African swine fever detection and transmission estimates using homogeneous versus heterogeneous model formulation in stochastic simulations within pig premises.

Background: African swine fever (ASF) is one of the most important foreign animal diseases to the U.S. swine industry.

Intrinsic features of Zika Virus non-structural proteins NS2A and NS4A in the regulation of viral replication.

Zika virus (ZIKV) is a mosquito-borne flavivirus and can cause neurodevelopmental disorders in fetus. As a neurotropic virus, ZIKV persistently infects neural tissues during pregnancy but the viral pathogenesis remains largely unknown. ZIKV has a positive-sense and single-stranded RNA genome, which encodes 7 non-structural (NS) proteins, participating in viral replication and dysregulation of host immunity.

Concomitant pyroptotic and apoptotic cell death triggered in macrophages infected by Zika virus.

Zika virus (ZIKV) is a positive-sense RNA flavivirus and can cause serious neurological disorders including microcephaly in infected fetuses. As a mosquito-borne arbovirus, it enters the bloodstream and replicates in various organs. During pregnancy, it can be transmitted from the blood of the viremic mother to the fetus by crossing the placental barrier.

Predicting the time to detect moderately virulent African swine fever virus in finisher swine herds using a stochastic disease transmission model.

Background: African swine fever (ASF) is a highly contagious and devastating pig disease that has caused extensive global economic losses. Understanding ASF virus (ASFV) transmission dynamics within a herd is necessary in order to prepare for and respond to an outbreak in the United States. Although the transmission parameters for the highly virulent ASF strains have been estimated in several articles, there are relatively few studies focused on moderately virulent strains.

Activation of the NLRP3 inflammasome and elevation of interleukin-1β secretion in infection by sever fever with thrombocytopenia syndrome virus.

Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging phlebovirus that causes a hemorrhagic fever known as the severe fever with thrombocytopenia syndrome (SFTS). Inflammasomes are a molecular platform that are assembled to process pro-caspase 1 and subsequently promote secretion of interleukin (IL)-1β/IL-18 for proinflammatory responses induced upon infection. We hypothesize that inflammasome activation and pyroptosis induced in SFTS results in elevated levels of IL-1β/IL-18 responsible for high fever and hemorrhage in the host, characteristic of SFTS.

Enterovirus A71 2B Inhibits Interferon-Activated JAK/STAT Signaling by Inducing Caspase-3-Dependent Karyopherin-α1 Degradation.

Enterovirus A71 (EV-A71) is a major pathogen that causes the hand, foot, and mouth disease, which could be fatal with neurological complications in children. The underlying mechanism for the severe pathogenicity remains obscure, but impaired or aberrant innate immunity is considered to play a key role in viral pathogenesis. We reported previously that EV-A71 suppressed type I interferon (IFN) responses by inducing degradation of karyopherin-α1 (KPNA1), a component of the p-STAT1/2 complex.

Simulated Flock-Level Shedding Characteristics of Turkeys in Ten Thousand Bird Houses Infected with H7 Low Pathogenicity Avian Influenza Virus Strains.

Understanding the amount of virus shed at the flock level by birds infected with low pathogenicity avian influenza virus (LPAIV) over time can help inform the type and timing of activities performed in response to a confirmed LPAIV-positive premises. To this end, we developed a mathematical model which allows us to estimate viral shedding by 10,000 turkey toms raised in commercial turkey production in the United States, and infected by H7 LPAIV strains. We simulated the amount of virus shed orally and from the cloaca over time, as well as the amount of virus in manure.

A Retrospective Study of Early . Late Virus Detection and Depopulation on Egg Laying Chicken Farms Infected with Highly Pathogenic Avian Influenza Virus During the 2015 H5N2 Outbreak in the United States.

The 2015 highly pathogenic avian influenza (HPAI) H5N2 outbreak affected more than 200 Midwestern U.S. poultry premises.

RIPK3-Dependent Necroptosis Is Induced and Restricts Viral Replication in Human Astrocytes Infected With Zika Virus.

Apoptosis, pyroptosis and necroptosis are regulated processes of cell death which can be crucial for viral disease outcomes in hosts because of their effects on viral pathogenicity and host resistance. Zika virus (ZIKV) is a mosquito-borne flavivirus, which infects humans and can cause neurological disorders. Neural developmental disorders and microcephaly could occur in infected fetuses.

Intrinsic apoptosis and cytokine induction regulated in human tonsillar epithelial cells infected with enterovirus A71.

Enterovirus A71 (EV-A71) has emerged as a clinically important neurotropic virus following poliovirus eradication. Recent studies have shown that human tonsillar epithelial cell lines (UT-SCC-60A and UT-SCC-60B) were susceptible to EV-A71, suggesting that human tonsillar crypt epithelium could be important in EV-A71 pathogenesis. However, the mechanism about how EV-A71 infects the upper oro-digestive tract remains largely unclear.

Estimating epidemiological parameters using diagnostic testing data from low pathogenicity avian influenza infected turkey houses.

Limiting spread of low pathogenicity avian influenza (LPAI) during an outbreak is critical to reduce the negative impact on poultry producers and local economies. Mathematical models of disease transmission can support outbreak control efforts by estimating relevant epidemiological parameters. In this article, diagnostic testing data from each house on a premises infected during a LPAI H5N2 outbreak in the state of Minnesota in the United States in 2018 was used to estimate the time of virus introduction and adequate contact rate, which determines the rate of disease spread.

Conducting Influenza Virus Pathogenesis Studies in Avian Species.

Avian infection studies with influenza A are an important means of assessing host susceptibility, viral pathogenesis, host responses to infection, mechanisms of transmission, viral pathotype, and viral evolution. Complex systems and natural settings may also be explored with carefully designed infection studies. In this chapter, we explore the elements of infection studies, general guidelines for choosing a virus to use, host selection, and many aspects of study design.

Reassortment and adaptive mutations of an emerging avian influenza virus H7N4 subtype in China.

Human infections with avian influenza viruses including H5, H7 and H9 hemagglutinin subtypes occur at a low rate. Among human infections with H7 viruses, regional outbreaks with H7N2, H7N3, H7N7 and H7N9 have been documented. Early in 2018, a human infection with a novel H7N4 avian influenza virus was reported in Jiangsu, China.

Isolation and Characterization of Newcastle Disease Virus from Live Bird Markets in Tanzania.

Chickens in live bird markets (LBMs) from six different regions of Tanzania were surveyed for Newcastle disease (ND) virus (NDV) and avian influenza virus in 2012. ELISA-based serology, virus isolation, and characterization, including pathotyping was conducted. Virulent NDV was isolated from almost 10% of the tested samples, with two distinct genotypes being detected.

Susceptibility of spotted doves (Streptopelia chinensis) to experimental infection with the severe fever with thrombocytopenia syndrome phlebovirus.

Background: Severe fever with thrombocytopenia syndrome virus (SFTSV), an emerging human pathogen naturally transmitted by ticks, has spread widely since it was first detected in 2010. Although SFTSV-specific antibodies have been detected in wild birds, these natural reservoir and amplifying hosts for the virus have not been well studied.

Methodology/principle Findings: Here we report an experimental infection of spotted doves (Streptopelia chinensis) with two strains of SFTSV, JS2010-14, a Chinese lineage strain, and JS2014-16, a Japanese lineage strain, which represent the main viral genotypes currently circulating in East Asia.

Mortality-Based Triggers and Premovement Testing Protocols for Detection of Highly Pathogenic Avian Influenza Virus Infection in Commercial Upland Game Birds.

Outbreaks involving avian influenza viruses are often devastating to the poultry industry economically and otherwise. Disease surveillance is critically important because it facilitates timely detection and generates confidence that infected birds are not moved during business continuity intended to mitigate associated economic losses. The possibility of using an abnormal increase in daily mortality to levels that exceed predetermined thresholds as a trigger to initiate further diagnostic investigations for highly pathogenic avian influenza (HPAI) virus infection in the flock is explored.

Environmental Sampling Survey of H5N2 Highly Pathogenic Avian Influenza-Infected Layer Chicken Farms in Minnesota and Iowa.

Respiratory secretions, feces, feathers, and eggs of avian influenza-infected hens provide ample sources of virus which heavily contaminate barn and farm environments during a disease outbreak. Environmental sampling surveys were conducted in the Midwestern United States on affected farms during the 2015 H5N2 highly pathogenic avian influenza (HPAI) outbreak to assess the degree of viral contamination. A total of 930 samples were obtained from various sites inside and outside layer barns housing infected birds and tested with real-time reverse transcriptase PCR.

Analysis of geographic location and pathways for influenza A virus infection of commercial upland game bird and conventional poultry farms in the United States of America.

Background: Avian influenza (AI) is an infectious viral disease that affects several species and has zoonotic potential. Due to its associated health and economic repercussions, minimizing AI outbreaks is important. However, most control measures are generic and mostly target pathways important for the conventional poultry farms producing chickens, turkeys, and eggs and may not target other pathways that may be specific to the upland game bird sector.

Suppression of the IFN-α and -β Induction through Sequestering IRF7 into Viral Inclusion Bodies by Nonstructural Protein NSs in Severe Fever with Thrombocytopenia Syndrome Bunyavirus Infection.

Induction of type I IFNs during viral infection is crucial for host defense. IRF 3 and IRF7 play a critical role as key transcription factors in the activation of the IFN induction. Viruses have evolved a variety of strategies to evade innate immunity.

Avian Influenza in the U.S. Commercial Upland Game Bird Industry: An Analysis of Selected Practices as Potential Exposure Pathways and Surveillance System Data Reporting.

Producing a smaller yield of higher-value birds compared to conventional poultry production, the U.S. commercial upland game bird industry deals primarily in the sale of live birds for recreational hunting.

Spatial transmission of H5N2 highly pathogenic avian influenza between Minnesota poultry premises during the 2015 outbreak.

The spatial spread of highly pathogenic avian influenza (HPAI) H5N2 during the 2015 outbreak in the U.S. state of Minnesota was analyzed through the estimation of a spatial transmission kernel, which quantifies the infection hazard an infectious premises poses to an uninfected premises some given distance away.