Anatomical Vascular Differences and Leishmania-Induced Vascular Morphological Changes Are Associated with a High Parasite Load in the Skin of Dogs Infected with Leishmania infantum.

Canine visceral leishmaniasis (CVL), caused by the protozoan Leishmania infantum, affects several organs, including the skin. Dogs are considered the major domestic reservoir animals for leishmaniasis, and through their highly parasitized skin, they can serve as a source of infection for sandfly vectors. Therefore, studies of the skin parasite-host relationship can contribute to the understanding of the infectious dissemination processes of parasites in the dermis and help to identify targets for diagnosis and treatment. Thus, the aim of this study was to evaluate the association of anatomical vascular differences and Leishmania-induced vascular morphological changes with clinical signs and parasite load by analyzing the ear and abdominal skin from dogs naturally infected with L. infantum. Paired samples of ear and abdominal skin from L. infantum-positive dogs (n = 26) were submitted for histological and immunohistochemistry analyses. The ear skin samples showed a more intense and more diffusely distributed granulomatous inflammatory reaction, a higher number and larger diameter of blood vessels, increased parasite load, higher expression of VEGF+ (vascular endothelial growth factor) and MAC 387+ (calprotectin) recently infiltrating cells, and more intense collagen disruption compared to the abdominal skin samples. Intracellular amastigotes were observed in blood vessels and inside endothelial cells and were diffusely distributed throughout the dermis in the ear skin samples. The NOS2/MAC387+ cell ratio was lower in the ear skin samples than in those of the abdomen, suggesting that in the ear dermis, the inflammatory infiltrate was less capable of producing NO and thereby control the parasite load. Together, these findings indicate how parasites and immune cells are distributed in the skin and suggest an important role for dermal vascularization in cellular influx and thereby in parasite dissemination through the skin of naturally infected dogs.

Comparative Study of Colorimetric In Situ Hybridization and Quantitative Real-Time Polymerase Chain Reaction for Diagnosis of Infection by Leishmania infantum in Dogs in Formalin-Fixed and Paraffin-Embedded Skin.

The zoonotic visceral leishmaniasis is caused by the protozoan Leishmania infantum and dogs are reservoirs for this parasite. For the diagnosis of Leishmania at the species level in dogs in formalin-fixed, paraffin-embedded skin (FFPES) samples, colorimetric in situ hybridization (CISH) and quantitative real-time polymerase chain reaction (qPCR) are options, but their sensitivities are not well established. Therefore, the aim of this study was to determine the sensitivity of these two techniques in FFPES for the diagnosis of the L. infantum infection in dogs using culture as the reference standard. The FFPES of 48 dogs with cutaneous infection by L. infantum confirmed by culture and by multilocus enzyme electrophoresis were examined by CISH and qPCR using specific probes for L. infantum. The sensitivities of qPCR, CISH and their combination were, respectively, 77.0%, 58.0% and 83.3%. The sensitivities of qPCR in dogs with and without clinical signs were, respectively, 74.2% and 82.4%. The sensitivities of CISH in dogs with and without clinical signs were, respectively, 61.3% and 52.9%. The CISH and qPCR showed satisfactory sensitivities for the diagnosis of L. infantum in the FFPES of dogs, even in dogs without clinical signs, and their combination increases the sensitivity for this diagnosis.

Morphological, histopathological and molecular assessments of Prosorhynchoides sp. (Digenea: Bucephalidae) in Perna perna (Bivalvia: Mytilidae) mussels sampled off the coast of Rio de Janeiro, southeastern Brazil.

Mussel production is expanding worldwide, and in Brazil the main species currently produced is the mussel Perna perna. Bucephalid trematodes have been recorded in P. perna but their larval identification is problematic. In this context, the aims of this paper were to evaluate the prevalence of bucephalids in P. perna, perform taxonomic and phylogenetic trematode studies, and analyze potential histopathological alterations in the infected host. Mussels obtained by fishers from Guanabara Bay, Rio de Janeiro, Brazil were weighed and measured, and internal organ tissues and parasites were collected. Of the 69 analyzed mussels, 24.6 % (17/69) were parasitized by bucephalid larvae. Sporocysts were located mainly in host mantle. Mussels presented sporocysts and cercaria within the connective tissue of mantle, all without associated inflammatory reactions. Parasite loads varied from less than 5 % to > 50 % of parasitized tissue. Histopathological examinations indicated that male or female gonads were not observed in 77 % (10/13) of parasitized mussels and in 4 % (2/56) identified as non-parasitized in the histology but previously classified as parasitized in the stereomicroscopic analysis. Thus, the absence of gonads may be associated with parasitism. Prosorhynchoides sp. is reported herein for the first time in mussels sampled on the coast of Rio de Janeiro, with genetic and histological data reported for the intermediate host, sporocysts and cercariae. New 28S rDNA, 18S rDNA and ITS1, 5.8S and ITS2 sequences are provided.

Investigation of SARS-CoV-2 infection in dogs and cats of humans diagnosed with COVID-19 in Rio de Janeiro, Brazil.

BACKGROUND: Infection by SARS-CoV-2 in domestic animals has been related to close contact with humans diagnosed with COVID-19. Objectives: To assess the exposure, infection, and persistence by SARS-CoV-2 of dogs and cats living in the same households of humans that tested positive for SARS-CoV-2, and to investigate clinical and laboratory alterations associated with animal infection. METHODS: Animals living with COVID-19 patients were longitudinally followed and had nasopharyngeal/oropharyngeal and rectal swabs collected and tested for SARS-CoV-2. Additionally, blood samples were collected for laboratory analysis, and plaque reduction neutralization test (PRNT90) to investigate specific SARS-CoV-2 antibodies. RESULTS: Between May and October 2020, 39 pets (29 dogs and 10 cats) of 21 patients were investigated. Nine dogs (31%) and four cats (40%) from 10 (47.6%) households were infected with or seropositive for SARS-CoV-2. Animals tested positive from 11 to 51 days after the human index COVID-19 case onset of symptoms. Three dogs tested positive twice within 14, 30, and 31 days apart. SARS-CoV-2 neutralizing antibodies were detected in one dog (3.4%) and two cats (20%). In this study, six out of thirteen animals either infected with or seropositive for SARS-CoV-2 have developed mild but reversible signs of the disease. Using logistic regression analysis, neutering, and sharing bed with the ill owner were associated with pet infection. CONCLUSIONS: The presence and persistence of SARS-CoV-2 infection have been identified in dogs and cats from households with human COVID-19 cases in Rio de Janeiro, Brazil. People with COVID-19 should avoid close contact with their pets during the time of their illness.

Integrative taxonomy reveals a new species of Dollfusentis (Acanthocephala: Illiosentidae), in Orthopristis ruber (Osteichthyes: Haemulidae) from Rio de Janeiro, Brazil.

The taxonomy of species of Dollfusentis is rather confused due to the overlap of morphological traits. The aim of this study was to follow an integrative taxonomy approach over the acanthocephalans collected from Orthopristis ruber in Brazil. Dollfusentis lenti n. sp. is described and is characterised by having an elongate trunk with spines sparsely distributed (largest 60-85 µm long) extending from the neck to almost reach the end of proboscis receptacle; additionally, the new species possesses a long proboscis with 12-14 longitudinal rows of 16-17 hooks each; 3-4 posterior hooks reduced in size, well-spaced from the eight ventrolateral crescent hooks, and lemnisci longer than proboscis receptacle. New sequences of 18S rDNA, ITS1, 5.8S and ITS2, 28S rDNA and COI mtDNA are provided. Dollfusentis bravoae is morphologically similar because it possesses the same number of proboscis hooks, although it differs by the size of testes and uterus and by having a higher number of trunk spines; additionally, new scanning electron micrographs and genetic data for both species support its distinction. Phylogenetic analysis obtained either with two nuclear genes or mitochondrial COI gene showed that Dollfusentis spp. belong to Illiosentidae, and the new species is yielded as the sister species of D. bravoae, with D. chandleri as the sister species of the latter two.

Feline heartworm (Dirofilaria immitis) infection: first case report of serological diagnosis in Brazil, confirmed by molecular assay.

The clinical importance of heartworm infection in cats has indeed increased in recent years. Dirofilaria immitis infection has been reported worldwide in cats and continues to be regularly diagnosed in endemic areas. The diagnosis can be overlooked easily, especially in Brazil, where there is not a specific feline immunodiagnostic test, forcing the veterinarians to use a test made for the canine host. In 2015, a 10-year-old female neutered cat was diagnosed with D. immitis using an antigen serological test, based on imunocromatography and designed for dogs. The modified Knott test was negative. As the disease progressed, the cat showed clinical signals of respiratory distress, such as dyspnoea and polypnea in addition to prostration and emaciation, and died a few weeks after the diagnosis. During necropsy, one adult nematode was found in the pulmonary artery. D. immitis infection was confirmed by molecular amplification, performed in the worm fragment. This is the first report of serological diagnosis of feline dirofilariasis in Brazil. A chemoprophylaxis routine in cats should be done, as is done in dogs from endemic areas.