Its the ability of our immune system to remember past infections, and pass this memory on to our kids, that allows us to survive infectious diseases.
This is the second article in a four-part series looking at how infectious diseases have influenced our culture and evolution, and how we, in turn, have influenced them.
Its easy to feel our survival is under threat from new and emerging infectious diseases that are going to wipe out the human race, or at least end our current way of life. The recent outbreaks of Ebola in West Africa re-ignited our interest in pandemics and reminded us of our potential frailty in the face of an overwhelming enemy.
With so many microbes capable of hijacking and destroying us, how are we as a species still enduring?
Humans are unique in the world. We are avid collectors of infectious diseases acquired from our environment throughout our evolution.
We share with our invaders a need to survive and propagate our genes. Infectious pathogens, such as bacteria and viruses, are parasitic they have to find and infect a susceptible host in order to maintain themselves and propagate. Therefore, its not really in their best interests to kill us. Our relationship with pathogens is shaped by our capacity to evolve genetically, to modify our behaviour, or to force the pathogens to evolve so that we all survive.
Viruses such as influenza replicate and spread to new hosts before the original host gets sick (with influenza symptoms such as a sore throat and sneezing), meaning the parasite can survive and thrive in new hosts.
On rare occasions the death of the host is necessary for the pathogen to reproduce. One example is trichinellosis (also known as trichinosis), which is caused by eating undercooked or raw meat from animals (usually carnivores and omnivores) infected with a worm (nematode).
To survive in the host the worm constructs a capsule around itself to avoid the immune system. The immature worms in the meat cause muscle weakness and paralysis, and eventually death, in the host. This means the victim is defenceless to predators that may come and gobble it up, thus giving the worm a new host to infect.
This is an old disease that we tackle either by avoiding eating meat (possibly the reason some religions avoid eating pork), or through cultural adaptation such as overcooking.
Evolutionary pressures through Darwinian selection, survival of the fittest, constantly shape life on Earth. This innate ability to adapt has enabled humans to develop defence mechanisms to counter some of the most devastating pathogens.
Malaria is a parasite of red blood cells that is estimated to have caused 429,000 deaths in 2015. When malaria became a human disease (it is thought to originate in primates) is unclear. One thing that is clear is that it emerged long enough ago for humans to evolve innate defences.
Sickle cell mutation is a potentially fatal blood disorder seen mainly in Africa. This mutation in a haemoglobin gene (responsible for red pigment in blood cells) is one of a number of genetic traits that actually protect against malaria. People who have this genetic mutation are protected against malaria and thus likely to reproduce and pass on their evolutionary advantage.
A second genetic mutation that protects humans against malaria affects an essential enzyme for red blood cell function. But individuals with this mutation may also develop life-threatening anaemia (deficiency in the number or quality of red blood cells) due to the destruction of red blood cells as a side effect of treatment with some modern anti-malarial drugs.
Perhaps the most significant and wondrous part of the evolutionary machinery that enables the human race to keep one step ahead of the pathogens is the major histocompatibility complex (MHC). The MHC proteins on the surface of our white blood cells evolved along with the vertebrates (animals with a spine), which makes them our oldest defence mechanism.
We have different types of white cells: mobile ones in the blood (lypmphocytes) and resident ones in lymph nodes (macrophages). When there is an infection the macrophages gobble up the bugs and present proteins from the organism on their surface like signals.
The lymphocytes containing MHC molecules that recognise this protein bind on. (Our immune system has memory cells that are produced after vaccination or past infections so we can remember how to fight them next time.) The lymphocytes then produce chemicals that recruit more lymphocytes to help. These multiply and you end up with a swollen gland.
Our bodys ability to remember past infections is one of the reasons the entire population of London didnt perish during the Black Death. MHC molecules are passed on to our offspring, which explains why we have such a wide variety of these molecules. When a disease enters a population for the first time it always more lethal than subsequent introductions because some people are now immune, and people have been born to the survivors.
Not all co-evolution leads to changes in human genetics, especially if there is no impact on our ability to procreate. Human tuberculosis is a chronic disease that continues to plague the world with little evidence that humans have developed any ability to resist infection. This is interesting because it is likely to have co-evolved with us from Neolithic times.
We will continue to face new and emerging diseases. So far our capacity to adapt and respond has served us well. But some scientists believe humans are no longer evolving due to the removal of many selection pressures, most importantly things that cause premature death.
The question is whether we are up to the challenges posed by what comes next. Perhaps the most pressing issue facing us now is that bugs seem to be evolving faster than we can create things to kill them known as anti-microbial resistance.
The spectre of life without antibiotics is terrifying given we never did overcome bacterial infections through evolution. Instead we used our ingenuity. Our future will reflect how well we exercise our collective intellect and will to dodge this bullet.
Read the first instalment in the series:
Four of the greatest infectious diseases of our time and how were overcoming them
Excerpt from:
How we've evolved to fight the bugs that infect us - The Conversation AU
- Copy number variation of the restorer Rf4 underlies human selection ... - Nature.com - November 15th, 2023 [November 15th, 2023]
- NYU Langone Health in the NewsThursday, November 9, 2023 - NYU Langone Health - November 15th, 2023 [November 15th, 2023]
- Eugenics: Plaguing scientific community with dark history | Opinion ... - The Arkansas Traveler - November 15th, 2023 [November 15th, 2023]
- Cranberries can bounce, float and pollinate themselves: The saucy ... - Japan Today - November 15th, 2023 [November 15th, 2023]
- Government Housing Assistance Linked to Increased Cancer ... - HealthDay - November 15th, 2023 [November 15th, 2023]
- Rate of New Lung Cancer Cases Has Decreased Over Last Five Years - HealthDay - November 15th, 2023 [November 15th, 2023]
- Clinically relevant antibiotic resistance genes are linked to a limited ... - Nature.com - November 15th, 2023 [November 15th, 2023]
- Disparities in Guideline-Concordant Care Found for Black CRC ... - HealthDay - November 15th, 2023 [November 15th, 2023]
- Mathematician Heather Harrington is new director at the Max Planck ... - EurekAlert - November 15th, 2023 [November 15th, 2023]
- New study finds genetic testing can effectively identify patients with ... - EurekAlert - November 15th, 2023 [November 15th, 2023]
- STK11 loss leads to YAP1-mediated transcriptional activation in ... - Nature.com - November 15th, 2023 [November 15th, 2023]
- CRISPR-broad: combined design of multi-targeting gRNAs and ... - Nature.com - November 15th, 2023 [November 15th, 2023]
- Master regulator of the dark genome greatly improves cancer T-cell ... - Science Daily - November 15th, 2023 [November 15th, 2023]
- Omega Therapeutics Showcases Bidirectional and Multiplexed ... - BioSpace - November 15th, 2023 [November 15th, 2023]
- Today is International 15q Day - ASBMB Today - November 15th, 2023 [November 15th, 2023]
- Evolution of taste: Sharks were already able to perceive bitter ... - EurekAlert - November 15th, 2023 [November 15th, 2023]
- Stanford Scientists Uncover New Indicators of Health, Disease, and ... - SciTechDaily - October 16th, 2023 [October 16th, 2023]
- NHGRI Director Eric Green elected to the National Academy of ... - National Human Genome Research Institute - October 16th, 2023 [October 16th, 2023]
- Monkey survives for two years after gene-edited pig-kidney transplant - Nature.com - October 16th, 2023 [October 16th, 2023]
- Opinion: Interest in RNA Editing Accelerates as Therapies Approach ... - BioSpace - October 16th, 2023 [October 16th, 2023]
- Regulation of dermal fibroblasts by human neutrophil peptides ... - Nature.com - October 16th, 2023 [October 16th, 2023]
- Consistent effects of the genetics of happiness across the lifespan ... - Nature.com - October 16th, 2023 [October 16th, 2023]
- Storytelling through the looking glass of genetics The Stute - The Stute - October 16th, 2023 [October 16th, 2023]
- Pet dogs shed light on human health, researchers say - UPI News - October 16th, 2023 [October 16th, 2023]
- Native microbiome dominates over host factors in shaping the ... - Nature.com - October 16th, 2023 [October 16th, 2023]
- Illinois-led project to sequence soybean genomes, improve future ... - Herald-Whig - October 16th, 2023 [October 16th, 2023]
- Unrealized targets in the discovery of antibiotics for Gram-negative ... - Nature.com - October 16th, 2023 [October 16th, 2023]
- How Biotech And AI Are Transforming The Human - Noema Magazine - October 16th, 2023 [October 16th, 2023]
- The Many Lives of Alexandria Forbes - BioSpace - October 16th, 2023 [October 16th, 2023]
- CEP20 promotes invasion and metastasis of non-small cell lung ... - Nature.com - October 16th, 2023 [October 16th, 2023]
- Genotyping, sequencing and analysis of 140,000 adults from Mexico ... - Nature.com - October 16th, 2023 [October 16th, 2023]
- The role and impact of alternative polyadenylation and miRNA ... - Nature.com - October 16th, 2023 [October 16th, 2023]
- Human - Simple English Wikipedia, the free encyclopedia - January 30th, 2023 [January 30th, 2023]
- Deep Dive Ties Together Dog Genetics, Brain Physiology and Behavior to Explain Why Collies Are Different from Terriers - Scientific American - December 12th, 2022 [December 12th, 2022]
- How oxytocin drives connections of newly integrated adult-born neurons: Research - Hindustan Times - December 12th, 2022 [December 12th, 2022]
- Alzheimer's Disease Genetics Fact Sheet - National Institute on Aging - December 2nd, 2022 [December 2nd, 2022]
- Human genetic clustering - Wikipedia - November 23rd, 2022 [November 23rd, 2022]
- Human Genome Project Fact Sheet - November 23rd, 2022 [November 23rd, 2022]
- Abstracts | International Congress of Human Genetics 2023 - November 23rd, 2022 [November 23rd, 2022]
- Ancient DNA and Neanderthals | The Smithsonian Institution's Human ... - November 16th, 2022 [November 16th, 2022]
- Biological Influences on Human Behavior: Genetics & Environment - November 16th, 2022 [November 16th, 2022]
- Fluent BioSciences showcasing breakthrough solutions to enable unprecedented scale, cost-efficiency and access for single-cell RNA sequencing at the... - October 28th, 2022 [October 28th, 2022]
- Human behaviour genetics - Wikipedia - October 23rd, 2022 [October 23rd, 2022]
- Nucleome Therapeutics raises oversubscribed 37.5 million Series A financing to decode the dark matter of the human genome and deliver first-in-class... - October 19th, 2022 [October 19th, 2022]
- Gladstone data scientist elected to the National Academy of Medicine - EurekAlert - October 19th, 2022 [October 19th, 2022]
- Ocugen to Host R&D Day in New York City on Tuesday, November 1, 2022 - Yahoo Finance - October 19th, 2022 [October 19th, 2022]
- Pharmacy researcher earns $2.3 million NIH award to study opioid addiction - EurekAlert - October 19th, 2022 [October 19th, 2022]
- Study shows age often plays a bigger role than genetics in gene expression and susceptibility to disease - Anti Aging News - October 19th, 2022 [October 19th, 2022]
- CSRWire - Direct Relief, Amgen and C/Can Team Up To Improve Access to Breast Cancer Diagnostics and Treatment in Paraguay - CSRwire.com - October 19th, 2022 [October 19th, 2022]
- Maze Therapeutics Appoints Harold Bernstein, M.D., Ph.D., as President, Research and Development and Chief Medical Officer - Business Wire - October 19th, 2022 [October 19th, 2022]
- New Rare Disease Therapy Effectively Lowers Plasma Phe in Patients with PKU - MD Magazine - October 19th, 2022 [October 19th, 2022]
- GSK : announces expanded collaboration with Tempus in precision medicine to accelerate R&D - Marketscreener.com - October 19th, 2022 [October 19th, 2022]
- Famous Scientific Discoveries That Changed the Course of History - 24/7 Wall St. - October 19th, 2022 [October 19th, 2022]
- Construction workers seek fulfilment of their demands - Star of Mysore - October 19th, 2022 [October 19th, 2022]
- Genetics | The Smithsonian Institution's Human Origins Program - October 13th, 2022 [October 13th, 2022]
- Genetics - Wikipedia - October 13th, 2022 [October 13th, 2022]
- Study looking at human genetics and Covid vaccine immune responses - Science Media Centre - October 13th, 2022 [October 13th, 2022]
- ASHG 2022 in Los Angeles brings together researchers from around the world to advance discoveries in genetics, genomics research - EurekAlert - October 13th, 2022 [October 13th, 2022]
- Maze Therapeutics Appoints Harold Bernstein, M.D., Ph.D., as President, Research and Development and Chief Medical Officer - Yahoo Finance - October 13th, 2022 [October 13th, 2022]
- The Age of the Pangenome Dawns - DNA Science - PLOS - October 13th, 2022 [October 13th, 2022]
- Influence of the microbiome, diet and genetics on inter-individual variation in the human plasma metabolome - Nature.com - October 13th, 2022 [October 13th, 2022]
- Genome editing technologies: final conclusions of the re-examination of Article 13 of the Oviedo Convention - Council of Europe - October 13th, 2022 [October 13th, 2022]
- Global Biobank Meta-analysis Initiative making genome-wide association studies more diverse and representative - EurekAlert - October 13th, 2022 [October 13th, 2022]
- New NHS genetic testing service could save thousands of children in England - The Guardian - October 13th, 2022 [October 13th, 2022]
- Covid protection may be boosted by genes, study shows - Yahoo News Australia - October 13th, 2022 [October 13th, 2022]
- Genomics in Cancer Care Market is estimated to be US$ 72.61 billion by 2032 with a CAGR of 16.3% during the forecast period 2032 - By PMI -... - October 13th, 2022 [October 13th, 2022]
- Identification of hub genes and candidate herbal treatment in obesity through integrated bioinformatic analysis and reverse network pharmacology |... - October 13th, 2022 [October 13th, 2022]
- Our *Homo sapiens* ancestors shared the world with Neanderthals, Denisovans and other types of humans whose DNA lives on in our genes -... - October 8th, 2022 [October 8th, 2022]
- Blue Eyed People Have a Single Ancestor | History of Yesterday - History of Yesterday - October 6th, 2022 [October 6th, 2022]
- Heart infection could be cause of death of Polish, US hero - ABC News - October 6th, 2022 [October 6th, 2022]
- 23andMe Announces Trials-in-Progress Poster Presentation on 23ME-00610, An Investigational Antibody Targeting CD200R1, at The Society for... - October 6th, 2022 [October 6th, 2022]
- The Genetic Drivers Of Longevity In Mice, Humans And Worms - Science 2.0 - October 6th, 2022 [October 6th, 2022]
- ANGPTL7, a therapeutic target for increased intraocular pressure and glaucoma | Communications Biology - Nature.com - October 6th, 2022 [October 6th, 2022]
- 'Neanderthal Man' Nobel Prize winner Svante Pbo revolutionized anthropology. Here is a look back at his groundbreaking 2014 memoir - Genetic Literacy... - October 6th, 2022 [October 6th, 2022]
- Understanding Human Genetic Variation - NCBI Bookshelf - September 14th, 2022 [September 14th, 2022]
- Genetics - National Institute of General Medical Sciences (NIGMS) - September 14th, 2022 [September 14th, 2022]
- People with ME invited to take part in major genetic study - The Independent - September 14th, 2022 [September 14th, 2022]
- Ketamine Promising for Rare Condition Linked to Autism - Medscape - September 14th, 2022 [September 14th, 2022]
- How a small, unassuming fish helps reveal gene adaptations - University of Wisconsin-Madison - September 14th, 2022 [September 14th, 2022]
- How Nutrigenomics Explores Links Between Nutrition And Genes - Health Digest - September 14th, 2022 [September 14th, 2022]