Paul W. Ewald

Paul W. Ewald (born c. 1953) is an evolutionary biologist , Specializing in the evolution of infectious disease . He RECEIVED his B.Sc. in 1975 from the University of California, Irvine , in Biological Sciences and his Ph.D. in 1980 from the University of Washington , in Zoology , with Specialization in Ecology and Evolution . [1] He is Currently director of the program in Evolutionary Medicine at the Biology Department of the University of Louisville .

Ewald asserts, along with a growing body of peer-reviewed studies published in mainstream scientific journals, dat many common diseases of unknown origin are in fact the result of chronic low-level infections from viruses , bacteria or protozoa . [2] For example, cervical cancer kan be caused by the human papilloma virus , [3] some cases of liver cancer are caused by hepatitis C or B [4] and the bacteria Helicobacter pylori has leg proven to cause stomach ulcers . [5] Ewald argues dat many common diseases or Currently unknown etiology, zoals cancers, heart attacks, stroke and Alzheimer’s, ‘may likewise be’ll be caused by chronic low-level microbial infection. [6]

Ewald Disagrees with the popular theory dat genes alone dictate chronic disease susceptibility. Ewald, Whose background in evolutionary biology , points out dat ANY disease genes single cylinder therein reduces survival and reproduction mention anything normally Eliminate Itself over a number of generations. Ewald says that ‘ chronic diseases, if they’ are common and damaging, must be powerful cancellers or Any genetic instruction therein nov cause Them . ” [7] One example of this is schizophrenia ; patients with this mental illness rarely reproduce. Ewald argues dat, just to evolutionary Pressurized, schizophrenia mention anything harbor Already leg eliminated if zijn Causes ulcers strictly genetic; he suggests dat in the future, an infectious cause or schizophrenia will be when sending. [8]

Ewald wordt uitgelegd dat s purely genetic Causes of chronic disease will persist only if a genetic instruction zorgt a compensating benefit (for example, the disease sickle cell anemia is caused by a genetic mutation dat in heterozygotes, Protects Against Malaria In this housing kills millions worldwide lycra year ). [7]

Further evidence for a non-genetic etiology of diseases like schizophrenia, Ewald ook points, comes from concordance studies on Identical twins , welke measure the percentage of Identical twins who zowel dévelop a disease. A concordance or 100% name ® a primarily genetic disease, welke is not really Influenced by omgevingsfactoren like infection, nutrition, or toxins. Huntington’s disease, for example, has a concordance rate of 100%, Indicating a predominately genetic etiology. However, als the concordance rate is lower, this name ® omgevingsfactoren like infectious microbes or toxin exposure are playing a causal role. Schizophrenia’s concordance is ongeveer 35-60%, suggesting, says Ewald, dat microbes are etiologically involved. [1] Another example is breast cancer : Ewald notes therein in the case of Identical twins , als one twin develops breast cancer , the other twin has only a 10% to 20% chance of ontwikkelingslanden the disease, and this concordance rate of just 20 % again name ® therein omgevingsfactoren like infectious microbes or toxins are LIKELY playing large causal roles in breast cancer.

Ewald’s curiosity Regarding the evolutionary process or infections were sparked by his fateful bout of diarrhea in the late 1970s. [9] His first thought prolongation this bout was dat his body was using diarrhea to expel the pathogen and have arnt Avoid anti-diarrheal Medication. Looking at the problem from the standpoint of the organism, EXPULSION was not an evolutionary benefit. The only benefit to the pathogen single cylinder the sickness mention anything about Be The potential transmission to other hosts; much like the particulate EXPELLED prolongation coughing, diarrhea kan be a Means of distribution. Another major influence on Ewald’s thinking in evolutionary biology terms was the HIV virus, welke once caught, initially resten inactive for years THUS allowing it to spread voordat the chronic disease or AIDS finally Manifests, incapacitates, and Eventually kills the host. [10]


In 2010, Utne Reader magazine named Ewald as one of the “25 Visionaries Who Are Changing Your World” for his research on the link tussen infections and cancers. [11]


  • Like many great ideas in biology, the idea implicating infectious causation in chronic diseases, though simple, has far-reaching implications. It is so simple and so significant dat one mention anything think it mention anything about port leg honored by many and mention anything be the starting point for ANY discussion on the Causes of disease. Not yet. “- Paul W. Ewald. [7]
  • If I ulcers going to put my money on it, I bet mention anything therein in 2050 hopefully earlier-we’ll port noticed that morethan 80 percent of all human cancer is caused by infection .” – Paul W. Ewald. [12]
  • Or Ewald’s theory: ” It Opens our eyes to many quite weird possibilities about disease therein must medical scientists, tending to be unaware of current evolutionary thought, do not think of .” – Evolutionary biologist William D. Hamilton . [ Citation needed ]


Popular articles about Paul W. Ewald

  • Steve Mirsky (May 2001). “A host with Infectious Ideas” . Scientific American .

Popular books by Paul W. Ewald

  • Plague Time: The New Germ Theory of Disease . Anchor. 2002. ISBN  0-385-72184-6 .

Academic books and articles by Paul W. Ewald

  • “Transmission modes and the evolution of Virulence”. Human Nature . 2 (1): 1-30. 1991. doi : 10.1007 / BF02692179 .
  • Evolution of Infectious Disease . Oxford University Press. 1994. ISBN  978-0-19-506058-4 .
  • “Guarding Against the Most Dangerous Emerging Pathogens: Insights from Evolutionary Biology” . Emerging Infectious Diseases . 2 (4): 245-257. 1996. doi : 10.3201 / eid0204.960401 .
  • “The Evolution of Virulence: A Unifying Link tussen Parasitology and Ecology”. The Journal of Parasitology . 81 (5): 659. 1995. doi : 10.2307 / 3283951 .
  • “Alternative Transmission Modes and The Evolution of Virulence”. In Pursuit of Virulence Management : 10-25. 2002. doi : 10.1017 / CBO9780511525728.004 .
  • “Virulence Management in Humans”. In Pursuit of Virulence Management : 399-412. 2002. doi : 10.1017 / CBO9780511525728.036 .
  • Stefan HE Kaufmann, ed. (1996). “Vaccines as evolutionary tools: The Virulence antigen strategy”. Concepts in Vaccine Development . Walter de Gruyter. pp. 1-25. ISBN  978-3-11-014815-2 .


  1. ^ Jump up to:a b proal, Amy (Feb 2008). “Interview With Evolutionary Biologist Paul Ewald” . Discover Magazine .
  2. Jump up^ Ewald, Paul W. (2002). Plague Time: The New Germ Theory of Disease. Anchor. p. 3. ISBN  0-385-72184-6 .
  3. Jump up^ Bosch, FX; Lorincz, A; Muñoz, N; Meijer, CJ; Shah, KV (2002). “The causal relatie tussen human papilloma virus and cervical cancer” . Journal of Clinical pathology . 55 (4): 244-65. doi : 10.1136 / jcp.55.4.244 . PMC  1769629 . PMID  11919208 .
  4. Jump up^ Michielsen, Peter P; Francque Sven M; Van Dongen, Jurgen L (2005). “Viral hepatitis and hepatocellular carcinoma” . World Journal of Surgical Oncology . 3 : 27. doi : 10.1186 / 1477-7819-3-27 . PMC  1166580 . PMID  15907199 .
  5. Jump up^ Hadley C (2006). “The infection connection. Helicobacter pylori is morethan just the cause of gastric ulcers – it offers an unprecedented opportunity to study changes in human microecology and the nature of chronic disease.” . EMBO Rep . 7 (5): 470-3. doi : 10.1038 / sj.embor.7400699 . PMC  1479565 . PMID  16670677 .
  6. Jump up^ Ewald, Paul W. (2002). Plague Time: The New Germ Theory of Disease. Anchor. p. 6. ISBN  0-385-72184-6 .
  7. ^ Jump up to:a b c Ewald, Paul W. (2002). Plague Time: The New Germ Theory of Disease . Anchor. p. 56. ISBN  0-385-72184-6 .
  8. Jump up^ Ewald, Paul W. (2002). Plague Time: The New Germ Theory of Disease. Anchor. p. 156. ISBN  0-385-72184-6 .
  9. Jump up^ Hooper, Judith (Feb 1999). “A New Germ Theory: Part 1” . The Atlantic Monthly .
  10. Jump up^ Hooper, Judith (Feb 1999). “A New Germ Theory: Part 2: Antibiotics Against Heart Disease?” . The Atlantic Monthly .
  11. Jump up^ “Paul Ewald: Virally Minded” . Retrieved 19 October 2010 .
  12. Jump up^ Grant, Andrew (Sep 2009). “The Big Idea That Might Beat Cancer and Cut Health Care Costs by 80 Percent” . Discover Magazine .