Introducción: El virus de la rabia (RABV) es una zoonosis letal con un impacto significativo en la salud pública y veterinaria. En Brasil, los murciélagos, especialmente Desmodus rotundus, son los principales reservorios en zonas rurales. Métodos: Este estudio analizó cuatro muestras de Capra hircus (2), Equus caballus (1) y Tapirus terrestris (1), lo cual confirmó la presencia del virus mediante inmunofluorescencia directa (DIF) y RT-PCR, que amplificó un fragmento de 264 pb del gen de la nucleoproteína. Resultados: El análisis filogenético identificó tres clados principales. Las muestras se agruparon en el Grupo A, con secuencias de Desmodus rotundus, Artibeus lituratus y Eptesicus furinalis, asociadas con la variante AgV3 (bootstrap >90%) y muestras de perros infectados. El clado B incluyó aislamientos históricos de perros con AgV2, actualmente erradicado en Brasil. El clado C agrupó primates (Callithrix jacchus) y casos humanos en Ceará. El alineamiento de nucleoproteínas mostró regiones conservadas y variaciones en la región intergénica N-P. Conclusiones: Los resultados confirman que los murciélagos siguen siendo los principales reservorios del virus de la rabia en São Paulo, siendo el AgV3 la variante predominante, lo que resalta la necesidad de una vigilancia epidemiológica continua.

Bats are natural reservoirs for diverse viruses, including coronaviruses, filoviruses, and paramyxoviruses, several of those known to be involved in zoonotic spillover events and demanding an integrated surveillance. Here, we present a framework that leverages Brazil's rabies passive surveillance programme to detect bat-borne viruses. Using an algorithm to select representative specimens from 2422 bats collected across São Paulo state, we submitted 150 paired lung and intestine samples to nanopore metagenomic sequencing. We detected 98 viral contigs from 12 families of public health relevance, including Arenaviridae, Coronaviridae, and Paramyxoviridae. Notably, the approach identified a previously unknown filovirus in bats in the Americas, validating the framework's capacity for epidemic preparedness. These findings reveal an undetected viral diversity and demonstrate how existing animal surveillance can monitor pathogen threats. Crucially, in a workshop involving multisectoral One Health experts in Brazil, this framework was validated as a scalable model for national expansion, adapted for low- and middle-income countries (LMICs).

O vírus da raiva (RABV) causa uma zoonose letal com grande impacto na saúde pública e veterinária. No Brasil, os morcegos, especialmente o Desmodus rotundus, são os principais reservatórios nas áreas rurais. Este estudo analisou quatro amostras: cabra - Capra hircus (2), cavalo - Equus caballus (1) e anta Tapirus terrestris (1), confirmando a presença do vírus por imunofluorescência direta (IFD) e RT-PCR, que amplificou um fragmento de 264 pb do gene da nucleoproteína. A análise filogenética identificou três clados principais. As amostras foram agrupadas no Cluster A, com sequências de Desmodus rotundus, Artibeus lituratus e Eptesicus furinalis, associadas à variante AgV3 (bootstrap >90%) e com amostras de cães infectados. O clado B incluiu isolados históricos de cães com AgV2, já eliminados no Brasil. O clado C agrupou primatas (Callithrix jacchus) e casos humanos no Ceará. O alinhamento da nucleoproteína mostrou regiões conservadas e variações na região intergênica N-P. Os resultados confirmam que os morcegos continuam sendo o principal reservatório do RABV em São Paulo, com o AgV3 como variante predominante, destacando a necessidade de vigilância epidemiológica contínua.

Feline stool-associated circular DNA virus (FeSCV), was identified in Japan (2018) and China (2021) but has not yet been detected outside Asia. In this study, 137 fecal or rectal swab samples from 83 cats were screened for circoviruses and FeSCV, with detection of two putative novel Cyclovirus species and 19.3% (16/83) of FeSCV. A higher incidence of FeSCV in kittens and young adults, and FCoV-positive cats with clinical signs of feline infectious peritonitis were observed. Further investigation will clarify the virus pathogenicity and its association with other pathogens.

Cetacean morbillivirus (CeMV) is a major threat to cetaceans worldwide, causing individual deaths and outbreaks of mass mortality. Based on partial sequences of the viral phosphoprotein, CeMV is subclassified into seven strains and two distinct lineages. To date, only CeMV-1 strains, including the dolphin morbillivirus (DMV), have been completely sequenced. The CeMV-2 lineage was first reported in Guiana dolphins (Sotalia guianensis) in Brazil and was associated with an unusual mortality event in 2017–2018. Here we provide the nearly complete Guiana dolphin morbillivirus (GDMV) genome sequence, representing the first within the CeMV-2 lineage. GDMV was isolated using Vero.DogSLAMtag cells, the viral RNA was extracted, and deep sequencing analysis was performed. Gaps in the viral genome were completed by Sanger sequencing. The final genome length was 15,607 nucleotides covering 99.3% of the DMV reference genome, including full sequences of the six structural proteins encoded by morbillivirus. The sequence similarity was 74–77.9% to other CeMV strains, with highest identity to the DMV. The complete L protein amino acid sequence comparison-based taxonomy indicates that GDMV is a distinct morbillivirus species; however, as GDMV and CeMV-1 strains infect a similar host spectrum, our findings support that GDMV represents a new CeMV-2 lineage.

Brazilian porcupinepox virus (BPoPV) is a recently described pathogen associated with severe cutaneous and systemic disease in Coendou spp. porcupines, posing potential conservation and zoonotic risks. Given the solitary behavior of porcupines and the unclear mechanisms of BPoPV transmission, this study investigated the presence of BPoPV DNA in porcupines and their associated ectoparasites (ticks and lice). We analyzed ticks and lice collected from 17 porcupines (C. longicaudatus and C. spinosus), with or without clinical signs of BPoPV infection. Ectoparasites were identified morphologically, separated into distinct pools for ticks and lice by host, and screened by PCR. BPoPV DNA was detected in all symptomatic porcupines and their ectoparasites—including Amblyomma longirostre, A. sculptum ticks, and Eutrichophilus spp. lice—except for one tick pool. Notably, an asymptomatic, BPoPV-negative porcupine harbored A. longirostre ticks that tested positive for the virus. Sequencing confirmed 100% identity with the BPoPV reference strain. These findings suggest that Eutrichophilus lice, A. sculptum, and particularly A. longirostre ticks may play a role in BPoPV transmission. Further studies are needed to elucidate whether these ectoparasites act as biological or mechanical vectors and to assess the zoonotic potential of BPoPV in contact with humans and domestic animals.

Brazilian porcupinepox virus (BPoPV) was recently identified in free-ranging Brazilian porcupines (Coendou longicaudatus) in Brazil. In this study, we investigated the histopathological and ultrastructural features of BPoPV infection in four individuals and documented the occurrence of BPoPV in Goiás state, Brazil, where the virus had not been reported previously. Cutaneous lesions exhibited characteristic poxviral cytopathic changes. Histopathological analysis and transmission electron microscopy (TEM) revealed intralesional poxvirus-like particles, confirming both epithelial and systemic viral tropism. These findings contribute to the current understanding of BPoPV-associated disease and raise concerns regarding its potential impact on wild porcupine populations and conservation efforts.

The authors have withdrawn this preprint because of the necessity of correcting fundamental information. A corrected version may be submitted in the future. Therefore, the authors do not wish this work to be cited as a reference for the project. If you have any questions, please contact the corresponding author.

BACKGROUND:Rabies, a lethal viral zoonotic disease, remains a significant global public health concern. In northeastern Brazil, in particular, its epidemiology is complex and dynamic, characterized by the presence of several reservoirs associated with human rabies infection. METHODS:This study, conducted from June 2022 to July 2023, was part of a passive epidemiological surveillance initiative under Brazil's National Rabies Surveillance Program. It investigated the presence of Rhabdovirus (RhabV) in 356 postmortem chiropteran brain samples using three diagnostic techniques for rabies and conducted an evolutionary study on both pan-RhabV- and pan-LYSSAV-positive PCR samples. The samples were collected from 20 bat species and different locations in the State of Ceará, an endemic region for the rabies virus (RABV). Rabies-positive samples were further explored through Bayesian, genetic distance mapping and recombination analyses. RESULTS:From a total of 356 samples collected, 43 (12.07%) were positive for direct immunofluorescence (DIF) and 40 (11.23%) for mouse intracerebral inoculation (MIT) tests. Among the positive results, 40 samples were confirmed by both DIF and MIT, while 13 (3.65%) had inconclusive results for one or both techniques. Molecular assays identified 38 rabies-positive samples (10.67%). Members of the Molossidae and Phyllostomidae families had the highest prevalence, highlighting the role of insectivorous and frugivorous bats in the cycle and dynamics of rabies transmission. Phylogenetic reconstructions revealed three distinct and well-supported clusters and clades, indicating the cocirculation of different RABV lineages in the region and shedding light on both intra- and interhost diversity. We also demonstrated genetic distance among the RABV clusters and inferred that their common ancestor originated in Europe, later diversifying across continents. No recombination breakpoints were identified. CONCLUSIONS:This study highlights the dynamic nature of RABV evolution within individual bat hosts, contributing to the understanding of the genetic diversity of RABV variants found in several bat species in northeastern Brazil. This study provides crucial insights into viral transmission dynamics within and between different host species and is essential for designing effective rabies control and prevention strategies tailored to endemic regions.

ABSTRACT Background: Rabies poses a serious public health challenge in Brazil, and its epidemiology has undergone significant changes over the past two decades. Although canine transmission of rabies has been controlled through national vaccination programs, new risks have emerged, particularly from wildlife reservoirs. Methods: We performed a retrospective analysis of human rabies cases reported in Brazil between 2001 and 2025 using epidemiological surveillance data, scientific literature, and public health reports. We focused on trends in transmission sources, changes in affected populations, and challenges in prevention and treatment, particularly regarding the availability of post-exposure prophylaxis (PEP). Results: A total of 188 human rabies cases were reported in Brazil between 2001 and 2025 (average: 7.52 cases per year). Most of the cases occurred in the northern and northeastern regions of the country. Bats were the most common source of transmission, followed by dogs and non-human primates. Although rabies is preventable, most of the cases reported within the study period resulted in death. PEP was administered in most cases; however, the treatment may have been delayed, incomplete, or initiated after the onset of symptoms, which limited its effectiveness. Only two patients survived, and both of them received intensive care and were treated using modified therapeutic protocols. Conclusion: The transition from canine- to bat-mediated rabies highlights the need for enhanced surveillance and targeted prevention strategies. Despite advances in canine rabies control, ensuring PEP accessibility and strengthening public health interventions in high-risk areas remain critical for reducing the incidence of human rabies in Brazil.

Resumo O sistema imunológico dos bezerros neonatos é imaturo e altamente suscetível a doenças, o que representa desafios para sua sobrevivência. Este estudo teve como objetivo avaliar a resposta imune de bezerros nos primeiros 30 dias de vida, com foco no leucograma, na imunofenotipagem dos linfócitos T (CD3+, CD4+ e CD8+) por citometria de fluxo e na expressão gênica das citocinas IL-10 e IL-12 por PCR em tempo real. Os resultados indicaram que o sistema imunológico dos bezerros passa por um processo de adaptação pós-natal, evidenciado por variações nos leucócitos totais e diferenciais, com aumento gradual de linfócitos até o 30º dia e flutuações em granulócitos e monócitos. As menores porcentagens de linfócitos T e a relação CD4+/CD8+ mais baixa ocorreram no terceiro dia de vida, com recuperação gradual. A expressão de IL-10 foi detectada nos dias 1, 3, 10 e 25, enquanto a IL-12 foi observada nos dias 1, 3 e 30. Essas citocinas indicam um equilíbrio dinâmico entre respostas Th1 (pro-inflamatórias) e Th2 (anti-inflamatórias), sugerindo uma regulação imunológica eficiente para controlar inflamações excessivas e combater patógenos. Conclui-se que o sistema imunológico do bezerro passa por uma fase de adaptação e maturação, com modulação da resposta imune observada nas variações nos leucócitos e na expressão das citocinas.

Xenarthrans face increasing viral threats from anthropogenic pressures and domestic animals. In this study, we investigated the presence of coronaviruses, paramyxoviruses, and poxviruses in anteaters and armadillos from Brazilian biomes. We screened 236 individuals for these viruses by molecular methods. Canine distemper virus (CDV) was identified in four giant anteaters and one six-banded armadillo. A poxvirus, showing 88% sequence identity to molluscum contagiosum virus, was detected in one giant anteater. No coronaviruses were detected. These findings expand our knowledge on the host range of CDV and the circulation of divergent poxvirus in wildlife, with implications for conservation and zoonotic disease surveillance.

Despite its 100% lethality and approximately 59,000 human deaths every year, rabies still lacks an effective treatment. Numerous trials have aimed to impair the life cycle of Lyssavirus rabies (RABV), the primary worldwide lyssavirus causing rabies, but with limited success. Treatments targeting host factors and attempting to mitigate the damage caused by RABV have also been unsatisfactory. This article describes the effects of intracerebral transfection of anti-RABV recombinant monoclonal nanobodies as antivirals against rabies in vivo, in a post-exposure protocol. Mice were intranasally inoculated with the RABV CVS strain and, 72 h later, were injected via the intracerebral route with two different anti-RABV llama-derived VHH nanobodies complexed with a transfection agent. One of the VHHs was able to reduce the viral load in mice, but no significant effect on survival was detected. Though not completely effective, nanobody therapy could be attempted in association with other antivirals to improve therapies against rabies.

Due to the COVID-19 pandemic and the uncertainty about aspects of its origin, in recent years there has been an increased interest in investigating coronaviruses in wild animals. Bats are hosts of the greatest diversity of coronaviruses to date, including the ancestors of viruses that have caused outbreaks in humans. Although in Brazil, information on coronaviruses in bats has expanded, still they remain unrepresentative. To help shed some light on this matter, we collected 175 samples from bats of different species from two Brazilian states. Here, we report the previously unknown presence of an alphacoronavirus in a bat (Molossus sp.) from Ceará. The phylogenetic analysis showed close relationships with alphacoronaviruses from Brazil and Argentina, but it was not possible to determine the subgenus or species of this virus using RNA-dependent RNA-polymerase (RdRp) domain of the nsp12 protein-coding sequence as it was distant from the specimens considered by the International Committee on Taxonomy of Viruses (ICTV). Finally, by performing High-Throughput Sequencing, we were able to find contigs mostly belonging to domains of the replicase of bat coronaviruses related to American bats of the Molossidae and Vespertilionidae families.

This publication reports on a rabid dog in São Paulo city, Brazil, with the AgV3 variant of rabies virus related to vampire and fruit bats, which is of significant importance to the surveillance of rabies in a region where the typical canine AgV2 rabies virus has been eradicated.

Samples of brain cortex of 12 free-range healthy wild boars from Southern Brazil were tested for RABV by dFAT and qPCR, all negative. The negative results in seropositive healthy wild boars may be associated with exposure of non-viable virus particles, virus proteins by bat saliva or consumption of contaminated carcasses.

Rabies is an emerging zoonosis of global significance in the context of one health. With the advent of mass vaccination campaigns for dogs and cats in Brazil, urban rabies maintained by these animals has been controlled, but not eradicated. In contrast, wildlife-maintained virus has always been a challenge. In Ceará, the primate Callithrix jacchus is a significant transmitter. The aim of this study was to investigate the occurrence and frequency of rabies virus in wildlife in the urban area of municipalities in Northwest Ceará and describe the species of infected animals. Active captures of non-hematophagous bats were carried out in the urban area of Sobral, as well as the reception of wild mammals from Sobral and surrounding regions. A total of 103 animals were collected, with 97 (100/103) between the years 2021 and 2022. Of these, 84.5% (87/103) were non-hematophagous bats, and 15.5% (16/103) were other wild animals. Only 12.6% (13/103) tested positive in the immunofluorescence assay (RIFI), including 11 bats (9 Molossus molossus, 1 Artibeus planirostris, and 1 Eumops glaucinus) and 2 non-human primates (Callithrix jacchus). All positive animals exhibited altered behavior. Positive animals had contact with humans. There was one case of aggression by a non-hematophagous bat. The results support the circulation of the virus in the wildlife cycle in the region, as well as the high risk of transmission and potential cases of human rabies. There is a diversity of wild animals in the study area. Continuous outreach activities are needed to educate on the importance of rabies monitoring to prevent future human cases in urban areas in Brazil.

Q fever is a zoonotic disease caused by the obligate intracellular pathogen Coxiella burnetii, for which domestic ruminants are the primary source of infection in humans. Herein, we investigated the presence of C. burnetii in humans, sheep, and goats in the semi-arid region of northeastern Brazil. The presence of anti-C. burnetii antibodies was surveyed using indirect immunofluorescence assay, and detection of C. burnetii DNA was performed by polymerase chain reaction (PCR). Anti-C. burnetii antibodies were detected in 60% of farms, 4.8% of goats, 1.5% of sheep, and 4.5% of human samples. PCR was positive in 18.9% of blood samples, 7.7% of milk samples, and 7.7% of vaginal mucus samples. A DNA sequence of a C. burnetii DNA sample extracted from the goat vaginal mucus showed 99.2-99.4% nucleotide identity with other strains previously reported in Brazil. These results indicate that C. burnetii is present in the surveyed area, where it poses a risk to both public and animal health. These findings indicate an urgent need for educative actions to protect population, as well as better training of veterinarians to detect and report Q fever.

ABSTRACT: Rabies is a fatal viral disease that affects animals and humans and is widespread among national ecological systems. We describe the anatomopathological and immunohistochemical findings of a case of rabies in a jaguarundi (Herpailurus yagouaroundi) found in a rural peri-domestic area after showing aggression and attacking two animals. Histopathology of brain tissue showed lymphoplasmacytic meningoencephalitis associated with intracytoplasmic eosinophilic inclusion bodies in neurons, gliosis and neuronophagia. The diagnosis of rabies was based on the lesions and confirmed by immunohistochemistry and qPCR. In Brazil, rabies in wild felines of the genus Puma has only been described in animals through serological examinations. The pathological findings are essential for the diagnosis and elucidation of the participation of this species in the wild cycle of the disease, as well as in the maintenance and conservation of the balance of wild fauna.