Biology subjects

Bansal, S.

Publications and source records attributed to Bansal, S..

48 records · Page 3Linked to original sources

bioRxiv2019

What would it take to describe the global diversity of parasites?

How many parasites are there on Earth? Here, we use helminth parasites to high-light how little is known about parasite diversity, and how insufficient our current approach will be to describe the full scope of life on Earth. Using the largest database of host-parasite associations and one of the worlds largest parasite collections, we estimate a global total of roughly 100,000 to 350,000 species of helminth endoparasites of vertebrates, of which 85% to 95% are unknown to science. The parasites of amphibians and reptiles remain the most poorly described, but the majority of undescribed species are likely parasites of birds and bony fish. Missing species are disproportionately likely to be smaller parasites of smaller hosts in undersampled countries. At current rates, it would take centuries to comprehensively sample, collect, and name vertebrate helminths. While some have suggested that macroecology can work around existing data limitations, we argue that patterns described from a small, biased sample of diversity arent necessarily reliable, especially as host-parasite networks are increasingly altered by global change. In the spirit of moon-shots like the Human Genome Project and the Global Virome Project, we consider the idea of a Global Parasite Project: a global effort to transform parasitology and inventory parasite diversity at an unprecedented pace.

ecology↗

bioRxiv2019

Rapid range shifts in African Anopheles mosquitoes over the last century

Facing a warming climate, many tropical species-including the arthropod vectors of several infectious diseases-will be displaced to higher latitudes and elevations. These shifts are frequently forecasted for the future, but rarely documented in the present day. Here, we use one of the most comprehensive datasets ever compiled by medical entomologists to track the observed range limits of African malaria mosquito vectors (Anopheles spp.) from 1898 to 2016. Using a simple regression approach, we estimate that these species ranges gained an average of 6.5 meters of elevation per year, and the southern limits of their ranges moved polewards 4.7 kilometers per year. These shifts are consistent with the local velocity of climate change, and might help explain the incursion of malaria transmission into new areas over the past few decades. Confirming that climate change underlies these shifts, and applying similar methods to other disease vectors, are important directions for future research.

ecology↗

bioRxiv2018

Getting personal: how vaccination exemptions shapeherd immunity

BackgroundState-mandated school entry immunization requirements in the United States play an important role in achieving high vaccine coverage and preventing outbreaks of vaccine-preventable diseases. Most states allow non-medical exemptions that let children remain unvaccinated on the basis of personal beliefs. However, the ease of obtaining such exemptions varies, resulting in a patchwork of state vaccination exemption laws, contributing to heterogeneity in vaccine coverage across the country. In this study, we evaluate epidemiological effects and spatial variations in non-medical exemption rates in the context of vaccine policies.\n\nMethods and FindingsWe first analyzed the correlation between non-medical exemption rates and vaccine coverage for three significant childhood vaccinations and found that higher rates of non-medical exemptions were associated with lower vaccination rates of school-aged children in all cases. We then identified a subset of states where exemption policy has recently changed and found that the effects on statewide non-medical exemption rates varied widely. Focusing further on Vermont and California, we illustrated how the decrease in non-medical exemptions due to policy change was concurrent to an increase in medical exemptions (in CA) or religious exemptions (in VT). Finally, a spatial clustering analysis was performed for Connecticut, Illinois, and California, identifying clusters of high non-medical exemption rates in these states before and after a policy change occurred. The clustering analyses show that policy changes affect spatial distribution of non-medical exemptions within a state.\n\nConclusionsOur work suggests that vaccination policies have significant impacts on patterns of herd immunity. Our findings can be used to develop evidence-based vaccine legislation.

epidemiology↗

bioRxiv2018

A multi-species repository of social networks

Social network analysis is an invaluable tool to understand the patterns, evolution, and consequences of sociality. Comparative studies over the spectrum of sociality across taxonomic groups are particularly valuable. Such studies however require quantitative information on social interactions across multiple species which is not easily available. We introduce the Animal Social Network Repository (ASNR) as the first multi-taxonomic repository that collates more than 650 social networks from 47 species, including those of mammals, reptiles, fish, birds, and insects. The repository was created by consolidating social network datasets from the literature on wild and captive animals into a consistent and easy-to-use network data format. The repository is archived at https://bansallab.github.io/asnr/. ASNR has tremendous research potential, including testing hypotheses in the fields of animal ecology, social behavior, epidemiology and evolutionary biology.

animal behavior and cognition↗

bioRxiv2018

Feeding the disparities: the geography and trends of breastfeeding in the United States

There is scientific consensus on the importance of breastfeeding for the present and future health of newborns, in high- and low-income settings alike. In the United States, improving breast milk access is a public health priority but analysis of secular trends are largely lacking. Here, we used data from the National Immunization Survey of the CDC, collected between 2003 and 2016, to illustrate the temporal trends and the spatial heterogeneity in breastfeeding. We also considered the effect sizes of two key determinants of breastfeeding rates. We show that, while access to breast milk both at birth and at 6 months old has steadily increased over the past decade, large spatial disparities still remain at the state level. We also find that, since 2009, the proportion of households below the poverty level has become the strongest predictor of breastfeeding rates. We argue that, because variations in breastfeeding rates are associated with socio-economic factors, public health policies advocating for breastfeeding are still needed in particular in underserved communities. This is key to reducing longer term health disparities in the U.S., and more generally in high-income countries.

epidemiology↗

bioRxiv2018

Reduced transfer of visuomotor adaptation is associated with aberrant sense of agency in Schizophrenia

One deficit associated with schizophrenia (SZ) is the reduced ability to distinguish sensations resulting from self-caused actions from those due to external sources. This reduced sense of agency (SoA, awareness of ownership over self-generated actions) is hypothesized to result from a diminished utilization of internal monitoring signals of self-movement (i.e., efferent copy) which subsequently impairs forming and utilizing sensory prediction errors (differences between the predicted and actual sensory consequences resulting from movement). Here, we investigated the connections between clinical SZ symptoms and motor adaptation, a process that uses sensory prediction errors to update motor output. Schizophrenia patients (SZP, N=30) and non-psychiatric healthy control subjects (HC, N=31) adapted to altered movement visual feedback, and then applied the motor recalibration to untested contexts (i.e., the spatial generalization to untrained targets). Although adaptation was similar for SZP and controls, the extent of generalization was significantly less for SZP; movement trajectories made by patients to the furthest untrained target (135{degrees}) before and after adaptation were largely indistinguishable. Interestingly, deficits in the generalization were correlated to positive symptoms of psychosis (e.g., hallucinations), but not negative symptoms. Generalization was also associated with subjective measures of SoA across both SZP and HC, emphasizing the major role action awareness plays in motor behavior, and suggesting that tendencies to misattribute agency, even in HC, manifest in abnormal motor performance. We discuss the possible link of these findings to cerebellar circuit abnormalities that may be a common source for deficits in the utilization of sensory prediction errors and aberrant SoA.

neuroscience↗

bioRxiv2018

The Impact of Reward on Attention in Schizophrenia

Traditionally, attention was thought to be directed by either top-down goals or bottom-up salience. Recent studies have shown that the reward history of a stimulus feature also acts as a powerful attentional cue. This is particularly relevant in schizophrenia, which is characterized by motivational and attentional deficits. Here, we examine the impact of reward on selective attention.\n\nForty-eight people with schizophrenia (PSZ) and 34 non-psychiatric control subject (NCS) discriminated the location of a target dot appearing inside a left circle or right circle. The circles were different colors, one of which was associated with reward via pre-training. In the first 2 blocks, targets were equally likely to appear in the left or right circle. In the last 4 blocks, the target was 75% likely on one side, thus allowing us to separately examine how attention was impacted by reward (color) and probability (location).\n\nPSZ had slower overall reaction times (RTs) than NCS. Both groups showed robust effects of spatial probability and reward history, with faster RTs for the rewarded color and for the more probable location. These effects were similar in PSZ and NCS. Negative symptom severity correlated with overall RT slowing, but there were no correlations between symptoms and reward-associated biasing of attention.\n\nPSZ demonstrated RT slowing but normal reward history and spatial probability-driven RT facilitation. These results are conceptually similar to prior findings showing intact implicit reward effects on response bias, and suggest that implicit processing of reward and probability is intact in PSZ.

neuroscience↗

bioRxiv2017

Social fluidity mobilizes infectious disease in human and animal populations

Humans and other group-living animals tend to distribute their social effort disproportionately. Individuals predominantly interact with a small number of close companions while maintaining weaker social bonds with less familiar group members. By incorporating this behaviour into a mathematical model we find that a single parameter, which we refer to as social fluidity, controls the rate of social mixing within the group. We compare the social fluidity of 13 species by applying the model to empirical human and animal social interaction data. To investigate how social behavior influences the likelihood of an epidemic outbreak we derive an analytical expression of the relationship between social fluidity and the basic reproductive number of an infectious disease. For highly fluid social behaviour disease transmission is revealed to be density-dependent. For species that form more stable social bonds, the model describes frequency-dependent transmission that is sensitive to changes in social fluidity.

epidemiology↗

bioRxiv2017

Identifying the dynamic contact network of infectious disease spread

The spread of pathogens fundamentally depends on the underlying contacts between individuals. Modeling infectious disease dynamics through contact networks is sometimes challenging, however, due to a limited understanding of pathogen transmission routes and infectivity. We developed a novel tool, INoDS (Identifying Network models of infectious Disease Spread) that estimates the predictive power of empirical contact networks to explain observed patterns of infectious disease spread. We show that our method is robust to partially sampled contact networks, incomplete disease information, and enables hypothesis testing on transmission mechanisms. We demonstrate the applicability of our method in two host-pathogen systems: Crithidia bombi in bumble bee colonies and Salmonella in wild Australian sleepy lizard populations. The performance of INoDS in synthetic and complex empirical systems highlights its role in identifying transmission pathways of novel or neglected pathogens, as an alternative approach to laboratory transmission experiments, and overcoming common data-collection constraints.

epidemiology↗

bioRxiv2017

Socio-environmental and measurement factors drive spatial variation in influenza-like illness

The mechanisms hypothesized to drive spatial heterogeneity in reported influenza activity include: environmental factors, contact patterns, population age structure, and socioeconomic factors linked to healthcare access and quality of life. Harnessing the large volume and high specificity of diagnosis codes in medical claims data for influenza seasons from 2002-2009, we estimate the importance of socio-environmental determinants and measurement-related factors on observed variation in influenza-like illness (ILI) across United States counties. We found that South Atlantic states tended to have higher ILI seasonal intensity, and a combination of transmission, environmental, influenza subtype, socioeconomic and measurement factors explained the variation in seasonal intensity across our study period. Moreover, our models suggest that sentinel surveillance systems should have fixed report locations across years for the most robust inference and prediction, and high volumes of data can offset measurement biases in opportunistic data samples.

epidemiology↗

bioRxiv2017

Assessing the distribution and determinants of vaccine underutilization in the United States

Despite advances in sanitation and immunization, vaccine-preventable diseases remain a significant cause of morbidity and mortality worldwide. In high-income countries such as the United States, coverage rates for vaccination against childhood infections remains high. However, the phenomenon of vaccine hesitancy makes maintenance of herd immunity difficult, impeding global disease eradication efforts. Reaching the last mile will require early detection of vaccine hesitancy (driven by philosophical or religious choices), identifying pockets of susceptibility due to underimmunization (driven by vaccine unavailability, costs ineligibility), determining the factors associated with the behavior and developing targeted strategies to ameliorate the concerns. Towards this goal, we harness high-resolution medical claims data to geographically localize vaccine refusal and underimmunization (collectively, underutilization) in the United States and identify the socio-economic determinants of the behaviors. Our study represents the first large-scale effort for vaccination behavior surveillance and has the potential to aid in the development of targeted public health strategies for optimizing vaccine uptake.

epidemiology↗

bioRxiv2017

Disease implications of animal social organization and network structure - a quantitative analysis

O_LIThe disease costs of sociality have largely been understood through the link between group size and transmission. However, infectious disease spread is driven primarily by the social organization of interactions in a group and not its size.\nC_LIO_LIWe used statistical models to review the social network organization of 47 species, including mammals, birds, reptiles, fish and insects by categorizing each species into one of three social systems, relatively solitary, gregarious and socially hierarchical. Additionally, using computational experiments of infection spread, we determined the disease costs of each social system.\nC_LIO_LIWe find that relatively solitary species have large variation in number of social partners, that socially hierarchical species are the least clustered in their interactions, and that social networks of gregarious species tend to be the most fragmented. However, these structural differences are primarily driven by weak connections, which suggests that different social systems have evolved unique strategies to organize weak ties.\nC_LIO_LIOur synthetic disease experiments reveal that social network organization can mitigate the disease costs of group living for socially hierarchical species when the pathogen is highly transmissible. In contrast, highly transmissible pathogens cause frequent and prolonged epidemic outbreaks in gregarious species.\nC_LIO_LIWe evaluate the implications of network organization across social systems despite methodological challenges, and our findings offer new perspective on the debate about the disease costs of group living. Additionally, our study demonstrates the potential of meta-analytic methods in social network analysis to test ecological and evolutionary hypotheses on cooperation, group living, communication, and resilience to extrinsic pressures.\nC_LI

epidemiology↗