Abstract
Dear Editors,
A valuable contribution to the current knowledge on feline leishmaniosis (FeL) has recently been published by Soares et al, 1 highlighting the importance of Leishmania infantum infection in cats living in areas where zoonotic visceral leishmaniosis is endemic 2 and the potential of these animals to act as a reservoir for this protozoan. 3 In fact, the development of sensitive and specific diagnostic techniques, such as serological and molecular methods, and the enhanced awareness of veterinarians regarding this parasitosis in cats have led to an increasing number of FeL documented reports and of subclinical infections. 2
We would like to add some complementary data to the epidemiological part of the paper, dealing with feline infection and disease in Portugal. The clinically diagnosed cases have predominantly involved skin lesions, although visceral involvement was also described. In the first case of FeL described in the country, in the 1990s, the cat presented asymmetric and non-pruritic areas of alopecia on the back and supraocular skin nodules on the right side of the head; and amastigotes were observed in cephalic nodular lesions as well as in popliteal lymph nodes. 4 It seems worth noting that, since the case mentioned in the review, more cases have been reported with ocular and/or visceral involvement in addition to cutaneous manifestations (P Pimenta et al, unpublished data).5–8 In a case reported by Sanches et al, the cat presented an ulcerative lesion in the nose, uveitis and demodicosis, 5 while in the case reported by Basso et al the animal presented with fever, multiple nodular skin lesions in the external ear and on the head (with the observation of Leishmania species amastigotes by fine needle aspiration of the nodules) and ulcers in the tibiotarsal and carpal regions. 6 Maia et al reported a cat with viscerocutaneous leishmaniosis associated with an invasive squamous cell carcinoma. 7 Initially, the cat presented a single cutaneous lesion in the right nostril that evolved to a crateriform non-encapsulated and poorly delineated mass in the nasal planum, with naso-oral fistulation and nasal destruction. Parasites were isolated from the skin mass, submandibular and popliteal lymph nodes, liver and spleen. In three cases recently diagnosed by Pimenta et al (unpublished data) the clinical manifestations were primarily ocular (ie, anterior uveitis, nodular conjunctivitis, keratitis and nodular dermal lesions of the eyelids). All three cats had highly positive antibody titres to Leishmania species, as assessed with the direct agglutination test (DAT), and two of them had hyperglobulinaemia (marked or mild).
Moreover, recent epidemiological surveys have confirmed that infection is endemic in the feline population (domestic and stray animals) of southern Portugal, with a seroprevalence of 4.8% found in 271 cats by means of the DAT and a 9.9% prevalence in 649 cats using PCR for blood DNA.9,10 These results further reinforce the assumption that conventional serology does not seem to be sensitive enough to detect L infantum infection in cats. From an epidemiological point of view, serology may underestimate the real number of infected cats in areas of endemicity and should preferably be used in combination with molecular techniques for DNA detection. 3
We strongly agree with the comment made by Soares et al that FeL should more often be taken into account as part of the differential diagnosis in cats. 1 We would also like to stress that not only cutaneous, but ocular and systemic clinical signs alike, as well as hyperproteinaemia and hyperglobulinaemia, should raise suspicion in cats living in or travelling to areas where leishmaniosis due to L infantum is endemic.