitive to poisoning by the pyrethroid products that are often used in parasite prevention for dogs. Given the large number of cats needing rehoming in the UK, consider whether it is appropriate to adopt a cat from an overseas shelter with an uncertain disease status.

Specific Diseases and Their Risks

1.  Rabies 

Rabies is a fatal viral disease transmitted through the saliva of infected animals. While the UK has been officially free of terrestrial rabies since 1922, imported cats must be microchipped and vaccinated against rabies to prevent reintroduction. 

Depending on where the cat is travelling from, a successful rabies antibody blood test and an at home quarantine may be required before travel. It’s important to follow the PETS travel scheme guidelines (https://www.gov.uk/bring-pet-to-great-britain). Rabies is a Notifiable Disease, meaning any suspicion of it must be reported as there is a government strategy in place to deal with any potential cases of rabies. 

2.  Babesiosis

Babesiosis is a vector-borne protozoal parasite that is spread by ticks and is found in many countries; it is rare in the UK and has been reported in cats imported from South Africa. The parasite most often spreads when a tick feeds on an infected cat, then transfers the parasite to an uninfected cat. However, it can be spread by an exchange of blood, such as during a cat fight. 

Clinical signs of babesiosis include fever, lethargy and pale or yellow gums and mucous membranes due to anaemia and jaundice. Cats may be able to cope with quite severe anaemia (blood loss) but show disease signs when stressed. The disease may be fatal. 

Babesiosis is typically diagnosed through microscopic examination of blood smears to identify the presence of the Babesia parasite within red blood cells or by a polymerase chain reaction (PCR) test to detect the Babesia parasite DNA in a blood sample with the latter being the preferred method. Babesiosis in cats can be treated with medication.

3.  Ehrlichiosis

Ehrlichiosis is another vector-borne disease transmitted by ticks and with similar clinical signs to babesiosis. It is caused by a Rickettsial bacteria that is found worldwide and is widespread in the USA. Rickettsial bacteria live inside other cells, causing disease in dogs, cats and humans. Ehrlichiosis is a rare, poorly understood tick-borne disease that affects white blood cells in cats. Ehrlichia can be transmitted to cats as quickly as three hours after a tick becomes attached. Bacteria enter the cat through the bite wound and saliva. 

Signs of Ehrlichiosis include intermittent fever, lethargy, weight loss, abnormal bleeding, swollen lymph nodes, vomiting, diarrhoea, muscle pain. Diagnosis includes blood tests to detect antibodies against Ehrlichia or to identify the bacteria in blood cells. 

Treatment typically involves administration of doxycycline antibiotics for 10-21 days and sometimes up to several weeks. Some cats may become carriers. Infection may recur despite treatment. More severe cases may require a blood transfusion. Early diagnosis and treatment are crucial for a positive outcome. The most effective prevention is tick control. 

4.  Leishmaniasis

Leishmaniasis is another vector-borne protozoan parasite transmitted by sandflies that suck blood. Sandflies are widespread in the Mediterranean, Africa and the Middle East; cases have been reported globally and especially in Brazil and the Mediterranean region.

Signs only occur in a proportion of cats; therefore, some cats may be infected without showing signs and become a ‘reservoir’ of infection. Wild cats are regarded as a reservoir of infection in areas where there is a high level of disease in dogs. 

These cats can aid the spread of the disease by infecting sandflies who bite them. While relatively rare compared to dogs, cats can develop both cutaneous (skin) and visceral (organ) forms of the disease. Leishmaniasis is a serious, often chronic, disease in cats. Immunosuppression is a risk factor so cats that are FIV or FeLV positive are more susceptible. 

Signs include skin lesions (Sores, rashes, hair loss and ulcers), anorexia, vomiting, diarrhoea, weight loss, weakness and enlarged lymph nodes. There can also be lesions in the mouth and around the eyes. Diagnosis involves blood tests, cytology and biopsy, with potential need for a PCR test although there are no tests at present that have been validated for cats. 

Treatment is available but has not been well studied in cats and focuses on managing signs as a cure is unlikely. An infected cat may always carry the disease, increasing the risk of spread. Although it is rare, humans and other animals can contract the disease from infected cats and the disease is potentially fatal for cats and humans.

5.  Heartworm

Heartworm is caused by a parasitic roundworm, Dirofilaria immitis. It affects the circulatory system (heart and blood vessels) and lungs, and can lead to heart failure and serious lung disease. Heartworm disease is spread by mosquitoes that carry heartworm larvae from infected animals and transmit the parasite during a blood meal.

Disease is widespread in the USA and worldwide. In areas with a high level of heartworm infection in dogs and wild canids, cats may also pick up the infection. It is more common in cats that have travelled to areas where the disease is prevalent. 

While cats are more resistant to infection than dogs, they are more likely to die from the disease. Cats may show no signs, vague signs or they may experience coughing, vomiting, lethargy, difficulty breathing, reduced appetite and weight loss. Diagnosis involves a combination of blood tests (antibody and antigen tests), chest X-rays, and sometimes ultrasound. 

Treatment focuses on managing signs and providing supportive care, as well as addressing any secondary complications, such as respiratory distress or heart failure. There are no approved medications to treat adult heartworms in cats. Preventive medication is available and highly recommended for all cats, even indoor-only cats, as mosquitoes can easily enter homes. There are several safe and effective medications available to prevent heartworm disease in cats. 

6.  Echinococcus multiocularis tapeworm

Echinococcus multiocularis tapeworm is a species of tapeworm that is different from the UK’s native type (Echinococcus granulosus) and is widespread in central and eastern Europe, particularly France, Switzerland and Germany. The E. multilocularis  tapeworm can infect foxes and other canids, including domestic dogs. The disease can also cause serious illness in humans. There have been no known domestically acquired cases of Echinococcus multilocularis in the UK. Echinococcus multilocularis is a Notifiable Animal Disease. 

If you suspect it, you must report it immediately by contacting Defra. Cats may be infected by Echinococcus tapeworm and show no outward signs, but the tapeworm can cause serious disease in humans. Human echinococcosis (hydatidosis, or hydatid disease) is caused by the larval stages of cestodes (tapeworms). Definitive diagnosis requires a PCR test. Treatment and prevention is done with a dewormer containing praziquantel. Tapeworm treatment is required under the PETS travel scheme and must be given 1-5 days before re-entry to the UK.

We hope you have found this interesting and informative. We feel this is an important article, particularly at this time of year, when many people are travelling to and from the UK with their cats. 

It is imperative to be mindful of the potential risks to cats and be vigilant in checking for signs & symptoms, so that the necessary treatment can be commenced as soon as possible, should any health issues arise. 

As with some of our previous articles, it has been written with the help of our medical specialist, Vicki Adams, who is a trained Veterinarian and Veterinary Epidemiology Consultant, working for the Animal Cancer Trust Charity. We thank her for her advice and expertise.