Search Results (47)

Small rodents are known hosts of various pathogens, including Hepatozoon, but until now, in Brazil, only Hepatozoon milleri has been described in these animals. In this study, liver samples and blood smears were obtained from 289 rodents belonging to 14 Cricetidae and two Muridae species that had been captured in municipalities of the states of Paraná and Rio de Janeiro. Smears were stained with Giemsa, and gametocytes were detected via microscopy in 10.72% (n = 31/289) of samples, with these individuals representing three rodent species. Significant morphometric differences were observed in gametocyte measurements in Akodon rodents. Using conventional PCR, Hepatozoon spp. 18S rDNA fragments were amplified in 24.91% (n = 72/289) of samples, with those individuals representing seven rodent species. Phylogenetic analyses clustered 41 sequences from this study into a subclade with other sequences from small mammals in Brazil, identifying four distinct haplotypes, and, for the first time, a relationship between Hepatozoon haplotype and gametocyte length was observed. Based on phylogenetic analysis, this study reinforces the trophic relationship between rodents and reptiles as a possible link in the Hepatozoon transmission cycle in South America. Furthermore, our findings expand knowledge on Hepatozoon spp. hosts, describing Oxymycterus nasutus and Oxymycterus quaestor as new host species and identifying two novel circulating haplotypes in rodents from Paraná State, southern Brazil. Full article

This study aimed to assess the emergence and/or re-emergence of Tick-borne Diseases (TBD) in Portugal by linking the hemoparasite burden in companion animals to vector-borne disease dynamics through a One Health approach. Between 2015 and 2024, 1169 clinically suspected animals with hemoparasite infections, treated at the Hospital Veterinário de Santarém (HVS), underwent serological confirmation for Rickettsia conorii, Babesia canis, Ehrlichia spp., and Haemobartonella spp. A total of 3791 serological tests (3.2 tests per animal) were performed and 437 animals tested positive for at least one of the four hemoparasites under investigation. From 2020 to 2024, tests nearly tripled from 894 to 2883, raising positive cases and prevalence from 29.5% to 39.9%, especially for rickettsiosis and hemobartonellosis, indicating an increased circulation of their vectors. A national vector surveillance initiative identified Hyalomma spp., Rhipicephalus sanguineus, Ixodes ricinus, and Dermacentor sp. as primary tick vectors in Portugal for the hemoparasites mentioned above and for other agents like arbovirus, such as Crimean-Congo Hemorrhagic Fever Virus (CCHFV) and tick-borne encephalitis virus (TBEV). This study found that the vectors responsible for transmitting hemoparasitosis, given the high number of serologically positive cases detected in the HVS, represent an increasing risk for TBD. These findings highlight the relevance of companion animal monitoring as an early-warning component within a One Health surveillance approach. Full article

The detection of food sources of blood-sucking vectors is essential for a better understanding of the hosts, reservoirs, and other fauna that participate in the transmission web of hemoparasites. The molecular identification of triatomine blood meal sources (BMSs) has been shown to be highly sensitive and taxonomically specific when compared to the immunological method. The application of molecular cloning makes it possible to identify multiple BMS species and/or different individuals/haplotypes of the same vertebrate species in a single triatomine specimen. In Brazil, the molecular detection of BMSs is incipient, with insufficient genetic information on the species of animals involved in the transmission of Trypanosoma cruzi. In this work, we evaluated the sensitivity and specificity of a molecular approach using molecular cloning for the detection of multiple Brazilian mammalian species. The DNA was extracted from blood clots of 13 species of canids, bats, xenarthral, marsupials, and rodents. Serial proportions were used to formulate mixtures combining taxonomically close (belonging to the same family or order) and taxonomically distant (different families) species. The results showed that GenBank lacks reference sequences for some native species tested, such as the sylvatic rodent, Necromys lasiurus, and the wild canid, Lycalopex gymnocercus, for cytb and 12S rDNA, and the rodent Oecomys cleberi for 12S rDNA. The study also demonstrated that it is possible to detect multiple different species, even for those that are taxonomically close. This approach was proven to be efficient for the detection of species in equal and even in disparate unequal proportions, which could represent complementary information about the diversity of potential hosts of T. cruzi. The detection of multiple BMS species in mixed samples provides a more comprehensive and accurate landscape of T. cruzi transmission in nature. Full article

Piroplasmids (Babesia spp., Rangelia spp., Theileria spp., Cytauxzoon spp.) are tick-borne apicomplexan protozoa that infect, depending on the species, erythrocytes and leucocytes in a wide variety of mammals and birds. The genera Bartonella and Borrelia include vector-borne bacteria that can infect and cause disease in both animals and humans. Detection of hemotropic bacteria and piroplasmids in wild animals is often challenging due to low bacteremia or parasitemia. Digital (d)PCR has proven to be an effective modality for the detection and quantification of DNA of hemotropic pathogens with low parasitemia. This study compared dPCR results from 366 biological samples from seven different Brazilian wild animal groups (5 Xenarthra species, 5 deer species, 3 felid species, 1 canid species, 3 rodent species, 1 bat species, 1 tapir species, and 12 bird species) to two other molecular diagnostic techniques: quantitative real-time (qPCR) and nested (nPCR). For this study, DNA extracted from wild animal blood and spleen samples were subjected to a multiplex dPCR assay for piroplasmids, Bartonella spp., and Borrelia spp. For comparison, the same primers and probes for each agent were used in qPCR assays. Additionally, an nPCR based on the 18S rRNA gene for piroplasmids was performed. The proportions of positive results obtained using dPCR were 85.5% for piroplasmids, 33.6% for Bartonella spp., and 16.7% for Borrelia spp. For all tested agents, dPCR proved to be the technique with the highest sensitivity, making it a useful tool for screening vector-borne agents in biological samples from wild animals with low parasitemia. Full article

Bovine trypanosomiasis, caused by Trypanosoma vivax, affects livestock productivity and is increasingly being reported in South America. This study aimed to detect and characterize Trypanosoma spp. infections, with a focus on T. vivax, in cattle from two distinct agroecological regions of central Argentina: a dairy-producing plain, located in the Espinal ecoregion, and a riparian zone, dedicated to beef production, located in the Delta and Islands of Paraná ecoregion. A total of 220 blood samples were collected from nine cattle farms and analyzed using real-time PCR, melting curve analysis, and the sequencing of 18S rRNA gene fragments. Trypanosoma vivax was detected at low prevalence (2.73%), exclusively in dairy cattle. In contrast, the prevalence of Trypanosoma theileri was much higher (10.91%), and it was found mainly in beef cattle from the riparian region. Phylogenetic analyses confirmed the species identity in all sequenced samples. No trypanosomes were observed by microscopy, and none of the animals showed clinical signs. The results indicate a differential distribution of T. vivax and T. theileri between regions and production systems. Although the study initially focused on T. vivax, the detection of T. theileri highlights the need to consider multiple Trypanosoma species in epidemiological surveys. This study contributes new data on the occurrence of bovine trypanosomes in central Argentina under extensive and semi-intensive management systems. Full article

This research introduces a novel method that integrates both unsupervised and supervised learning, leveraging SimCLR (Simple Framework for Contrastive Learning of Visual Representations) for self-supervised learning along with different pre-trained models to improve microscopic image classification of Babesia parasite in canines. We focused on three popular CNN architectures, namely ResNet, EfficientNet, and DenseNet, and evaluated the impact of SimCLR pre-training on their performance. A detailed comparison of the different variants of ResNet, EfficientNet, and Densenet in terms of classification accuracy and training efficiency is presented. Base models such as different variants of the ResNet, EfficientNet, and DenseNet models were utilized within the SimCLR framework. Firstly, the models were pre-trained on unlabeled images, followed by training classifiers on labeled datasets. This approach significantly improved the robustness and accuracy, demonstrating the potential benefits of combining contrastive learning with conventional supervised techniques. The highest accuracy of 97.07% was achieved by Efficientnet_b2. Thus, detection of Babesia or other hemoparasites in microscopic blood smear images could be automated with high accuracy without using a labelled dataset. Full article

Although quilombola individuals and their dogs may be exposed to hemoparasites such as A. phagocytophilum, B. microti, and E. chaffeensis, no study to date has been conducted in these populations. The aim of this study was to investigate the presence of antibodies against Anaplasma phagocytophilum, Babesia microti, and Ehrlichia chaffeensis in humans and dogs from quilombola communities in Brazil. Serum samples from humans and dogs were collected from four rural quilombola communities and analyzed using indirect immunofluorescence assays. The results revealed antibody levels of 8% for A. phagocytophilum, 3% for B. microti, and 1% for E. chaffeensis in humans and 60%, 50%, and 65%, respectively, in dogs. Notably, women were significantly more likely to be seropositive for A. phagocytophilum than men (p = 0.0289). Dogs from the Serra do Apon community more commonly had A. phagocytophilum (p = 0.0477) and B. microti (p = 0.0448) than those from the other areas. To the best of our knowledge, this is the first study to report human exposure to A. phagocytophilum and the ocurrence of B. microti in Brazil. The antibody level of vector-borne diseases in humans is a public health concern, particularly in vulnerable populations and rural areas. The dogs were universally hosted Rhipicephalus sanguineus ticks, suggesting their possible role in transmission. Thus, further epidemiological surveillance studies should be conducted in vulnerable populations to mitigate the impact of such zoonotic diseases. Full article

Bovine anaplasmosis is a tick-borne disease caused by Anaplasma marginale, although mechanical transmission by biting flies also occurs. Infection with A. marginale can reach 26% mortality and morbidity is associated with reduced beef and milk production, causing economic losses for livestock producers. Between March 2022 and July 2023, 1920 ticks were collected from 52 cattle production units in major cattle-producing states in Mexico, including Chiapas, Jalisco, Michoacán, Tabasco, and Veracruz. Of all the ticks collected, 35.57% were morphologically identified as Amblyomma mixtum. Samples of A. mixtum from each state, totaling 271, were tested for A. marginale via polymerase chain reaction (PCR). A. marginale was detected molecularly in 15.3% of A. mixtum samples. A. mixtum from Chiapas had the highest prevalence of A. marginale (24.0%), followed by Tabasco and Veracruz (20.0% each), Jalisco (15.2%), and Michoacán (6.6%). Phylogenetic analysis supported the morphological identification of A. mixtum and confirmed the genetic identity of A. marginale. This research is the first report on the molecular detection of A. marginale in A. mixtum ticks in Mexico. Results suggest that this 3-host tick species might be a potential vector. A. mixtum is Mexico’s second most economically significant tick feeding on cattle after Rhipicephalus microplus. This information about A. marginale prevalence in A. mixtum expands our understanding of bovine anaplasmosis epidemiology in Mexico. Further research is needed to assess the role of A. mixtum as a vector of A. marginale. Full article

Vector-borne parasitic diseases (VBPDs) are diseases that have a major impact on the health and productivity of livestock. VBPDs, including trypanosomosis, theileriosis, and anaplasmosis, are caused by blood parasites and Rickettsiales infections that can be transmitted by biting insects. The control and elimination of VBPDs is difficult and challenging. This study contributed to better understanding the impact of hematophagous insects on carrying pathogens to livestock by investigating the detection of Trypanosoma evansi, Theileria spp. and Anaplasma spp. in hematophagous insects collected from five livestock farms in Northeastern Thailand using polymerase chain reaction (PCR). The Stomoxys and Tabanus samples were collected using Nzi and Vavoua traps. Morphological and molecular identifications of hematophagous insects were performed. The Stomoxys samples were dissected into head and abdomen parts, while the Tabanus samples were dissected into head, salivary glands, and abdomen parts before DNA extraction individually. The host blood meal in the DNA of each part of the hematophagous insects was identified using PCR targeting the prepronociceptin (PNOC) gene. PCR detection of T. evansi, Theileria spp., and Anaplasma spp. were performed by targeting the ITS2, 18s rRNA, and msp4 genes, respectively. In total, 131 insect samples were collected, with Stomoxys calcitrans being the most common species at 40 (30.53%), followed by Tabanus spp. at 14 (10.69%) and the other Stomoxys spp. at 7 (5.34%), respectively. The hemoparasite detection results identified Theileria spp. in the abdomen (21.43%; 3/14) of three Tabanus samples. Neither Anaplasma spp. nor T. evansi were detected in this study. Additionally, host blood meal DNA was found in the abdomen of Stomoxys calcitrans (4.17%; 1/24) and Stomoxys spp. (20%; 1/5). For the Tabanus spp., host blood meal DNA was detected in the head (7.14%; 1/14), salivary glands (7.14%; 1/14), and abdomen (14.29%; 2/14). These results highlighted that Tabanus spp. might play an important role in Theileria transmission. Full article

Hemoparasitic diseases represent a significant problem with a considerable impact on tropical and subtropical areas of the world. These conditions cause economic losses associated with multi-organic failure and even the death of animals. In these areas, the hemoparasites are transmitted in an enzootic cycle when infectious cattle, such as persistently infected animals, including cows, contribute to the success of transmission. However, the factors associated with transmission have always been considered environmental issues, disregarding herd management and practices. In this sense, we conducted a cross-sectional study sampling 360 female cattle older than one year to identify infectious cattle using the PCR technique. We employed a dichotomic questionnaire for association analyses in 150 herds of the southern Andean region of Colombia. Overall prevalence with infectious cattle was 52.5% for Babesia spp., Anaplasma spp., and Trypanosoma spp., and the significant risk factors (p < 0.05) included geographic area, animal weight, purchase of cattle for fattening, disinfection of clothing after contact with neighboring animals, self-medication, separation of animals in pens, supply of mineralized salt, presence of livestock from other owners on the farm, prevention of joint trauma, documented milking routine, and sending blood samples for analysis. These practices permitted the maintenance of persistently infected animals and their movement to shed the agents to other animals in the presence of vectors. This suggests the importance of implementing comprehensive control and training measures to reduce the infectious cattle and, therefore, the profitability of dual-purpose livestock farms in the Andean region of southwestern Colombia. Full article

Babesia caballi is a tick-borne hemoparasite that causes equine piroplasmosis. It has a significant economic impact, decreasing performance and affecting animal welfare. This study aimed to identify B. caballi DNA in the blood of horses from households in the southwestern and western regions of Romania. We included 310 animals, from which blood was collected via EDTA. To test the samples for the B. caballi parasite genome, we used real-time PCR and conventional PCR. The prevalence of B. caballi was 5.81% (18/310) in apparently healthy horses, suggesting that this parasite is enzootic in the regions studied, although veterinarians did not indicate any symptoms resembling clinical babesiosis. In Romania, there are insufficient epidemiologic data on equine babesiosis, and the results of the present study suggest the need for further investigations into the dynamics of transmission and to identify potential prevention and control strategies. Full article

Background/Objectives: Trypanosomiasis and bovine babesiosis correspond to important diseases that cause great economic losses, but there are still no studies evaluating their occurrence in herds of dairy cattle in Ceará. The aim of this study was to perform molecular diagnosis of the main hemoparasites of dairy cows in the microregion of the central hinterland of Ceará. Methods: For the molecular diagnosis of parasites, genomic material was extracted and polymerase chain reaction directed to the cdCatL-like gene for Trypanossoma vivax and SS rRNA of Babesia bigemina and Babesia. bovis was performed. In addition, the mean corpuscular volume of the samples was evaluated. The data were statistically processed. Results: T. vivax was detected in 0.40% (1/246) of the samples, while B. bigemina and B. bovis were detected in 20.62% (33/160) and 11.87% (19/160) of the samples, respectively. It was found that there was a reduction in mean corpuscular volume in animals that presented with co-infection and those infected by B. bovis only, but not in those hosting B. bigemina alone. The variables “purchase of recent animals” and “tick control” had no association with or influence on B. bovis and/or B. bigemina infection. It was possible to identify epidemiologically important factors that may facilitate the transmission of trypanosoma to healthy animals, such as the recent purchase of animals and use of the same needle and syringe for oxytocin application. Conclusions: The pathogens studied were present in the evaluated population. Daily cow management practices can facilitate the transmission of the diseases they cause. Full article

We developed and evaluated a semi-nested PCR assay for the detection of Babesia aktasi infection in goats based on the sequence of the B. aktasi 18S ribosomal RNA gene. Following in silico screening, the specificity of the primers was assessed using reference DNA samples, including B. ovis, B. motasi, B. crassa, B. venatorum, B. divergens, B. capreoli, Theileria ovis, and T. annulata. To determine the sensitivity of the method, blood infected with 2% parasitemia of B. aktasi was diluted to 10-fold serial dilutions. The method specifically amplified a 438 bp fragment of B. aktasi DNA, but did not demonstrate cross-amplification with the other hemoparasites tested. The sensitivity assay indicated that this PCR method was able to detect infection at a dilution of 10⁻⁸ of 2% parasitemia (0.074 parasites/200 µL). Ninety-seven blood samples collected from goats were used to analyze for B. aktasi, and the infection was detected in 18.5% of the goats. Additionally, the method was also applied to 44 field DNA samples that were detected to be positive for B. aktasi by reverse line blotting (RLB), and showed 84.1% agreement. The findings revealed that newly developed semi-nested PCR can detect B. aktasi infections in goats with high sensitivity and specificity. Full article

Bovine babesiosis, caused by the protozoan Babesia bigemina, is one of the most important hemoparasite diseases of cattle in Mexico and the world. An attenuated B. bigemina strain maintained under in vitro culture conditions has been used as a live attenuated vaccine; however, the biological mechanisms involved in attenuation are unknown. The objective of this study was to identify, through a comparative transcriptomics approach, the components of the B. bigemina virulent parasites that are differentially expressed in vivo, as opposed to those expressed by B. bigemina attenuated vaccine parasites when inoculated into naïve cattle. The biological material under study was obtained by inoculating spleen-intact cattle with infected erythrocytes containing either the attenuated strain or a virulent field strain. After RNA extraction, transcriptomic analysis (RNA-seq) was performed, followed by bioinformatic Differential Expression (DE) analysis and Gene Ontology (GO) term enrichment. The high-throughput sequencing results obtained by analyzing three biological replicates for each parasite strain ranged from 9,504,000 to 9,656,000, and 13,400,000 to 15,750,000 reads for the B. bigemina attenuated and virulent strains, respectively. At least 519 differentially expressed genes were identified in the analyzed strains. In addition, GO analysis revealed both similarities and differences across the three categories: cellular components, biological processes, and molecular functions. The attenuated strain of B. bigemina derived from in vitro culture presents global transcriptomic changes when compared to the virulent strain. Moreover, the obtained data provide insights into the potential molecular mechanisms associated with the attenuation or pathogenicity of each analyzed strain, offering molecular markers that might be associated with virulence or potential vaccine candidates. Full article

Amphibians and reptiles represent a considerable proportion of the vertebrate fauna in Brazil. Different blood parasitic infections have been reported in these groups, such as Haemogregarina, Hepatozoon, Trypanosoma and microfilariae. However, insufficient research on interactions between these parasites and their hosts has been carried out in some regions of the country. Samples were collected from populations of wild herpetofauna in different microhabitats throughout Brazil, totaling 111 samples of reptiles from the states of Mato Grosso and Pernambuco. We used an integrative approach, with classical microscopy, morphometry and molecular analysis, in order to identify hemoparasites present in the analyzed fauna. Genomic DNA was extracted for the PCR protocol based on the 18S ribosomal RNA gene for Hepatozoon spp. A total of 53 positives were obtained with molecular screening (47.7%), all confirmed as Hepatozoon spp. using DNA sequencing. Among positive samples, 23 slides were examined, confirming the presence of Hepatozoon spp. in 91.3% of the smears. The phylogenetic analysis performed with sequences from 43 samples resulted in a tree containing several distinct clades. Sequences were generally grouped according to the taxonomic order of the host. Co-infections with microfilariae and Trypanosoma spp. were also found in microscopy analyses. This study describes the presence of Hepatozoon caimani in a new host species (Paleosuchus palpebrosus) that can be a paratenic host in the natural environment. The existence of parasitic co-infections in alligator species underscores the significance of recognizing the impact of infections by various parasitic taxa on the host populations. Full article