Explore the vast range of titles available.

Influenza is a major cause of mortality and morbidity worldwide. Despite numerous studies of the pathogenesis of influenza in humans and animal models the dynamics of infection and transmission in individual hosts remain poorly characterized. In this study, we experimentally modelled transmission using the H1N1pdm09 influenza A virus in pigs, which are considered a good model for influenza infection in humans. Using an experimental design that allowed us to observe individual transmission events occurring within an 18-hr period, we quantified the relationships between infectiousness, shed virus titre and antibody titre. Transmission event was observed on 60% of occasions when virus was detected in donor pig nasal swabs and transmission was more likely when donor pigs shed more virus. This led to the true infectious period (mean 3.9 days) being slightly shorter than that predicted by detection of virus (mean 4.5 days). The generation time of infection (which determines the rate of epidemic spread) was estimated for the first time in pigs at a mean of 4.6 days. We also found that the latent period of the contact pig was longer when they had been exposed to smaller amount of shed virus. Our study provides quantitative information on the time lines of infection and the dynamics of transmission that are key parts of the evidence base needed to understand the spread of influenza viruses though animal populations and, potentially, in humans.

Pigs are natural hosts for the same subtypes of influenza A viruses as humans and integrally involved in virus evolution with frequent interspecies transmissions in both directions. The emergence of the 2009 pandemic H1N1 virus illustrates the importance of pigs in evolution of zoonotic strains. Here we generated pig influenza-specific monoclonal antibodies (mAbs) from H1N1pdm09 infected pigs. The mAbs recognized the same two major immunodominant haemagglutinin (HA) epitopes targeted by humans, one of which is not recognized by post-infection ferret antisera that are commonly used to monitor virus evolution. Neutralizing activity of the pig mAbs was comparable to that of potent human anti-HA mAbs. Further, prophylactic administration of a selected porcine mAb to pigs abolished lung viral load and greatly reduced lung pathology but did not eliminate nasal shedding of virus after H1N1pdm09 challenge. Hence mAbs from pigs, which target HA can significantly reduce disease severity. These results, together with the comparable sizes of pigs and humans, indicate that the pig is a valuable model for understanding how best to apply mAbs as therapy in humans and for monitoring antigenic drift of influenza viruses in humans, thereby providing information highly relevant to making influenza vaccine recommendations.

Porcine respiratory disease is multifactorial and most commonly involves pathogen co-infections. Major contributors include swine influenza A (swIAV) and porcine reproductive and respiratory syndrome (PRRSV) viruses. Experimental co-infection studies with these two viruses have shown that clinical outcomes can be exacerbated, but how innate and adaptive immune responses contribute to pathogenesis and pathogen control has not been thoroughly evaluated. We investigated immune responses following experimental simultaneous co-infection of pigs with swIAV H3N2 and PRRSV-2. Our results indicated that clinical disease was not significantly exacerbated, and swIAV H3N2 viral load was reduced in the lung of the co-infected animals. PRRSV-2/swIAV H3N2 co-infection did not impair the development of virus-specific adaptive immune responses. swIAV H3N2-specific IgG serum titers and PRRSV-2-specific CD8β + T-cell responses in blood were enhanced. Higher proportions of polyfunctional CD8β + T-cell subset in both blood and lung washes were found in PRRSV-2/swIAV H3N2 co-infected animals compared to the single-infected groups. Our findings provide evidence that systemic and local host immune responses are not negatively affected by simultaneous swIAV H3N2/PRRSV-2 co-infection, raising questions as to the mechanisms involved in disease modulation.

Influenza A virus infection is a global health threat to livestock and humans, causing substantial mortality and morbidity. As both pigs and humans are readily infected with influenza viruses of similar subtype, the pig is a robust and appropriate model for investigating swine and human disease. We evaluated the efficacy of the human cold-adapted 2017-2018 quadrivalent seasonal LAIV in pigs against H1N1pdm09 challenge. LAIV immunized animals showed significantly reduced viral load in nasal swabs. There was limited replication of the H1N1 component of the vaccine in the nose, a limited response to H1N1 in the lung lymph nodes and a low H1N1 serum neutralizing titer. In contrast there was better replication of the H3N2 component of the LAIV, accompanied by a stronger response to H3N2 in the tracheobronchial lymph nodes (TBLN). Our data demonstrates that a single administration of human quadrivalent LAIV shows limited replication in the nose and induces detectable responses to the H1N1 and H3N2 components. These data suggest that pigs may be a useful model for assessing LAIV against influenza A viruses.

[This corrects the article DOI: 10.1371/journal.ppat.1009330.].

Cooperative behavior by nonrelatives is an evolutionary puzzle, because costs of cooperation are often strong while selective factors favoring cooperative groups remain unclear. In some populations of the seed harvester ant P ogonomyrmex californicus , unrelated queens form groups at colony founding (pleometrosis), whereas in other populations, colonies are initiated by single queens (haplometrosis). We tested the hypothesis that energetic savings of grouping contribute a benefit that may enhance queen success during colony founding and early growth for pleometrotic colonies. We measured metabolic rates and locomotor activity of individuals or pairs of freshly collected, newly mated P. californicus queens from pleometrotic and haplometrotic populations. Population source did not significantly affect metabolic rates, but paired queens from both populations had mass-specific metabolic rates only 86% of those of individual queens. The metabolic effect of grouping was not explained by differences in locomotion. To test whether this degree of energetic saving could be biologically significant, we assessed metabolic rate, body mass, and egg production for pleometrotic pairs at four time points of colony founding and compared the energetic content of stored lipid to energy use up to the point of worker emergence. Metabolic rates dropped over time for queens, as did body mass, and gas exchange switched from continuous to discontinuous, suggestive of metabolic suppression. Total joules required for queens to reach the worker emergence stage were 1.5 times the energy content of stored lipids, consistent with the need for foraging for these queens, and supporting the hypothesis that energetic savings of grouping can be beneficial by extending energetic stores and reducing the need for risky foraging. Significance statement Animal cooperation has fascinated people since well before Darwin, but the factors impacting whether cooperation occurs remain controversial. We investigated the energetic cost of nest initiation in ant queens that naturally vary in their propensity to cooperate. We determined that the energy costs of nest initiation prior to worker emergence exceed the energy in the queen’s lipid stores, partly explaining why these queens forage and experience high mortality. Queen pairing significantly lowered metabolic rates, demonstrating that energetic savings from grouping can be an important advantage of cooperation in this system.

Delayed or impaired language development is a common developmental concern, yet there is little agreement about the criteria used to identify and classify language impairments in children. Children's language difficulties are at the interface between education, medicine and the allied professions, who may all adopt different approaches to conceptualising them. Our goal in this study was to use an online Delphi technique to see whether it was possible to achieve consensus among professionals on appropriate criteria for identifying children who might benefit from specialist services. We recruited a panel of 59 experts representing ten disciplines (including education, psychology, speech-language therapy/pathology, paediatrics and child psychiatry) from English-speaking countries (Australia, Canada, Ireland, New Zealand, United Kingdom and USA). The starting point for round 1 was a set of 46 statements based on articles and commentaries in a special issue of a journal focusing on this topic. Panel members rated each statement for both relevance and validity on a seven-point scale, and added free text comments. These responses were synthesised by the first two authors, who then removed, combined or modified items with a view to improving consensus. The resulting set of statements was returned to the panel for a second evaluation (round 2). Consensus (percentage reporting 'agree' or 'strongly agree') was at least 80 percent for 24 of 27 round 2 statements, though many respondents qualified their response with written comments. These were again synthesised by the first two authors. The resulting consensus statement is reported here, with additional summary of relevant evidence, and a concluding commentary on residual disagreements and gaps in the evidence base.

In this short article, we discuss what is specific language impairment (SLI) and why it is a hidden disability that few people have heard about. We describe the impact on research, policy and practice of SLI being a neglected condition. We end by providing the background and rationale of a new internet campaign, RALLI (www.youtube.com/rallicampaign), aimed at changing this state of affairs and raising awareness of SLI.

Summary Despite its central importance in organismal physiology, we have poor understanding of how metabolic rate is influenced by two key factors – food nutritional content and an organism's physiological characteristics. We examined how variation in nutrients and physiological aspects of life history affect standard metabolic rate in Gryllus firmus cricket morphs that differ dramatically in flight capability and early‐age fecundity. Newly moulted female morphs were fed one of 13 diets that differed in concentrations of protein and carbohydrate. Carbon dioxide production, respiratory exchange ratios (RERs), nutrient intake and mass and lipid levels were measured. CO2 production and RERs increased to a similar degree in both morphs as food macronutrient content increased. In contrast, no difference in whole‐organism O2 consumption was observed across the protein–carbohydrate landscape or between morphs. Both morphs similarly increased food intake as nutrient concentration – particularly protein – decreased, but differed in mass and lipid gains, across the diets. Modulation of the substrate used for respiration coupled with compensating aspects of morph‐specific metabolism appears to buffer the effects of variable nutrient intake and life history on standard metabolic rate. That is, respiration rate can be highly canalized in the face of dramatic variation in both the external nutritional environment and internal aspects of intermediary metabolism. Lay Summary

Like organisms, cohesive social groups such as insect colonies grow from a few individuals to large and complex integrated systems. Growth is driven by the interplay between intrinsic growth rates and environmental factors, particularly nutritional input. Ecologically inspired population growth models assume that this relationship remains constant until maturity, but more recent models suggest that it should be less stable at small colony sizes. To test this empirically, we monitored worker population growth and fungal development in the desert leafcutter ant, Acromyrmex versicolor, over the first 6 months of colony development. As a multitrophic, symbiotic system, leafcutter colonies must balance efforts to manage both fungus production and the growth of the ants consuming it. Both ants and fungus populations grew exponentially, but the shape of this relationship transitioned at a size threshold of 89±9 workers. Above this size, colony mortality plummeted and colonies shifted from hypometric to hypermetric growth, with a distinct stabilization of the relationship between the worker population and fungus. Our findings suggest that developing colonies undergo key changes in organizational structure and stability as they grow, with a resulting positive transition in efficiency and robustness.