Morphological and molecular characterizations of Pratylenchus coffeae infecting Ming aralia and coffee in Vietnam.

Pratylenchus coffeae, belonging to the root-lesion nematode group, is a highly prevalent and destructive plant-parasitic nematode that is able to infest a wide range of host plants. Although this species' devastating impacts on coffee plantations across the world are widely known on other host plants, its association with Ming aralia has never been reported. Our study characterized two popu lations of P. coffeae (associated with Ming aralia and coffee) and compared them with other popu lations from previous studies in Vietnam and other countries in the world. The identification of P. coffeae in our study was confirmed by the comprehensive analysis encompassing morphological examination, morphometric data, and molecular characterizations of the COI mtDNA and D2D3 of 28S rRNA regions. The cluster and MDS analyses revealed that the two populations of P. coffeae from Vietnam are closely related to those from Japan and Indonesia. The D2-D3 sequences of 28S rRNA and COI mtDNA regions exhibited high similarity among these populations, indicating a stable genetic profile. Our research contributes to a better understanding of the distribution and genetic characterizations of P. coffeae by offering new morphological and molecular insights into the presence of this nematode in Vietnam. Additionally, this nematode species was found to be associated with host plant's symptoms such as chlorotic leaves, stunted growth and root lesion in both hosts. Given the economic significance of both Ming aralia and coffee crops in Vietnam, as well as the damaging potential of P. coffeae, this study emphasizes the need of proactive nematode management measures to control this destructive pest.

Method for taking Scanning Electron Microscope photographs of nematodes and meiofauna with the support of a low-cost and easy-made container.

This paper presents a method for capturing Scanning Electron Microscope (SEM) photographs of small specimens, including nematodes, arthropods, small insects, and other meiofauna. Our method is tailored to handle nematode specimens mounted on permanent slides, an area with relatively limited documentation. Besides, the process of transferring such delicate specimens from one solution to another has historically posed numerous challenges. To address this issue, we introduce a low-cost and easy-made container designed specifically to facilitate the aforementioned procedure, with a particular focus on SEM photography. The newly introduced container offers a practical solution that enhances the efficiency and effectiveness of specimen handling, ultimately enabling high-quality SEM imaging. This method holds significant promise for researchers working in the field of micro-scopic organism analysis, providing a valuable tool for their investigations with minimum cost.

Description of Hemicycliophora cardamomi sp. n. (Nematoda: Hemicycliophoridae) associated with Amomum longiligulare T.L. Wu and a web-based key for the identification of Hemicycliophora spp.

During a survey of plant diseases in the Central Highlands of Vietnam, a new plant-parasitic nematode, Hemicycliophora cardamomi sp. n., was discovered in the growing areas of Amomum longiligulare, a valuable medicinal plant with high economical value. The new species is characterized by a cuticular sheath loosely fitting body; a labial region continuous to the body contour bearing 3 annuli; a lateral field frequently marked by a discontinuous single line with indistinct additional short lines in some parts along the body; a modified vulval lip with an anterior lip c. 4 annuli long; and a post-vulval body tapering to a pointed tail tip with an abrupt constriction at the last third of the post-vulval body. Morphology and molecular characterizations of D2-D3 expansion segment of 28S rRNA, ITS, and COI mtDNA gene regions clearly distinguish the new species from all other 133 known species. This study also provides a newly developed web-based key for the identification of Hemicycliophora spp. in order to accelerate the identification process, to minimize the increasing error load associated with larger datasets, and to avoid any dependence on a single starting entry. This key includes both an existing Bray-Curtis similarity measure and a newly developed similarity formula.

First Report of an Important Sheat Nematode, Hemicycliophora Poranga, Associated with Sugar Beet (Beta Vulgaris L.) in Vietnam.

Several species of the sheat nematodes, Hemicycliophora spp., have been known to cause significant damage to agricultural crops, including Hemicycliophora arenaria, H. conida, H. parvana, H. poranga, H. similis, and H. typica. Remarkably, our study reported on the presence of H. poranga for the first time in Vietnam. This species was found on 83.33% of the total samples with an average density of 270 individuals/100ml of soil (positive samples). In this study, the Vietnamese population of H. poranga was characterized based on both morphology and molecular characterization of D2-D3 expansion segment of 28S rRNA sequence. Besides, a molecular phylogenetic tree of the genus Hemicycliophora was also provided.

Meloidogyne daklakensis n. sp. (Nematoda: Meloidogynidae), a new root-knot nematode associated with Robusta coffee (Coffea canephora Pierre ex A. Froehner) in the Western Highlands, Vietnam.

The root-knot nematode species Meloidogyne daklakensis n. sp. was discovered on the roots of Robusta coffee (Coffea canephora Pierre ex A. Froehner) in Dak Lak Province, Vietnam. This species is characterized by the females having rounded or oval perineal patterns, smooth, regular, continuous striae, and reduced lateral lines. The dorsal arch is low, rounded and encloses a quite distinct vulva and tail tip. The stylet is normally straight with well-developed and posteriorly sloped knobs. The males have a rounded cap that extends posteriorly into the lip region. The procorpus is outlined distinctly, and is three times longer than the metacorpus. The metacorpus is ovoid, with a strong valve apparatus. The species closely resembles M. marylandi, M. naasi, M. ovalis, M. panyuensis, M. lopezi, M. mali and M. baetica in the perineal pattern of the females, and the morphology of the males and the second-stage juveniles. Nonetheless, it can be differentiated from other species by a combination of morphometric, morphological and molecular characteristics. Phylogenetic analysis was conducted based on the internal transcribed spacer (ITS) and 28S rDNA as well as the region between the cytochrome c oxidase I (COI) and cytochrome c oxidase II (COII) mitochondrial genes. Herein, this nematode is described, illustrated, and designated as a new species, Meloidogyne daklakensis sp. n., based on morphometric, morphological and molecular analyses.

A New Root-knot Nematode, Meloidogyne Moensi n. Sp. (Nematoda: Meloidogynidae), Parasitizing Robusta Coffee from Western Highlands, Vietnam.

A new root-knot nematode, parasitizing Robusta coffee in Dak Lak Province, Western Highlands of Vietnam, is described as Meloidogyne moensi n. sp. Morphological and molecular analyses demonstrated that this species differs clearly from other previously described root-knot nematodes. Morphologically, the new species is characterized by a swollen body of females with a small posterior protuberance that elongated from ovoid to saccate; perineal patterns with smooth striae, continuous and low dorsal arch; lateral lines marked as a faint space or linear depression at junction of the dorsal and ventral striate; distinct phasmids; perivulval region free of striae; visible and wide tail terminus surrounding by concentric circles of striae; medial lips of females in dumbbell-shaped and slightly raised above lateral lips; female stylet is normally straight with posteriorly sloping stylet knobs; lip region of second stage juvenile (J2) is not annulated; medial lips and labial disc of J2 formed dumbbell shape; lateral lips are large and triangular; tail of J2 is conoid with rounded unstriated tail tip; distinct phasmids and hyaline; dilated rectum. Meloidogyne moensi n. sp. is most similar to M. africana, M. ottersoni by prominent posterior protuberance. Results of molecular analysis of rDNA sequences including the D2-D3 expansion regions of 28S rDNA, COI, and partial COII/16S rRNA of mitochondrial DNA support for the new species status.

Contribution of bone turnover markers to the variation in bone mineral density: a study in Vietnamese men and women.

The present cross-sectional study constructed reference ranges for bone resorption marker beta isomerized form of C-terminal crosslinking telopeptides of type I collagen (beta-CTX) and bone formation marker procollagen type 1 N-terminal propeptide (PINP) for the Vietnamese population. We have further shown that for a given age and weight, higher levels of beta-CTX were significantly associated with bone mineral density in men and women. INTRODUCTION: Normal bone is constantly renewed by two opposing processes of resorption and formation which can be reflected by bone turnover markers (BTMs). This study sought to define the contribution of BTMs to the variation in bone mineral density (BMD) in normal individuals. METHODS: The study involved 205 men and 432 women aged between 18 and 87, who were randomly selected from various districts within Ho Chi Minh City, Vietnam. Fasting serum levels of PINP and beta-CTX were determined by electrochemiluminescence (Roche, ECLIA). BMD at the lumbar spine (LS) and femoral neck (FN) was measured by dual-energy x-ray absorptiometry (Hologic, Waltham, MA, USA). RESULTS: Among those aged < 50 years, women had lower PINP and beta-CTX levels than men, but among those aged > 50 years, women had higher PINP and beta-CTX levels than men. In the multiple linear regression analysis, beta-CTX-but not PINP-was significantly associated with both femoral neck (P = 0.008) and lumbar spine BMD (P = 0.008) and the association was independent of gender, age, and body weight. The proportion of variance in BMD attributable to beta-CTX was 1% for femoral neck BMD and 2% for lumbar spine BMD. CONCLUSION: The elevation in bone formation marker PINP and bone resorption marker beta-CTX in postmenopausal women was greater than in elderly men. However, only beta-CTX was modestly but significantly associated with BMD.

Postoperative imaging of orthopaedic hardware in the hand and wrist: is there an added value for tomosynthesis?

AIM: To prospectively investigate digital tomosynthesis (DTS) as an alternative to digital radiography (DR) for postoperative imaging of orthopaedic hardware after trauma or arthrodesis in the hand and wrist. MATERIALS AND METHODS: Thirty-six consecutive patients (12 female, median age 36 years, range 19-86 years) were included in this institutional review board approved clinical trial. Imaging was performed with DTS in dorso-palmar projection and DR was performed in dorso-palmar, lateral, and oblique views. Images were evaluated by two independent radiologists for qualitative and diagnosis-related imaging parameters using a four-point Likert scale (1=excellent, 4not diagnostic) and nominal scale. Interobserver agreement between the two readers was assessed with Cohen's kappa (k). Differences between DTS and CR were tested with Wilcoxon's signed-rank test. A p-value <0.05 was considered statistically significant. RESULTS: Regarding image quality, interobserver agreement was higher for DTS compared to DR, especially for fracture-related parameters (delineation osteosynthesis material [OSM]: KDTS0.96 versus KDR0.45; delineation fracture margins: KDTS0.78 versus KDR0.35). Delineation of fracture margins and delineation of adjacent joint spaces scored significant better for DTS compared to DR (delineation fracture margins: DTS1.54, DR2.28, p0.001; delineation adjacent joint spaces: DTS1.31, DR2.24, p0.001). Regarding diagnosis-related findings, interobserver agreement was almost equal. DTS showed a significant higher sharpness of fracture margins (DTS1.94, DR2.33, p0.04). Mean dose area product (DAP) for DTS was significant higher compared to DR (mean DR0.219 Gy·cm2, mean DTS0.903 Gy·cm2, p0.001). CONCLUSION: Fracture healing is more visible and interobserver agreement is higher for DTS compared to DR in the postoperative assessment of orthopaedic hardware in the hand and wrist.

Quantitative value chain approaches for animal health and food safety.

Economic impact assessments are increasingly important in the context of animal health and food safety, although much of the existing literature does not address the broader systems context in which disease transmission takes place. In this paper, we discuss the role of system dynamics modeling in addressing the value chain impacts associated with animal health and food safety issues. System dynamics methods hold promise as a means of capturing the complex feedbacks that exist between the biology, economics, and behavioral aspects of food safety and animal health systems. We provide a proof-of-concept of this approach in the context of food safety and animal health in the smallholder pig sector of Viet Nam. Results highlight the important tradeoffs that exist between policy objectives and the costs required to achieve them.

Understanding the responses of Saccharomyces cerevisiae yeast strain during dehydration processes using synchrotron infrared spectroscopy.

For the first time, synchrotron infrared spectroscopy was performed on yeast during dehydration processes in real time with simultaneously controlled relative humidity and temperature. This led us to investigate the biochemical modification in relation to the dehydration of Saccharomyces cerevisiae. The correlation between the hydration level and yeast survival was observed. Following the test conditions, the modification of the protein structure was observed. However, no evident modification of the lipid composition resulting from dehydration was observed. Furthermore, the results showed that the medium rich in nutrients and glutathione precursors can improve yeast survival during dehydration at 45 °C. This could be related to the high relative amounts of CH3 groups in the lipid composition assigned to the low lipid oxidation level in this case. Our work demonstrated the feasibility of using S-FTIR for investigating yeast responses to dehydration processes in real time. This method can be used for understanding the effect of dehydration/rehydration on the biochemical modification of yeast.

Visualisation of passive middle ear implants by cone beam and multi-detector computed tomography: a comparative in vitro study.

OBJECTIVES: Modern passive middle ear titanium prostheses are filigree structures, resulting in poorer depiction on CT compared to prostheses used in the past. We compared the visibility of newer prostheses on cone beam CT (CBCT) to multi-detector CT (MDCT) with standard and lower dose in vitro, and analysed image noise and metal artefacts. METHODS: Six different titanium middle ear prostheses (three partial and one total ossicular replacement prostheses, two stapes prostheses) were implanted twice in formalin-fixed head specimens-first correctly and then with displacement. Imaging was performed using standard CBCT and MDCT as well as MDCT with lower dose (36 single imaging investigations). Images were analysed with knowledge of the used types of middle ear prostheses, but blinded with respect to the positioning in the specific case. RESULTS: On all images the type of prostheses and their positions could be clearly recognized. Their identifiability including their details was rated as statistically significantly higher for all CBCT investigations than for MDCT. MDCT with lower dose showed the worst results. No statistical differences were found in image noise and metal artefacts. CONCLUSIONS: If available, CBCT should be preferred over MDCT in diagnostic evaluation of passive middle ear prostheses. KEY POINTS: • Middle ear prostheses became more filigree, leading to poorer visibility on CT. • High spatial resolution and paraxial reconstructions are necessary requirements for imaging evaluation. • CBCT and MDCT can identify type and positioning of titanium prostheses. • Metal artefacts play a minor part in filigree titanium prostheses. • Regarding visualisation of prostheses details, cone beam CT aids the evaluation.

Semiautomatic superimposition improves radiological assessment of curve flexibility in scoliosis.

OBJECTIVE: Assessment of scoliotic curve flexibility and stiffness is essential for planning surgical treatment in adolescent idiopathic scoliosis (AIS). Measurement of curve flexibility is currently insufficiently precise. The purpose of this study was to introduce and validate a novel method of superimposing radiographs for more reliable measurement of curve flexibility. MATERIAL AND METHODS: Two independent radiologists measured Cobb angles separately on standard anterior-posterior (AP) (n = 48) and supine bending radiographs (n = 48), in patients with AIS, who were randomly included from a surgical database. The same readers repeated the measurements after the bending radiographs were semi-automatically superimposed on the AP radiographs by fusing the caudad end vertebra. Curve flexibility was calculated. Inter-reader agreement between the two independent readers was calculated using interclass correlation coefficient (ICC). RESULTS: A moderate inter-reader agreement was achieved in the upper curve (ICC = 0.57) and a good agreement in the lower curve (ICC = 0.72) with the standard method of assessing curve flexibility. With the use of the semiautomatic superimposition, however, almost perfect agreement was achieved for both the upper and the lower curves flexibilities (ICC = 0.93 and 0.97, respectively). CONCLUSION: The introduced semi-automatic superimposition technique for measurement of scoliotic curve flexibility in AIS is more precise and reliable than the current standard method.

Functional characterization of ABCC2 promoter polymorphisms and allele-specific expression.

Multidrug resistance protein 2 (MRP2, ABCC2) is an efflux membrane transporter highly expressed in liver, kidney and intestine with important physiological and pharmacological roles. The goal of this study was to investigate the functional significance of promoter region polymorphisms in ABCC2 and potential allele-specific expression. Twelve polymorphisms in the 1.6 kb region upstream of the translation start site were identified by resequencing 247 DNA samples from ethnically diverse individuals. Luciferase reporter gene assays showed that ABCC2 -24C>T both alone and as part of a common haplotype (-24C>T/-1019A>G/-1549G>A) increased promoter function 35% compared with the reference sequence (P<0.0001). No other common variants or haplotypes affected ABCC2 promoter activity. Allele-specific expression was also investigated as a mechanism to explain reported associations of the synonymous ABCC2 3972C>T variant with pharmacokinetic phenotypes. In Caucasian liver samples (n=41) heterozygous for the 3972C>T polymorphism, the 3972C allele was preferentially transcribed relative to the 3972T allele (P<0.0001). This allelic imbalance was particularly apparent in samples with haplotypes containing two or three promoter/untranslated region variants (-1549G>A, -1019A>G and -24C>T). The observed allelic imbalance was not associated with hepatic or renal ABCC2 mRNA expression. Additional mechanisms will need to be explored to account for the interindividual variation in ABCC2 expression and MRP2 function.

Fine tuning the disassembly time of thermoresponsive polymer nanoparticles.

Timed-released disassembly of nanoparticles without a remote trigger or environmental cues is demonstrated in this work. The reversible addition-fragmentation chain transfer (RAFT) polymerization allowed the fine-tuning of the chemical composition in the diblock copolymers, in which the first block consisted of a hydrophilic monomer (DMA) and the second random block consisted of three different monomers: (a) the thermoresponsive NIPAM, (b) the self-catalyzed hydrolyzable DMAEA, and (c) the hydrophobic BA. These diblock copolymers were solubilized in water below the lower critical solution temperature (LCST) of the thermoresponsive second block, and heated to 37 °C (i.e., >LCST) to form small micelle nanoparticles with a narrow particle size distribution. As DMAEA hydrolyzed to acrylic acid groups, the LCST of the diblock increased, and the time at the start of micelle disassembly (t(start)) corresponded to the point where the LCST was equal to the solution temperature (i.e., 37 °C). The high water content in the PNIPAM core allowed an even degradation of the core over time. The copolymer composition allowed fine control over t(start), as this time was linearly dependent upon the BA units in the second block. These nanoparticles could also be designed to be stable (i.e., not disassemble) over a wide pH range or disassemble below a pH of 7.3. Additionally, the time from the start of disassembly to full unimer formation (t(degrade)) could be controlled by the amount of DMAEA units in the second block. A longer t(degrade) (~5.5 h) was found when the number of DMAEA units was 42 compared to t(degrade) of 1.1 h for 25 units. The nanoparticles designed in this work, through fine control of the polymer chemical composition, have the potential for drug delivery purposes for timed-release of drugs and prodrugs and other wide-ranging applications where timed-release would be beneficial.

Timed-release polymer nanoparticles.

Triggered-release of encapsulated therapeutics from nanoparticles without remote or environmental triggers was demonstrated in this work. Disassembly of the polymer nanoparticles to unimers at precise times allowed the controlled release of oligo DNA. The polymers used in this study consisted of a hydrophilic block for stabilization and second thermoresponsive block for self-assembly and disassembly. At temperatures below the second block's LCST (i.e., below 37 °C for in vitro assays), the diblock copolymer was fully water-soluble, and when heated to 37 °C, the polymer self-assembled into a narrow size distribution of nanoparticles with an average diameter of approximately 25 nm. The thermoresponsive nature of the second block could be manipulated in situ by the self-catalyzed degradation of cationic 2-(dimethylamino)ethyl acrylate (DMAEA) units to negatively charged acrylic acid groups and when the amount of acid groups was sufficiently high to increase the LCST of the second block above 37 °C. The disassembly of the nanoparticles could be controlled from 10 to 70 h. The use of these nanoparticles as a combined therapy, in which one or more agents can be released in a predetermined way, has the potential to improve the personal point of care treatment of patients.

Evaluation of the vaccination efficacy against H5N1 in domestic poultry in the Red River Delta in Vietnam.

The domestic poultry population in Vietnam has been vaccinated against highly pathogenic avian influenza (HPAI) H5N1 since 2005. Since then, outbreaks have continued to occur without a clear understanding of the mechanisms involved. The general objective of this study was to understand the epidemiology of the disease in the context of vaccination and to draw some conclusions about vaccination efficacy in the domestic poultry population of the Red River Delta area. Five cross-sectional surveys to measure the serological and virological prevalence in vaccinated and unvaccinated poultry were performed from the end of 2008 to June 2010. The global seroprevalence was 24% (95% confidence interval 19·9-28·2). Determinants of vaccine immunogenicity were identified separately in chickens and ducks as well as determinants of the seroconversion in unvaccinated birds. The results highlight the difficulties in maintaining good flock immunity in poultry populations using inactivated vaccine in the field with two vaccination rounds per year, and in preventing circulation of virus in co-existing unvaccinated poultry.

[Prospective evaluation of radiation-induced thyroid disorders after breast and supraclavicular irradiation]. / Évaluation prospective des dysthyroïdies radio-induites après irradiation mammaire et sus-claviculaire.

PURPOSE: The thyroid is an endocrine gland playing a major role in metabolism and development by the secretion of T4 and T3 thyroid hormones. Due to its anatomical position, it is often included in the target volume for the irradiation of certain tumours and thus receives significant doses (10 to 80Gy). The treatment of breast cancer requires in most cases a breast irradiation associated or not with a lymph node irradiation. The aim of our study was to investigate prospectively the frequency of thyroid disorders in patients with breast cancer treated by radiation, with or without irradiation of the supra- and subclavicular lymph nodes. MATERIAL AND METHODS: This prospective multicentre study (institut Godinot, institut de cancérologie Strasbourg Europe and institut de cancérologie de Lorraine) concerned adult patients with non-metastatic breast carcinoma treated by adjuvant irradiation. They were included in a non-randomized way between February 2013 and June 2015 and divided into two groups according to treatment: (i) breast radiotherapy associated with irradiation of the supra- and subclavicular lymph nodes (group 1), or (ii) breast irradiation alone (group 2). The dose - volume histogram of the thyroid was systematically edited by the physics department. Each patient had a consultation with an endocrinologist at the beginning of the treatment and was monitored by blood analyses including TSH, T4L, antithyroglobulin and antiperoxidase antibodies every 6 months until the 60th month after the end of radiotherapy. Data were described by numbers and percentages for qualitative variables; by means, medians, standard deviation and ranges for quantitative variables. Statistical associations were tested by Chi2, Fisher's, Student's, or analysis of variance tests depending on the conditions of application. Survival analyses were performed by log rank tests and Cox models. RESULTS: This study initially included 500 patients, 245 in group 1 and 252 in group 2 (three patients were later excluded for false inclusion). Thyroid abnormalities occurred in 76 patients, representing an incidence of 15.3%. The mean time of the first occurrence of thyroid disorders was 24.3 months. It was more frequent in group 1 with a prevalence of 19.2% against 11.5% in group 2 (P=0.01745). A maximal radiation dose delivered to the thyroid gland greater than 20Gy (odds ratio [OR]: 1.82; P=0.018) or 30Gy (OR: 1.89; P=0.013) was significantly associated with a higher incidence of thyroid disorders, as was a mean dose greater than 30Gy (OR: 5.69; P=0.049). A percentage of thyroid volume receiving 30Gy (V30) greater than 50% (P=0.006) or greater than 62.5% (P=0.021) was significantly associated with an increased incidence of thyroid disorder and more precisely, hypothyroidism (P=0.0007). In multivariate analysis, no factor associated with the occurrence of thyroid disorder was identified. However, in the subgroup analysis concerning group 1 (receiving supraclavicular irradiation), a maximal radiation dose greater than 30Gy appeared to be a risk factor for the occurrence of thyroid disorders (P=0.040). CONCLUSION: Thyroid disorder, and in particular hypothyroidism, may be a late side effect of locoregional breast radiotherapy. Patients receiving this treatment should have a biological monitoring of thyroid function.

Evaluation of the Statistical Detection of Change Algorithm for Screening Patients with MS with New Lesion Activity on Longitudinal Brain MRI.

BACKGROUND AND PURPOSE: Identification of new MS lesions on longitudinal MR imaging by human readers is time-consuming and prone to error. Our objective was to evaluate the improvement in the performance of subject-level detection by readers when assisted by the automated statistical detection of change algorithm. MATERIALS AND METHODS: A total of 200 patients with MS with a mean interscan interval of 13.2 (SD, 2.4) months were included. Statistical detection of change was applied to the baseline and follow-up FLAIR images to detect potential new lesions for confirmation by readers (Reader + statistical detection of change method). This method was compared with readers operating in the clinical workflow (Reader method) for a subject-level detection of new lesions. RESULTS: Reader + statistical detection of change found 30 subjects (15.0%) with at least 1 new lesion, while Reader detected 16 subjects (8.0%). As a subject-level screening tool, statistical detection of change achieved a perfect sensitivity of 1.00 (95% CI, 0.88-1.00) and a moderate specificity of 0.67 (95% CI, 0.59-0.74). The agreement on a subject level was 0.91 (95% CI, 0.87-0.95) between Reader + statistical detection of change and Reader, and 0.72 (95% CI, 0.66-0.78) between Reader + statistical detection of change and statistical detection of change. CONCLUSIONS: The statistical detection of change algorithm can serve as a time-saving screening tool to assist human readers in verifying 3D FLAIR images of patients with MS with suspected new lesions. Our promising results warrant further evaluation of statistical detection of change in prospective multireader clinical studies.

Age-dependent heterogeneity in the antigenic effects of mutations to influenza hemagglutinin.

Human influenza virus evolves to escape neutralization by polyclonal antibodies. However, we have a limited understanding of how the antigenic effects of viral mutations vary across the human population, and how this heterogeneity affects virus evolution. Here we use deep mutational scanning to map how mutations to the hemagglutinin (HA) proteins of the A/Hong Kong/45/2019 (H3N2) and A/Perth/16/2009 (H3N2) strains affect neutralization by serum from individuals of a variety of ages. The effects of HA mutations on serum neutralization differ across age groups in ways that can be partially rationalized in terms of exposure histories. Mutations that fixed in influenza variants after 2020 cause the greatest escape from sera from younger individuals. Overall, these results demonstrate that influenza faces distinct antigenic selection regimes from different age groups, and suggest approaches to understand how this heterogeneous selection shapes viral evolution.