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meeting_notes.md

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Epidemiological trends (11/17)

What do we know?

  • Taxonomic classification is all over the place - lots of different names for the same thing, lots of shifts in which areas of the biological tree different fungi are placed on.
  • Candida is a major issue, and is possibly related to global warming
  • Frogs and white-nosed bats are both high-profile non-human epidemics
    • Check out some background in The 6th extinction by Elizabeth Kolbert

Fungal pathogens and the medical system

  • Clinically it's very difficult to diagnose many diseases caused by fungal pathogens
    • For pneumocystis pneumonia, need an anatomically deeper sample than for most respiratory pathogens.
    • Some diagnostic markers aren't especially specific.
  • Bigger question: how does the medical system respond to emerging threats? Adaptation to new challenges is limited in lots of settings (see COVID)... how do treatment strategies for new diseases get incorporated into the medical system?

Ecology of fungal pathogens

  • Bacterial antibiotics can be derived from fungi! What are the roles of these other microbial players? How do fungi affect them in turn?
    • Frog fungus - probiotics can help here, so maybe elsewhere?
  • Can you determine/predict host range of fungal pathogens using genetic information?
  • Host ranges can be vast... which is a major challenge for control.
  • High basal tempreatures can help to resist fungi.
    • White nose fungus - only infects hibernating bats, when temperature goes down to 7 degrees
    • So... are other hibernating species at risk?
  • If there's enough diversity, is it harder for fungal pathogens to emerge?
  • Is the climate change hypothesis a good one? there are a lot of hot places in the globe, so wouldn't pathogens have already emerged there? (but maybe hot places are more likely to be dry... so something there?)
  • Do fungi get diseases? They can get infected by bacteria... presumably?

Fungal evolution

  • CDC is tracking drug resistance in fungi that are causing mucormicosis
  • How does drug resistance spread in fungi?
    • They have sexual and asexual reproduction
    • Can they horizontally transfer genes between different species?
  • There's not a lot of incentive to evade any single immune system because fungi have so many possible hosts. Selection pressures maybe aren't from our immune systems at all.
  • What selection pressures do fungi have...? Maybe competition with bacteria? Alarmingly few it seems...

Fungal pathogen threats

  • Who would a fungal epidemic affect?
    • Most are not communicable!
    • Deforestation/natural diseasters(/raking leaves) releasing fungal load
    • People who are immunocompromised (e.g., cryptoxxxx - fungal pathogen - causes cryptococcal meningitis).
    • Opportunistic fungal infections after steriod treatment for COVID in India
    • Other ways of getting immunocompromised? Asthma, diabetes,
  • Antifungals may not be the best approach for clearing fungal infection - you need immune reconstitution. But, this is probably not feasible for people with HIV, leukemia, etc.

Fungi and the immune system

  • Why is the immune system so good at clearing fungi as compared with bacteria and viruses?
    • Maybe just a difference in growth rates? Fungi grow extremely slowly? Is the ability to cause acute infection directly related to a mismatch between the time scales of pathogen reproduction and the immune response?
  • Do cancer therapies have anything to teach us, since they target cells that are antigenically similar to the host?
  • An evolutionary argument: maybe the immune system developed in part to clear cancers, and this helps it to clear fungi too, since they're genetically fairly similar to humans?

Fungal life cycles and virulence (12/1)

Fungal infections: vaccination and immunity (12/8)

Fungal infections: treatment and resistance (12/15)

Virulence

Reproduction yeasts and molds mycelium more important for pathogenesis, generally sexual and asexual reproduction

sexual reproduction responsible for big leaps in evolution, asexual reproduction gives you large numbers.

Fungi are working on an utterly different timescale than bacteria and viruses - can leisurely find new nieches to reproduce sexually and then find a new host for asexual reproduction.

Seems like stress can induce sexual reproduction

copy number variation? big player in antifungal resistance