Leishmaniasis in Cats

Sandflies transmit the parasite through bites to the skin and the incubation period of the transmitted parasite can range from a few weeks to years. Leishmaniasis is acquired in specific areas where the disease is prevalent: the Mediterranean, central and southern America and Mexico, although there have been several cases reported in Texas recently. While there is treatment for this disease, animals may remain persistently infected.

Leishmaniasis is a serious, chronic disease caused by a protozoal organism. It is not common in cats but is more often seen in dogs and normally transmitted to other hosts (including humans) through a mechanical vector (phlebotomine sandfly). Whilst uncommon in cats, when symptoms present they usually affect the skin or visceral organs.

Leishmaniasis in cats may be asymptomatic as cats are often thought to be carriers that do not necessarily contract the disease, however, when symptoms appear they include the same symptoms as in other animals affected with the disease, such as:

• Skin lesions (ulcerative, crusty, nodular or scaly dermatitis)

• Lymph node enlargement

• Weight loss

• Ocular lesions (nodular blepharitis, uveitis, panophthalmitis)

• Decreased appetite

• Chronic gingivostomatitis

• Lethargy

Leishmaniasis is acquired from infected sandfly bites that transmit a protozoal organism that causes infection. Infected sandflies are not common in North America or northern Europe, but disease outbreaks are found in the Mediterranean, Middle East, Asia, Central America and South America. Cases in Mexico and Texas have also manifested. Animals that have travelled to these areas can be exposed to infected sandflies and acquire the disease through bites. The disease can also be spread between animals through blood transfusions.

Some animals are thought to be carriers who do not exhibit symptoms. Cats are suspected to be carriers in affected regions, who do not usually exhibit symptoms, but can carry the causal organism and acquire and transmit it to the sandfly population, which in turn infect other animals that are more likely to exhibit symptoms such as dogs, rodents and humans.

Your veterinarian will perform a complete physical exam, looking for skin and ocular lesions which are common signs of leishmaniasis. As symptom of this disease are diverse, you will need to provide your veterinarian with a complete list of symptoms your pet has been experiencing. It is important to give your veterinarian a complete history of your pet’s travel to any commonly affected locations. As the incubation period can be long, even travel to an affected area several years ago should be communicated. Diagnosis is usually confirmed using cytology, histology, isolation or polymerase chain reaction (PCR) on samples of skin, lymph nodes, blood or any affected tissue.

If the outbreak is not severe, your cat will be treated as an outpatient. The most commonly administered drug is allopurinol, which is usually effective. Other medications that may be tried are miltefosine and N-methylglucamine antimoniate. In addition, skin nodules may be surgically removed. Your veterinarian will discuss risk factors and how to manage outbreaks. Leishmaniasis is a long-term disease and, although outbreaks can be treated, it may recur. If outbreaks are uncontrolled by medication or organ failure has begun, prognosis is poor and euthanasia may be recommended.

You will need to monitor your pet for signs of leishmaniasis outbreaks which will recur every few months. When an outbreak occurs, treatment with medication and veterinarian follow up will be required. As an impaired immune system functioning is commonly associated with leishmaniasis; your cat's exposure to other disease sources should be limited and your pet closely monitored by you and your vet for signs of other infections and diseases. Complete recovery is unlikely and euthanasia may be recommended if uncontrolled outbreaks occur or your pet’s condition worsens.