Molecular diagnosis of Leishmania spp. in dogs of a subtropical locality of Argentina

Leishmania tropica and Leishmania infantum infection in dogs and cats in central Israel

Background

Three species of Leishmania cause disease in humans in Israel and are endemic in the Middle East: Leishmania infantum, Leishmania tropica and Leishmania major. These species infect dogs and cats, but little is known about their prevalence in pet populations and their clinical manifestations. A study on dog and cat Leishmania infection was conducted in a focus of human L. tropica infection in central Israel with the aim of getting insight on leishmaniosis in pets in an area where human infection is highly prevalent.

Methods

Blood, demographic and clinical data were collected from dogs and cats brought for veterinary care in a focus of human L. tropica infection during 2018–2020. kDNA PCR and internal transcribed spacer1 high-resolution melt analysis PCR (ITS1 HRM PCR) with DNA sequencing were performed for the detection of Leishmania and species determination.

Results

Forty-three of 189 dogs (22.8%) and 44 of 152 cats (28.9%) were positive for Leishmania spp. infection by kDNA PCR. The ITS1 HRM PCR detected six dogs (3.3%) infected with L. infantum and one (0.5%) with L. tropica, whereas six cats (3.9%) were found infected by L. infantum and five (3.3%) by L. tropica. Four of the five L. tropica-positive cats suffered from weight loss, four had azotemia, two with mild and two with severe azotemia and progressive renal disease. Three cats had gingivostomatitis; three had skin lesions with abscess and ulcers in two and scales and hair loss in another cat, which was also FIV +. This is the first report of feline L. tropica infection in Israel. Clinical information on cats with this infection from previous studies elsewhere is scarce.

Conclusions

A high rate of Leishmania spp. infection, mostly estimated as sub-clinical, was found in dogs and cats admitted for veterinary care in an L. tropica focus. Among the animals in which infection could be characterized to the species level, more dogs were infected with L. infantum than with L. tropica while 5 of 11 cats were infected with L. tropica and had signs of systemic and skin disease not described before in feline L. tropica infection.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05272-0.

Exploring the paradox of defense between host and Leishmania parasite

Leishmaniasis, a neglected tropical disease, still remains a global concern for the healthcare sector. The primary causative agents of the disease comprise diverse leishmanial species, leading to recurring failures in disease diagnosis and delaying the initiation of appropriate chemotherapy. Various species of the Leishmania parasite cause diverse clinical manifestations ranging from skin ulcers to systemic infections. Therefore, host immunity in response to different forms of infecting species of Leishmania becomes pivotal in disease progression or regression. Thus, understanding the paradox of immune arsenals during host and parasite interface becomes crucial to eliminate this deadly disease. In the present review, we have elaborated on the immunological perspectives of the disease and discussed primary host immune cells that form a defense line to counteract parasite infection. Furthermore, we also have shed light on the immune cells and effector molecules responsible for parasite survival in host lethal milieu/ environment. Next, we have highlighted recent molecules/compounds showing potent leishmanicidal activities pertaining to their pro-oxidant and immuno-modulatory mechanisms. This review addresses an immuno-biological overview of the factors influencing the parasitic disease, as this knowledge can aid in the unraveling/ identification of potential biomarkers, novel therapeutics, and vaccine candidates against leishmaniasis.

Autochthonous Outbreak of Cutaneous Leishmaniasis due to Leishmania infantum in Corrientes Province, Argentina

Endemic cutaneous leishmaniasis (CL) in northern Argentina has traditionally been caused by Leishmania braziliensis. This study aims to describe an outbreak of Leishmania infantum-caused human CL in the Department Capital of Corrientes Province, Argentina. We retrospectively analyzed the reported cases of CL in this area from May 2015 to December 2016. Eighty cases of CL were clinically and analytically diagnosed, and there was one case of visceral leishmaniasis in a boy who also had CL. Patients' median age was 33.6 years (range 1-89 years), and 18.5% were younger than 15 years; the male:female ratio was 3.5:1. Cases lived mostly in the municipality of Corrientes (72.8%), whereas 27.2% resided in Riachuelo. Although 67.9% had a single lesion, 32.1% had several. Molecular analyses showed that L. infantum was the causative species in all cases. Our results show that for the first time, there was an outbreak of CL by L. infantum in an urban area of Argentina.