Toxoplasma gondii infection in European brown hares (Lepus europaeus) in Brazil.

Toxoplasmosis is a worldwide zoonosis that affects warm-blooded animals, including humans. Wild animals can act as intermediate hosts of this pathogen; thus, this study aims to detect Toxoplasma gondii infection in invasive European brown hares in Brazil. For this, 72 wild European brown hares were captured from July 2020 to June 2022 in three Brazilian states: São Paulo, Paraná, and Rio Grande do Sul. The diagnostic of Toxoplasma gondii infection was performed by bioassay in mouse, histopathology in Hematoxylin-Eosin-stained tissue sections (brain, liver, lungs, kidneys, and small intestine), serology by IFAT, and molecular techniques by conventional PCR and qPCR. The combined prevalence of the different diagnostic methods was 51.4% (37/72, CI= 40.1 - 62.6 %), and there was no statistical difference between sexes, age range, or geographical region of the hosts. Mouse bioassay was the technique that detected more positive hares. To our knowledge, this is the first confirmation of Toxoplasma gondii infection in invasive European brown hares in Brazil. These animals act as reservoirs and potential infection source for carnivores and other wild and domestic animals, including humans, thus contributing to perpetuate the disease cycle in São Paulo, Paraná, and Rio Grande do Sul States. Research such as the present study is necessary to raise awareness about the role of animals in the disease cycle.

SEROLOGICAL SURVEY FOR SELECTED PATHOGENS IN FREE-RANGING COUGARS (PUMA CONCOLOR) IN SÃO PAULO, BRAZIL.

This study performed a serological assay to assess the exposure of free-ranging cougars (Puma concolor) to four selected infectious agents, including Toxoplasma gondii, Leptospira spp., the feline immunodeficiency virus (FIV), and the feline leukemia virus (FeLV). Serum samples were collected from 27 free-ranging cougars along the Tietê River Basin, in the central region of the State of São Paulo, Brazil. The presence of antibodies against T. gondii was detected in 59.3% (16/27) of the serum samples through the modified agglutination test (MAT-t), which was the most prevalent agent. The microscopic agglutination technique (MAT-1) was used to investigate the occurrence of anti-Leptospira spp. antibodies, showing that 11.1% (3/27) of the sampled cougars were seropositive. The only serovar detected was Djasiman (L. interrogans). A commercial enzyme-linked immunosorbent assay (ELISA) licensed for use in domestic felines was used to investigate the occurrence of retroviruses. The ELISA test kits detected a prevalence of 11.1% (3/27) of FIV antibodies, while none of the samples tested showed any evidence of FeLV antigen. These results suggest that free-ranging cougars are exposed to potentially pathogenic agents. This study presented the first recorded occurrence of the serovar Djasiman in P. concolor.

High titers of anti-Leishmania spp. antibodies in apparently healthy dogs in the North Pioneer Mesoregion of the state of Paraná, Brazil.

Leishmaniasis is an anthropozoonosis with vector transmission, and knowledge regarding the occurrence of this parasitosis in sentinels can contribute to infection and disease control measures in humans. The objectives of this study were to evaluate the occurrence of Leishmania exposure and infection in dogs from urban and rural areas in the North Pioneer Mesoregion of the state of Paraná, to evaluate possible risk factors, and to analyze the statistical agreement between the serological techniques that were used. Using a convenience sampling, serum and whole blood samples were collected to perform serological and molecular assays, respectively. The enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent antibody test (IFAT) identified 29/204 (14.2%) and 20/204 (9.8%) seropositive dogs, respectively. Five dogs (2.4%) were seropositive for both serological tests, and four dogs presented high titers in the IFAT. None of the samples tested positive for Leishmania spp. DNA according to polymerase chain reaction analysis. No factors were significantly associated with infection. Leishmania parasites circulate in urban and rural dogs in the North Pioneer Mesoregion of the state of Paraná. Despite the absence of clinical cases, seropositive animals with high antibody titers should serve as a warning to the local population that should be properly informed regarding the prevention.

Biogenic silver nanoparticles (AgNp-Bio) reduce Toxoplasma gondii infection and proliferation in HeLa cells, and induce autophagy and death of tachyzoites by apoptosis-like mechanism.

Toxoplasma gondii is a protozoan parasite that can cause severe and debilitating diseases, especially in immunocompromised individuals. The available treatment is based on drugs that have low efficacy, high toxicity, several adverse effects, and need long periods of treatment. Thus, the search for therapeutic alternatives is urgently needed. Biogenic silver nanoparticles (AgNp-Bio) have been associated with several biological effects, as antiproliferative, pro-apoptotic, antioxidant, antiviral, antifungal, and antiprotozoal activity. Thus, the objective was evaluating AgNp-Bio effect on HeLa cells infected with T. gondii (RH strain). First, nontoxic AgNp-Bio concentrations for HeLa cells (1.5 - 6 µM) were determined, which were tested on cells infected with T. gondii. A significant reduction in infection, proliferation, and intracellular parasitic load was observed, also an increase in ROS and IL-6. Additionally, the evaluation of the action mechanisms of the parasite showed that AgNp-Bio acts directly on tachyzoites, inducing depolarization of the mitochondrial membrane, ROS increase, and lipid bodies accumulation, as well as triggering an autophagic process, causing damage to the parasite membrane, and phosphatidylserine exposure. Based on this, it was inferred that AgNp-Bio affects T. gondii by inducing immunomodulation and microbicidal molecules produced by infected cells, and acts on parasites, by inducing autophagy and apoptosis.

Seroprevalence of Toxoplasma gondii, Neospora caninum, and Leishmania spp. in hunting dogs from Mato Grosso do Sul, Brazil / Soroprevalência de Toxoplasma gondii, Neospora caninum e Leishmania spp. em cães de caça do Mato Grosso do Sul, Brasil

ABSTRACT: Toxoplasmosis, neosporosis, and leishmaniasis are important diseases of worldwide distribution and can affect both pets and humans. Hunting dogs have been trained to hunt domestic and wild animals, which makes them more exposed to parasitic infections. The present study aimed to evaluate the seroprevalence of Toxoplasma gondii, Neospora caninum, and Leishmania spp. in hunting dogs from a rural area in Mato Grosso do Sul, Brazil. Serum samples were collected from 39 American Foxhound dogs, and the sex and age variables were recorded. Serum samples were subjected to an indirect fluorescent antibody test (IFAT) to detect antibodies. Seroprevalence was 35.9%, 15.4%, and 2.6% for Toxoplasma gondii, Neospora caninum e Leishmania spp., respectively. There was no statistical difference between genders for these diseases (P>0.05). Results demonstrated a circulation of these protozoa in hunting dogs in a rural area of ​​the state of Mato Grosso do Sul, which can contribute to the epidemiology of these diseases.

RESUMO: Toxoplasmose, neosporose e leishmaniose são importantes doenças de distribuição mundial e podem afetar tanto os animais de companhia quanto os humanos. Os cães de caça têm sido treinados para caçar animais domésticos e selvagens, o que torna esses animais mais expostos a infecções parasitárias. O presente estudo teve como objetivo avaliar a soroprevalência de Toxoplasma gondii, Neospora caninum e Leishmania spp. em cães de caça de área rural do Mato Grosso do Sul, Brasil. Foram coletadas amostras de soro de 39 cães da raça Foxhound-americano e as variáveis sexo e idade foram registradas. As amostras de soro foram submetidas a reação de imunofluorescência indireta (RIFI) para detecção dos anticorpos. A soroprevalência foi de 35,9%, 15,4% e 2,6% para Toxoplasma gondii, Neospora caninum e Leishmania spp., respectivamente. Não foi observado diferença estatística entre os sexos para todas as doenças (P>0.05). Os resultados demonstram circulação desses protozoários em cães de caça de uma área rural do estado do Mato Grosso do Sul, o que pode contribuir para a epidemiologia dessas doenças.