RESUMO
Leishmaniasis is a neglected tropical disease caused by protozoa parasites from the Leishmania genus. Vertebrate hosts acquire the infection through the bite of a female sandfly, initiating a complex parasite development cycle. Contrary to previous beliefs regarding cats' resistance, these animals have recently been identified as potential reservoirs for leishmaniasis. Clinical symptoms in cats can manifest in diverse forms, including cutaneous, mucocutaneous, and visceral manifestations. The diagnosis of feline leishmaniasis is complicated by nonspecific symptoms and the relatively lower specificity of serological tests. The recommended treatment for feline leishmaniasis involves the administration of medications; however, success varies in each cat. This review aims to present cases of feline leishmaniasis, highlighting clinical symptoms, diagnostic methods, therapy schedules, and outcomes. Among the 24 cases documented in the available literature, 12 achieved successful treatment without relapses, resulting in a reduced parasite load and improved symptoms. Three cases responded well but presented persistent sequelae. Two feline leishmaniasis cases initially had treatment success but later experienced recurrences. Finally, no response was observed in seven cases, leading to the euthanasia of cats due to ineffectiveness or irregularities along the therapy. Conventional treatments, despite potential hepatotoxicity and nephrotoxicity, exhibit a high efficacy in reducing parasitic load, thereby improving clinical symptoms and increasing the life expectancy of affected cats. Nevertheless, consistent adherence is crucial, as interruptions may render the therapy ineffective and contribute to parasite resistance. Therefore, addressing the challenges associated with feline leishmaniasis treatment necessitates the development of new strategies to ensure a more effective and sustained approach.
RESUMO
Visceral leishmaniasis (VL) caused by Leishmania infantum is a lethal disease transmitted by sand flies. Although, considered a zoonosis with dogs held as the main reservoirs, humans are also sources of infection. Therefore, control policies currently focused on dog culling may need to consider that VL and human immunodeficiency virus (HIV)/VL patients may also be infectious, contributing to transmission. Reservoir competence of patients with VL without and with HIV infection and of persons asymptomatically infected with Leishmania was assessed by xenodiagnosis with the vector Lutzomyia longipalpis. Parasites in sand fly's guts were identified by using optical microscopy and by conventional polymerase chain reaction (PCR). Leishmania infantum blood parasite burden was determined by quantitative PCR. Among the 61 participants, 27 (44%) infected sand flies as seen by microscopy or PCR. When infectiousness was assessed by microscopy, xenodiagnosis was positive in five (25%) patients not infected with HIV, whereas nine (45%) of those harboring HIV were positive. Among the 19 asymptomatic patients four (21%) infected sand flies only demonstrated by PCR. One (50%) asymptomatic patient with HIV had a positive xenodiagnosis by microscopy. 9/372 (2.4%) and 37/398 (9.2%) sand flies were infected when feeding in patients without and with HIV, respectively. Infectiousness was poorly correlated with quantitative PCR. The study shows that asymptomatic humans are capable of transmitting L. infantum, that ill persons with HIV infection are more infectious to sand flies, and that humans are more important reservoirs than previously thought. This fact may be considered when designing control policies for zoonotic VL.