Diagnosing Leishmaniasis in Dogs

Anne O'Connor adopted Livia, a podenco with leishmania. She has written in great detail about their journey together to find the best and optimum treatment to enable Livia to live a normal long life. I am pleased to say Anne agreed to the article being included as a chapter in my definitive guide to the Podenco, From Pyramid to Perrera, on sale above.

Now Anne has taken the time out to write another very informative article on understanding the symptoms of leishmania, to be able to asses your own dog. Thank you Anne, for sharing this with everyone.

The joy of welcoming a rescued podenco into the family can be tinged with anxiety about the health and well-being of an animal that has all too often suffered hunger, fear and abuse. One of the things that can worry new owners is the threat of a disease that is relatively unknown in many parts of Northern Europe but all too common in the Mediterranean countries. That disease is leishmaniasis.

Leishmaniasis in Mediterranean countries is caused by the parasite known as Leishmania Infantum. It can affect skin and organs and if left untreated can escalate, causing renal failure and death.

Even if your dog has tested negative for leishmaniasis it is important to note that the Leishmania parasite can lay dormant for a number of years before it shows itself. So if you own a dog from an area where the disease is endemic, such as Spain, then you may want to consider annual blood tests to ensure that your dog is safe from the disease. It is worth noting podencos are known to have an extra level of resistance, but this is no guarantee that they will not be affected by it.

This post is an attempt to give you all the information you need on the possible signs and symptoms of Leishmaniasis, so you know if your dog needs testing. It also gives an overview of the different tests that are available.

External Signs and Symptoms of Leishmania.

Leishmaniasis is a difficult disease to pin down and may produce a number of low level and more worrying symptoms that can easily be mistaken for other conditions. Here is a list of known signs and symptoms of Leishmaniasis. If conventional treatment does not work for these symptoms, then a blood test for Leishmania is advisable.

Skin and fur

Very dry and flaky skin
Alopecia — dry, brittle hair with symmetrical hair loss.
Facial hair loss, noticeable around the eyes on the eyelids and behind the ears.
Hair loss, scaly skin or ulcers in the hock joint area.
Crusty dry skin at the tips of the ears
Skin on the muzzle and the pads become hard, thick, scaly and chapped. This is known as Hyperkeratosis and is a common sign where the skin fails to slough off and builds up.
Skin pads can lose colour and become white and translucent.
Pigment changes, either colour loss or dark pigment patches, can occur on skin, around the eyes and gums.
Abnormally long or brittle nails. Discolouration of nails. Dog bites nails constantly.
Nodules that develop on the skin surface
Nodules and ulcers WITHIN the layers of the skin and gums. (Petechia)
Skin lesions and sores that do not heal, or that come and go
Wounds that fail to heal.
Mouth ulcers.

Face and eyes

Facial hair loss, noticeable around the eyes on the eyelids and behind the ears.
Milky eyes (keratitis) and problems with vision (ocular disease)
Conjunctivitis
Uveitis, which shows as squinting and discharge from the eye.
Swollen and inflamed upper eyelid (blephritis)
Nosebleeds or other types of haemorrhage.
Muscle atrophy of the face (making the dog look very gaunt, thin and old in the face)

Digestive system
Unexplained weight loss
Loss of appetite
Vomiting
Diarrhoea
Tar-like faeces or blood in faeces (this is not so common)

General signs

Joint swelling and joint problems, difficulty in walking (stiff gait).
Lethargy and reluctance to go for walks
Constant shivering and shaking. This could be rigours, which indicates that the kidneys are involved. If your dog has this, get to a vet as soon as possible and get the kidneys checked.
Enlarged, hard lymph glands which can be felt as lumps in the neck, just behind the jaw joint.

These are additional signs and symptoms that owners of dogs with the disease have also noticed

Sneezing, and a cold or chest infection blocked nostrils.
Bad smell coming from the dog. Described as “Gorgonzola”, a “monkey cage” etc.
Overheating with panting.

Laboratory Testing for Leishmaniasis

Leishmaniasis often (but not always) comes with a co-infection so symptoms of one disease and another can overlap. This can be confusing and delay a proper diagnosis and treatment. So scientists have developed a variety of tests that detect the presence of the parasites in the body.

Certain blood and urine characteristics give strong indications of the presence of Leishmania and any initial tests should include a full blood analysis, biochemistry analysis and urine analysis to detect any anomalies and assess what, if any damage is being caused to the internal organs, especially the kidneys.

“Immunocomb” or “Snap” Testing

These tests are more usually available from vets in endemic areas. They are test kits that allow a vet to quickly establish whether the antibody to the Leishmania parasite is present. They can perform this test at the clinic so there is no long wait for results. It is meant to be a quick test giving a positive or negative result. It is not highly sensitive.

Protein Electrophoresis

This is a blood test that looks closely at the composition of the blood itself. It is usually used as part of initial diagnosis. Blood carries two different types of protein that do different jobs. They are Albumin and Globulin. Protein electrophoresis isolates the proteins into their specific groups and measures the levels in each sample.

The ones to look at here are :

Albumin: This is responsible for keeping the blood in the veins and arteries. It stops blood leaking from the blood vessels and is important for growth and healing

Beta Globulin : These carry substances such as iron and help fight infection

Gamma Globulins: Better known as antibodies. These fight infection by binding to bacteria and viruses

Higher than normal concentrations of proteins in the blood, alongside low levels of Albumin and high levels of Beta and Gamma Globulins suggest that Leishmania may be present. However these results must be checked for the presence of other possible parasites (such as Ehrlichia).

Urine analysis will look for elevated levels of protein in urine as an indicator of Leishmania Infantum parasites affecting the kidneys.

Checking the level of infection

To check the amount of infection two main tests exist.

Serology test:

Serological Tests are laboratory procedures carried out on a sample of blood serum, the clear liquid that separates from the blood when it is allowed to clot.

There are a number of serology tests available but the IFAT (Indirect Immunofluorescence Test) is the most widely used test in Europe for checking the levels of Leishmania parasites in an infected dog. In Canada, the ELISA test is more widely used. In the US, both ELISA and IFAT tests are available. What the test actually measures is the amount of antibodies and antigens (the antibody factories) that are present in the blood. The higher the level, the higher the infection.

The IFAT does have certain limits. If there are insufficient amounts of antibodies in the blood then the test will not show a positive reading (this also applies to the SNAP and Immunocomb tests mentioned earlier) even though a very low level of infection is present. This is why many vets and rescue organisations recommend annual testing. Even if a dog tests negatively one year, it is not a guarantee that they are free of the disease.

PCR test:

The PCR (Polymerase Chain Reaction) method involves the amplification and detection of minute amounts of the parasite's DNA levels in the dog. The technique works quickly and is usually very effective. It is also highly sensitive. In theory this technique can be applied to any tissue in the body (blood skin, conjunctival fluid from swabs, lymph nodes, marrow). Blood samples are believed give a less sensitive reading so a more solid substance, such as tissue or cartilage is often recommended.

Cases do exist where an initial PCR test has failed to show an infection at all even though an infection is present. This may be due to laboratory errors. It is a highly sensitive test and can be subject to mistakes as well.

Vets experienced in treating the disease emphasise the importance of not subjecting an infected dog to more trauma than absolutely necessary. So if you are contemplating using cartilage , be sure that you are comfortable with tissue samples being taken. Some vets will see this as a routine procedure but others may argue that it is an invasive procedure and recommend other less invasive methods. Ultimately the choice is yours.

Real time PCR, also known as Quantitative PCR (qPCR) is the latest and most sensitive test available which allows for an even more accurate analysis Leishmania Infantum DNA levels present.

Most people choose either the PCR test or the Serology test as an indicator of infection although it possible to have both tests

Biopsy:

In rarer cases, serology and PCR tests fail to show a positive reading for Leishmania although the dog shows definite signs of the disease. In such circumstances vets will often take samples of the affected tissues and look for the presence of parasites there.

Leishmaniasis can express itself in many different ways so the clearer and more accurate a picture you can get, the more confident you will feel about the problem you are dealing with.

The most important thing to remember is that the disease is manageable with the correct treatment and a healthy, stress-free lifestyle for your dog. Many dogs live well into old age and are never troubled by the disease at all.