Rapid diagnosis helps dog recover from leishmaniasis

A dog with severe chronic weight and muscle loss and concurrent dermatological changes, has made a remarkable recovery after he was diagnosed with canine leishmaniasis — a serious parasitic disease increasingly seen in dogs imported to the UK.

Presentation 

Winston, a one-year-old male Rhodesian Ridgeback, was referred to the Internal Medicine Service at the Hospital for Small Animals due to progressive loss of body condition over several months, and skin lesions including periocular alopecia. 

A critical clue to the dog’s condition was uncovered when clinicians asked about his travel background; Winston had been imported from Spain at 15 weeks of age. Given leishmaniasis is endemic in the Mediterranean basin, it immediately increased the team’s suspicions that the dog was infected by the Leishmania parasite.

Diagnostic challenges

The diagnosis of Leishmaniasis can be difficult due to the wide spectrum of clinical signs. There is also a high prevalence of subclinical infection, as the parasite can lie dormant in the spleen, bone marrow, and lymph nodes for several months or years, as might have been the case with Winston.

However, the combination of a travel or import history, lymphadenopathy, alopecia - especially periocular, crusty skin lesions suspicious of vasculitis and typical laboratory abnormalities, mainly hyperglobulinaemia, hypoalbuminaemia, anaemia or even pancytopenia, with and without renal protein loss or polyarthritis raises suspicion, which can then be confirmed by high Leishmania antibody titres.

Clinical investigation

Initial imaging and laboratory testing supported systemic inflammation and early renal involvement, typically glomerulonephritis leading to proteinuria/ protein-losing nephropathy. An abdominal ultrasound confirmed involvement of the lymphoreticulate system as the dog had an enlarged spleen and lymph nodes, as well as non-specific renal changes.

On serum biochemistry, marked hyperglobulinaemia and hypoalbuminemia and anaemia was present. Proteinuria was confirmed via urinalysis and elevated UPC of 0.6 (ref range < 0.2). Interestingly, the dog also showed marked ionised hypercalcaemia (1.8 mmol/l, reference range 1.15-1.5 mmol/l). This finding is not typical of Leishmaniasis. For this reason, there were initial concerns for another underlying pathology (for example potentially lymphoma given the enlarged lymph nodes), but this was later excluded based on normal PTH-related peptide levels, lymph node cytology and the fact that ionised calcium completely normalised with anti-Leishmania treatment. Resolution after treatment supports that hypercalcaemia was secondary to the marked granulomatous inflammation caused by Leishmaniasis.

At four weeks, he had gained around 10 kg and showed marked clinical and biochemical improvement: His blood globulin levels had dropped significantly, from 61.4 g/l to 48.5 g/l, and his serum albumin had increased from 17.9 g/l to 24.8 g/l. His haematocrit levels had normalised to 0.30 l/l, and his total and ionised calcium levels were in the normal range (1.45 mmol/l). 

Winston will need to remain on medication and have regular check-ups to monitor his renal function and proteinuria and ensure that his parasite burden remains under control via Leishmania serum titers, but the clinical team, and his owner, are delighted with his incredible recovery.

Guidance for vets

The team has shared four key tips for vets who suspect leishmaniasis in a patient. 

• Obtain travel/import history. Even remote exposure in endemic regions can be relevant years later.
• Use differential diagnosis. Leishmaniasis can mimic dermatological, renal, immune-mediated, and neoplastic disease patterns and subclinical infection can obscure timelines.
• Confirm when possible. Serology is supportive, but direct parasite identification in tissue with FNA cytology can be decisive - particularly when differentials (e.g., lymphoma) remain plausible.
• Monitor long term. While leishmaniasis cannot be cured, parasite activity can be controlled; ongoing monitoring of kidney function and proteinuria is essential to assess chronic organ impact and guide therapy duration (see Leishvet guidelines).