REVIEW | doi:10.20944/preprints202111.0350.v1
Online: 19 November 2021 (12:33:53 CET)
The newly established virus family Phenuiviridae in Bunyavirales harbors viruses infecting three kingdoms of host organisms (animals, plants, and fungi), which is rare in known virus families. Many phenuiviruses are arboviruses and replicate in two distinct hosts (e.g., insects and humans or rice). Multiple phenuiviruses, such as Dabie bandavirus, Rift Valley fever phlebovirus, and Rice stripe tenuivirus, are highly pathogenic to humans, animals, or plants. They impose heavy global burdens on human health, livestock industry, and agriculture and are research hotspots. In recent years the taxonomy of Phenuiviridae has been expanded greatly, and researches on phenuiviruses have made significant progress. With these advances, this review drew a novel panorama regarding the biomedical significance, distribution, morphology, genomics, taxonomy, evolution, replication, transmission, pathogenesis, and control of phenuiviruses, to aid researchers in various fields to recognize this highly adaptive and very important virus family.
ARTICLE | doi:10.20944/preprints202111.0290.v1
Online: 16 November 2021 (13:32:37 CET)
Arboviruses have two ecological transmission cycles, sylvatic and urban. For some, the sylvatic cycle has not been thoroughly described in America. To study the role of wildlife in a putative sylvatic cycle, we sampled free-ranging bats and birds in two arbovirus endemic locations and analyzed them using molecular, serological, and histological methods. No current infection was detected, and no significant arbovirus-associated histological changes were observed. Neutralizing antibodies were detected against selected arboviruses. In bats, positivity in 34.95% for DENV-1, 16.26% for DENV-2, 5.69% for DENV-3, 4.87% for DENV-4, 2.43% for WNV, 4.87% for SLEV, 0,81% for YFV, 7.31% for EEEV, and 0.81% for VEEV was found. Antibodies against ZIKV were not detected. In birds, PRNT results were positive against WNV in 0.80%, SLEV in 5.64%, EEEV in 8.4%, and VEEV in 5.63%. An additional retrospective PRNT analysis was performed using bat samples from three additional DENV endemic sites resulting in a 3.27% prevalence for WNV and 1.63% for SLEV. Interestingly one sample resulted unequivocally WNV positive confirmed by serum titration. These results suggest that free-ranging bats and birds are exposed to not currently reported hyperendemic-human infecting Flavivirus and Alphavirus, however, their role as reservoirs or hosts is still undetermined.
ARTICLE | doi:10.20944/preprints202208.0359.v1
Online: 19 August 2022 (05:52:42 CEST)
Dengue Fever (DF) is an important arthropod-borne viral infection, which has repeatedly oc-curred as outbreaks in eastern and northeastern Ethiopia since 2013. A cross-sectional epidemio-logical outbreak investigation was carried out from September - November 2019 on febrile pa-tients (confirmed malaria negative) who presented with suspected and confirmed DF at both public and private health facilities in Gewane District, Afar Region, northeastern Ethiopia. Ento-mological investigation of containers found in randomly selected houses belonging to DF positive patients was undertaken, to survey for the presence of Aedes larvae or pupae. A total of 1185 DF cases was recorded from six heath facilities during the 3-month study period. The mean age of DF cases was 27.2 years and 42.7% of the cases were female. The most affected age group was 15-49 years (78.98%). However, the attack rate (AR) was highest in the 49+ age group (134.2). A total of 162 artificial containers were inspected from 62 houses, with 49.4% found positive for Aedes larva/pupae. Aedes mosquitoes were mostly found breeding in buckets/bowls, clay jars, plastic tanks, and tires. World Health Organization entomological indices classified the study site as high risk for dengue outbreaks (House Index=45.2%, Container Index=49.4% and Breteau In-dex=129). Study findings highlight the importance of vector control to prevent future dengue out-breaks in the region. The scarcity of drinking water and changing climactic conditions may have also contributed to the occurrence of this outbreak.
REVIEW | doi:10.20944/preprints202011.0256.v2
Subject: Biology, Anatomy & Morphology Keywords: marmoset; Neotropical; Brazil; biomedical; arbovirus; conservation; hybridization; biological invasion
Online: 18 February 2021 (15:52:32 CET)
We provide here a current overview of marmoset (Callithrix) evolution, hybridization, species biology, basic/biomedical research, and conservation initiatives. Composed of two subgroups, the aurita group (C. aurita and C. flaviceps) and the jacchus group (C. geoffroyi, C. jacchus, C. kuhlii and C. penicillata), this relatively young primate radiation is endemic to the Brazilian Cerrado, Caatinga, and Atlantic Forest biomes. Significant impacts on Callithrix within these biomes resulting from anthropogenic activity include: (1) population declines, particularly for the aurita group; (2) widespread geographic displacement, biological invasions, and range expansions of C. jacchus and C. penicillata; (3) anthropogenic hybridization; and (4) epizootic Yellow Fever and Zika viral outbreaks. A number of Brazilian legal and conservation initiatives are now in place to protect the threatened aurita group and increase research about them. Due to their small size and rapid life history, marmosets are prized biomedical models. As a result, there are increasingly sophisticated genomic Callithrix resources available and burgeoning marmoset functional, immuno-, and epi- genomic research. In both the laboratory and the wild, marmosets have given us insight into cognition, social group dynamics, human disease, and pregnancy. Callithrix jacchus and C. penicillata are emerging Neotropical primate models for arbovirus disease, including Dengue and Zika. Wild marmoset populations are helping us understand sylvatic transmission and human spillover of Zika and Yellow Fever viruses. All of these factors are positioning marmosets as preeminent models to facilitate understanding of facets of evolution, hybridization, conservation, human disease, and emerging infectious diseases.
ARTICLE | doi:10.20944/preprints202203.0387.v1
Subject: Life Sciences, Biochemistry Keywords: Asian longhorned tick; Haemaphysalis longicornis; Bourbon virus; Emerging arbovirus; Virginia
Online: 30 March 2022 (08:24:04 CEST)
Haemaphysalis longicornis (Neumann, 1901) (Acari: Ixodidae), the Asian longhorned tick, is an invasive tick species present in the USA since at least 2017 and has been detected in one-third of Virginia counties. While this species is associated with the transmission of multiple pathogens in its native geographical range of eastern Asia, little is known about its ability to acquire and transmit pathogens in the USA, specifically those that are transmissible to humans, although from an animal health perspective it has already been shown to vector Theileria orientalis Ikeda strains. Emerging tick-borne viruses such as Bourbon virus (genus: Thogotovirus) are of concern as these newly discovered pathogenic agents have caused fatal clinical cases, and little is known about their distribution or enzootic maintenance. This study examined H. longicornis collected within Virginia (from ten counties) for Bourbon and Heartland virus using PCR methods. All ticks tested negative for Heartland virus via qRT-PCR. Bourbon virus-positive samples were confirmed on two different gene targets, and with Sanger sequencing of the PB2 (segment 1) gene. Bourbon virus RNA was detected in one nymphal stage H. longicornis from Patrick County, one nymph from Staunton City, one larval pool and one adult female tick from Wythe County, Virginia. An additional 100 Amblyomma americanum (Linnaeus 1758; lone star tick) collected at the same Patrick County site revealed one positive nymphal pool, suggesting that Bourbon virus may have spilled over from the native vector, potentially by co-feeding on a shared Bourbon virus-infected vertebrate host. Blood tested from local harvested deer revealed a 12.0% antibody seroprevalence against Bourbon virus, exposure which further corroborates that this tick-borne virus is circulating in the Southwest Virginia region. Through these results it can be concluded that H. longicornis can carry Bourbon virus and that pathogen spillover may occur from native to invasive tick species.
Subject: Life Sciences, Biochemistry Keywords: viral persistence; flaviviruses; mosquito; tick; autophagy; interferon; wildlife; infection; arbovirus
Online: 12 August 2021 (18:28:52 CEST)
A substantial number of humans are at risk for infection by vector-borne flaviviruses, resulting in considerable morbidity and mortality worldwide. These viruses also infect wildlife at a considerable rate, persistently cycling between either the tick or mosquito vector to small mammals (e.g. rodents, skunks) and reptiles to non-human primates and humans. Substantially increasing evidence of viral persistence in wildlife continue to be reported. In addition to in humans, viral persistence can also be established in mammalian, reptile, arachnid, and mosquito systems, as well as insect cell lines in culture. Although a considerable amount of research has focused on the potential roles of defective virus particles, autophagy and/or apoptosis induced evasion of the immune response, the precise mechanism of flavivirus has yet to be elucidated. In this review, we present findings that aid in further understanding of how vector-borne flavivirus persistence is established in wildlife. Research studies to be discussed include determining the critical roles universal flavivirus non-structural proteins played in viral persistence, the development of relevant animal models of viral persistence, and investigating the host responses that allow vector-borne flavivirus replication without destructive effects on infected cells. These findings underscore the viral–host relationships in wildlife animals and could be used to elucidate the mechanisms for the establishment of viral persistence in these animals.
REVIEW | doi:10.20944/preprints201908.0147.v2
Subject: Life Sciences, Virology Keywords: Zika; NS5; Flavivirus; Arbovirus; TBK1; STAT2; IFN1; IFN3; RdRp; MTase
Online: 4 September 2019 (13:19:24 CEST)
ZIKV is the latest addition to an ever-growing list of arboviruses that are causing outbreaks with serious consequences. 14 mild cases were recorded between 1960 and 1980 until the first major outbreak was recorded in 2007 on Yap island followed by more severe outbreaks in French Polynesia (2013) and Brazil (2015) leading to a 20-fold increase in GBS and Microcephaly cases respectively. Various transmission methods have been recorded ranging from Aedes mosquito vector transmission to sexual and vertical transmission. No current vaccines or treatments are available but recent studies have taken interest in the NS5 protein which has both the RdRp & MTase domains making it important for viral replication alongside other important functions such as inhibiting the innate immune system thus ensuring virus survival and replication. Structural studies can help design inhibitors while biochemical studies can help understand the various mechanisms utilized by NS5 thus counteracting them can inhibit or abolish the viral infection. Drug repurposing has proven to be an effective tool since hundreds of thousands of compounds can be screened in-silico thus saving time and resources while also having information available on such compounds especially if they are already used to treat other ailments.
ARTICLE | doi:10.20944/preprints201811.0022.v1
Subject: Life Sciences, Virology Keywords: rift valley fever virus; arbovirus; caprine; challenge model; animal vaccine; zoonosis
Online: 2 November 2018 (05:25:35 CET)
Rift Valley Fever virus (RVFV) is a zoonotic arbovirus of the Phenuiviridae family. Infection causes abortions in pregnant animals, high mortality in neonate animals and mild to severe symptoms in both people and animals. There is currently an ongoing effort to produce safe and efficacious veterinary vaccines against RVFV in livestock to protect against both primary infection in animals and zoonotic infections in people. To test the efficacy of these vaccines it is essential to have a reliable challenge model in relevant target species, including ruminants. We evaluated two goats breeds (Nubian and LaMancha), three routes of inoculation (intranasal, mosquito-primed subcutaneous and subcutaneous) using an infectious dose of 107 pfu/ml, a virus strain from the 2006-07 Kenyan/Sudan outbreak and compared the effect of using virus stocks produced in either mammalian or mosquito cells. Our results demonstrated that Nubian goats achieved the highest levels and longer duration of viremia. In the Nubian goats, all three routes of inoculation were equally efficient at producing clinical signs, consistent viremia (peak viremia: 1.2x103 - 1.0x105 pfu/ml serum), nasal and oral shedding of viral RNA (1.5x101 – 8x106 genome copies/swab), a systemic infection of tissues, and robust antibody responses. The Nubian goat breed and a needle-free intranasal inoculation technique could both be utilized in future vaccine and challenge studies.
ARTICLE | doi:10.20944/preprints201910.0121.v1
Subject: Life Sciences, Virology Keywords: alphavirus; vaccine; arbovirus; animal models; nonhuman primates; electrocardiography; ecg; aerosol; encephalitis; equine
Online: 11 October 2019 (03:32:33 CEST)
Eastern (EEEV) and Venezuelan (VEEV) equine encephalitis viruses (EEVs) are related, (+)ssRNA arboviruses that can cause severe, sometimes fatal, encephalitis in humans. EEVs are highly infectious when aerosolized, raising concerns for potential use as biological weapons. No licensed medical countermeasures exist; given the severity/rarity of natural EEV infections, efficacy studies require animal models. Cynomolgus macaques exposed to EEV aerosols develop fever, encephalitis, and other clinical signs similar to humans. Fever is nonspecific for encephalitis in macaques. Electrocardiography (ECG) metrics may predict onset, severity, or outcome of EEV-attributable disease. Macaques were implanted with thermometry/ECG radiotransmitters and exposed to aerosolized EEV. Data was collected continuously, and repeated-measures ANOVA and frequency-spectrum analyses identified differences between courses of illness and between pre-exposure and post-exposure states. EEEV-infected macaques manifested widened QRS-intervals in severely ill subjects post-exposure. Moreover, QT-intervals and RR-intervals decreased during the febrile period. VEEV-infected macaques suffered decreased QT-intervals and RR-intervals with fever onset. Frequency-spectrum analyses revealed differences in the fundamental frequencies of multiple metrics in the post-exposure and febrile periods compared to baseline and confirmed circadian dysfunction. Heart rate variability (HRV) analyses revealed diminished variability post-exposure. These analyses support using ECG data alongside fever and clinical laboratory findings for evaluating medical countermeasure efficacy.
ARTICLE | doi:10.20944/preprints202205.0209.v1
Subject: Biology, Ecology Keywords: spatiotemporal modeling; arbovirus transmission; remote sensing; eastern equine encephalitis virus; West Nile virus
Online: 16 May 2022 (12:22:14 CEST)
The irregular timing and spatial variation in zoonotic arbovirus spillover from vertebrate hosts to humans and livestock present challenges to predicting their occurrence from year to year and within their broader geographic range, compromising effective prevention and control strategies. The objective of this study was to quantify effects of landscape composition and configuration and dynamic temperature and precipitation values on the 2018 spatiotemporal distribution of eastern equine encephalitis virus (EEEV) (Togaviridae, Alphavirus) and West Nile virus (WNV) (Flaviviridae, Flavivirus) sentinel chicken seroconversion in northeastern Florida using Earth Observation (EO) data and a modeling framework that incorporated joint spatial and temporal effects. We investigated environmental effects using Bernoulli generalized linear mixed effects models (GLMMs) including a site level random effect, and then added spatial random effects and spatiotemporal random effects in subsequent runs. Models were executed using integrated nested Laplace approximation (INLA) and a stochastic partial differential equation (SPDE) approach in R-INLA. GLMMs that included a spatiotemporal random effect performed better relative to models that included only spatial random effects and better than non-spatial models. Results indicated strong spatiotemporal structure in seroconversion for both viruses, but EEEV exhibited more punctuated and compact structure at the beginning of the sampling season, while WNV exhibited more gradual and diffuse structure across the study area toward the end of the sampling season. Percentage of cypress/tupelo wetland land cover within 3500 m of coop sites and edge density of forest land cover within 500 m had a strong positive effect on EEEV seroconversion, while the best fitting model for WNV was the intercept only model with spatiotemporal random effects. Lagged temperature and precipitation variables included in our study did not have a strong effect on seroconversion for either virus when accounting for temporal autocorrelation, demonstrating the utility of capturing this structure to avoid Type I errors. Predictive accuracy on out-of-sample data for EEEV seroconversion demonstrates the potential to develop a temporally dynamic framework to predict arbovirus transmission.
REVIEW | doi:10.20944/preprints202106.0228.v1
Subject: Life Sciences, Biochemistry Keywords: arbovirus, dengue, viral hemorrhagic fever, viral immunopathogenesis, viral toxin, NS1, dengue vaccine strategies
Online: 8 June 2021 (13:10:53 CEST)
Mosquito-borne viral disease dengue is a global public health problem causing a wide spectrum of clinical manifestations ranging from mild dengue fever to severe dengue with plasma leakage and bleeding which are often associated to fatality. To date, there are no specific medications to treat dengue and prevent the risk of hemorrhage. Dengue is caused by one of the four related antigenically distinct serotypes, DENV-1 to DENV-4. The growing burden that represents the four DENV serotypes has intensified both basic and applied researches to better understand the dengue physiopathology. It has been proposed a significant role for the secreted soluble DENV nonstructural protein 1 (sNS1) glycoprotein in the pathogenesis of severe dengue. Here, we provided an overview on current knowledge about the role of sNS1 in the immunopathogenesis of dengue disease. The reasons for the consideration of sNS1 in the design of future dengue vaccine candidates will be discussed.
REVIEW | doi:10.20944/preprints202009.0103.v1
Subject: Medicine & Pharmacology, Other Keywords: climate change; vector-borne disease; artificial intelligence; explainable AI; geospatial modeling; infectious disease; arbovirus
Online: 4 September 2020 (12:21:32 CEST)
As recent history has shown, changing climate not only threatens to increase the spread of known disease, but also the emergence of new and dangerous phenotypes. This occurred most recently with West Nile virus: a virus previously known for mild febrile illness rapidly emerged to become a major cause of mortality and long-term disability throughout the world. As we move forward, into increasingly uncertain times, public health research must begin to incorporate a broader understanding of the determinants of disease emergence – what, how, why, and when. The increasing mainstream availability of high-quality open data and high-powered analytical methods presents promising new opportunities. Up to now, quantitative models of disease outbreak risk have been largely based on just a few key drivers, namely climate and large-scale climatic effects. Such limited assessments, however, often overlook key interacting processes and downstream determinants more likely to drive local manifestation of disease. Such pivotal determinants may include local host abundance, human behavioral variability, and population susceptibility dynamics. The results of such analyses can therefore be misleading in cases where necessary downstream requirements are not fulfilled. It is therefore important to develop models that include climate and higher-level climatic effects alongside the downstream non-climatic factors that ultimately determine individual disease manifestation. Today, few models attempt to comprehensively address such dynamics: up until very recently, the technology simply hasn’t been available. Herein, we present an updated overview of current perspectives on the varying drivers and levels of interactions that drive disease spread. We review the predominant analytical paradigms, discuss their strengths and weaknesses, and highlight promising new analytical solutions. Our focus is on the prediction of arboviruses, particularly West Nile virus, as these diseases represent the pinnacle of epidemiological complexity – solution to which would serve as an effective “gatekeeper”. We present the current state-of-the-art with respect to known drivers of arbovirus outbreak risk and severity, differentially highlighting the impact of climate and non-climatic drivers. The reality of multiple classes of drivers interacting at different geospatial and temporal scales requires advanced new methodologies. We therefore close out by presenting and discussing some promising new applications of AI. Given the reality of accelerating disease risks due to climate change, public health and other related fields must begin the process of updating their research programs to incorporate these much needed, new capabilities.