Revista Brasileira De Parasitologia Veterinaria最新文献

Tick-borne diseases are a leading cause of death and illness worldwide. Disulfide isomerase (DSI) is an essential protein that helps tick bodies form natural protein structures so they can perform their biological functions after engorgement. In this study, we are exploring the role of DSI and present a potential strategy for tick management by interfering with DSI in ticks. HlDSI cDNA contains 1,119 nucleotides encoding 372 amino acids, and its molecular weight is 93.69 kilodaltons. BLAST analysis showed that the HlDSI protein was 99.10% identical to DSI-like proteins of other parasites. We identified the Jeju strain of Haemaphysalis longicornis and characterized its transcriptional and functional status. Each tick's dsRNA was injected into a female tick and soaked in nymph to further examine its biological functions. RT-PCR and real-time PCR were used to identify and decrease the gene expression of HlDSI RNA interference (RNAi). In adult tick dsRNA-injected groups, HlDSI RNAi significantly impaired tick blood-feeding efficiency and tick viability,and disrupted the molting process in nymphs. According to our analysis, DSI is a significant molecule that is involved in both feeding and reproduction during the tick life cycle,and is therefore a valid target for future tick control strategies.

This research aimed to identify the species that make up the helminth fauna of Batrachoides surinamensis, a commercially important fish on Marajó Island and the Bragança region, Pará, Brazil. A total of 146 specimens of B. surinamensis from Marajó Island and 60 specimens from Bragança were analyzed between 2021 to 2024. The samples were acquired from artisanal fishers at the time of landing. The helminth parasites found were processed for analysis by light and scanning electron microscopy. Taxonomic identification was performed using phylum keys, and scientific articles with original descriptions and redescriptions of species were used to identify the taxa present. Helminths were quantified to determine prevalence, mean intensity of infection and mean abundance parameters. In the collections from Marajó Island, of Nematoda had the highest prevalence at 76.71%, followed by Trematoda at 25.34%, Cestoda at 86.98% and Acanthocephala at 0.68%. In the collection from Bragança of Nematoda had the highest prevalence at 83.33%, followed by Cestoda at 40%, Trematoda at 81.66% and no Acanthocephala were recorded. It was possible to make the first record of the gastrointestinal helminths of B. surinamensis from Marajó Island and the Bragança region in the state of Pará.

The diversity of Hepatozoon spp., piroplasmids, and onchocercids that parasitize birds worldwide has been underestimated, especially in Brazil. The present work aimed to investigate, using molecular assays, the occurrence of Hepatozoon spp., piroplasmids, and onchocercids in tropical birds from the Brazilian Pantanal wetland, in the states of Mato Grosso and Mato Grosso do Sul. Blood sampling and DNA extraction were performed on 517 birds from 13 avian orders. DNA samples positive to endogenous gene (avian β-actin) were subjected to PCR assays targeting the 18S rRNA gene of Hepatozoon spp. and piroplasmids as well as PCR assays for onchocercids (cox-1, 28S rRNA and 18S rRNA genes). As a result, two onchocercids (0.4%) were identified. None was positive in the PCR assays for Hepatozoon spp. or piroplasmids. The cox-1 sequence detected in Ramphocelus carbo grouped with Cardiofilaria sp., and onchocercid cox-1 sequence obtained from Taraba major grouped with Splendidofilaria spp. This is the first molecular report of onchocercids closely related to Cardiofilaria spp. and Splendidofilaria spp. in birds from the Brazilian Pantanal.

Parasite-host interactions are shaped by environmental and biological factors, leading to diverse host impacts ranging from tissue damage to physiological impairments. The Tocantins-Araguaia basin, particularly the Upper Rio Tocantins region, harbors remarkable fish diversity and endemism, making it a critical area for parasitological research. Here, we report the first record of parasitism by isopods of the genus Paracymothoa in Moenkhausia species (M. aurantia and M. goya) from the Upper Rio Tocantins basin. The parasites (Paracymothoa astyanaxi) were located in the buccal cavity and frequently associated with visible lesions, including tongue amputation, a known outcome of their trophic behavior. This finding contributes to the understanding of parasitic diversity associated with Moenkhausia and underscores the relevance of parasitological surveys in Neotropical freshwater systems. It also provides insights into local ecological pressures and supports the development of conservation strategies for endemic ichthyofauna in biodiversity-rich and ecologically sensitive areas.

The study of the diversity of tick-borne agents in wild animals enables a better understanding of the distribution of pathogens in the country, the identification of potential reservoirs for these agents, the mapping of possible infection hotspots, the implementation of local fauna management, and the development of species conservation strategies, as well as the creation of disease control and prevention strategies. Piroplasmids are apicomplexan protozoa that primarily infect blood cells of vertebrates and can cause diseases in animals and humans. In Brazil, several studies have identified a wide diversity of piroplasmids in different species of wild animals. This review article aims to compile these studies, with an emphasis on the species detected according to host orders and families, the diagnostic methods used, the occurrence of clinical signs, and the distribution of these agents across the country. It also aims to review the phylogenetic topology of piroplasmids by including the new species and clades detected in the country.

Ticks, being ectothermic, are highly sensitive to climate variables, such as temperature, humidity, and precipitation. Over the past century, fossil fuel use has altered the climate and significantly affected the tick-host-pathogen system. These changes influence tick lifecycles, behavior, vector competency, host dynamics, and pathogen transmission. Consequently, tick-borne diseases (TBDs) have experienced shifts in their geographical range, incidence, and host preferences, particularly in the Northern Hemisphere. While climate change drives the emergence of vector-borne diseases, key aspects, such as tick infestations on alternative hosts, remain understudied. However, some studies have highlighted the establishment of ticks and tick-borne pathogens (TTBPs) in previously unaffected areas of Europe and North America, dispersed through hosts migration, including birds. Understanding these changes is crucial for mitigating the risks to public health, livestock, and wildlife. This review examined geographical spread of TTBPs, TBD incidence, and alternative host infestations to identify challenges and opportunities for disease control. Since TBD epidemiology is also shaped by other anthropogenic factors, isolating climatic impacts is difficult. Multidisciplinary approaches that combine ecological modeling, molecular research, and surveillance are essential for clarifying climate-driven trends and improving TBD management.

The red piranha (Pygocentrus nattereri) is a carnivorous fish of significant ecological and economic value, widely distributed across tropical and neotropical regions of South America, particularly within the Amazon basin. This study investigated the presence of Myxobolus sp. infection in the ovaries of red piranhas collected in the municipality of Pracuúba, in the state of Amapá, Brazil. During necropsy, whitish cysts suggestive of parasitic infection were observed. Microscopic examination revealed spores with morphological characteristics consistent with Myxobolus sp., predominantly located in the ovarian parenchyma. These infections caused tissue lesions and disrupted the normal ovarian architecture, although no inflammatory infiltrates were detected. While Myxobolus sp. infections in reproductive organs are rare, they can significantly impact fish health and reproduction. This study is the first to report of Myxobolus sp. infection in the ovaries of P. nattereri, underscoring the importance of monitoring parasitic infections in this species, which plays a vital role in the food security of riverside communities in the Amazon.

The aim of this study was to diagnose anthelmintic resistance (AR) of gastrointestinal nematodes to different anthelmintics in crossbred Dorper X Santa Inês sheep using the new research guidelines of the World Association for the Advancement of Veterinary Parasitology. After estimating and identifying an approximate number of 10,000 sheep in the study area, a total of 256 sheep at different reproductive stages, presenting faecal egg count per gram of faeces (FEC) ≥ 400 were used. The faecal egg count reduction test (FECRT) was carried out to evaluate the pre- and post-treatment of anthelmintics, including albendazole, closantel, disophenol, ivermectin, levamisole, monepantel, moxidectin and trichlorfon, using the new classification criteria to analyze the results of an FECRT, which defined three possible classifications: susceptible, resistant and inconclusive. The highest average FEC was observed when the ewes were lactating, while the lowest FEC was observed in ewe lambs. Resistance was observed for albendazole, closantel, disophenol, ivermectin, levamisole and moxidectin. Two drugs (trichlorfon and monepantel) proved to be highly effective in treating gastrointestinal nematodes, presenting CI varying from 98 to 100% and 97 to 100%, respectively. Gastrointestinal nematodes from sheep raised in the in the Rio Grande do Norte State, Brazil are susceptible to the active principles trichlorfon and monepantel.

Representatives of the families Didelphidae, Echimyidae, Cricetidae, and Muridae have been identified as significant reservoirs or amplifiers of zoonotic agents. This study aimed to investigate the molecular occurrence of Bartonella spp., Ehrlichia spp., Anaplasma spp., and hemotropic Mycoplasma spp. (hemoplasmas) in small synanthropic mammals in different urban complexes in Brazil's northern Amazon region. Between January and August 2022, blood samples were collected from 36 small mammal specimens, belonging to ten different species living in three vegetation fragments located in the metropolitan areas of Macapá, in the state of Amapá, and in Santarém and Marabá, state of Pará, Brazil. After DNA extraction, samples were subjected to real-time quantitative PCR (qPCR) for Bartonella spp. based on the nuoG gene, and to conventional PCR assays for Ehrlichia spp., Anaplasma spp., and hemoplasmas based on the dsb and 16S rRNA genes, respectively. This is the first record of Anaplasma spp. and hemotropic Mycoplasma sp. in marsupials in northern Brazil. Bartonella spp. was detected only in small mammals from Macapá, expanding the list of known hosts. This study describes findings on potentially zoonotic pathogens associated with small mammals living in green areas of large urban complexes in the Brazilian Amazon.

Stomoxys calcitrans is a hematophagous dipteran. The study aimed to evaluate the influence of spraying pressure on the efficacy of entomopathogenic nematodes (EPNs) on S. calcitrans larvae in sugarcane byproducts. Infectious juveniles (IJs) of Heterorhabditis bacteriophora, Heterorhabditis baujardi and Heterorhabditis indica were applied (200 IJs/larva) in water or 50% vinasse suspensions at pressures of 60, 70 and 80 psi to sugarcane straw, sugarcane bagasse and filter cake in plastic trays containing larvae. Control groups were not subjected to spraying. The efficacy of EPNs carried in water was not significantly reduced by spraying pressure when applied to bagasse and filter cake, but a lower larvae mortality was observed in straw for all EPNs applied at 80 psi and for H. baujardi and H. indica at 60 and 70 psi. Spraying of EPNs in vinasse did not significantly reduce the efficacy of all species in bagasse, but a reduction was observed in straw and filter cake depending on pressure. EPNs caused above 80% larvae mortality in most experiments. Spray-applied EPNs can infect and kill stable fly larvae in sugarcane substrates; however, their efficacy is influenced by spray pressure and carrier, as well as the treated substrate itself.