Publications by authors named "Brad Biggerstaff"

Cache Valley virus (CVV), a mosquito-borne orthobunyavirus, causes epizootics in ruminants characterized by congenital malformations and fetal death in North America. Only seven human infections have been identified; limited information exists on its potential as a human teratogen. Diagnosis of CVV infections relies on the plaque reduction neutralization test (PRNT), which requires live virus, is time-consuming, and cannot differentiate between recent and past infections.

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  • - COVID-19 convalescent plasma (CCP) may be beneficial for immunocompromised patients, but the FDA's current threshold for qualifying plasma based on antibody levels might be too low.
  • - A study evaluated antibody levels in blood donors with different infection and vaccination histories, revealing that those with hybrid immunity (infection followed by vaccination) had higher antibody levels and better neutralizing capabilities.
  • - The research suggests establishing new test-based criteria for qualifying CCP, highlighting that plasma with high antibody levels could effectively neutralize various COVID-19 variants for several months after infection or vaccination.
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  • * A study involving 142,599 blood donors established a new, lower threshold for detecting past infections using the Ortho VITROS Anti-SARS-CoV-2 Total-N Antibody assay, which boosted detection sensitivity while keeping specificity above 98%.
  • * The updated test showed a high sensitivity of 98.1% for unvaccinated individuals and 95.6% for those who were vaccinated, though sensitivity was influenced by factors like the virus variant, donor age,
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Group testing is the process of testing items as an amalgamation, rather than separately, to determine the binary status for each item. Its use was especially important during the COVID-19 pandemic through testing specimens for SARS-CoV-2. The adoption of group testing for this and many other applications is because members of a negative testing group can be declared negative with potentially only one test.

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  • * New Jersey mosquito control agencies have been using wooden resting boxes for surveillance since 1975 and conducted studies to evaluate mosquito traps, aiming to optimize the collection of the main EEEV vector, Culiseta melanura.
  • * The studies found that corrugated plastic boxes were better at trapping blood-fed Cs. melanura than other types of traps, and non-CO2 baited traps were more effective than dry ice traps for capturing host-seeking mosquitoes, highlighting the need for agencies to reassess their EEE
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Background: Alpha-gal syndrome (AGS) is an allergy to galactose-α-1,3-galactose (alpha-gal), a carbohydrate found in most mammals. Evidence indicates that AGS develops after a tick bite, and in the United States, AGS is most associated with bites from Amblyomma americanum (lone star tick); however, not all persons bitten by ticks develop clinical AGS.

Objective: To investigate intrinsic risk factors associated with the development of AGS.

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  • * Testing for these viruses is complicated due to a lack of human samples needed for accurate serological analysis.
  • * Researchers developed a murine monoclonal antibody that mimics human IgM, which was tested as a potential replacement for human-positive controls in diagnostic tests.
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  • The U.S. Nationwide Blood Donor Seroprevalence Study tracked SARS-CoV-2 antibody levels from July 2020 to December 2021, adapting testing methods as vaccine uptake increased and pandemic conditions changed.* -
  • The study assessed the effectiveness of the Ortho anti-nucleocapsid (NC) test as a substitute for the Roche NC test, finding high agreement in results and confirming that most specimens provided consistent reactivity.* -
  • Overall, the use of parallel testing on both Roche and Ortho platforms demonstrated high efficiency and agreement, making it valuable for large-scale seroprevalence studies that monitor the spread of COVID-19.*
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In 2020, Montana, USA, reported a large increase in Colorado tick fever (CTF) cases. To investigate potential causes of the increase, we conducted a case-control study of Montana residents who tested positive or negative for CTF during 2020, assessed healthcare providers' CTF awareness and testing practices, and reviewed CTF testing methods. Case-patients reported more time recreating outdoors on weekends, and all reported finding a tick on themselves before illness.

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Background: The disaccharide galactose-α-1,3-galactose (alpha-gal) is expressed in mammals other than humans, apes, and old-world monkeys. In humans, elevated immunoglobulin E (IgE) antibodies specific for alpha-gal can result in allergic hypersensitivity known as alpha-gal syndrome (AGS). Case reports and series suggest that tick bites can induce alpha-gal-specific IgE (sIgE) antibodies.

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Background: Current isolation techniques for spotted fever group Rickettsia from clinical samples are laborious and are limited to tissue, blood and blood derivatives with volumes ideally greater than 1 mL. We validated the use of simplified methodologies for spotted fever group Rickettsia culture isolation that overcome sample volume limitations and provide utility in clinical diagnostics and research studies.

Methodology/principal Findings: A modified cell culture method is evaluated for the isolation of Rickettsia ssp.

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Background: Alpha-gal syndrome (AGS) is an IgE-mediated allergy to galactose-alpha-1,3-galactose. Clinical presentation ranges from hives to anaphylaxis; episodes typically occur 2-6 h after exposure to alpha-gal-containing products. In the United States, lone star tick bites are associated with the development of AGS.

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Background: Previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) vaccination, independently and combined ("hybrid immunity"), result in partial protection from subsequent infection and strong protection from severe disease. Proportions of the US population who have been infected, vaccinated, or have hybrid immunity remain unclear, posing a challenge for assessing effective pandemic mitigation strategies.

Methods: In this serial cross-sectional study, nationwide blood donor specimens collected during January-December 2021 were tested for anti-spike and anti-nucleocapsid antibodies, and donor COVID-19 vaccination history of ≥1 dose was collected.

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Flaviviruses are important human pathogens worldwide. Diagnostic testing for these viruses is difficult because many of the pathogens require specialized biocontainment. To address this issue, we generated 39 virus-like particle (VLP)- and nonstructural protein 1 (NS1)-secreting stable cell lines in HEK-293 cells of 13 different flaviviruses, including dengue, yellow fever, Japanese encephalitis, West Nile, St.

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  • Lyme disease and other tick-borne diseases are significant public health concerns in the Upper Midwest, particularly in Michigan, Minnesota, and Wisconsin, prompting officials to recommend various prevention measures.
  • A survey conducted in 2019 across 48 high-risk counties revealed that while 98% of people had heard of Lyme disease and many recognized its seriousness, only about 25% thought tick-borne diseases were common in their community.
  • Despite this, there seems to be a high willingness among the population to adopt preventive behaviors, with 82% willing to perform daily tick checks and over 60% open to using bug repellent and tick control products for pets.*
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serosurveys can estimate cumulative incidence for monitoring epidemics, requiring assessment of serologic assays to inform testing algorithm development and interpretation of results. We conducted a multilaboratory evaluation of 21 commercial high-throughput SARS-CoV-2 serologic assays using blinded panels of 1,000 highly characterized specimens. Assays demonstrated a range of sensitivities (96%-63%), specificities (99%-96%), and precision (intraclass correlation coefficient 0.

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  • Lyme disease cases are rising, prompting the development of new vaccine candidates, but understanding public acceptance is crucial before market release.
  • A survey conducted in June-July 2018 across several states found that 64% of respondents were willing to get vaccinated, while 30% were uncertain, and 7% were unwilling.
  • Factors influencing vaccine hesitancy included being non-White, having less education, safety concerns, low confidence in vaccines, and a low perceived risk of Lyme disease.
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Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus testing among first responders and healthcare personnel who participated in a May 2020-August 2020 serosurvey that assessed spike protein antibodies provided an opportunity to assess reinfection.

Methods: Serology survey data were merged with virus testing results from Rhode Island (1 March 2020-17 February 2021) and New York City (10 March 2020-14 December 2020). Participants with a positive virus test ≥14 days before their serology test were included.

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Objectives: The number of SARS-CoV-2 infections is underestimated in surveillance data. Various approaches to assess the seroprevalence of antibodies to SARS-CoV-2 have different resource requirements and generalizability. We estimated the seroprevalence of antibodies to SARS-CoV-2 in Denver County, Colorado, via a cluster-sampled community survey.

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We estimated the distributions of duration of SARS-CoV-2 nucleic acid shedding and time to reinfection among 137 persons with at least 2 positive nucleic acid amplification test (NAAT) results from March to September 2020. We analyzed gaps of varying length between subsequent positive and negative NAAT results and estimated a mean duration of nucleic acid shedding of 30.1 days (95% confidence interval [CI], 26.

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  • A study aimed to estimate how many people in the US have SARS-CoV-2 antibodies due to past infection or vaccination, revealing that both factors significantly reduce the risk of getting COVID-19 again.
  • The research involved over 1.5 million blood samples collected from donors across all US states and territories between July 2020 and May 2021, providing a broad representation of the population.
  • The results indicated that seroprevalence estimates were notably higher than reported COVID-19 case rates, suggesting many more people may have been infected than documented.
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West Nile virus (WNV) and Zika virus (ZIKV) are mosquito-borne viruses in the family . Residents in, and travelers to, areas where the viruses are circulating are at risk for infection, and both viruses can cause an acute febrile illness. Given known cross-reactivity in flavivirus serologic assays, it is possible a patient with acute WNV infection could be misdiagnosed as having ZIKV infection if appropriate testing is not conducted.

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Tickborne diseases are an increasing public health problem in the northeastern USA. Bait boxes that apply acaricide to rodents have been shown in small field studies to significantly reduce abundance of Ixodes scapularis ticks as well as their pathogen infection rates in treated areas. The effectiveness of this intervention for preventing human tickborne diseases (TBDs) has not been demonstrated.

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