Search Results (178)

Toscana virus (TOSV) and Schmallenberg virus (SBV) are arthropod-borne viruses from the Bunyaviricetes class, posing significant human and animal health threats. TOSV, endemic to the Mediterranean region, is a notable human pathogen detected in various animals, suggesting potential zoonotic reservoirs. SBV emerged in Europe in 2011, affecting ruminants and causing reproductive issues, with substantial economic implications. The rapid spread of both viruses underscores the need for novel antiviral strategies. Host defense peptides (HDPs), particularly those derived from scorpion venom, are gaining attention for their antiviral potential. This study investigated pantinin-1 and pantinin-2 for their inhibitory activity against TOSV and SBV by plaque reduction assay, tissue culture infective dose (TCID₅₀) determination, and the analysis of M gene expression via qPCR. Both peptides exhibited potent virucidal activity, with IC₅₀ values of approximately 10 µM, depending on the specific in vitro cell model used. Additionally, the selectivity index (SI) values were favorable across all virus/cell line combinations, with particularly optimal results observed for pantinin-2. In human U87-MG neuronal cells, both peptides effectively blocked TOSV infection, a critical finding given the virus’s association with neurological conditions like encephalitis. The strong efficacy of these peptides against these viruses underscores the broader applicability of venom-derived peptides as promising antiviral agents, particularly in the context of emerging viral pathogens and increasing resistance to conventional therapeutics. Further studies are needed to optimize their antiviral potency and to assess their safety in vivo using animal models. Full article

Arthropod-borne viruses (arboviruses) significantly impact human, domestic animal, and wildlife health. While most arboviruses are transmitted to vertebrate hosts by blood-feeding mosquitoes and ticks, a growing body of evidence highlights the importance of other hematophagous arthropods in arboviral transmission. These lesser-known vectors, while often overlooked, can play crucial roles in the maintenance, amplification, and spread of arboviruses. This review summarizes our understanding of hematophagous arthropods, other than mosquitoes and ticks, in arboviral transmission, as well as their associations with non-arboviral viruses. Thirteen arthropod groups are discussed: bat flies, blackflies, cimicids (bat bugs, bed bugs, and bird bugs), Culicoides midges, fleas, hippoboscid flies, lice, mites, muscid flies (including horn flies and stable flies), phlebotomine sandflies, tabanids (including deer flies and horse flies), triatomines, and tsetse flies. Some of these arthropods are regarded as known or likely arboviral vectors, while others have no known role in arbovirus transmission. Particular attention is given to species associated with arboviruses of medical and veterinary significance. As the burden of arboviruses continues to grow, it is critical not to overlook the potential contribution of these lesser-known vectors. Full article

Arthropod-borne viral infections, ranging from asymptomatic to fatal diseases, are expanding from endemic to nonendemic areas. Climate change, deforestation, and globalization favor their spread. Although arboviral manifestations mainly determine the onset of generalized symptoms, distinct clinical signs have been assessed, depending on the particular arthropod-borne virus (arbovirus) involved in the infectious process. A number of arboviruses cause neuroinvasive diseases in vertebrate hosts, with acute to chronic outcomes. Long-term neurological sequelae can include cognitive dysfunction and Parkinsonism. To increase knowledge of host interactions with arboviruses, in-depth investigations are needed to highlight how arboviruses exploit a host cell for efficient infection and clarify the molecular alterations underlying human brain diseases. This review focuses on the involvement of host cytoskeletal networks and associated signalling pathways in modulating the neurotropism of emerging arboviruses. A better understanding at the molecular level of the potential for emerging infectious diseases is fundamental for prevention and outbreak control. Full article

Arthropod-borne viruses (arboviruses) represent a growing concern for global public and veterinary health, with cases reported across all continents. This review presents a broad overview of the geographic distribution of arboviruses transmitted by insect vectors, emphasizing the importance of early viral detection as a cornerstone of surveillance and outbreak preparedness. Special attention is given to the phenomenon of zoonotic spillover, where viruses maintained in natural transmission cycles often involving wildlife reservoirs and arthropod vectors cross into human populations, triggering emergent or re-emergent outbreaks. This article discusses key arboviral families of medical and veterinary significance, including Togaviridae, Flaviviridae, Nairoviridae, Phenuiviridae, Peribunyaviridae, and Orthomyxoviridae, highlighting their molecular and structural characteristics. These features are essential for guiding the development and implementation of specific and sensitive detection strategies. In addition, this work provides a comparative analysis of diverse laboratory methodologies for viral detection in vectors. From serological assays and viral isolation to advanced molecular tools and next-generation sequencing, we explore their principles, practical applications, and context-dependent advantages and limitations. By compiling this information, we aim to support researchers and public health professionals in selecting the most appropriate tools for vector surveillance, ultimately contributing to improved response strategies in the face of arboviral threats. Full article

Flaviviruses are arthropod-borne RNA viruses that can cause a wide range of human diseases, from mild symptoms to severe illness with multiorgan failure and death. Effective prevention of these diseases relies on identifying reliable vaccine targets, typically measured by correlates of protection (CoPs), which help indicate host immunity after vaccination. Current vaccines primarily focus on neutralizing antibodies (nAbs) against the viral envelope E protein, though emerging evidence suggests other potential targets may also be effective in disease prevention. Additionally, there is growing evidence of cross-protection between different flaviviruses when immunity to one virus is achieved, although this can be limited by antibody-dependent enhancement. This review examines the current understanding of flavivirus immunity, CoPs, and the potential for cross-protection in the context of existing vaccine strategies. Full article

Mosquitoes, comprising over 300 species, are pivotal vectors for transmitting arthropod-borne viruses (arboviruses) to vertebrates via bites, posing a significant public health threat with approximately 700,000 annual deaths. In contrast, insect-specific viruses (ISVs) exclusively infect insects and have no direct impact on human health. Yunnan Province in China, located in tropical and subtropical regions, provides an ideal environment for mosquito habitation and has the highest diversity of known mosquito-borne viruses. In this study, mosquito samples were collected from eight cities and states in Yunnan Province, totaling 15,099 specimens. Based on the collection sites and mosquito species, the samples were divided into 110 groups for virus isolation. Four insect-specific viruses (Tanay virus [TANV], Culex orthoflavivirus [CxFV], Aedes orthoflavivirus [AeFV], La Tina virus [LTNV]) were successfully isolated, and co-infection studies with dengue virus (DENV-2) were conducted in C6/36 cells. Preliminary results suggested that these four insect-specific viruses may reduce the viral titer of DENV-2 in C6/36 cells. Understanding the intricate interactions between insect-specific viruses and mosquito-borne viruses is crucial for elucidating the multifaceted role of mosquitoes in arboviral transmission dynamics. Insect-specific viruses exhibit considerable potential as innovative biocontrol agents, with promising capacity to attenuate mosquito-borne viral transmission through the targeted modulation of mosquito innate immunity and physiological adaptations. Full article

We performed serologic surveillance for selected arthropod-borne viruses (arboviruses) in bats and opossums in the Lacandona Rainforest, Chiapas, Mexico, in 2023–2024. Sera were collected from 94 bats of at least 15 species and 43 opossums of three species. The sera were assayed by the plaque reduction neutralization test (PRNT) for antibodies to eight orthoflaviviruses (dengue viruses 1–4, St. Louis encephalitis virus, T’Ho virus, West Nile virus, and Zika virus) and one alphavirus (chikungunya virus; CHIKV). Twelve (12.8%) bats and 15 (34.9%) opossums contained orthoflavivirus-specific antibodies. One bat (a Jamaican fruit bat) was seropositive for Zika virus, and 11 bats contained antibodies to an undetermined orthoflavivirus, as did the 15 opossums. All bats and most opossums seropositive for an undetermined orthoflavivirus had low PRNT titers, possibly because they had been infected with another (perhaps unrecognized) orthoflavivirus not included in the PRNTs. Antibodies that neutralized CHIKV were detected in three (7.0%) opossums and none of the bats. The three opossums had low CHIKV PRNT titers, and therefore, another alphavirus may have been responsible for the infections. In summary, we report serologic evidence of arbovirus infections in bats and opossums in Chiapas, Mexico. Full article

Active and passive surveillance, followed by gene sequencing, continue to be used to identify a diverse range of novel bacteria, viruses, and other microorganisms in ticks with the potential to cause disease in vertebrate hosts following tick bite. In this study, we describe the isolation and characterization of a novel virus from Bothriocroton hydrosauri ticks collected from a blotched blue-tongue, Tiliqua nigrolutea. In an attempt to isolate rickettsia, the inoculation of Vero cell cultures with tick extracts led to the isolation of a virus, identified as a novel tick Orthomyxovirus by electron microscopy and gene sequencing. Transmission electron microscopic analysis revealed that B. hydrosauri tick virus-1 (BHTV-1) is a spherical orthomyxovirus, 85 nm in size. Multiple developmental stages of the virus were evident in vitro. Analysis of putative BHTV-1 amino acid sequences derived from a genomic analysis of virus-infected host cell extracts revealed the presence of six putative RNA segments encoding genes, sharing the closest sequence similarity to viral sequences belonging to the arthropod-borne Thogotovirus genus within the Orthomyxoviridae. Thogotoviruses are an emerging cause of disease in humans and animals following tick bite. The detection of this new thogotovirus, BHTV-1, in B. hydrosauri, a competent vector for human tick-borne infectious diseases, warrants follow-up investigation to determine its prevalence, host range, and pathogenic potential. Full article

Insect-borne viruses may account for a significant proportion of non-malaria and non-bacterial febrile illnesses in Liberia. Although the presence of many arthropod vectors has been documented, the collective burden of arbovirus infections and baseline pre-existing immunity remains enigmatic. Our goal was to determine the seroprevalence of arbovirus exposure across the country using a resource-sparing, multiplex immunoassay to determine IgG responses to immunodominant antigens. 532 human serum samples, from healthy adults, collected from 10 counties across Liberia, were measured for IgG reactivity against antigens of eight common flavi-, alpha-, and orthobunya/nairoviruses suspected to be present in West Africa. Approximately 32.5% of our samples were reactive to alphavirus (CHIKV) E2, ~7% were reactive separately to West Nile (WNV) and Zika virus (ZIKV) NS1, while 4.3 and 3.2% were reactive to Rift Valley Fever virus (RVFV) N and Dengue virus-2 (DENV-2) NS1, respectively. Altogether, 21.6% of our samples were reactive to ≥1 flavivirus NS1s. Of the CHIKV E2 reactive samples, 8.5% were also reactive to at least one flavivirus NS1, and six samples were concurrently reactive to antigens of all three arbovirus groups, suggesting a high burden of multiple arbovirus infections for some participants. These insights suggest the presence of these four arbovirus families in Liberia with low and moderate rates of flavi- and alphavirus infections, respectively, in healthy adults. Further confirmational investigation, such as mosquito surveillance or other serological tests, is warranted and should be conducted before initiating additional flavivirus vaccination campaigns. The findings of these studies can help guide healthcare resource mobilization, vector control, and animal husbandry practices. Full article

The family Phenuiviridae, part of the order Hareavirales, includes arboviruses and arthropod-associated viruses, with sandflies, mosquitoes, and ticks as primary vectors. Historically, only sandfly/mosquito-borne phenuiviruses were associated with human diseases, but the emergence of severe fever with thrombocytopenia syndrome (SFTS) has highlighted the potential of tick-borne phenuiviruses as human pathogens. Recent discoveries of new arthropod-associated viruses, some of which remain unclassified, underscore the need for sensitive detection and differentiation methods, particularly in regions where these viruses may co-circulate. This study aimed to develop real-time PCR test systems for identifying and differentiating unclassified viruses within the Phenuiviridae family. In this study, tick suspensions containing phenuiviruses, previously obtained during the screening of ticks from various regions of Russia using pan-phenuivirus primers, were used. Specific primers and probes were designed to differentiate five Phenuiviridae viruses of genera Uukuvirus, Ixovirus, Phlebovirus and one unclassified phenuivirus, and their analytical sensitivity and specificity were evaluated. These PCR-based tools provide a robust method for detecting and classifying uncharacterized phenuiviruses, contributing to improved surveillance and understanding their potential epidemiological and epizootological impacts. Full article

Orthoflavivirus, a genus encompassing arthropod-borne, positive-sense, single-stranded RNA viruses in the Flaviviridae family, represents clinically relevant viruses that pose significant threats to human and animal health worldwide. With warming climates and persistent urbanization, arthropod vectors and the viruses they transmit continue to widen their geographic distribution, expanding endemic zones. Flaviviruses such as dengue virus, Zika virus, West Nile virus, and tick-borne encephalitis virus cause debilitating and fatal infections globally. In 2024, the World Health Organization and the Pan American Health Organization declared the current dengue situation a Multi-Country Grade 3 Outbreak, the highest level. FDA-approved treatment options for diseases caused by flaviviruses are limited or non-existent, and vaccines are suboptimal for many flaviviruses. Understanding the molecular characteristics of the flavivirus life cycle, virus-host interactions, and resulting pathogenesis in various cells and model systems is critical for developing effective therapeutic intervention strategies. This review will focus on the virus-host interactions of mosquito- and tick-borne flaviviruses from the virus replication and assembly perspective, emphasizing the interplay between viral non-structural proteins and host pathways that are hijacked for their advantage. Highlighting interaction pathways, including innate immunity, intracellular movement, and membrane modification, emphasizes the need for rigorous and targeted antiviral research and development against these re-emerging viruses. Full article

Arthropod-borne viruses (arboviruses) dengue (DENV), chikungunya (CHIK), and Zika (ZIKV) have been responsible for a high number of outbreaks worldwide. However, their screening in blood donors is not mandatory, and asymptomatic cases might act as an important cause of virus transmission via transfusion. A study was conducted to assess the presence of DENV (serotypes 1–4), ZIKV, and CHIKV in pooled samples (pool size: six) from asymptomatic blood donors. A total of 9463 plasma pools, corresponding to 56,778 blood donations from asymptomatic blood donors who attended donor sessions at HEMORIO and other blood centers in Rio de Janeiro and Espírito Santo, was submitted to automated nucleic-acid extraction and PCR amplification using ZC D-Tipagem molecular assay (Bio-Manguinhos). In general, a pool prevalence of 1% (95/9463) and a donor prevalence of 0.17% (95/56,778) were observed. January and February 2024 had a total of 62 positive pools out of 95 (65.3%). Targets DENV-1 and -2 had a higher prevalence in the studied months—early summer—with 24 and 28 positive pools, respectively. ZC D-Tipagem molecular assay was able to detect the best-known arboviruses circulating in asymptomatic blood donors; this study suggested that ZIKV, CHIK, and DENV are circulating in asymptomatic blood donors before blood donations and can be transmitted to blood transfusion recipients. Full article

The rise and resurgence of vector-borne diseases (VBDs) in Europe pose an expanding public health challenge, exacerbated by climate change, globalization, and ecological disruptions. Both arthropod-borne viruses (arboviruses) transmitted by ticks such as Crimean–Congo hemorrhagic fever and arboviruses transmitted by mosquitoes like dengue, Chikungunya, Zika, and Japanese encephalitis have broadened their distribution due to rising temperatures, changes in rainfall, and increased human mobility. By emphasizing the importance of interconnected human, animal, and environmental health, integrated One Health strategies are crucial in addressing this complex issue. Europe faces increased risk due to the expanding habitats of disease-carrying organisms, the spread of new species like Aedes albopictus since 2013, and increased movement of infected individuals between countries, leading European countries to implement strategies such as enhanced surveillance systems, public awareness campaigns, and prompt outbreak response strategies. However, the lack of both targeted antiviral therapies and vaccines for many arboviruses, together with undetected or asymptomatic cases, hamper containment efforts. Therefore, it is important to have integrated strategies that combine climate modeling, disease surveillance, and public health interventions to address expected changes in disease patterns due to global changes. This review explores the spread of arboviruses in Europe, highlighting their historical context, current transmission dynamics, and their impact on public health. Full article

Flaviviruses are arthropod-borne viruses primarily transmitted through the mosquito Aedes aegypti or Culex genus of mosquitos. These viruses are predominantly found in tropical and subtropical regions of the world with their geographical spread predicted to increase as global temperatures continue to rise. These viruses cause a variety of diseases in humans with the most prevalent being caused by dengue, resulting in hemorrhagic fever and associated sequala. Current approaches for therapeutic control of flavivirus infections are limited, and despite recent advances, there are no approved drugs. Vaccines, available for a few circulating flaviviruses, still have limited potential for controlling contemporary and future outbreaks. Mouse models provide us with a valuable tool to test the effectiveness of drugs and vaccines, yet for many flaviviruses, well-established mouse models are lacking. In this review, we highlight the current state of flavivirus vaccines and therapeutics, as well as our current understanding of mouse models for various flaviviruses. Full article

Viruses transmitted by arthropods (arboviruses) pose a global public health threat. Sporadic cases or outbreaks caused by West Nile virus, Crimean–Congo haemorrhagic fever virus, tick-borne encephalitis virus, and phleboviruses are often reported in Europe. Recently, they expanded their distribution in geographic areas where they had never been observed before, while tropical viruses, like Dengue, Chikungunya, and Zika, started to cause autochthonous cases and outbreaks following the return of viraemic travellers from endemic countries. The primary or secondary vectors of these viruses are established in Europe, and the incidence of arboviral diseases is expected to increase due to several anthropogenic and/or environmental factors (mainly climate change, which affects the survival and amplification of the arthropod vectors). This is an update on the emerging arboviruses in Europe, associated challenges, and future perspectives. Full article