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Leptospirosis is an infectious disease that affects domestic animals, wild animals, and humans. It represents a public health problem and has an important economic impact on livestock. This study aims to investigate the importance of genital and transplacental infection in the epidemiology of leptospirosis in cows maintained in Caatinga biome conditions, Northeastern Brazil, as well as reporting organs colonized by Leptospira spp. in embryos and fetuses. Blood, urinary tract (urine, bladder, and kidney), and reproductive tract (vaginal fluid, uterus, uterine tube, ovary, and placenta) samples were collected from 15 slaughtered pregnant cows. Two embryos and 13 fetuses were sampled. Central nervous system and choroid ovoid samples were collected from embryos. Blood, central nervous system, lung, peritoneal liquid, abomasal content, liver, spleen, urine, bladder, kidney, and reproductive system samples were collected from fetuses. Diagnostic methods included the microscopic agglutination test (MAT) using a collection of 24 serovars belonging to 17 different pathogenic serogroups of five species as antigens, as well as polymerase chain reaction (PCR). Anti-Leptospira spp. antibodies were found in 9 cows (60%), while 13 cows (86.67%) had at least one organ or urine with leptospiral DNA. No fetus was seroreactive. Among the embryos and fetuses, 13 (86.67%) presented leptospiral DNA, proving a high frequency of transplacental infection (100%). For cows, the most frequent biological materials regarding Leptospira spp. DNA detection were placenta (13 out of 15 samples; 86.7%), uterus (10 out of 15 samples; 66.7%), and vaginal fluid (5 out of 15 samples; 33.3%), while, for fetuses/embryos, the most frequent PCR-positive samples were choroid ovoid (1/2; 50%), spleen (6/13; 46.2%), kidney (5/13; 38.5%), and central nervous system (5/15; 33.3%). Sequenced samples based on the LipL32 gene presented 99% similarity with L. borgpetersenii. The results indicate that transplacental infection is an efficient way of spreading Leptospira spp. in cows maintained in Caatinga biome conditions. Therefore, prevention and control strategies must include actions that interrupt transmission through this alternative route.
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Marseilleviruses (MsV) are a group of viruses that compose the Marseilleviridae family within the Nucleocytoviricota phylum. They have been found in different samples, mainly in freshwater. MsV are classically organized into five phylogenetic lineages (A/B/C/D/E), but the current taxonomy does not fully represent all the diversity of the MsV lineages. Here, we describe a novel strain isolated from a Brazilian saltwater sample named Marseillevirus cajuinensis. Based on genomics and phylogenetic analyses, M. cajuinensis exhibits a 380,653-bp genome that encodes 515 open reading frames. Additionally, M. cajuinensis encodes a transfer RNA, a feature that is rarely described for Marseilleviridae. Phylogeny suggests that M. cajuinensis forms a divergent branch within the MsV lineage A. Furthermore, our analysis suggests that the common ancestor for the five classical lineages of MsV diversified into three major groups. The organization of MsV into three main groups is reinforced by a comprehensive analysis of clusters of orthologous groups, sequence identities, and evolutionary distances considering several MsV isolates. Taken together, our results highlight the importance of discovering new viruses to expand the knowledge about known viruses that belong to the same lineages or families. This work proposes a new perspective on the Marseilleviridae lineages organization that could be helpful to a future update in the taxonomy of the Marseilleviridae family. IMPORTANCE: Marseilleviridae is a family of viruses whose members were mostly isolated from freshwater samples. In this work, we describe the first Marseillevirus isolated from saltwater samples, which we called Marseillevirus cajuinensis. Most of M. cajuinensis genomic features are comparable to other Marseilleviridae members, such as its high number of unknown proteins. On the other hand, M. cajuinensis encodes a transfer RNA, which is a gene category involved in protein translation that is rarely described in this viral family. Additionally, our phylogenetic analyses suggested the existence of, at least, three major Marseilleviridae groups. These observations provide a new perspective on Marseilleviridae lineages organization, which will be valuable in future updates to the taxonomy of the family since the current official classification does not capture all the Marseilleviridae known diversity.
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Genoma Viral , Vírus , Brasil , Evolução Molecular , Genômica/métodos , Fases de Leitura Aberta , Filogenia , RNA Viral/genética , Vírus/classificação , Vírus/genéticaRESUMO
OBJECTIVE: This study aimed to evaluate the fecal shedding of C. difficile in calves on farms in Sao Paulo State, Brazil. MATERIALS AND METHODS: Fecal samples (n = 300) were collected from diarrheic (n = 78) and nondiarrheic (n = 222) calves less than 60 days of age from 20 farms. Fecal samples were inoculated into enrichment broth supplemented with taurocholate and cultured under anaerobic conditions. Colonies suspected to be C. difficile were harvested for DNA extraction and then multiplex PCR for the detection of genes encoding toxins A and B and binary toxins. All toxigenic isolates were ribotyped and tested for antimicrobial susceptibility, and five selected strains were subjected to whole-genome sequencing to determine their sequence type. RESULTS AND DISCUSSION: C. difficile was isolated from 29.3 % (88/300) of the samples. All toxigenic isolates (17/88, 19.3 %) were classified as ribotypes RT046 (13/17-79.47 %, A+B+ CDT-) and RT126 (4/17 = 20.53 %, A+B+ CDT+). The sequenced strains from RT046 were classified as ST35 (Clade 1), while those from RT126 were classified as ST11 (Clade 5). No associations between the epidemiological factors in any of the groups and C. difficile isolation were observed. Most of the toxigenic isolates (16/17 = 94.41 %) were classified as multidrug-resistant. Calves can be an important source of toxigenic C. difficile strains, including multidrug-resistant isolates from ribotypes commonly observed in humans.
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In this new methodology, plasmonic ELISA (pELISA) was used to detect Circovirus porcine2 (PCV2) in serum samples without the need for plate reading equipment. This process occurs by adapting the conventional ELISA test with gold nanoparticles (AuNPs) to promote a color change on the plate and quickly identify this difference with the naked eye, generating a dark purple-gray hue when the samples are positive and red when the samples are negative. The technique demonstrated high efficiency in detecting samples with a viral load ≥ 5 log10 copies/mL. Plasmonic ELISA offers user-friendly, cost-effective, and reliable characteristics, making it a valuable tool for PCV2 diagnosis and potentially adaptable for other pathogen detection applications.
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Santa Ines (SI) and Ile de France (IF) sheep are known to be resistant and susceptible to Haemonchus contortus infection, respectively. Several studies have shown some genes as potential biological markers for sheep resistance against gastrointestinal nematodes using molecular tools, including transcriptomic analysis. In this study, we sequenced the polyadenylated RNA of the abomasal tissue of SI and IF suckling lambs to identify mucosa-specific transcript alterations between breeds artificially infected with H. contortus. Naïve SI (n = 4) and IF (n = 4) lambs were artificially infected every other day, over a period of 52 days, from 14 to 66 days old, with a total of 5,400 H. contortus infective larvae. Fundic abomasal tissue samples were collected at 68 days old, and submitted to high-throughput RNA sequencing (RNA-seq). Differential expression analysis (P value < 0.001 and False Discovery Rate (FDR) < 0.05) between SI and IF samples identified 292 genes, most of which showed greater expression in SI lambs. To help annotate and assign possible function to differentially expressed genes (DEGs), we used previously available single-cell RNA-seq (scRNA-seq) data from ovine abomasal mucosa to putatively identify cell types and possible mechanisms involved in resistance to H. contortus. In particular, genes associated with endothelial and tuft cells showed the greatest increases in expression in SI relative to IF lambs. SI lambs had higher percentages of tuft cells than IF lambs in the fundic abomasal mucosa. Although we found innate immunity (cell-mediated in mucosa) acting as a protagonist in impairing H. contortus infection, a stronger acquired immune response was being modulated at an earlier stage by SI lambs. We suggest that the complex connection between innate and adaptive immunity is via cellular antigen processing and presentation (APP). Based on comparison with scRNA-seq data, SI lambs showed a robust APP mechanism characterized mainly by greater T cell APP, macrophage differentiation, and cytokine signalling. We identified potential mechanisms and markers to advance knowledge for selection of H. contortus resistance at a very early age, in SI as well as in other commercial sheep breeds.
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Hemoncose , Haemonchus , Doenças dos Ovinos , Ovinos , Animais , Haemonchus/genética , RNA-Seq , Imunidade Inata , Imunidade Adaptativa , Suscetibilidade a Doenças , Doenças dos Ovinos/genética , Hemoncose/genética , Hemoncose/veterinária , Fezes , Contagem de Ovos de Parasitas/veterináriaRESUMO
Obesity in adolescents has reached epidemic proportions and is associated with the inflammatory response and viral infections. The aim of this study was to understand the profile of inflammatory cytokines and chemokines associated with the inflammatory response and metabolic syndrome (MetS) in obese adolescents with positive serology for adenovirus 36 (ADV36). Thirty-six overweight, 36 obese, and 25 severe obesity adolescents aged 10 to 16 years were included in the study. The following variables were analyzed: sex, age, body mass index (BMI), blood pressure, total cholesterol and fractions, triglycerides, glucose, serum cytokine concentrations, and ADV36 antibodies. Cytokines and chemokines were quantified by cytometry and ADV36 serology was determined by enzyme-linked immunosorbent assay (ELISA). The results showed higher levels of the cytokines interleukin-1beta (IL-1ß), IL-6, IL-10 and of the chemokine interferon-gamma-inducible protein 10 (IP-10) in severe obesity adolescents compared to the obese and overweight groups, as well as in the group with MetS compared to the group without this syndrome. The frequency of ADV36-positive individuals did not differ between groups. The findings revealed differences in BMI between the obese and severe obesity groups versus the overweight group in the presence of positivity for ADV36, suggesting an association with weight gain and possibly MetS installation.
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Infecções por Adenoviridae , Síndrome Metabólica , Obesidade Mórbida , Obesidade Infantil , Adolescente , Humanos , Adenoviridae , Sobrepeso , Citocinas , Infecções por Adenoviridae/epidemiologia , Índice de Massa CorporalRESUMO
The COVID-19 pandemic was triggered by the coronavirus SARS-CoV-2, whose peak occurred in the years 2020 and 2021. The main target of this virus is the lung, and the infection is associated with an accentuated inflammatory process involving mainly the innate arm of the immune system. Here, we described the induction of a pulmonary inflammatory process triggered by the intranasal (IN) instillation of UV-inactivated SARS-CoV-2 in C57BL/6 female mice, and then the evaluation of the ability of vitamin D (VitD) to control this process. The assays used to estimate the severity of lung involvement included the total and differential number of cells in the bronchoalveolar lavage fluid (BALF), histopathological analysis, quantification of T cell subsets, and inflammatory mediators by RT-PCR, cytokine quantification in lung homogenates, and flow cytometric analysis of cells recovered from lung parenchyma. The IN instillation of inactivated SARS-CoV-2 triggered a pulmonary inflammatory process, consisting of various cell types and mediators, resembling the typical inflammation found in transgenic mice infected with SARS-CoV-2. This inflammatory process was significantly decreased by the IN delivery of VitD, but not by its IP administration, suggesting that this hormone could have a therapeutic potential in COVID-19 if locally applied. To our knowledge, the local delivery of VitD to downmodulate lung inflammation in COVID-19 is an original proposition.
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COVID-19 , Pneumonia , Camundongos , Animais , Feminino , Humanos , SARS-CoV-2 , Vitamina D/farmacologia , Pandemias , Camundongos Endogâmicos C57BL , Vitaminas , Camundongos TransgênicosRESUMO
Each year, the Brazilian Society for Virology promotes a national meeting during the second semester of the year. In October 2022, the 33rd meeting took place at Arraial da Ajuda, Porto Seguro, Bahia, in-person:.this was the first in-person meeting since 2019, as the 2020 and 2021 events occurred online due to the issues imposed by COVID-19. It was a great pleasure for the whole audience to return to an in-person event, which certainly improved the interactions between the attendees in all ways. As usual, the meeting involved massive participation of undergraduate, graduate, and postdoc students, and several noteworthy international researchers were present. During five afternoons and evenings, attendees could discuss and learn about the most recent data presented by distinguished scientists from Brazil and other countries. In addition, young virology researchers from all levels could present their latest results as oral presentations and posters. The meeting covered all virology areas, with conferences and roundtables about human, veterinary, fundamental, environmental, invertebrate, and plant virology. The costs associated with attending the in-person event caused a slight reduction in the number of attendees compared to the two online events. However, even with this issue, the attendance was impressive. The meeting successfully achieved its most important goals: inspiring young and senior scientists and discussing high-quality, up-to-date virology research.
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COVID-19 , Humanos , Brasil , Sociedades Científicas , VirologiaRESUMO
Bovine leptospirosis causes economic losses and raises public health concerns. It is possible that there are peculiarities in the epidemiology of leptospirosis in regions with a semiarid climate, such as the Caatinga biome in Brazil, where the climate is hot and dry, and the etiological agent require alternative routes of transmission. This study aimed to close knowledge gaps to the diagnosis and epidemiology of Leptospira spp. infection in cows from the Caatinga biome, Brazil. Samples of the blood, urinary tract (urine, bladder and kidney) and reproductive tract (vaginal fluid, uterus, uterine tube, ovary and placenta) were collected from 42 slaughtered cows. Diagnostic tests included were the microscopic agglutination test (MAT), polymerase chain reaction (PCR) and bacterial isolation. Anti-Leptospira spp. antibodies were found in 27 (64.3%) of the animals analyzed using MAT at a 1:50 dilution (cut-off 50), while 31 (73.8%) animals had at least one organ/fluid where the presence of Leptospira spp. DNA was identified, and 29 animals (69%) were positive at bacteriological culture. The highest sensitivity values for MAT were obtained at the cut-off point of 50. In conclusion, even under hot and dry climate conditions, it is possible that Leptospira spp. can spread through alternative routes such as venereal transmission; moreover, a cut-off of 50 is recommended for the serological diagnosis of cattle from the Caatinga biome.
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The objective of this study was to report the occurrence of Mycobacterium avium subspecies paratuberculosis (MAP) in dairy goats, via description of their clinical presentation, histopathological findings, and molecular identification of the infectious agent. Screening was performed using IS900 real-time PCR (qPCR) in milk samples from 179 properties in the semiarid of Northeast region of Brazil. Pooled milk samples from all lactating goats from processing plants were submitted to molecular diagnosis. One property had a positive result at qPCR. The production unit which had the positive sample for MAP was located, and an on-site visit to this property was performed to collect individual milk samples, seven of which tested MAP positive by IS900 qPCR. With permission from the owner, two goats (Animal 1 was positive and Animal 2 was negative on first qPCR for MAP) were acquired and euthanized. Animals 1 and 2 had milk and portions of the duodenum, ileum, colon, and mesenteric lymph nodes positive at qPCR for MAP. Animal 1 also had MAP DNA detected in part of the jejunum and cecum. In animal 2, the ileocecal valve tested positive. MAP was not detected in the blood or feces of either animal; however; it was confirmed for the association of clinical findings, histopathology, and qPCR. The gene IS900 from the positive samples were sequenced and showed a 99% similarity with MAP. The MAP was identified for the first time in the goat milk and tissues in the semiarid region of Northeast Brazil.
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Mycobacterium avium subsp. paratuberculosis , Mycobacterium tuberculosis , Paratuberculose , Animais , Feminino , Mycobacterium avium subsp. paratuberculosis/genética , Paratuberculose/diagnóstico , Paratuberculose/epidemiologia , Paratuberculose/microbiologia , Lactação , CabrasRESUMO
The aim of this study was to investigate the coinfection of feline retroviruses (feline immunodeficiency virus-FIV, and the feline leukemia virus-FeLV) with Leishmania infantum and Toxoplasma gondii and the factors associated with these pathogens in domestic cats from Mossoró, a city endemic for canine and human leishmaniasis situated in the semiarid region of Northeast Brazil. Blood samples from 120 cats were collected, and an epidemiological questionnaire was applied to investigate the risk factors associated with the infections. Retroviruses, L. infantum, and T. gondii infections were assessed using a point-of-care ELISA and quantitative PCR (qPCR), indirect fluorescent antibody test (IFAT) and qPCR, and IFAT, respectively. The overall seroprevalences observed were 35% (95% CI = 27.0-43.8%) for FIV, 0.8% (95% CI = 0.1-4.5%) for FeLV, 25.8% (95% CI = 18.8-34.3%) for T. gondii, and 4.2% (95% CI = 1.7-9.3%) for L. infantum. Coinfection with FIV and L. infantum was observed in 2.5% (3/120) of the assessed cats, while 12.5% (15/120) were coinfected with FIV and T. gondii. No significant association was found among the investigated agents (p > 0.05). The factors associated with FIV infection in the multivariable analysis were male sex and age above 78 months. The findings of this study demonstrated a high rate of FIV infection in cats from the Brazilian semiarid region and the exposure of these animals to zoonotic and opportunistic agents. Due to the immunosuppressive potential of FIV, cats infected with this retrovirus should be screened for coinfections with L. infantum and T. gondii, and preventative measures should be adopted.
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Studies related to the prevalence of leptospirosis in the semiarid region showed that even during long periods of drought, the disease has a remarkable frequency in herds in the region. It is a neglected disease and the extent of its effects in the Brazilian semiarid region is not known. The dynamics of this agent is well studied in the urinary tract, however, there are not many studies regarding the genital tract in female goats. Observing this scenario, the present work aimed to diagnose Leptospira spp. in female goats kept in the Brazilian semiarid region by means of serological, molecular and isolation techniques. Blood samples, vaginal fluid, urine and fragments of organs from the genitourinary tract were collected from 40 goats destined for slaughter. Microscopic agglutination test (MAT) was used as a serological technique, with a battery of 24 serovars. The Polymerase Chain Reaction (PCR) of the vaginal fluid, urine and organ fragments was performed, as well as the bacterial growth of these same products in a selective medium. Isolation positive samples were subjected to PCR. It was observed that two (5%) animals were serologically positive for the Pyrogenes serogroup. A total of 29 (72.5%) animals were PCR positive, with DNA present in 51/160 (31.8%) samples from the genital tract and 34/120 (28.3%) from the urinary tract, with no statistical difference. For bacterial growth, 22/40 (55%) animals were positive for growth, with morphology being observed in 19/160 (11.8%) for the genital tract and 16/120 (13.3%) for the urinary tract, with no statistical difference. Two uterus samples showed 99% similarity with L. interrogans after sequencing. Thus, female goats kept under semiarid conditions were positive for Leptospira spp, with positive samples from both the urinary and genital tracts, which possible is an alternative way of adapting and maintaining the agent for severe and adverse conditions.
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Leptospira , Leptospirose , Sistema Urinário , Animais , Feminino , Brasil/epidemiologia , Cabras , Leptospirose/diagnóstico , Leptospirose/epidemiologia , Leptospirose/veterinária , SorogrupoRESUMO
BACKGROUND: Zika virus (ZIKV) was discovered in 1947 with the virus isolation from Rhesus monkey (Macaca mulatta) in Uganda forest, Africa. Old World Primates are involved in a sylvatic cycle of maintenance of this arbovirus, however a limited knowledge about the role of New World primates in ZIKV transmission cycles has been established. OBJECTIVE: This work aimed to investigate the presence of enzootic circulation of ZIKV in New World Primates from three Brazilian states: São Paulo, Paraíba, and Paraná. METHODS: We analyzed 100 non-human primate samples collected in 2018 and 2020 from free-ranging and captive environments from São Paulo (six municipalities belonging to Sorocaba region), Paraíba (João Pessoa municipality), and Paraná (Foz do Iguaçu municipality) using reverse transcriptase quantitative polymerase reaction (RT-qPCR) assays, indirect enzyme-linked immunosorbent assay (ELISA), and plaque reduction neutralization test (PRNT). FINDINGS: All samples (n = 141) tested negative for the presence of ZIKV genome from tissue and blood samples. In addition, all sera (n = 58) from Foz do Iguaçu' non-human primates (NHPs) were negative in serological assays. MAIN CONCLUSION: No evidence of ZIKV circulation (molecular and serological) was found in neotropical primates. In addition, the absence of antibodies against ZIKV suggests the absence of previous viral exposure of NHPs from Foz do Iguaçu-PR.
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Infecção por Zika virus , Zika virus , Animais , Anticorpos Antivirais , Brasil , Ensaio de Imunoadsorção Enzimática , Primatas , Zika virus/genéticaRESUMO
The aim of the current study is to present a low-cost and easy-to-interpret colorimetric kit used to diagnose porcine circovirus 2 (PCV-2) to the naked eye, without any specific equipment. The aforementioned kit used as base hybrid nanoparticles resulting from the merge of surface active maghemite nanoparticles and gold nanoparticles, based on the deposition of specific PCV-2 antibodies on their surface through covalent bonds. In total, 10 negative and 40 positive samples (≥102 DNA copies/µL of serum) confirmed by qPCR technique were tested. PCV-1 virus, adenovirus, and parvovirus samples were tested as interferents to rule out likely false-positive results. Positive samples showed purple color when they were added to the complex, whereas negative samples showed red color; they were visible to the naked eye. The entire color-change process took place approximately 1 min after the analyzed samples were added to the complex. They were tested at different dilutions, namely pure, 1:10, 1:100, 1:1000, and 1:10,000. Localized surface plasmon resonance (LSPR) and transmission electron microscopy (TEM) images were generated to validate the experiment. This new real-time PCV-2 diagnostic methodology emerged as simple and economic alternative to traditional tests since the final price of the kit is USD 4.00.
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The Brazilian Society of Virology has been organizing annual meetings for 32 years now. The 32nd annual meeting, which occurred in 2021, was once again an online meeting in consequence of the issues imposed by COVID-19, even with the vaccination advances. As in the 2020 meeting, the number of attendees was high, with considerable participation by undergraduate, graduate, and postdoc students. Distinguished scientists from different countries offered high-quality conferences, and oral presentation sessions were presented by young scientists showing their newest research results. For almost five hours a day during five days, attendees discussed high-quality science related to all areas of virology. Even with the difficulties imposed by another pandemic year, the 32nd SBV annual meeting achieved its most important goal-to inspire young scientists and discuss high-quality virology research.
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COVID-19 , Brasil/epidemiologia , HumanosRESUMO
Haemotropic mycoplasmas (haemoplasmas) are small pleomorphic bacteria infecting erythrocytes of several mammalian species, including human beings. No study to date has focused on the risk of bacteria exposure in hunting activities, particularly in natural environments of highly tick-infested areas. Accordingly, the present study aimed to assess haemoplasma occurrence in the complex encompassing wild boars, hunting dogs and hunters of Brazil. A total of 38/65 (58.5%) wild boars and 94/159 (59.1%) dogs were positive by qPCR for at least one haemoplasma. All 25 hunters were negative. Dogs with high hunting frequency were 2.4 more likely to be infected. Sequencing revealed a probable novel haemoplasma species in wild boars. Although exposure to haemoplasma species was present, the study herein found no evidence of cross-species transmission.
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Doenças do Cão , Infecções por Mycoplasma , Mycoplasma , Doenças dos Suínos , Animais , Brasil/epidemiologia , Doenças do Cão/epidemiologia , Doenças do Cão/microbiologia , Cães , Caça , Infecções por Mycoplasma/epidemiologia , Infecções por Mycoplasma/microbiologia , Infecções por Mycoplasma/veterinária , Sus scrofa/microbiologia , Suínos , Doenças dos Suínos/epidemiologiaRESUMO
BACKGROUND Zika virus (ZIKV) was discovered in 1947 with the virus isolation from Rhesus monkey (Macaca mulatta) in Uganda forest, Africa. Old World Primates are involved in a sylvatic cycle of maintenance of this arbovirus, however a limited knowledge about the role of New World primates in ZIKV transmission cycles has been established. OBJECTIVE This work aimed to investigate the presence of enzootic circulation of ZIKV in New World Primates from three Brazilian states: São Paulo, Paraíba, and Paraná. METHODS We analyzed 100 non-human primate samples collected in 2018 and 2020 from free-ranging and captive environments from São Paulo (six municipalities belonging to Sorocaba region), Paraíba (João Pessoa municipality), and Paraná (Foz do Iguaçu municipality) using reverse transcriptase quantitative polymerase reaction (RT-qPCR) assays, indirect enzyme-linked immunosorbent assay (ELISA), and plaque reduction neutralization test (PRNT). FINDINGS All samples (n = 141) tested negative for the presence of ZIKV genome from tissue and blood samples. In addition, all sera (n = 58) from Foz do Iguaçu' non-human primates (NHPs) were negative in serological assays. MAIN CONCLUSION No evidence of ZIKV circulation (molecular and serological) was found in neotropical primates. In addition, the absence of antibodies against ZIKV suggests the absence of previous viral exposure of NHPs from Foz do Iguaçu-PR.
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Visceral leishmaniasis is a parasitic zoonosis that mainly affects poorest and most vulnerable populations, and domestic dogs are considered to be the main source of infection to the vector and therefore humans. However, several studies have investigated the role of other vertebrate hosts in the disease cycle. In this context, the aim of the present study was to conduct a survey of Leishmania infantum infection in donkeys and mules living in a semiarid region of Brazil. Whole blood sampled from 72 equids (65 donkeys and 7 mules) was used to perform molecular diagnosis using the real-time polymerase chain reaction (qPCR) technique. A total of 25% of the samples (18/72) were positive through qPCR, but there were no significant differences between the species (donkeys or mules), sex (male or female) and abandonment situation of the animals (yes or no). Donkeys and mules living under semiarid conditions have high frequency of L. infantum infection. It is therefore worth assigning importance to these species in the epidemiological cycle of visceral leishmaniasis, either as potential reservoirs or just as an abundant food source for vectors.
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Doenças do Cão , Leishmania infantum , Leishmaniose Visceral , Leishmaniose , Animais , Brasil/epidemiologia , Cães , Equidae , Feminino , Leishmania infantum/genética , Leishmaniose/veterinária , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/epidemiologia , Leishmaniose Visceral/veterinária , MasculinoRESUMO
Researchers worldwide have been studying alternatives to detect SARS-CoV-2 (COVID-19), and accurate and timely diagnosis is crucial for controlling the outbreaks of the disease. Surface plasmon resonance (SPR) is an effective strategy based on antibodies, and it can be used for simple and fast detection of antibodies due to COVID-19 infection. Accordingly, this paper reports on the highly sensitive and specific detection of antibody responses to SARS-CoV-2 spike (S) and nucleocapsid (N) proteins in COVID-19 patients. In this methodology, spike (S) and nucleocapsid (N) proteins belonging to the coronavirus genome were immobilized on the surface of a gold sensor using self-assembled monolayers. Previously, serum from COVID-19 patients was screened by immunochromatography-based COVID-19 IgG rapid test and/or ELISA in house to determine the presence of IgG titers. Serum from COVID-19-positive patients presenting with IgG were added on the surface and, at the time they bound to proteins, they caused refractive changes in the SPR angle. The antibody detection limit was determined through successive injections into the SPR apparatus - these injections ranged from pure (without dilution) to 1 : 200 µL. The system has shown good reproducibility between runs after coated surface regeneration with 0.1 M glycine-HCl solution (pH 3.0); all experiments were tested in triplicate. The antibodies targeted both S and N fragments and gave a high assay sensitivity by identifying 19 out of 20 COVID-19-positive patients. Most importantly, the assay time took less than 10 min. The results of this study indicate that the proposed simple strategy demonstrates high sensitivity and time-saving in the detection of SARS-CoV-2 response antibodies.