Key Takeaways
1. The human immune system evolved with parasites and microbes
Homo sapiens ranks among the most parasitised of all animals.
Coevolution shaped immunity. For millions of years, humans coexisted with a diverse array of parasites and microbes. This long-term relationship profoundly influenced the development of our immune system. Parasites like hookworms and whipworms were ubiquitous, as were various bacteria and viruses. Our bodies adapted to their presence, developing regulatory mechanisms to maintain a delicate balance.
Parasites as old friends. Rather than viewing all parasites as harmful, many acted as "old friends" to our immune system. They helped calibrate immune responses, preventing overreaction to harmless stimuli. This symbiotic relationship allowed our ancestors to thrive despite constant microbial exposure. Examples include:
- Helminths (intestinal worms) that modulate inflammation
- Commensal bacteria that aid in digestion and immunity
- Viruses that may offer protection against other pathogens
2. Modern hygiene has disrupted our ancient microbial relationships
We may have made a mistake equivalent to studying and cataloging an exotic-seeming ecosystem, only to discover that we weren't in the jungle at all; we were actually at the Bronx Zoo.
The hygiene revolution. The advent of modern sanitation, antibiotics, and improved living conditions dramatically reduced our exposure to many parasites and microbes. While this undoubtedly saved countless lives from infectious diseases, it also disrupted the delicate ecosystem our immune systems had come to expect.
Unintended consequences. The rapid change in our microbial environment has led to unexpected health challenges:
- Increased rates of allergies and autoimmune diseases
- Rising incidence of inflammatory bowel diseases
- Potential links to neurological disorders like autism
- Altered gut microbiome composition and function
These shifts occurred faster than our genes could adapt, leaving our immune systems in a state of confusion and potential overreaction.
3. Parasites and microbes play a crucial role in immune system regulation
Coevolution leads to codependence.
Immune education. Parasites and microbes act as natural immunomodulators, teaching our immune system to distinguish between harmful invaders and benign substances. This "education" process is critical for developing a balanced immune response.
Regulatory mechanisms. Specific examples of immune regulation include:
- Helminths inducing regulatory T cells (Tregs) that suppress inflammation
- Commensal bacteria producing short-chain fatty acids that maintain gut barrier integrity
- Certain viruses potentially enhancing innate immune responses
Without these regulatory influences, the immune system may become hyperactive, leading to inappropriate responses against harmless substances or the body's own tissues.
4. Autoimmune diseases may result from missing "old friends"
We may actually be born allergic.
The old friends hypothesis. This theory proposes that the absence of evolutionary partners—parasites, bacteria, and viruses we coevolved with—contributes to the rise of autoimmune and allergic diseases. Without these "old friends," our immune system lacks the stimuli it expects to encounter during development.
Evidence from epidemiology and experiments:
- Higher rates of autoimmune diseases in developed countries with less parasite exposure
- Successful treatment of some autoimmune conditions using controlled helminth therapy
- Animal studies showing protective effects of certain parasites against allergic and autoimmune reactions
- Inverse relationship between H. pylori colonization and asthma rates
This hypothesis suggests that reintroducing specific microbes or mimicking their effects could potentially treat or prevent autoimmune disorders.
5. The maternal immune environment shapes fetal development
[M]aternal farm exposure might reflect a natural mode of immunotherapy . . . shaping a child's immune system at an early stage.
Prenatal programming. The immune status of a pregnant mother significantly influences her child's future health. Factors such as maternal infections, stress, and environmental exposures can alter fetal immune development through epigenetic changes.
Key influences on fetal immunity:
- Maternal antibodies and cytokines crossing the placenta
- Microbial exposures during pregnancy (e.g., farm environments)
- Presence of regulatory T cells in the placenta
- Maternal diet and microbiome composition
These early-life influences can have long-lasting effects on the child's immune function, potentially predisposing them to allergies, autoimmune diseases, or neurodevelopmental disorders like autism.
6. Autism spectrum disorders may have roots in prenatal inflammation
Something environmental is causing the rise [of autism].
Maternal immune activation. Growing evidence suggests that inflammation during pregnancy, whether from infection or other causes, may contribute to the development of autism spectrum disorders (ASD). This inflammation can disrupt normal fetal brain development.
Potential mechanisms:
- Maternal antibodies targeting fetal brain proteins
- Elevated pro-inflammatory cytokines affecting neurodevelopment
- Altered microglial activation in the developing brain
- Epigenetic changes induced by maternal immune responses
While genetics play a role in ASD susceptibility, the rapid increase in prevalence points to environmental factors. The link between maternal immune activation and autism offers a potential explanation for this trend and suggests possible avenues for prevention or intervention.
7. Reintroducing certain microbes could potentially treat immune disorders
If some omniscient being had come and said, 'That button on the wall, you press it and Lawrence not only doesn't exist, but he never existed.' I mean, I would have lunged for it.
Helminth therapy. Controlled reintroduction of specific parasites or their products has shown promise in treating some autoimmune and allergic conditions. This approach aims to restore the regulatory immune functions that coevolved with these organisms.
Promising areas of research:
- Use of Trichuris suis ova (pig whipworm eggs) for inflammatory bowel disease
- Hookworm therapy for asthma and allergies
- Potential applications for multiple sclerosis and other autoimmune disorders
While still experimental, these treatments highlight the potential benefits of harnessing our evolutionary relationships with certain microbes. However, careful consideration of risks and ethical implications is necessary.
8. The human virome is an integral part of our immune ecosystem
There is a dimension to human evolution—a microbial evolution—that is likely occurring at a very rapid rate as our societies undergo dramatic shifts.
Viral coevolution. Viruses, often viewed solely as pathogens, have played a crucial role in human evolution. Many have become integrated into our genome, contributing to important biological functions.
Virome functions:
- Potential protection against other pathogens
- Modulation of immune responses
- Contribution to genetic diversity
- Possible influences on brain development and function
Understanding the complex relationship between humans and our virome may lead to new insights into health and disease, as well as novel therapeutic approaches.
9. Diet and antibiotics have profoundly altered our gut microbiome
You are really an ecosystem, a mutually dependent aggregation of life-forms, what scientists call a superorganism.
Microbiome disruption. Modern diets high in processed foods and frequent antibiotic use have dramatically changed the composition of our gut microbiota. These changes may contribute to various health problems, including obesity, diabetes, and inflammatory disorders.
Factors affecting the microbiome:
- Overuse of broad-spectrum antibiotics
- Lack of dietary fiber and complex carbohydrates
- Increased consumption of artificial sweeteners and emulsifiers
- Reduced exposure to diverse environmental microbes
Restoring a healthy, diverse microbiome through dietary changes, probiotics, and reduced antibiotic use may help prevent or treat various modern diseases.
10. Epigenetics links environmental factors to immune system function
Genes are not Stalinist dictators. . . . They live in a democracy, and what they do is conditioned by what else is going on around them.
Environmental influences on gene expression. Epigenetic mechanisms allow environmental factors to influence how our genes are expressed without changing the DNA sequence itself. This provides a link between our experiences and our immune function.
Key epigenetic factors:
- Early-life exposures to microbes and parasites
- Maternal diet and stress during pregnancy
- Environmental toxins and pollutants
- Chronic stress and lifestyle factors
Understanding these epigenetic influences offers new possibilities for disease prevention and treatment by targeting the environmental factors that shape our immune responses.
Last updated:
FAQ
1. What is An Epidemic of Absence by Moises Velasquez-Manoff about?
- Immune dysfunction in modernity: The book explores the dramatic rise of allergies, autoimmune diseases, and other inflammatory conditions in modern societies, linking them to the loss of ancient microbial and parasitic exposures.
- Evolutionary and ecological context: Velasquez-Manoff situates human immune health within our evolutionary history, emphasizing how coevolution with microbes and parasites shaped immune regulation.
- Personal and scientific narrative: The author combines rigorous scientific research with personal experiments, including self-infection with hookworms, to illustrate the complexities of immune system dysfunction.
- Collapse of the human superorganism: The book frames human health as dependent on a diverse community of microbes and parasites, warning that their loss disrupts immune balance and increases disease risk.
2. Why should I read An Epidemic of Absence by Moises Velasquez-Manoff?
- Paradigm shift in understanding: The book challenges conventional views on allergies and autoimmune diseases, offering a new perspective that emphasizes missing environmental exposures over genetics or new pathogens.
- Accessible and engaging: Velasquez-Manoff blends personal narrative with scientific rigor, making complex immunology understandable and compelling for general readers.
- Public health implications: The book raises important questions about the unintended consequences of modern hygiene and sanitation, encouraging readers to rethink medical and environmental policies.
- Practical and controversial insights: It discusses emerging therapies and the underground movement of self-infection with parasites, providing a balanced view of both promise and risk.
3. What are the key takeaways from An Epidemic of Absence by Moises Velasquez-Manoff?
- Loss of “old friends”: The disappearance of ancient microbes and parasites, with which humans coevolved, is a major driver of immune dysfunction in modern societies.
- Immune system needs training: Early-life exposure to diverse microbes and parasites is essential for developing a balanced, tolerant immune system.
- Modern lifestyle consequences: Urbanization, antibiotics, C-sections, and Western diets disrupt the microbiota, increasing susceptibility to allergies, autoimmune diseases, and even metabolic and neurological disorders.
- Potential for new therapies: Restoring microbial and parasitic exposures, or mimicking their effects, could offer novel ways to prevent and treat immune-mediated diseases.
4. What is the “hygiene hypothesis” and how does it relate to An Epidemic of Absence by Moises Velasquez-Manoff?
- Original concept: The hygiene hypothesis, first proposed in 1989, suggested that childhood infections protect against allergies by training the immune system.
- Evolved understanding: The book explains how this idea has shifted to the “old friends” hypothesis, which emphasizes the importance of ancient microbes and parasites, not just infections, in immune regulation.
- Evidence and nuance: Velasquez-Manoff presents epidemiological and experimental evidence supporting these hypotheses, while also noting their limitations and the need for further research.
- Implications for health: The hygiene hypothesis underpins the book’s argument that excessive cleanliness and loss of microbial diversity contribute to the epidemic of immune-related diseases.
5. What is the “old friends” hypothesis as described in An Epidemic of Absence by Moises Velasquez-Manoff?
- Definition and origin: The “old friends” hypothesis, championed by scientists like Graham Rook, posits that humans evolved with a set of microbes and parasites essential for proper immune regulation.
- Role in immune balance: These organisms stimulate regulatory T cells and other immune circuits that prevent allergies and autoimmunity.
- Modern loss and consequences: The absence of these “old friends” in sanitized, urban environments leads to immune system overreactions and increased disease prevalence.
- Therapeutic potential: The hypothesis suggests that reintroducing or mimicking these exposures could help restore immune health.
6. How do parasites and helminths (worms) influence immune health according to An Epidemic of Absence by Moises Velasquez-Manoff?
- Immune modulation: Parasites like hookworms and whipworms induce regulatory immune responses, preventing excessive inflammation and autoimmunity.
- Co-evolutionary partners: Humans coexisted with helminths for millions of years, and our immune systems evolved expecting their presence.
- Therapeutic experiments: The book discusses studies and personal stories where controlled helminth infection led to improvements in conditions like Crohn’s disease, allergies, and multiple sclerosis.
- Risks and challenges: While promising, helminthic therapy carries risks and is not universally effective, highlighting the need for scientific rigor and safety.
7. What is the “disappearing microbiota hypothesis” in An Epidemic of Absence by Moises Velasquez-Manoff?
- Loss of microbial diversity: Modern hygiene, antibiotics, and lifestyle changes have led to the extinction of many beneficial microbes inherited from mothers and the environment.
- Generational decline: Each generation may start life with fewer microbial allies, increasing vulnerability to immune-mediated diseases.
- Health consequences: The loss of ancient microbes is linked to rising rates of allergies, autoimmune diseases, and even metabolic and neurological disorders.
- Restoration efforts: The book discusses strategies like fecal transplants and probiotics to rebalance the microbiota and improve health.
8. How does An Epidemic of Absence by Moises Velasquez-Manoff explain the rise of allergies and autoimmune diseases in modern societies?
- Loss of critical exposures: Improved sanitation, deworming, and urbanization have removed essential immune system stimuli, leading to immune dysregulation.
- Epidemiological evidence: Populations with higher exposure to parasites and microbes, such as rural or traditional communities, have lower rates of asthma, allergies, and autoimmune diseases.
- Genetic and environmental interplay: Genes predisposing to immune diseases become problematic mainly when the environmental context changes—specifically, when “old friends” are lost.
- Modern lifestyle factors: Factors like C-sections, antibiotics, and Western diets further disrupt immune development and increase disease risk.
9. What is the “fetal origin hypothesis” of allergic disease in An Epidemic of Absence by Moises Velasquez-Manoff?
- Prenatal immune imprinting: Maternal inflammation during pregnancy can program the fetal immune system, increasing the child’s risk for asthma and allergies.
- Evidence from studies: Research shows deficits in regulatory T cells and altered immune responses in cord blood and placental tissues of children who develop allergies.
- Potential for reversal: Early microbial exposure after birth, such as through day care or farm environments, may help correct immune dysregulation.
- Epigenetic mechanisms: The book discusses how these changes can be reversible and may even affect future generations.
10. How does An Epidemic of Absence by Moises Velasquez-Manoff connect immune dysfunction to other diseases like obesity, diabetes, and neurological disorders?
- Chronic inflammation link: Low-grade systemic inflammation, driven by immune dysregulation and altered microbiota, underlies metabolic syndrome, cardiovascular disease, and some cancers.
- Gut-brain axis: Altered microbiota and chronic gut inflammation may contribute to neurological conditions like autism and multiple sclerosis.
- Role of parasites and microbes: Helminths and certain bacteria can modulate inflammation and metabolism, offering protection against obesity and tumor growth.
- Modern lifestyle impact: Western diets and reduced microbial exposures simplify gut ecosystems, promoting inflammation and disease.
11. What are the practical and public health implications of An Epidemic of Absence by Moises Velasquez-Manoff?
- Rethinking hygiene and sanitation: While sanitation has saved lives, the book warns of unintended consequences for immune health, suggesting a need to balance cleanliness with beneficial microbial exposure.
- Potential new therapies: Experimental treatments using parasites or microbial products could restore immune balance, offering alternatives to traditional immune suppressants.
- Personalized medicine: Genetic diversity in immune responses means that therapies may need to be tailored to individual genotypes for safety and effectiveness.
- Ecosystem restoration: The book advocates for restoring environmental biodiversity and fostering healthy microbial exposures in urban settings to improve public health.
12. What are the best quotes from An Epidemic of Absence by Moises Velasquez-Manoff and what do they mean?
- On immunology’s blind spots: “We as immunologists are now faced with the unsettling realization that the immune system we have spent all of our effort and energy studying over . . . the past fifty years has turned out to be dramatically different than the system derived by natural selection.” This highlights how modern research may have misunderstood the immune system by ignoring its evolutionary context.
- On human-environment connection: “We’re part of our environment; we’re not separate from it, and we can’t be separate from it.” This underscores the book’s central theme that human health depends on continuous interaction with microbes and parasites.
- On coevolution and codependence: “Coevolution leads to codependence.” This quote explains that humans and their microbial partners have evolved interdependently, making some microbes essential for normal immune function.
- On disease and normality: “Life is naturally tattered, infested, bitten off, bitten into... Disease is part and parcel of how we are supposed to look, of how we are supposed to live.” This emphasizes that imperfection and microbial interactions are natural and essential to life.
Review Summary
An Epidemic of Absence explores the "hygiene hypothesis" and its potential link to autoimmune diseases. Velasquez-Manoff presents compelling research on how modern sanitation may have disrupted our symbiotic relationship with microbes and parasites, possibly leading to increased allergies and autoimmune disorders. While some readers found the book fascinating and well-researched, others criticized its reliance on anecdotal evidence. The author's personal experience with worm therapy adds an intriguing element. Overall, the book offers a thought-provoking perspective on the complex relationship between human health and our microbial environment.
Similar Books
Download PDF
Download EPUB
.epub digital book format is ideal for reading ebooks on phones, tablets, and e-readers.
