We are frequently approached by dog ​​owners whose four-legged friends suffer from chronic illnesses. They want to know which dog foods are suitable for the presence of various illnesses. A frequently discussed issue is leishmaniasis. But what exactly is it, and what should be considered when feeding it? Why should a dog's diet be as low in purines as possible?

Leishmaniasis - an overview

Leishmaniasis is an infectious disease. The pathogens are protozoa, i.e., single-celled organisms transmitted by sand flies. Other modes of transmission (blood transfusions, smear infections) are rare. For a long time, sand flies were found exclusively south of the 45th parallel. Thus, dogs originating from Mediterranean countries or accompanying their owners on vacations in these areas became infected. Recently, sand flies have been observed in southern Germany. Leishmania infections could occur in these regions in the future as well.

Transmission and symptoms

The pathogens are transmitted during the female mosquito's feeding. The Leishmania then parasitize intracellularly, particularly in macrophages (cells of the immune system). Interestingly, infected dogs do not necessarily become ill. This means that they may harbor the Leishmania but may never develop symptoms. Whether and when the disease will break out is difficult to predict. There is a correlation between the antibody titer (the number of antibodies in the blood produced by the dog's body against the pathogens) and the likelihood of symptoms occurring.

These symptoms are often initially non-specific and occur in bouts. Symptoms include fever, apathy, weight loss, and a thinning coat. Depending on the progression, different forms of manifestation eventually become apparent. A distinction is made between cutaneous (skin: including hair loss on the bridge of the nose, tips of the ears, and "glasses" around the eyes), mucocutaneous (mucous membranes: ulcers), and visceral (internal organs: particularly glomerulonephritis → inflammation of the kidneys) forms. All of these can also occur in a mixed form. Without treatment, up to 90% of dogs with an actual outbreak of leishmaniasis die.

What does therapy look like and what does it all have to do with nutrition?

First, it's important to note that leishmaniasis is NOT curable in dogs. While the targeted use of various medications can alleviate symptoms, the pathogens most likely remain in the dog's body for life. A recurrence of the disease is not unlikely, even after symptoms have successfully resolved, necessitating further treatment.

A commonly used medication is "allopurinol," which is used, among other things, to treat gout in humans. It is absorbed by Leishmania and ultimately inhibits their reproduction. However, it also has another effect directly in the dog itself: It inhibits the enzymatic breakdown of purines into allantoin. Purines are important components of DNA and RNA and can be synthesized by the dog itself. Any purines that enter the body through food and are not required for genetic material must be broken down and excreted through the kidneys.

If the degradation of allantoin is inhibited by the leishmaniasis drug allopurinol, the intermediate xanthine accumulates. This increases the risk of urinary stones ("xanthine stones") forming. This is why dogs receiving allopurinol should be fed a low-purine diet.This may not be easy, as few pet food manufacturers declare the purine content of their products, and creating your own recipe is time-consuming and requires specialist knowledge. Pet owners should not hesitate to contact the producers of their dog food directly and inquire about the purine content. If this information is withheld, it is advisable to switch products.

Low-purine diet - an overview

Purines are also found in foods rich in nuclei. These include meat (especially offal and connective tissue chews), but also legumes. Depending on their composition, a vegetarian or vegan diet can be an extremely beneficial alternative to meat.

The purine contents of our VEGDOG varieties are as follows:

There are currently no official recommendations or limits for low-purine feeds. However, based on current studies, complete feeds with a purine content of approximately 40 mg/100 g dry matter can be classified as low-purine (see: Kaempfle et al. (2023), Animals, 13, 3060). https://doi.org/10.3390/ani13193060).

This allows us to FARMER'S CRUNCH recommend for a low-purine diet.

It should also be noted that dogs with leishmaniasis should drink a lot. Diluting food portions with water can be very helpful.

What is the life expectancy of infected dogs?

Leishmaniasis is not a death sentence. The majority of infected dogs have the chance of a long and happy life. As owners, we have a responsibility to promote this. This includes, among other things, reducing stress (which weakens the immune system) by creating a structured daily routine, providing plenty of love and attention, regular veterinary checkups, administering appropriate medications if necessary, and, of course, a wholesome and balanced diet.

Is leishmaniasis contagious?

Leishmaniasis is generally not contagious—neither from dog to dog nor from dog to human. Only a pregnant dog can transmit the parasites to her puppies via the placenta. Otherwise, transmission occurs through the bite of an infected female sand fly. However, a sand fly can also become infected with leishmania from a dog and pass the infection on to humans or animals with the next bite.

If you have any questions about this disease, please contact our veterinarians at tierarzt@vegdog.de.