Treatment and prognosis for canine Leishmaniasis
Current treatment of canine Leishmaniasis leads to a notable and fast clinical improvement, but we know that it is not associated with a total elimination of the tissue parasite. In most cases, combined treatment is recommended which includes a leishmanicidal drug (meglumine antimoniate or miltefosine) and a leishmaniostatic drug (allopurinol).
Meglumine antimoniate is probably the most effective drug and acts by selectively inhibiting the glycolysis and oxidation of the parasite's fatty acids. According to various authors (Torres et al, 2011; Maia et al, 2016) the combination of meglumine antimoniate (4-8 weeks) and allopurinol (6-12 months) is the most effective and a high percentage of sick dogs show a very fast and tangible clinical improvement 5 in 1-3 months. Miltefosine has proved to be a powerful leishmanicidal drug and is recommended as an alternative to meglumine antimoniate (Miró et al, 2009).
Monitoring patients once treatment has started is of great importance for the detection of adverse effects, complications and recurrences. It is recommended that at every visit, as well as a full physical examination, a blood count, clinical biochemistry, urine analysis with protein/creatinine ratio and proteinogram all be performed. The frequency of the examinations will vary from case to case, but a higher frequency is recommended initially (every month, for example) and a lower frequency later on, when the clinical improvement is evident. Once a full clinical improvement has occurred and most parameters have normalised, it is advisable for a complete check-up to be carried out every six months, in order to facilitate an early detection of any recurrences. Don't forget that although the dogs are clinically well, infection by Leishmania, with low parasite loads, does persist.
The most recent studies have shown that, during treatment, in parallel with clinical improvement there is a slow and gradual decrease in the antibody score in sick animals (Torres et al, 2011). It is therefore advisable to take an antibody reading 3, 6 and 12 months after the start of treatment and subsequently every 6 months for animals in treatment.
The prognosis of the disease varies depending on the clinical-pathological situation and it is therefore not the same for all dogs with clinical Leishmaniasis. The LeishVet group (Solano-Gallego et al, 2011) has proposed a classification system for dogs that are sick with Leishmaniasis in clinical stages of increasing seriousness. This system includes four clinical stages based on clinical signs, clinical-pathological disorders (especially kidney function) and the antibody score.
The four stages present the following characteristics:
Stage I: Mild disease: dogs with mild clinical signs such as peripheral lymphadenopathy or papular dermatitis. They present no clinical-pathological disorders and the antileishmania antibody score is negative or low positive. Recommended treatment consists of allopurinol alone and/or domperidone, or simply observation and rigorous monitoring of its course. The prognosis is good.
Stage II. Moderate disease: in addition to the clinical signs mentioned above, dogs may present cutaneous lesions (exfoliative dermatitis, ulcers, nodules), onychogryphosis, anorexia, weight loss, fever, diarrhoea and epistaxis. Common clinical-pathological disorders consist of non-regenerative anaemia and hyperproteinaemia. There are two substages according to kidney function. In substage IIa kidney function is normal, serum creatinine is below 1.4 mg/dl and there is no proteinuria (UPC>0.5). In substage IIb serum creatinine is below 1.4 mg/dl but UPC is between 0.5 and 1. Antileishmania antibody scores range between low positives and high positives. Recommended treatment 6 is to combine meglumine antimoniate (or miltefosine as an alternative) and allopurinol. The prognosis is reserved.
Stage III. Serious disease: dogs that present, in addition to the clinical signs mentioned above, lesions caused by immunocomplexes, such as vasculitis, arthritis, uveitis and glomerulonephritis. The clinical-pathological disorders are the same as in stage II, except that serum creatinine is between 1.4 - 2 mg/dl and UPC is >1. The antileishmania antibody score is medium to high. The same treatment is recommended for the Leishmaniasis and the treatment of the kidney disease is in accordance with the IRIS group recommendations. Prognosis ranges from reserved to unfavourable, depending on the kidney function.
Stage IV. Very serious disease. Antibody scores from medium to high: dogs with clinical signs and lesions mentioned in section 3 as well as serious disorders such as thromboembolism, nephrotic syndrome or terminal kidney disease. The creatinine scores correspond to level 3 of the IRIS classification (2-5 mg/dl) or stage 4 of the IRIS group (creatinine >5 mg/dl). Nephrotic syndrome is characterised by high proteinuria scores with a UPC >5. In this stage the antibody scores are medium or high. Allopurinol is recommended as monotherapy and the IRIS group recommendations for controlling kidney disease should be followed. The prognosis is unfavourable.
- Torres et al, 2011
- Maia et al, 2016
- Miró et al, 2009
- Solano-Gallego et al, 2011