Publications by authors named "Douglas Walsh"

Broad-spectrum crop protection technologies, such as abamectin and bifenthrin, are globally relied upon to curb the existential threats from economic crop pests such as the generalist herbivore Koch (TSSM). However, the rising cost of discovering and registering new acaricides, particularly for specialty crops, along with the increasing risk of pesticide resistance development, underscores the urgent need to preserve the efficacy of currently registered acaricides. This study examined the overall genetic mechanism underlying adaptation to abamectin and bifenthrin in populations from commercial hop fields in the Pacific Northwestern region of the USA.

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  • Researchers have successfully applied chemical species tomography (CST) to image the exhaust plume of gas turbines used in commercial aircraft, focusing on a specific near-infrared absorbing species.
  • The study employs advanced tunable diode laser spectroscopy to measure absorption spectra, capturing data across various thrust levels and utilizing multiple data inversion techniques for image reconstruction.
  • Notably, the images reveal a consistent ring structure of high concentration in the exhaust, indicating promising applications for CST in advancing turbine combustion, engine development, and fuel research.
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  • Malaria remains a significant health issue in Thailand, particularly in border areas with mobile populations that facilitate its spread.
  • A study of 112 Plasmodium falciparum isolates showed prevalent resistance mutations, including pfmdr1-Y184F and various pfk13 point mutations, linked to increased survival rates against treatment.
  • The rise in resistant genotypes during 2014-2015 implies a connection with treatment failures in neighboring Cambodia, highlighting the need for coordinated efforts among countries to address malaria elimination.
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The two-spotted spider mite, Tetranychus urticae, is a polyphagous pest feeding on over 1100 plant species, including numerous highly valued economic crops. The control of T. urticae largely depends on the use of acaricides, which leads to pervasive development of acaricide resistance.

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Larvae of Prionus californicus Motschulsky feed on the roots of many woody perennial plants and are economically important pests of hop Humulus lupulus L. (Urticales: Cannabaceae) and sweet cherry Prunus avium (L.) (Magnoliopsida: Rosaceae) in the United States Pacific Northwest and Intermountain West.

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Tetranychus urticae Koch is a generalist pest of economic crops and is notorious for its rapid development of acaricide resistance. This poses a significant threat to the sustainability of integrated pest management (IPM) in cropping systems plagued by T. urticae.

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The grape mealybug, Pseudococcus maritimus (Ehrhorn; Hemiptera: Pseudococcidae), is the primary vector of Grapevine Leafroll associated Viruses (GLRaVs) in Washington State vineyards. Rearing laboratory colonies of grape mealybug has proven difficult. Several host plants were tested to determine their suitability for use as an alternate host plants for laboratory colonies of grape mealybug.

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Background: While intensive Plasmodium falciparum multidrug resistance surveillance continues in Cambodia, relatively little is known about Plasmodium vivax drug resistance in Cambodia or elsewhere. To investigate P. vivax anti-malarial susceptibility in Cambodia, 76 fresh P.

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Artemisinin-based combination therapies are recommended as first-line agents for treating uncomplicated malaria. Ferroquine, a 4-aminoquinolone, is a novel long-acting combination partner for fast-acting drugs like artesunate (AS). We did a small phase 2a, multicenter, open-label, safety-focused dose-ranging randomized study of ferroquine at three African hospitals: two Gabonese and one Kenyan.

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Contracted commercial beekeeping operations provide an essential pollination service to many agricultural systems worldwide. Increased use of genetically engineered crops in agriculture has raised concerns over pollinator-mediated gene flow between transgenic and conventional agricultural varieties. This study evaluated whether contracted migratory beekeeping practices influence transgenic pollen flow among spatially isolated alfalfa fields.

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Background: The recent dramatic decline in dihydroartemisinin-piperaquine (DHA-PPQ) efficacy in northwestern Cambodia has raised concerns about the rapid spread of piperaquine resistance just as DHA-PPQ is being introduced as first-line therapy in neighbouring countries.

Methods: Ex vivo parasite susceptibilities were tracked to determine the rate of progression of DHA, PPQ and mefloquine (MQ) resistance from sentinel sites on the Thai-Cambodian and Thai-Myanmar borders from 2010 to 2015. Immediate ex vivo (IEV) histidine-rich protein 2 (HRP-2) assays were used on fresh patient Plasmodium falciparum isolates to determine drug susceptibility profiles.

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Quantitative real-time PCR (qRT-PCR) is an extensively used, high-throughput method to analyze transcriptional expression of genes of interest. An appropriate normalization strategy with reliable reference genes is required for calculating gene expression across diverse experimental conditions. In this study, we aim to identify the most stable reference genes for expression studies of xenobiotic adaptation in Tetranychus urticae, an extremely polyphagous herbivore causing significant yield reduction of agriculture.

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In a Phase 1 trial, we evaluated the safety of AERAS-402, an adenovirus 35-vectored TB vaccine candidate expressing 3 Mycobacterium tuberculosis (Mtb) immunodominant antigens, in subjects with and without latent Mtb infection. HIV-negative, BCG-vaccinated Kenyan adults without evidence of tuberculosis, 10 QuantiFERON(®)-TB Gold In-Tube test (QFT-G)(-) and 10 QFT-G(+), were randomized 4:1 to receive AERAS-402 or placebo as two doses, on Days 0 and 56, with follow up to Day 182. There were no deaths, serious adverse events or withdrawals.

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The increased urbanization of a growing global population makes imperative the development of sustainable integrated pest management (IPM) strategies for urban pest control. This emphasizes pests that are closely associated with the health and wellbeing of humans and domesticated animals. Concurrently there are regulatory requirements enforced to minimize inadvertent exposures to insecticides in the urban environment.

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Background: In addition to evidence for a protective role of antibodies to the malaria blood stage antigen merozoite surface protein 1 (MSP1), MSP1 antibodies are also considered as a marker of past malaria exposure in sero-epidemiological studies.

Methods: In order to better assess the potential use of MSP1 serology in malaria chemoprophylaxis trials in endemic areas, an analysis for the prevalence of antibodies to both Plasmodium falciparum and Plasmodium vivax MSP142 in healthy Cambodian adults was conducted at two sites as part of an active, observational cohort evaluating the efficacy of dihydroartemisinin-piperaquine (DP) for uncomplicated malaria (ClinicalTrials.gov identifier NCT01280162).

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The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations.

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The vinegar fly, Drosophila suzukii (Diptera: Drosophilidae), is a recent invader in North America that has become a serious threat to small fruit production. It was first detected in California in 2008 and in Washington state in 2009. In this study, D.

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Drosophila suzukii Matsumara, also referred to as the spotted wing drosophila, has recently expanded its global range with significant consequences for its primary host crops: blueberries, blackberries, raspberries, cherries, and strawberries. D. suzukii populations can increase quickly, and their infestation is difficult to predict and prevent.

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ATP-binding cassette (ABC) transporters are a large superfamily of proteins that mediate diverse physiological functions by coupling ATP hydrolysis with substrate transport across lipid membranes. In insects, these proteins play roles in metabolism, development, eye pigmentation, and xenobiotic clearance. While ABC transporters have been extensively studied in vertebrates, less is known concerning this superfamily in insects, particularly hemipteran pests.

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Introduction: Emerging antimalarial drug resistance in mobile populations remains a significant public health concern. We compared two regimens of dihydroartemisinin-piperaquine in military and civilians on the Thai-Cambodian border to evaluate national treatment policy.

Methods: Efficacy and safety of two and three-day regimens of dihydroartemisinin-piperaquine were compared as a nested open-label evaluation within a malaria cohort study in 222 otherwise healthy volunteers (18% malaria-infected at baseline).

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We tested an immunomarking system that used egg white as marker and enzyme-linked immunosorbent assay as a detection assay to characterize face fly (Musca autumnalis DeGeer) dispersal from cow pats in a pastured beef cattle operation. In microcage assays, adult flies acquired marker after contact with cow pats that were treated with marker and field aged up to 11 d. In arena assays on sprayed full-size cow pats, 77% of eclosed face flies acquired the marker.

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We studied cross-reactive antibodies against avian influenza H5N1 and 2009 pandemic (p) H1N1 in 200 serum samples from US military personnel collected before the H1N1 pandemic. Assays used to measure antibodies against viral proteins involved in protection included a hemagglutination inhibition (HI) assay and a neuraminidase inhibition (NI) assay. Viral neutralization by antibodies against avian influenza H5N1 and 2009 pH1N1 was assessed by influenza (H5) pseudotyped lentiviral particle-based and H1N1 microneutralization assays.

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Background: Despite widespread coverage of the emergence of artemisinin resistance, relatively little is known about the parasite populations responsible. The use of PCR genotyping around the highly polymorphic Plasmodium falciparum msp1, msp2 and glurp genes has become well established both to describe variability in alleles within a population of parasites, as well as classify treatment outcome in cases of recurrent disease. The primary objective was to assess the emergence of minority parasite clones during seven days of artesunate (AS) treatment in a location with established artemisinin resistance.

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Background: Knockdown resistance (kdr) has been identified as a main mechanism against pyrethroid insecticides in many arthropod pests including in the onion thrips, Thrips tabaci. To characterize and identify pyrethroid-resistance in onion thrips in Washington state, we conducted insecticide bioassays and sequenced a region of the voltage gated sodium channel gene from several different T. tabaci populations.

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