Parasitic worms cause huge economic loss to farmers and can infest humans too.
Creationists who believe nothing happens unless their invisible magic god wants it to have to have all manner of intellectual gymnastics to avoid giving it credit for all the nasty things to be found in nature, such as parasitic worms.
Their favourite strategy is the old trick of believing two mutually exclusive ideas simultaneously - that only their god is capable of designing living systems, so anything too complex for them to understand must have been created by it, whilst simultaneously believing that all pathogens are created by another entity, called 'Sin', no matter how complex or difficult to understand they may be.
And of course, they are forbidden by dogma to believe in more than one creator and must believe, also by dogma, that that creator is omni-everything - omnibenevolent, omniscient and omnipotent - so they have to believe that whatever its designs do, they were designed to do it, and whatever the future may bring, they were aware of that whilst designing their creations.
What percentage of the surface of Earth is habitable to humans without special equipment? Approximately 29% of the Earth's surface is comprised of land, which is habitable to humans without special equipment. The remaining 71% is covered by water, primarily in the form of oceans, which generally require specialized equipment for prolonged habitation. Therefore, without considering other factors such as climate, terrain, and resources, roughly 29% of Earth's surface is habitable to humans without special equipment.That means, creationists have no choice but to accept that the results of climate change were part of their designer creator's plan, as was the response of their creations to it. And one of those responses to climate change may be an increase in parasitic worms in parts of the world they have not been prevalent in before.
Many of these worms are, or have been, confined to the tropics and sub-tropical zones, and the northern and southern part of the world, where most advanced economies are based, have been relatively free from them. But, as Earth gets warmer, the 'habitable zone' for parasitic worms expands to incorporate more of the advanced economies, but the habitable zone for humans shrinks even further.
This is the prediction of a team of researchers from the Center for Infectious Disease Dynamics and Department of Biology, The Pennsylvania State University (PennState), Pennsylvania, USA, and Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy, led by Professor Isabella Cattadori and Dr. Chiara Vanalli of PennState, who have just published their findings, open access, in the journal Ecology Letters. Their work is explained in a PennState news release:
As climate changes, temperature isn’t the only factor to influence the spread of infectious diseases. Humidity plays a role, too, according to new research published this week (Feb. 25) in Ecology Letters. The international team, led by Penn State researchers, developed a model to examine how parasitic worms, specifically species that infect livestock and wildlife, respond to changes in temperature and humidity and how those variables may shape the risk of infection and the development of new hot spots in the future. The findings, which may suggest similar behavior among worms that infect humans, could guide improvements in livestock management and public health interventions in endemic areas.So, what creationism’s malevolent designer has in store for us, if you subscribe to the creationist superstition, is more infestations by parasitic worms with peaks of infections by intestinal parasites in spring and autumn with a peak of stomach infestations in summer. Perhaps creationists will then be praising their divine malevolence for sparing us in winter.
Parasitic worms, specifically soil-transmitted helminths, are common and infect roughly 25% of the global human population, according to the World Health Organization. They’re also a major source of infection in animals, causing large economic loss to the livestock industry. Yet, Cattadori said, studies on climate and infections typically look at diseases carried by vectors like mosquitoes and ticks.We need to understand how climate change can affect the future of these infections. Are they going to get worse? Are they going to shift into different habitats and create new hotspots? Will they mutate and develop into more pathogenic infections?
There isn’t much attention on helminth infections because they’re not as threatening as vector-borne diseases, and people tend to underestimate the importance of worm infections [most studies focus on temperature, and few consider other climate-related variables, like humidity, as drivers of infection.]
We need to start thinking about how to adapt our strategies to a world where climate is changing.
Professor Isabella Cattadori, senior author Professor of biology
Center for Infectious Disease Dynamics and Department of Biology,
The Pennsylvania State University, University Park, Pennsylvania, USA>
The lifecycle of soil-transmitted helminths has two phases — a free-living stage as eggs and larvae in the environment and an adult stage inside the host. Researchers sought to understand how the free-living stages were affected by climate. They reviewed current scientific literature to gather data on the effect of temperature and relative humidity on helminth egg and larval stages of nine species of helminth that commonly infect livestock and wildlife. These species were then divided into two groups depending on where they reside in their host: worms that live in the stomach and worms that live in the intestines.
Based on this information, they developed a mathematical model to describe how helminth hatching, development and mortality of each helminth group responds to temperature and humidity. They then applied this model to look at historical and future projections of infection risk under different climate change scenarios across Southern, Central and Northern Europe. For future projections, they considered short-term, from 2041 to 2060, and long-term, from 2081 to 2100, scenarios.
The study is one of the first, Cattadori said, to look at the interaction between multiple climate variables across multiple parasitic worm species to understand how these factors may alter the seasonal profile of disease transmission, as well as when and where these patterns might arise.We didn’t just look at correlation or linear relationships between variables. We disentangled how each component of the free-living stages is affected by climatic conditions, developing a mechanistic understanding of how helminths respond to these environmental stressors. This is essential for understanding what might happen in the future.
The intensity of these peaks and the way they shift will depend on location and specific climatic conditions as well as helminth species type.
Dr. Chiara Vanalli, lead author
Center for Infectious Disease Dynamics and Department of Biology,
The Pennsylvania State University, University Park, Pennsylvania, USA>
Researchers discovered that not all parasite species behave the same way. Those that reside in the host’s intestines were strongly affected by temperature, reaching the highest risk of infection at 50 degrees Fahrenheit. On the other hand, helminths that reside in the stomach responded strongly to humidity, reaching their peak when humidity was 80% or higher. When researchers looked at the seasonality in these patterns across Europe, they found that historically, infection risk has one or two peaks in the spring and summer for the intestinal group and one peak for the stomach group. However, in the future, they expect these peaks may change.
Response of the infection hazard of intestinal and stomach helminths under different temperatures and relative humidities, estimated from laboratory data.Credit: Provided by Cattadori Lab/Penn State. All Rights Reserved.
A two-season trend, with one peak in spring and one in fall, is expected to intensify for intestinal helminths while stomach helminths may be more likely to maintain the summer peak, especially at northern regions.
Researchers also considered how spatial distribution may change too. Historically, infection risk is low in Northern Europe. However, when researchers looked into the future, they found that infection hot spots will shift north, facilitated by increasingly milder climate in central and northern regions while southern regions will undergo more extreme temperature and drier conditions. Over the long-term, Scandinavian countries are projected to experience the greatest risk among both groups of helminths, up to an increase of 100% for the intestinal species and 55% for the stomach species compared to the rest of the continent. What’s more, the drastic increase in infection risk at mid-to-high latitudes may likely intensify the risk of co-infection since multiple species of helminths could thrive together.
With a better understanding of how animals are exposed to these infections and potential changes in the future, the findings could lead to the development of better livestock management and preventative control strategies, the researchers said. The dynamics described by the researchers could also shed light on the potential risk for human health because some of the family groups studied include parasites that also affect humans.
Technical detail and background to their research is given in the abstract and introduction to the team's open access paper in Ecology Letters:
AbstractIf you're gullible enough to have fallen for creationist disinformation then, you have to believe that your divine sadist has something especially unpleasant planned for you as an added bonus to all the suffering that will be caused by climate change as large parts of the world become uninhabitable, and the habitable part of the planet you believe was fine tuned for human life shrinks even further and becomes a refuge for parasitic worms.
Outbreaks and spread of infectious diseases are often associated with seasonality and environmental changes, including global warming. Free-living stages of soil-transmitted helminths are highly susceptible to climatic drivers; however, how multiple climatic variables affect helminth species, and the long-term consequences of these interactions, is poorly understood. We used experiments on nine trichostrongylid species of herbivores to develop a temperature- and humidity-dependent model of infection hazard, which was then implemented at the European scale under climate change scenarios. Intestinal and stomach helminths exhibited contrasting climatic responses, with the former group strongly affected by temperature while the latter primarily impacted by humidity. Among the demographic traits, larval survival heavily modulated the infection hazard. According to the specific climatic responses of the two groups, climate change is expected to generate differences in the seasonal and spatial shifts of the infection hazard and group co-circulation. In the future, an intensification of these trends could create new opportunities for species range expansion and co-occurrence at European central-northern latitudes.
INTRODUCTION
The many forms of disruption associated with climate change, like warming temperature, extreme climatic events or shifts in climatic ranges, are expected to strongly affect ectotherm species by altering components of their life cycle and dynamics of transmission (Deutsch et al., 2008; Paaijmans et al., 2013; Wagner et al., 2023). These climatic changes are also predicted to alter the severity and spread of many circulating infections, several of which are also caused by ectotherm parasites whose transmission depends on the survival and development of stages that live in the environment, as is the case of soil-transmitted helminths with direct life cycle (Hoar et al., 2012; Molnár et al., 2017; Molnár, Kutz, et al., 2013.1; Rose et al., 2016; Smith, 1990), as well as of those parasites that require intermediate invertebrate hosts or vectors for maturation and transmission (Brown et al., 2023.1; Carraro et al., 2017.1; Kutz et al., 2005, 2002; Molnár, Dobson, & Kutz, 2013.2; Schjetlein & Skorping, 1995). Assessing the net effect of climate warming on parasite transmission has proved to be challenging because of the non-linear thermal responses often exhibited by parasite traits (Gehman et al., 2018; Molnár et al., 2017). Indeed, the trade-off of faster development but lower survival commonly observed for parasites (Hoar et al., 2012; Rose et al., 2016; Smith, 1990) and vectors (Mordecai et al., 2019, 2017.2) exposed to increasing temperatures suggests that transmission is far from being linearly related to temperature, but more likely the result of complex interactions that often generate asymmetric humped-shaped thermal responses. Therefore, the assumption that warming will aggravate the prevalence and severity of current endemic infections cannot be fully generalized among parasite species, and needs to be carefully evaluated across a broad range of temporal and spatial settings (Lafferty & Mordecai, 2016.1).
Seasonal fluctuations in climate are one of the strongest environmental forces that affect parasite prevalence and abundance over time (Altizer et al., 2006; Dowell, 2001; Harvell et al., 2002.1). Temperature warming could increase or decrease the intensity of parasite transmission without affecting the seasonal trend; alternatively, it could impact both the magnitude and duration of transmission and thus its seasonal shape (Altizer et al., 2006). This latter scenario has been proposed for a few helminth species, whose current season of spring-to-fall transmission is expected to split into two separate periods, spring and fall, separated by the emergence of a summer minimum (Altizer et al., 2013.3). For example, a bimodal pattern has been described for the sheep helminth Haemonchus contortus in southern Europe (Rose et al., 2016) and for the reindeer nematode Ostertagia gruehneri in the artic Canada (Hoar et al., 2012; Kutz et al., 2014; Molnár, Kutz, et al., 2013.1) where temperatures have been found to exceed the parasite thermal optimum. In addition to seasonal changes, we should also expect the geographical expansion of parasites to those areas where climate will become more suitable for survival and persistence but range contraction where parasites have limited thermal tolerance or slow adaptation to rapid climate changes (Kafle et al., 2020; Kenyon et al., 2009; Kutz et al., 2013.4, 2009.1; Short et al., 2017.3). Importantly, given the strong heterogeneity of global warming predicted across geographical areas, these spatial trends should be more apparent at the extremes of the parasite range of distribution, where life history traits are under stronger constraints.
While studies on parasites and vectors suggest that climate warming can alter the seasonal profile of disease transmission and the range of species distribution, when and where changes in these patterns arise, what climatic variables affect these trends and whether the observed patterns will be maintained as climate becomes warmer need careful investigation. The frequent assumption is that many of the relationships between parasite life-history strategies and climate can be generalizable across species. However, the same demographic trait might show different thermal responses among parasite species, and it is relevant to examine how these responses change when species have distinct ecological requirements (Molnár, Dobson, & Kutz, 2013.2). Importantly, given that wild and domestic animal populations are often infected by a community of parasites, evaluating whether climate change will promote or prevent the co-circulation of multiple species and the risk of co-infection remains an overlooked issue (Clerc et al., 2018.1; Graham et al., 2007; Johnson & Buller, 2011). In fact, although these patterns ultimately depend on the distribution and abundance of the host populations, climate modulates the dynamics of free-living stages, including the viability of infective forms, and thus the hazard of infection (Dobson et al., 2015; Molnár et al., 2017; Rose et al., 2016).
In this study, we focused on the most common soil-transmitted helminths of a few domestic and wild herbivore species and examined the historical and future impact of climate on the related life-history traits of free-living stages (i.e. egg hatching and mortality, larval development and survival), the resulting hazard of infection and the probability of species co-circulation. Our goal is to identify commonalities and dissimilarities in the temporal and spatial demography of parasites with diverse life histories under the direct effect of temperature and relative humidity. Given our interest in the free-living stages, and to reduce the complexity of using several host species, we did not explicitly address the role of the host populations or additional anthropogenic factors on the hazard of infection, like anthelminthic treatment or livestock management. We selected parasites from the Trichostrongylidae family, which includes the genera Trichostrongylus, Haemonchus, Ostertagia, Cooperia and Nematodirus. These parasites commonly infect a large number of herbivores, such as sheep, goats and cattle for livestock as well as rabbits and hares for wildlife (Anderson, 2000), and frequently co-circulate in the same host populations. The life cycle is direct where infection occurs by ingestion of infective larvae available on the pasture. Larvae develop into adults in the gastrointestinal tract of their hosts, either the intestine or the stomach, and shed eggs in the environment via host's faeces. The Trichostrongylidae are among the helminth families that cause large economic loss to the livestock industry (Charlier et al., 2020.1). Therefore, a better understanding of the relationship between hazard of infection and climate could contribute to improve animal health and livestock management. Moreover, the selected species have many similarities with soil-transmitted helminths of humans, and insights from their thermal dynamics can be useful for guiding public health interventions in endemic areas under climate warming.Fig. 1Life cycle of free-living helminths (top) and climate dependencies of demographic rates (bottom) for egg mortality (a, e), egg hatching (b, f), larval development (c, g) and larval mortality (d, h), for intestinal (a–d) and stomach (e–h) helminths. Circles represent observations, lines the fitted climate-driven models and shaded areas the 90% confidence intervals (CIs) of model simulations obtained via bootstrap. Temperature is reported on the x-axis while the humidity dependency for the L3 mortality rate (d, h) is represented by three different humidity intervals (H < 60%, 60 < H < 100% and H = 100%) in coloured shades. Intestinal L3 mortalities overlap at different humidity intervals (d).
Fig. 3Average historical (1981–2000, bold lines) trend, and future short-term (2041–2060, dashed lines) and long-term (2081–2100, dotted lines) trends under the RCP 4.5 scenario. The seasonality of average (a) temperature, (b) relative humidity and (c, d) infection hazard of (c) intestinal and (d) stomach helminths in northern (blue), central (green) and southern (orange) Europe is depicted and plotted with a two-week moving average for visual representation.
Fig. 4Average hazard of infection of intestinal (a, c, e) and stomach (b, d, f) helminths in the historical period (1981–2000, a, b) and expected percentage changes in the short-term (2041–2060, c, d) and in the long-term (2081–2100, e, f) under the RCP 4.5 climate change scenario. Horizontal lines separate northern, central and southern European zones. Dark red regions (c–f) correspond to both high increase areas and areas of helminth emergence.
The Unintelligent Designer: Refuting The Intelligent Design Hoax
ID is not a problem for science; rather science is a problem for ID. This book shows why. It exposes the fallacy of Intelligent Design by showing that, when examined in detail, biological systems are anything but intelligently designed. They show no signs of a plan and are quite ludicrously complex for whatever can be described as a purpose. The Intelligent Design movement relies on almost total ignorance of biological science and seemingly limitless credulity in its target marks. Its only real appeal appears to be to those who find science too difficult or too much trouble to learn yet want their opinions to be regarded as at least as important as those of scientists and experts in their fields.
Available in Hardcover, Paperback or ebook for Kindle
The Malevolent Designer: Why Nature's God is Not Good
This book presents the reader with multiple examples of why, even if we accept Creationism's putative intelligent designer, any such entity can only be regarded as malevolent, designing ever-more ingenious ways to make life difficult for living things, including humans, for no other reason than the sheer pleasure of doing so. This putative creator has also given other creatures much better things like immune systems, eyesight and ability to regenerate limbs that it could have given to all its creation, including humans, but chose not to. This book will leave creationists with the dilemma of explaining why evolution by natural selection is the only plausible explanation for so many nasty little parasites that doesn't leave their creator looking like an ingenious, sadistic, misanthropic, malevolence finding ever more ways to increase pain and suffering in the world, and not the omnibenevolent, maximally good god that Creationists of all Abrahamic religions believe created everything. As with a previous book by this author, "The Unintelligent Designer: Refuting the Intelligent Design Hoax", this book comprehensively refutes any notion of intelligent design by anything resembling a loving, intelligent and maximally good god. Such evil could not exist in a universe created by such a god. Evil exists, therefore a maximally good, all-knowing, all-loving god does not.
Illustrated by Catherine Webber-Hounslow.
Available in Hardcover, Paperback or ebook for Kindle
Illustrated by Catherine Webber-Hounslow.
No comments :
Post a Comment
Obscene, threatening or obnoxious messages, preaching, abuse and spam will be removed, as will anything by known Internet trolls and stalkers, by known sock-puppet accounts and anything not connected with the post,
A claim made without evidence can be dismissed without evidence. Remember: your opinion is not an established fact unless corroborated.