Cutaneous leishmaniosis in naturally infected dogs in Paraná, Brazil, and the epidemiological implications of Leishmania (Viannia) braziliensis detection in internal organs and intact skin

Abstract

Environmental changes have occurred over the years, altering the eco-epidemiological pattern of leishmaniosis in the State of Paraná, Brazil, involving the pillars of the cycle (parasite, vectors, reservoir, and environment) and their interaction. Much has been discussed about the dog's role as a reservoir of the Leishmania (Viannia) braziliensis Vianna, 1911 transmission cycle. However, this question remains unanswered. The purpose of this study was to investigate, using parasitological and molecular methods, different samples in eight naturally infected dogs from an endemic rural locality where only L. (V.) braziliensis is present, and where human cases have been previously notified. Blood and biopsied organ samples from naturally infected dogs were analyzed by culture media, PCR, random amplified polymorphic DNA and sequencing methodologies. Only skin lesions from all dogs yielded positive cultures and when PCR was performed, L. (V.) braziliensis DNA was amplified from intact skin, peripheral blood, bone marrow, spleen, liver and lymph nodes. RAPD was also applied to isolates from the skin lesions, exhibiting the genetic variability of the parasite identified. To confirm which species of Leishmania was amplified in PCR, the sequencing method was performed, verifying 100% similarity with the Viannia subgenus. This study showed that L. (V.) braziliensis can spread to other sites besides the ulcerous lesions, such as intact skin, peripheral blood and internal organs, making it possibility for dogs to serve as active sources of parasite transmission. For definitive proof, xenodiagnostic test on intact skin of infected dogs, should be done.

Clinical and histopathologic features of canine tegumentary leishmaniasis and the molecular characterization of Leishmania braziliensis in dogs

“…However, the majority of these studies lack documentation that L . braziliensis was the causal agent of the infection [8, 31–39]. Here, evaluating 61 dogs with ulcerated lesions, evidence of leishmaniasis infection was observed in 89%, and 67% of the animals had detection of DNA of L .…”

Molecular diagnosis of American Cutaneous Leishmaniasis (ACL) in dogs from an endemic area in Pernambuco State, Brazil

“…The same authors suggested that dogs play an important role in the peridomestic transmission of ACL to human beings as confirmed by Membrive et al (2012). Recently, evidences that dogs can possibly act as reservoir of L. (V.) braziliensis were reported in study performed in an endemic rural area in northern Paraná State -Brazil (Marquez et al, 2017), however, no correlation or association between human and canine seroprevalences was recorded in another study in Londrina -PR (Benitez et al, 2018).…”

Intraspecific Genomic Divergence and Minor Structural Variations in Leishmania (Viannia) panamensis

“…Several nuclear and mitochondrial DNA markers (cytochrome b, COII, gp63, 18S-rRNA, mini-exon, HSP-70, and ribosomal internal transcribed spacer regions (ITS-rDNA)) as well as different molecular techniques such as polymerase chain reaction (PCR) [9], multilocus sequence typing (MLST) [10], multilocus enzyme electrophoresis (MLEE) [5,11], random amplified polymorphism (RAPD) [12], amplified fragment length polymorphisms (AFLP) [13] and microsatellites [14], have been used to evaluate the inter and intraspecific genetic variability of different Leishmania species (L. tropica, L. major, L. donovani, L. braziliensis, L. peruviana, L. guyanensis, and L. panamensis) [13][14][15][16][17][18][19]. However, the identification of such genetic variants across the whole genome has become possible only with the arrival of DNA-seq.…”