Interspecies co-feeding transmission of Powassan virus between a native tick, Ixodes scapularis, and the invasive East Asian tick, Haemaphysalis longicornis.

Background: Powassan virus, a North American tick-borne flavivirus, can cause severe neuroinvasive disease in humans. While Ixodes scapularis are the primary vectors of Powassan virus lineage II (POWV II), also known as deer tick virus, recent laboratory vector competence studies showed that other genera of ticks can horizontally and vertically transmit POWV II. One such tick is the Haemaphysalis longicornis, an invasive species from East Asia that recently established populations in the eastern USA and already shares overlapping geographic range with native vector species such as I.

Horizontal and Vertical Transmission of Powassan Virus by the Invasive Asian Longhorned Tick, , Under Laboratory Conditions.

The Asian longhorned tick, , is an ixodid tick native to East Asia that was first detected in North America outside a port of entry in 2017. This invasive species has since been detected in 17 states. As the invasive range of the tick continues to expand, the vector competence of for pathogens native to North America must be assessed.

Transovarial Transmission of Heartland Virus by Invasive Asian Longhorned Ticks under Laboratory Conditions.

We demonstrated experimental acquisition and transmission of Heartland bandavirus by Haemaphysalis longicornis ticks. Virus was detected in tick salivary gland and midgut tissues. A total of 80% of mice exposed to 1 infected tick seroconverted, suggesting horizontal transmission.

Development of a small animal model for deer tick virus pathogenesis mimicking human clinical outcome.

Powassan virus (POWV) is a tick-borne flavivirus that encompasses two genetic lineages, POWV (Lineage I) and deer tick virus (DTV, Lineage II). In recent years, the incidence of reported POWV disease cases has increased, coupled with an expanded geographic range of the DTV tick vector, Ixodes scapularis. POWV and DTV are serologically indistinguishable, and it is not known whether clinical manifestations, pathology, or disease outcome differ between the two viruses.

Utilization of RNA Hybridization to Understand the Cellular Localization of Powassan Virus RNA at the Tick-Virus-Host Interface.

Skin is the interface between an attached, feeding tick and a host; consequently, it is the first line of defense against invading pathogenic microorganisms that are delivered to a vertebrate host together with tick saliva. Central to the successful transmission of a tick-borne pathogen are complex interactions between the host immune response and early tick-mediated immunomodulation, all of which initially occur at the skin interface. The focus of this work was to demonstrate the use of RNA hybridization (RNA ISH) as a tool for understanding the cellular localization of viral RNA at the feeding site of Powassan virus (POWV)-infected ticks.

Detection of Rickettsiae, Borreliae, and Ehrlichiae in Ticks Collected from Walker County, Texas, 2017-2018.

Cases of tick-borne diseases, including spotted fever rickettsioses, borreliosis, babesiosis, anaplasmosis and ehrlichiosis, in the United States and territories have more than doubled from 2004 to 2016 and account for 77% of all vector-borne disease reports. In an effort to inform control efforts, the presence of tick-borne pathogens and their vectors was assessed in a recreational park in Walker County, Texas. Here we report data from questing ticks collected on three dates from June 2017 to June 2018.

Ixodes scapularis salivary gland microRNAs are differentially expressed during Powassan virus transmission.

Successful tick feeding is facilitated by an assortment of pharmacologically-active factors in tick saliva that create an immunologically privileged micro-environment in the host's skin. Through a process known as saliva-assisted transmission, bioactive tick salivary factors modulate the host environment, promoting transmission and establishment of a tick-borne pathogen. This phenomenon was previously demonstrated for Powassan virus (POWV), a North American tick-borne flavivirus that is the causative agent of a severe neuroinvasive disease in humans.

Tick⁻Virus⁻Host Interactions at the Cutaneous Interface: The Nidus of Flavivirus Transmission.

Tick-borne viral diseases continue to emerge in the United States, as clearly evident from the increase in Powassan encephalitis virus, Heartland virus, and Bourbon virus infections. Tick-borne flaviviruses (TBFVs) are transmitted to the mammalian host along with the infected tick saliva during blood-feeding. Successful tick feeding is facilitated by a complex repertoire of pharmacologically active salivary proteins/factors in tick saliva.

An Overview of Animal Models for Arthropod-Borne Viruses.

Arthropod-borne viruses (arboviruses) have continued to emerge in recent years, posing a significant health threat to millions of people worldwide. The majority of arboviruses that are pathogenic to humans are transmitted by mosquitoes and ticks, but other types of arthropod vectors can also be involved in the transmission of these viruses. To alleviate the health burdens associated with arbovirus infections, it is necessary to focus today's research on disease control and therapeutic strategies.

Powassan Virus: An Emerging Arbovirus of Public Health Concern in North America.

Powassan virus (POWV, Flaviviridae) is the only North American member of the tick-borne encephalitis serogroup of flaviviruses. It is transmitted to small- and medium-sized mammals by Ixodes scapularis, Ixodes cookei, and several other Ixodes tick species. Humans become infected with POWV during spillover transmission from the natural transmission cycles.

Tick Saliva Enhances Powassan Virus Transmission to the Host, Influencing Its Dissemination and the Course of Disease.

Unlabelled: Powassan virus (POWV) is an encephalitic tick-borne flavivirus which can result in serious neuroinvasive disease with up to a 10% case fatality rate. The study objective was to determine whether the salivary gland extract (SGE) from Ixodes scapularis ticks facilitates the transmission and dissemination of POWV in a process known as saliva-activated transmission. Groups of BALB/c mice were footpad inoculated with either a high dose of POWV with and without SGE or a low dose of POWV with and without SGE.

A novel live-attenuated vaccine candidate for mayaro Fever.

Mayaro virus (MAYV) is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge.