The Invisible Empire
1 BOUNTY
This chapter delves into the abundance and diversity of microbes, emphasizing their crucial role in ecological balance and interdependence. It also explores the enigmatic nature of viruses, highlighting their complexity and unique place outside conventional life classifications.
Microbial Diversity and Ubiquity
A single gram of the stale-smelling yellow grimy film on our teeth, good old plaque, has approximately 1011 bacteria, which is about the same number as that of all the humans that have ever lived.
- Microbes are tiny life forms that are pervasive in every part of the world, existing in vast numbers far surpassing any other living organisms.
- A single gram of soil can house numerous tiny organisms like nematodes, protozoa, and algae, demonstrating their essential role in ecosystems.
Roles and Interdependence of Microbes
The effect of this interdependence is deeply significant as it sets the tone of relationships for all life on � Earth.
- A very few microbes cause illness, while many pass through or benefit their hosts, contributing to ecological balance.
- Scientists explore microorganisms' diverse roles as predators, prey, producers, and parasites, living in a complex web akin to a multi-storey forest.
- Microbial communities' interdependence significantly impacts all life forms on Earth.
The Complex World of Viruses
The problem with viruses is that they do not fit into any of the conventionally accepted domains of life� they are neither archaea, eukaryotes nor prokaryotes.
- Viruses, though outnumbering all other microbes, don't fit easily into traditional life classifications as they aren't strictly 'alive' until in a host.
- Scientists grapple with defining viruses and often need special methods to study their structures and behaviors.
- Despite their complexity, viruses are not part of the established tree of life, making them enigmatic compared to other organisms.
2 A WHOLE NEW WORLD
The chapter explores significant scientific revelations, particularly in the field of microbiology, tracing the evolution of microscope technology and its impact on our understanding of the natural world. Key pioneers like Copernicus, Vesalius, Hooke, and van Leeuwenhoek are highlighted for their discoveries that revealed the microscopic universe, expanding knowledge on organisms within and around us. The chapter underscores how these advancements led to major breakthroughs in medicine and science, particularly in understanding microorganisms and their role in disease.
Discoveries and Scientific Revolution
- In 1543, two pivotal works by Copernicus and Vesalius challenged the understanding of the universe and the human body.
- Their ideas marked the beginning of modern scientific inquiry, leading to the Renaissance.
- This period saw numerous discoveries and inventions, like telescopes that unveiled celestial wonders and microscopes that revealed the microscopic world.
- Microscopes allowed scientists to see previously invisible details, such as sperm and insects' compound eyes.
Microscopy and Its Pioneers
- Microscopes became essential in demystifying natural phenomena, including human physiology.
- Early microscopists' work led to detailed drawings that expanded knowledge about the invisible world.
- Robert Hooke's 'Micrographia' made the microcosmos visible and inspired scientific curiosity.
- The book's illustrations and descriptions challenged existing views of human creation versus nature's perfection.
Impact of Microbial Discoveries
- Pioneers like van Leeuwenhoek discovered microbes, revealing a menagerie of life within us.
- His works, alongside others, disproved spontaneous generation and highlighted the role of microorganisms in disease.
- The notion that microscopic entities caused diseases shifted away from divine explanations.
- Advancements in microbiology led to significant medical breakthroughs, such as the rabies vaccine by Pasteur.
Evolution of Microscopy
- The trade of microscopes advanced alongside glass and lens-making techniques, contributing to science.
- By the 19th century, microscopes facilitated the study of pathogens smaller than visible bacteria.
- During this era, many communities recognized the link between microscopic entities and infectious diseases.
- The development of electron microscopes allowed the visualization of viruses like the Tobacco Mosaic Virus.
Birth of Virology and Beyond
- The discovery and visualization of viruses led to the birth of virology, fostering a deeper understanding of microbes.
- Electron microscopy revealed the structures of viruses, providing insight into their functionality.
- The capacity to visualize microscopic life forms continues to propel scientific exploration of viruses and diseases.
- The quest for more advanced microscopy tools continues, opening possibilities for discoveries in infectious diseases.
3 SUPERSIZE ME
The chapter explores the evolutionary significance and diversity of viruses, focusing on giant viruses such as mimivirus and medusavirus, their unique characteristics, complex interactions, and their impact on evolution and human health. The origin of viruses remains debated, with theories ranging from ancient existence alongside cellular life to their evolution from genetic elements of cells.
Role of Water in Evolution
- Major evolutionary leaps occurred in deep water or at water's edge where the first cellular life emerged.
- Water is rich in cells, microbes, and viruses with vast diversity and numbers.
Discovery of Mimivirus
- Timothy Rowbotham discovered a microbe that resembled a bacterium inside amoeba while investigating a pneumonia outbreak.
- Rowbotham's samples led to identifying a giant virus, mimivirus, with a vast genome, mistaken as bacteria due to its structure.
- Mimivirus does not only have a large size but also a complex genetic structure comparable to bacteria.
Impact of Viral Discoveries
- Discovery of giant viruses like medusavirus and their unique traits have challenged traditional views on viruses.
- Virus impacts include transforming host cells, having genes resembling eukaryotic cells, and potentially redefining virus classification domains.
Viral Complexity and Evolution
- Giant viruses can host smaller viruses, highlighting complex viral interactions.
- Cafeteria roenbergensis virus and its parasitic virophage Mavirus depict viral-host gene exchanges, impacting evolution.
Viruses and Human Impact
- Giant viruses are found in various environments, including the human gut, affecting both healthy and sick individuals.
- Viruses play a critical role in evolution by gene shuffling and interaction with host species, driving new species formation.
Theories of Viral Origin
- Theories on viral origins include virus-first, escape hypothesis, and reduction hypothesis, though no single theory dominates.
- Viruses might not stem from a linear evolutionary path, challenging definitions of life and living organisms.
4 THE VIRUS IS US
This chapter explores the integral role viruses have played in evolution and human development. It covers how viruses, including endogenous retroviruses, have integrated into human DNA, influencing everything from placenta formation to immune responses. Authentic assessments highlight the necessity and complexity of viral genes in reproduction and potential vulnerabilities from their absence.
Viruses and Evolution
- Viruses shuffle genes, acting as a potent force of evolution.
- Viruses use strategies like tricking host cells to replicate.
- Their gene integration can affect a host's reproduction and evolution.
Endogenous Retroviruses (ERVs)
In the nearly two decades since the Human Genome Project, scientists have identified more than fifty distinct Human ERVs (or HERV) �families� in human DNA. Of these, the HERV-L family is considered the oldest, and is estimated to have invaded the genome of an ancestor of all mammals some 150 million years ago. This was a momentous development for all modern mammals because it caused mammals to split into two distinct lines.
We had help from our virus friends because syncytin was originally a viral protein.
This particular HERV meddles with mechanisms associated with pleasure in the brain and drives individuals to different types of addictions. Increasingly, this HERV and the proteins it produces is being incriminated for neurological disorders like multiple sclerosis, Lou Gehrig�s disease, and even depression and schizophrenia. Can HERVs perhaps explain our Monday morning blues?
- Human DNA contains more than fifty ERV families, with HERV-L being the oldest.
- ERV genes like syncytin play roles in human reproduction, aiding placenta formation.
- ERVs have been implicated in neurological disorders and may drive addictions.
Foetal Cells and Placenta
Some types of foetal cells travel across organs and reach the mother�s tissues, mostly those underlying her skin, liver, kidney and bone marrow. The role of foetal cells is not fully understood but they perhaps help heal minor injuries or diseases that the mother may encounter. Some studies have found that pregnant mothers make better survival decisions, and know when to fight, flee or fly.
Some mammals consume their placenta after birth. This is because after an exhausting labour, the placenta offers an easy and rich source of iron, protein and vitamins for the mother. Physiologists have found that animals that consume the placenta immediately after birth are able to reduce post-delivery bleeding, restore their hormones quickly, increase their energy and, therefore, begin the supply of milk for their newborn.
- Foetal cells can travel to the mother's tissues, assisting in healing and survival decisions.
- The placenta, aided by viral genes, offers nourishment and protection to the foetus.
- Consumption of the placenta can benefit mammals postpartum.
Virus Contribution in Evolution
In some ways, a developing foetus is a little bit like a virus, in that it exists inside the body of another organism where it needs to avoid detection and rejection by the (mother�s) immune system. So perhaps it is fitting that it should be helped by syncytin, which is a protein synthesised from a gene taken from a virus.
So, it seems that an obligate parasite that gave us HERVs is an obligate requirement for human reproduction. Without it, we would perhaps still be laying eggs!
It was about 400 million years or so ago that an ancestor of the coelacanth became infected by novel foamy viruses (2) which led to the development of its muscular fin, and that enabled an amphibious descendant to take the first steps out of water onto land. Most life forms� from deep-sea-dwelling coelacanths to chimpanzees� have their unique foamy virus infections. So you may have a series of viral infections in fish to thank for your dextrous fingers and toes, as well as for your mobile arms and legs.
- Some foetal cell behaviors are virus-like, assisting in immunity and hormonal modulation.
- Viral genes, specifically HERVs, are crucial for human reproduction.
- Coelacanth infected by foamy viruses may have enabled early amphibians.
Loss and Importance of ERVs
Virologists at Oxford University have reconstructed the history of our viral DNA and estimate that there were at least thirty to thirty-five separate invasions which embedded ERVs into our genome. The virus that endowed us with HERV-H (they are critical in the development and fusion of the sperm and egg cells and in subsequent cell development) was a super-spreader because it got transmitted through the germ line or from parent to child.
But losing ERVs also increases our risks to invasion by other viruses, and this may explain the rising numbers of cancers or how exogenous (outside) residents like HIV became a persistent infection.
- ERVs helped in the development and fusion of cells essential for reproduction.
- Despite fewer ERVs in modern humans, they play a role in preventing some diseases.
- Losing ERVs might heighten susceptibility to invasions by other viruses.
5 A DEEP CONTROL
The chapter explores the critical roles of microbes and viruses in maintaining life on Earth. Cyanobacteria and marine microbes play significant roles in oxygen production and carbon dioxide consumption. Viruses, particularly bacteriophages, regulate microbial populations and contribute to long-term carbon burial, essential for climate balance.
Role of Cyanobacteria
For over 3 billion years, free-living cyanobacteria and other photosynthetic organisms in water, together with stromatolite colonies, were the only life forms on Earth, and it is these early microbes and their partnerships that produced all the oxygen we breathe today.
Stromatolites are all but gone now, except in a few places like a lagoon in the Bahamas and Hamelin Pool in Western Australia, where they are still growing very slowly, adding about 5 centimetres every century.
With the stromatolites all but gone, it is free-living cyanobacteria and other photosynthetic organisms that have been chipping away at carbon dioxide levels in the atmosphere and are producing most of the oxygen we breathe today.
- Cyanobacteria, existing for over 3 billion years, and stromatolite colonies were the only life forms on Earth, producing all the oxygen we breathe today.
- Stromatolites, large colonies of cyanobacteria, are mostly gone except in places like the Bahamas and Hamelin Pool in Western Australia.
- Free-living cyanobacteria and other photosynthetic organisms currently reduce carbon dioxide and produce most of the Earth's oxygen.
Importance of Marine Photosynthesis
The photosynthetic bacterial community collaborates with other microbes like sulphur-producing bacteria to produce nearly 70 per cent of all the Earth�s oxygen and bury more than 4 gigatonnes of carbon dioxide (a gigatonne is a billion metric tonnes, GtC) every year.
This is more than all trees and human efforts to scrub carbon achieve. In all, oceans sink 9 GtC while forests and vegetation on land absorb about 11 GtC. The important point here is that forests and vegetation on land are both a source and sink of carbon, while oceans are just sinks of carbon and net oxygen producers.
Anywhere between 50 and 80 per cent of Earth�s free breathable oxygen comes from oceans, thanks to micro-photosynthesisers. Among a variety of these primary producers, the champion cyanobacterium, Prochlorococcus, is the smallest photosynthetic organism on Earth. It alone produces up to 20 per cent of all oxygen, which is higher than all of the tropical rainforests put together.
- Photosynthetic bacteria and microbes in the ocean produce nearly 70% of Earth's oxygen and bury over 4 gigatonnes of carbon dioxide each year.
- Oceans, unlike forests on land, serve only as carbon sinks and net oxygen producers.
- Cyanobacteria like Prochlorococcus are significant, contributing up to 20% of the planet's oxygen.
Role of Viruses and Bacteriophages
Left to themselves, marine photosynthetic bacteria would multiply endlessly, turning the ocean into a slimy green, stinky pea soup, like sewage-filled rivers or drying ponds. This is where viruses come in. More specifically, viruses that infect bacteria which are called �bacteriophages�, or simply �phages�
Together, carbon, phosphorus, nitrogen and sulphur are the building blocks of life, and viruses play a role in regulating the life cycle of each one of these elements.
The moral of the story, if we are to look for one, is this� in order to reverse the earth-warming effects of producing excessive carbon dioxide and methane, we need to bury vast amounts of carbon in the depths of the earth or seas. Moreover, carbon needs to stay buried and unperturbed for a very long time. This is precisely what happens when myriad bacteria, viruses and a multitude of other minutiae busily carry on their wild rumpus in the oceans, in open seas, lakes, rivers, ponds and soils. They are friends of the Earth and of life. We must let them be.
- Viruses, particularly bacteriophages, regulate marine bacterial populations to prevent overgrowth.
- Viruses are crucial in regulating the life cycles of carbon, phosphorus, nitrogen, and sulfur, essential for life.
- Viral infection in bacteria contributes to long-term carbon burial, essential for mitigating climate change.
6 INVADERS, HITCH-HIKERS, SENTINELS, KILLERS
The chapter explores the diverse and complex roles of microbes, especially viruses, in human health and evolutionary history. It discusses how viruses like herpes and adenoviruses contribute to various health conditions and traces their evolutionary origins and global spread, providing insights into human migration and ancient interactions.
Our Viral Passengers
- Humans are colonized by various microbes before and after birth, including endoretroviruses essential for gestation.
- Herpesvirus, a well-researched virus family, includes HSV1 and HSV2, which become dormant after initial infection.
- Polyomaviruses like JCV can cause tumors and are found in most adults, offering clues on human migrations.
- Anelloviruses, such as TTV, are common and may influence the immune system, serving as a marker for immune status.
Viruses and Health Impacts
And while we incriminate fizzy drinks, confection, fries and burgers for the rise in diabetes and obesity, there are at least five confirmed human adenoviruses and several animal obesogenic viruses that can induce weight gain.
- Adenovirus-36 (Ad36) can induce weight gain in animals and possibly humans, linked to obesity.
- Other viruses can trigger diseases such as juvenile diabetes or play roles in health conditions.
Evolutionary and Historical Perspective on Viruses
- Herpesviruses have deep evolutionary roots, tracing back to early vertebrates and evolving through primate hosts.
- HSV1 and HSV2 have spread historically via migration and interaction, with HSV1 more prevalent.
- Scientific studies on viruses like JCV and HSV2 illuminate aspects of human migration and evolution.
- Our ancestors transmitted various pathogens during migrations, influencing populations worldwide.
7 A SPOTTY HISTORY OF THE SPECKLED MONSTER
The chapter discusses the history and impact of smallpox, detailing its origin, effect on civilizations, and eventual eradication through vaccination. It highlights Edward Jenner's contributions to vaccination, which saved millions of lives by preventing smallpox.
Origins of Smallpox
- Smallpox is a member of the poxvirus family and its ancestor is believed to have originated in the Sahel, Africa.
- Gerbils in the Sahel carried the ancestral virus, which transferred to camels and eventually evolved into smallpox in humans.
Impact on Empires and Civilizations
In a letter written to Colonel Henry Bouquet in 1763, Sir Jeffrey Amherst, commander-in-chief of British forces in North America, advocated dusting scabs of smallpox on to blankets and leaving them outside native settlements that were under siege; or distributing and trading bison skins laced with the pox with native American people before the onset of winter.
- Smallpox epidemics caused significant demographic and societal changes, contributing to the decline of various empires and civilizations.
- The introduction of smallpox to the Americas by Europeans led to the collapse of native populations like the Aztec and Inca empires.
Advancements in Smallpox Vaccination
On 17 May 1803, at the first meeting of the Royal Jennerian Society (founded by fellow doctors and admirers), Edward Jenner insisted that his friend and fellow physician, Richard Dunning, be credited for coining the term �vaccination� (Greek; vacca: cow). The era of smallpox vaccination had dawned. Vaccination became a common practice in England, and gradually in Europe and the Americas too, and was introduced into British colonies like India, where it saved millions of lives.
- Edward Jenner's work on cowpox led to the development of the first smallpox vaccine, establishing the practice of vaccination.
- Vaccination spread globally, drastically reducing smallpox cases and eventually leading to the disease's eradication.
8 GUT FEELING
The chapter discusses the role and diversity of gut microbes, challenging previous beliefs about microbial numbers and dominance, emphasizing the impact of diet and birth on microbiome composition, and exploring the microbiome-gut-brain axis. It highlights the potential consequences of shifts in microbial populations and questions the efficacy of probiotic products in supporting gut health.
Quantifying Gut Microbes
- Until recently, it was believed that an average person has 10 trillion human cells with 100 trillion bacteria inside.
- Scientific methods later challenged this estimate, leading to a revised bacterial-to-human cell ratio of about 1.3:1.
Classification and Impact of Microbiota
The fourth bacterium E. coli (and others in genus Escherichia) which, for the longest time had been thought to be the most dominant organism in the human gut, was found to make up less than 1 per cent of the total bacterial population.
- Gut contains diverse bacteria like Bacteroides, Prevotella, and Ruminococcus.
- E. coli, once thought dominant, makes up less than 1% of the total bacterial population.
Influence of Diet and Birth on Microbiome
What this means, in essence, is that what you have eaten since you were an infant and as a child has an important bearing on your gut microbiome, which, to a large extent, is a critical determinant of your overall health.
The infant microbiome is strongly influenced by how the baby is born� whether through the birth canal or by caesarean section.
- Diet influences the proportions of gut bacteria and affects overall health.
- The infant microbiome is influenced by birth method, affecting the types of bacteria colonizing the infant.
Changes and Consequences in Microbiota
H. pylori to disappear and be replaced by a new set of microbes. Localised extinction of microbes within our gut can have consequences that we know little about as yet.
New evidence suggests that the composition of the intestinal microbiota when we were young determines whether we are predisposed as adults to allergies such as asthma.
- H. pylori's decline due to antibiotics and preservatives causes shifts in gut microbiota.
- Microbial composition in early life can affect adult predispositions to conditions like asthma.
Microbiome-Gut-Brain Axis
Another interesting phenomenon that several studies have shown is that there is a clear pathway linking the action of microbes and gut cells to the functioning of the brain. Physiologists call such a connection an �axis�. The microbiome-gut-brain axis is a two-way communication system between bacteria and gut cells on the one hand, with the brain.
- A connection exists between gut microbes, gut cells, and brain function, known as the microbiome-gut-brain axis.
Probiotics and Microbiome Health
Probiotic products contain proprietary strains of bacteria that have been heavily domesticated. They are present in these products in very low numbers and the species are chosen for the ease with which they can be manufactured, stored and for their shelf life, and not necessarily because they are the best for our bodies.
- Probiotic products have domesticated strains of bacteria and may not be best for gut health.
9 A VIRUS VANISHES
The chapter discusses the effects of the Little Ice Age on Europe, particularly on agriculture and disease spread. It highlights the emergence of sweating sickness, a mysterious disease causing significant mortality in England, linked possibly to rodent-borne hantaviruses. Cultural practices evolved in response to epidemics, influencing hygiene and urban sanitation. The chapter underscores challenges in identifying new infectious diseases and preventing outbreaks amidst ecological changes and human activities.
Climate Impact on Society and Disease
- The Little Ice Age, marked by sharp climate changes, affected populations and agriculture.
- Cooling periods caused crop failures and cultural changes, such as shifts in alcohol consumption patterns.
- Deforestation and intensive farming increased rodent populations, reservoirs for diseases like plague and smallpox.
Sweating Sickness and Historical Outbreaks
- Sweating sickness emerged in England with symptoms similar to the plague, but with stinking sweat.
- Multiple outbreaks occurred between 1483 and 1551, affecting robust adults and causing significant mortality.
- The disease spread in Europe but waned quickly, with unclear causes potentially linked to rodent-borne hantaviruses.
Cultural and Hygiene Practices
- Beliefs against bathing to avoid disease shaped hygiene practices, leading to use of powders and lotions instead.
- Waste management in urban areas like London evolved, with rivers often used as cesspits, leading to environmental issues.
Hantavirus and Rodent-Borne Diseases
- Hantaviruses, spread by rodents, cause respiratory and renal disorders, with rare outbreaks in Europe and America.
- The potential for hantavirus outbreaks exists with human encroachment on rodent habitats.
Emerging Infectious Diseases and Challenges
- New diseases often emerge due to ecological changes and human activities like trade and habitat encroachment.
- Advanced techniques are needed to identify pathogens and prevent or mitigate outbreaks before they spread.
10 BEAUTY
The chapter explores the historical impact of viruses on tulips, notably during the Tulipmania in 17th-century Netherlands, where viral 'breaking' transformed tulips into commodities of speculative value. It dives into the scientific understanding of viruses creating streaked tulips and highlights their positive roles in shaping both ornamental and agricultural plants, enhancing beauty and crop yields.
Tulipmania and its Impact
- A virus gave unique qualities to tulips, transforming them into sought-after commodities which led to the first economic bubble.
- Tulips were introduced to Europe from the Ottoman Empire and became central to the Dutch economy, leading to Tulipmania.
- The Dutch mania for tulips in the 1630s led to a surge in their economic value, driven by speculation around 'broken' tulips.
- Carolus Clusius was influential in spreading tulips in the Netherlands, contributing to their speculative market boom.
- Tulipmania ended in a market crash in 1637, illustrating the first documented case of an economic bubble due to speculative trade.
Role of Viruses in Tulip Patterns
- 'Broken' tulips, characterized by streaked patterns, were caused by viral infections that impacted tulip aesthetics.
- Dorothy Cayley discovered in 1928 that a virus, through aphid transmission, caused streaking in tulips.
- Potyvirus was identified as the primary virus responsible, creating unique streaks and patterns by affecting pigment production in tulips.
Viruses and Flowers
- Besides tulips, viruses can transform various flowers like camellias, roses, and lilies, making them more attractive and aiding pollination.
- Viruses cause variations and sometimes enhance fragrance and size in infected flowers without harming them.
- The potyviruses manipulate pigments, offering varieties like 'rosen', 'violetten', and 'bizarden', leading to sought-after flower forms.
Viruses and Agriculture
- Viruses can also benefit fruits and crops, such as enhancing grapevine yields and improving wine quality.
- In agriculture, specific viral strains are used to induce desirable traits in plants, contributing to economic and environmental benefits.
11 HOW A VIRUS SAVED A GIANT
The chapter discusses the devastation of American chestnut trees by Cryphonectria parasitica and subsequent ecological impact. Hybridization efforts offered limited success, but the introduction of Cryphonectria hypovirus-1 reduced the fungus's virulence, suggesting viral strategies could manage other fungal diseases.
Historical Context and the Impact of Chestnut Blight
- American chestnut trees once formed a vast forest area in the eastern United States but were devastated by chestnut blight caused by Cryphonectria parasitica.
- The blight led to ecological crises, reducing animal populations and impacting various ecosystems that depended on the trees.
Efforts to Combat the Blight
- Attempts to hybridize American chestnuts with Asian varieties met limited success, retaining resistance but losing other desirable traits.
- The European chestnuts developed partial immunity to the fungus over time, thanks partly to coexisting with Asian chestnut species.
Role of Hypovirulence in Recovery and Future Prospects
- Introduction of a virus (Cryphonectria hypovirus-1) within the fungus reduced its virulence, helping some chestnut trees recover.
- The idea of hypovirulence introduces potential strategies for managing other fungal plant diseases using viral interventions.
12 ZOMBIES
The chapter explores the historical and scientific background of zombies and other myths, like vampires, as well as the role of parasitic organisms in influencing behavior, including Toxoplasma gondii and parasitic wasps. It highlights how parasitic infections and prion diseases like kuru have informed current understanding of neurological disorders. Additionally, it discusses the beneficial use of viruses in nature for plant survival and pest control.
Impact of Parasitic Organisms
- Humans have historically been affected by brain-manipulating parasites.
- Toxoplasma gondii, a parasite carried by cats, alters the behavior of mice.
- The impact of T. gondii on humans is linked to mental disorders and increased risk-taking.
- Kuru, a disease from New Guinea, is caused by cannibalism-related prion infections.
- Kuru and similar prion diseases involve brain degeneration and have informed research on neurological disorders.
Zombies and Related Myths
In much of Victorian literature, the lifespan of a vampire was said to be forty days, which is the same as the average time that it takes from the first symptoms of human rabies until death. G�mez-Alonso concludes that vampires and werewolves in historical accounts were rabid individuals, and their transmogrifying and facial distortions were construed as demonic by naive and god-fearing people.
- Zombie myths often arise from misunderstandings of diseases and phenomena.
- Zombie and vampire concepts have origins in historical disease patterns like rabies.
- The rabies virus may have contributed to the myth of vampires due to similar symptoms.
- Worldwide fascination with zombies is reflected in literature and films.
Role of Parasitic Wasps and Beneficial Viruses
- Parasitic wasps use caterpillars and viruses to propagate their species.
- Viruses can have positive effects, aiding plant survival and deterring pests.
- Researchers study wasps and viruses for pest control and potential agricultural benefits.
13 ENEMY�S ENEMY
Chapter 13 explores the beneficial role of viruses, notably bacteriophages, in combating bacterial infections like cholera. While early scientists like Hankin, Twort, and d'H�relle recognized their potential, phage therapy was overshadowed by antibiotics. With rising antibiotic resistance, phage therapy offers hope for targeted and effective treatments, emphasizing the need to understand microbial ecosystems and personalized medicine approaches.
Hankin's Discovery and Early Observations
- Ernest Hankin discovered antibacterial properties in the Ganges and Jamuna rivers, noting the absence of cholera bacteria due to an unknown 'protective substance'.
- Hankin's work hinted at the presence of viruses that could kill bacteria, though his findings remained largely unnoticed.
Discovery and Exploration of Bacteriophages
- Frederick W. Twort and Felix d'H�relle independently discovered bacteriophages, viruses that can destroy bacteria, marking the beginnings of phage therapy.
- D'H�relle successfully used bacteriophages to treat diseases like dysentery and cholera, proving their potential in infectious disease control.
Challenges and Evolution of Phage Therapy
- Phage therapy faced challenges from competing scientific theories and lack of recognition, leading to limited uptake especially in Western countries.
- Despite promising results, the dominance of antibiotics overshadowed phage therapy, which remained relatively unknown outside certain regions.
Antibiotic Resistance and the Red Queen Effect
The evolution of antibiotic resistance is a textbook case of what is called the Red Queen Effect (RQE) in evolution. This name derives from Lewis Carroll�s Through the Looking Glass, where Alice is told by the Red Queen: �It takes all the running you can do, to keep in the same place.� Like being on a treadmill� speed it up and you need to run faster and faster just to stay in the same place or risk falling flat on your face.
- Antibiotic resistance is compared to the Red Queen Effect, where bacteria continuously adapt to survive antibiotic treatments, making resistance inevitable.
- Phage therapy offers potential solutions to antibiotic resistance by targeting specific bacteria, avoiding the broad-spectrum effect of antibiotics.
Reviving Phage Therapy for Modern Challenges
Perhaps now more than ever before, we need to understand that our bodies are an ecosystem and each of us is a microcosm. Every pathogen that affects us has a set of its own pathogens� the enemy�s enemy. This is how nature plays out. The revival of safe and responsive public health systems to address disease will depend upon how well we understand the ecology of viruses and the human microbiome in the context of disease and wellness. The harnessing of viruses to fight potential pathogens is a viable strategy for the advancement of medicine, both for public and individualised use� the future of human and planetary health may well lie in the hands (or rather, in the tails) of phages.
- The resurgence of phage therapy is driven by the need to combat antibiotic-resistant bacteria and emphasizes personalized medicine.
- Understanding the ecology of viruses and the human microbiome is crucial for advancing phage therapy and maintaining public health.
14 QUO VADIS?
The chapter explores human genetics, emphasizing our evolutionary connection to various species including microbes. It discusses how genetic mutations and interactions with viruses influence evolution, using SARS-CoV-2 as a case study to showcase human misbelief in controlling nature. The need to respect and collaborate with microbes for planetary and health benefits is stressed, suggesting a shift towards sustainable living with nature.
Human Genetics and Microbial Influence
- Humans, like all living things, are genetic amalgams, receiving genes from various ancestors including microbes.
- Mutations in genes drive evolution, contributing to species development and adaptation.
- Viruses and microbes facilitate genetic exchanges across species.
The Role of SARS-CoV-2 in Human Interactions with Nature
Our technological progress, our ability to acquire instant (albeit often ephemeral) gratification, has lulled us into believing that we possess enough power to subdue and manipulate nature. We choose which relationships we want to foster and which we will cull and sever, and try to make nature serve us selectively and indefinitely. This kind of brinkmanship makes us feel that we can control nature, but as we have been slow to realise, this control is delusional.
- SARS-CoV-2 acquired the ability to infect humans through gene changes from animals.
- The virus's behavior is complex due to shared genes with humans and unique viral genes.
- Technological advances have misled humans into believing they can completely control nature.
Microbial World and Climate Change
- Microbes regulate essential planetary processes, including the carbon-oxygen cycle.
- Each ecosystem relies on microbial activity to maintain its balance.
- Microbes can process and transform materials more efficiently than machinery.
Understanding and Appreciating Microbes
If we continue to speak of microbes and viruses using the lexicon of war, then it is a war we have already lost. It is ironic that we are supposedly at war with this invisible force, which can cause disruption, but which also binds all life.
If we are to survive in the future as a civilization and as cultures, now is our moment to find ways to share our planet with all the life on Earth. And this change should start with our smallest denizens. It may not seem so at the moment but viruses are our friends.
- Humans need to respect and understand microbes' role in supporting life.
- Destructive approaches, like excessive use of antibiotics, harm ecosystems and should be reassessed.
- Viruses, as integral parts of life, offer opportunities for learning and advancement in various fields.
Future Directions and Coexistence with Nature
What inspiration can we take from this moment? This past year, nature has been telling us that we must slow down our greed machine. We need an anthropo-pause. We must awaken to the fact that we can share our spaces with nature in its many forms. The old ways were not �normal� in any way, and that is not the normal that we should strive to return to.
- The pandemic suggests the need to reduce human impact on nature and embrace sustainable practices.
- Humans should aim to coexist with nature, adopting an 'anthropo-pause' to reconsider interactions with the environment.