The family Anisakidae includes parasite genera that are important for public health due to their zoonotic potential. Among these, the genus Anisakis contains some of the most prevalent parasites found in fish that are consumed and commercially exploited in Brazil. Thus, this study aimed to investigate records of the presence of third-stage larvae of Anisakis spp. fish parasites found in Brazilian territory, focusing on their morphological, morphometric, biogeographic, and prevalence aspects over a period of 40 years. This analysis identified the presence of Anisakis larvae in 18 orders, 2 groups, 40 families, 60 genera and 69 species of infected marine, brackish and freshwater fish, demonstrating the lack of specificity to a particular group, which was also evident in the different morphometric data, as well as in the site of infection and habitat of the hosts, with predominantly marine fish being the most infected.. The presence of different Anisakis morphotypes highlights parasitic biodiversity and reinforces the need for taxonomic studies of these zoonotic agents found in fish consumed as food. Special attention should be given to the Amazonian ichthyofauna, located in one of the aquatic ecoregions considered a research priority in Brazil, with the identification of these zoonotic parasites being a matter of food security and public health.

The diagnosis of canine visceral leishmaniasis (CVL) relies on parasitological, molecular methods and serological. However, there are difficulties in using these methods to monitor the disease, and there is a need for more efficient diagnostic alternatives for dogs with suspected visceral leishmaniasis, also using clinical aspects of the animals, which that can be useful for surveillance and control. This study aimed to evaluate the serological diagnostic potential of recombinant antigens in order to improve CVL diagnosis. Disease diagnosis, clinical evaluation, and collection of biological samples for laboratory analysis were performed on dogs from the Tirirical District in São Luís, Maranhão, Brazil. The animals were divided into four groups: clinically suspected dogs for visceral leishmaniasis (VL), subclinical dogs for VL, animals with infections, and healthy animals from an endemic area. Subsequently, the animals were tested for the soluble liver antigen (SLA) antigen and recombinant Leishmania infantum chagasi antigens rP2a, rP2b, rP0, rHSP70, rHSP83, rH2A, and rKMP-11 using ELISA. The results demonstrate that the recombinant antigens that presented the best sensitivity, specificity, and high or moderate accuracy according to the Receiver Operating Characteristic (ROC) curves were rP2a, rP2b, and rH2A. These results indicate that rP2a, rP2b, and rH2A proteins are candidates for improving the diagnosis of CVL.

This study aimed to identify larval forms of trematodes in Pseudosuccinea columella from rural properties with a history of bovine fasciolosis in the southern region of Espírito Santo, Brazil. A malacological survey was carried out on waterbodies from ten properties between June 2022 and March 2023. Aquatic snails were collected, identified, and evaluated for infection with trematode larvae by artificial photostimulation. The larvae found were morphologically characterized under a light microscope, and samples of the snails were subjected to histological analysis to observe larval trematodes in development in snails' tissues. A total of 678 specimens of P. columella were collected in nine properties, and larval trematodes were identified in 24 (4.08%) specimens from seven properties. A xiphidiocercaria morphotype, compatible with Haematoloechidae, was found in six properties. A morphotype of echinostome cercaria, compatible with the Echinostoma genus, was found in one property (2.17%). Larval Fasciola hepatica was not observed. Ecological studies are needed to investigate the environmental factors that may be related to the absence of natural infection of snails by F. hepatica, especially considering the presence of positive cattle in the evaluated properties. The data presented here reveal that P. columella a potencial vector role in the studied area.

Equine Piroplasmosis (EP) is a tick-borne disease caused by the protozoan parasites Babesia caballi, Theileria equi, and Theileria haneyi, characterized by intravascular hemolysis and associated systemic illness. Although T. equi and B. caballi have been widely reported in some regions of Brazil, data from other states are limited. Additionally, despite reports of T. equi genotype C, currently recognized as T. haneyi, has been identified in Brazil, there are no investigations using T. haneyi-specific molecular tools. This study assessed the presence of these three agents in horses from Baixada Maranhense microregion (n = 34), northeastern Brazil, and in horses from an equestrian center (n = 12) in Guará, southeastern Brazil. Of 46 horse DNA samples, one (2.1%) from an imported animal in the equestrian center tested positive for T. haneyi in ema-10 and ema-11-based PCR assays. Two animals tested positive for T. equi in a species-specific PCR (ema-1), and all samples were negative for B. caballi. BLASTn analysis showed ema-10 and ema-11 sequences shared 98.9% to 99.3% identity with T. haneyi detected in a horse at the U.S.-Mexico border. Despite the small sample size, this study confirms the presence of T. haneyi in Brazil and the need for monitoring imported animals.

The objective of this study was to evaluate the hatching percentage of tick larvae of Amblyomma sculptum, Dermacentor nitens, Rhipicephalus linnaei, and three strains of Rhipicephalus microplus. The egg masses laid by females of each tick species were weighed in different amounts (125, 250 and 500mg), placed in adapted 3 and 5 mL syringes, and incubated at 27°C and 80% relative humidity for 25 days for A. sculptum and 21 days for the remaining species. After this period, larval hatching rate was evaluated and data were analyzed through correlation and comparison between groups. The results showed that the average hatching rates varied from 27.9% to 42.2% for A. sculptum, 86.6% to 87.7% for D. nitens, 74.4% to 80.0% for R. linnaei, and R. microplus: 75.3% to 82.6% (UFRRJ strain), 64.6% to 72.2% (Mozo strain), and 71.8% to 75.2% (Porto Alegre strain). Although statistically significant differences were observed in the mean percentages between groups, the correlation was weak. We concluded that the weight of the egg masses and the volume of the containers did not significantly affect larval hatching.

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 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 objective of this study was to synthesize and evaluate the in vitro activity of aminochalcones against Haemonchus contortus eggs and adults. Aminochalcones 1 and 2 were synthesized using Claisen-Schmidt condensation and characterized using Fourier-transform infrared spectroscopy, nuclear magnetic resonance, and mass spectrometry. The activity of both aminochalcones was assessed in the egg hatch test and that of aminochalcone 1 was further evaluated in the adult worm motility test using multiresistant H. contortus. The chemical structures of the synthesized compounds were confirmed, and changes induced in eggs and adults were assessed using scanning electron microscopy (SEM). Aminochalcones 1 and 2 inhibited larvae hatching by 98.70 and 99.89%, respectively, at concentrations of 0.25 and 1 mg/mL. SEM images revealed structural and morphological changes in eggs treated with both compounds. After 12 h of exposure to aminochalcone 1 (1.25 mg/mL), all adult nematodes were immobile, and wrinkling of the cuticle was observed. These findings indicate the ovicidal effect of aminochalcones and the inhibition of worm motility by aminochalcone 1. Our preliminary study demonstrated, for the first time, the anthelmintic activity of this class of compounds against gastrointestinal nematodes of small ruminants and suggest further anthelmintic evaluation.

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.

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.

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.

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.

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.

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.

The genus Ceratomyxa is composed of approximately 300 described species, most of which are found parasitizing hosts in marine aquatic environments. The present study, through phylogenetic, molecular and morphological analyses, described a new species of Ceratomyxa found parasitizing Leporinus affinis specimens from the Tartarugalzinho River, in municipality of Tartarugalzinho, state of Amapá, Brazil. The new species was found parasitizing the urinary bladder of L. affinis. The myxospores of Ceratomyxa affinis n. sp. are 7.2 µm long and 43.2 µm thick with a posterior angle of 170º. The polar capsules measure 3.9 µm long and 4.05 µm wide. Based on morpho-molecular analyses, it was possible to prove that Ceratomyxa affinis n. sp. is a new species, contributing to the knowledge of the parasitic fauna of fish in the Amazon region.

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.

The aim of this study was to verify the prevalence of Trypanosoma vivax using hematological and molecular techniques and to evaluate possible associated risk factors in goats and sheep. A total of 192 animals from 14 farms in the municipalities of São Domingos and Valente da Bahia were used. Blood was collected from each animal to prepare stained blood smears and verify the presence of Trypanosoma spp. trypomastigotes testing and molecular (polymerase chain reaction [PCR], and sequencing). All blood smears were negative for trypomastigote forms of Trypanosoma sp. In the molecular analysis, nested-PCR detected 57.8% (111/192) of the samples as positive for Trypanosoma spp. and 10.9% (21/192) as positive for T. vivax using a specific primer. Sequencing indicated 97% - 99% similarity with catL of T. vivax. The use of shared needles was significant in the analysis of risk factors (p=0.049). Thus, T. vivax is present in small ruminants in Bahia, making it necessary for producers to be careful, especially when sharing needles, to avoid transmission between animals.

The aim of this study was to report infection by Toxoplasma gondii in free-ranging mammals from Pantanal, as well as to compare the laboratory methods used to detect this parasite among native wildlife species. Blood samples from ocelots, crab-eating foxes, and coatis were included for serological analysis and molecular testing. In addition, tissue samples from wild rodents and jaguarundi were collected for molecular analysis. Seropositivity for T. gondii was 100% (2/2) in ocelots across all tests; ranged from 39.1% (9/23) by indirect hemagglutination assay (IHA) to 47.8% (11/23) by modified agglutination test (MAT) and indirect fluorescent antibody test (IFAT) in crab-eating foxes; and from 12.5% (3/24) by IHA to 20.8% (5/24) by MAT in coatis. The level of agreement between the serological techniques ranged from fair to moderate (Kappa=0.353-0.516). Furthermore, PCR analysis revealed the presence of T. gondii DNA in 100% (2/2 and 1/1) of the ocelots' blood and jaguarundi's brain, 30.4% (7/23) of the crab-eating foxes' blood, 45.8% (11/24) of the coatis' blood, and 23.8% (10/42) of the Thrichomys spp.'s tissues. Potentially atypical strains (incomplete genotyping) of T. gondii were identified by Restriction Fragment Length Polymorphism (PCR-RFLP) from ocelot, jaguarundi, and coati. These findings indicate the circulation of T. gondii among wild mammals at the Nhumirim Farm.

Although toxoplasmosis is well documented in New World non-human primates, data on its clinical impact and genotypic diversity in neotropical rodents remain limited. This study investigated fatal toxoplasmosis in Coendou spinosus through histopathological, immunohistochemical, and molecular analyses, with genotypic characterization of the infecting strain. Between September 2016 and October 2019, eight individuals were analyzed, including rescued animals and post-mortem cases from a local zoo in Southern Brazil. Tissue samples underwent histopathology and immunohistochemistry using anti-T. gondii antibodies, and molecular assays were conducted by nested PCR and PCR-Restriction Fragment Length Polymorphism (PCR-RFLP). Severe necrotizing lesions, especially in the central nervous system, were observed in five animals, associated with abundant bradyzoites and tachyzoites. Molecular detection confirmed T. gondii DNA in all animals, and subsequent genotyping revealed a previously undescribed atypical strain in the animal CS8. These findings demonstrate the high mortality associated with T. gondii infections, presenting documented clinical signs of toxoplasmosis in C. spinosus and highlighting its vulnerability to zoonotic pathogens, particularly due to habitat encroachment and increased interactions with humans and other wildlife.

This study examines the presence of gastrointestinal parasites in fecal samples from free-ranging jaguars (Panthera onca) in the Pantanal biome and assesses their potential as bioindicators of environmental health at the human-animal interface using a noninvasive approach. In 2024, ten fresh fecal samples were collected from the ground at Piuval Lodge in the northern Pantanal, state of Mato Grosso, Brazil. All samples were morphologically consistent with large felids, suggesting a high likelihood of originating from jaguars, based on field evidence. Coproparasitological analysis using sedimentation and flotation techniques identified Spirometra spp. eggs, with a positivity rate of 100%. Additionally, 20% of the samples tested positive for Toxocara spp. and one sample was positive for the genus Ancylostoma. This study highlights that jaguars (Panthera onca) are a potential bioindicator of environmental health and a sentinel species in the Pantanal, thus emphasizing the interaction between wildlife, domestic animals and human activities.