INTEGBI 169 Chapter Notes - Chapter 10: Trichuris Suis, Evolutionary Arms Race, Sickle-Cell Disease
5 Jun 2018
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■ There has been a fall in morbidity from infectious diseases seen in
developing countries over the past 100 years due to public health
measures, vaccines, & antibiotics.
■ However, over this same period of time there has been a dramatic rise in
the prevalence of asthma, allergies, and chronic inflammatory disorder’s
such as inflammatory bowel disease.
■ There is an inverse relationship to the exposure to certain infectious
diseases over the past 100 years and the prevalence of a number of
autoimmune diseases.
■ People in rural farm communities have more exposure to animals than
people in urban communities.
■ There is a lower prevalence of asthma and atopic disease (e.g., eczema)
in children in rural farm communities compared with urban communities.
■ Inflammatory bowel disease (e.g., Crohn’s disease) is much more
common in highly sanitized, industrialized areas of the world, whereas it
is uncommon in rural areas where living quarters are crowded and
unhygienic.
■ Germ-free mice experience abnormal development of their immune
system which can be corrected by re-introduction of intestinal
commensal bacteria or the administration of purified polysaccharides
from this bacteria.
●
Hygiene hypothesis:
○ A proposed underlying mechanism for this hypothesis is that the vertebrate
adaptive immune system has co-evolved with both commensal and pathogenic
micro-organisms, and that appropriate exposure to this microbiota early in life is
beneficial to setting up normal immuno-regulatory pathways.
○ Lack of such exposure can lead to inappropriate activation of immune responses
which are then manifest as allergic or autoimmune diseases.
○ The more viral respiratory infections and fevers an infant gets in the first year of
life is associated with a lower risk for developing allergies and asthma later in
life.
○ So the respiratory virus-human relationship is beneficial both to the virus and the
human host.
○ Children who take antipyretics (e.g. acetaminophen or ibuprofen) when they
receive vaccines do not develop as good of an immune response from the
vaccine as children who have not received antipyretics.
Document Summary
There has been a fall in morbidity from infectious diseases seen in developing countries over the past 100 years due to public health measures, vaccines, & antibiotics. However, over this same period of time there has been a dramatic rise in the prevalence of asthma, allergies, and chronic inflammatory disorder"s such as inflammatory bowel disease. There is an inverse relationship to the exposure to certain infectious diseases over the past 100 years and the prevalence of a number of autoimmune diseases. People in rural farm communities have more exposure to animals than people in urban communities. There is a lower prevalence of asthma and atopic disease (e. g. , eczema) in children in rural farm communities compared with urban communities. Inflammatory bowel disease (e. g. , crohn"s disease) is much more common in highly sanitized, industrialized areas of the world, whereas it is uncommon in rural areas where living quarters are crowded and unhygienic.
