# Presentation: 002434

## Solving the Emerging Disease Crisis: Finding Them Before They Find Us

**Daniel R. Brooks**
**Department of Ecology & Evolutionary Biology **
**University of Toronto**

## Evolution of Human Pattern Recognition

**The fragility of early hominids placed a premium on accurately perceiving and generalizing the complexity of their surroundings**
**Underestimate it and you are lunch**
**Overestimate it and you starve**

## How Well Did Evolution Work?

**We have an excellent ability to perceive complex patterns – in fact, we do that better than computers**
**Object-oriented programming helps computers emulate human pattern recognition**

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## Why Do We Fear Complexity?

**Successful generalizing gave us a sense of security, so we trusted it – good became synonymous with generalization, evil with contingency, the complexity that cannot be generalized, that frightens us and does us harm.**
**We distrust complexity because that’s where the sabertooths, cave bears and boogeymen are. **

## Fear and Loathing Before the Enlightenment

**We thanked supernatural forces for the generalities, then began to use them to manipulate and control our surroundings**
**then**
**We thanked supernatural forces for giving us the ability to control our surroundings**

## Fear and Loathing in the Enlightenment

**We discarded the supernatural and decided to thank our own cleverness for the ability to control our surroundings.**
** **
**The Newtonian Revolution**
**The world ought to be simple, therefore it is simple. The appearance of complexity is due to incomplete knowledge.**

## Kant’s Angst

**When reason and experience conflict, which do we choose? **
**There is no easy answer, leading to tension between theory and data. This can be a good thing if it stimulates us to cooperative efforts. **

## Kant’s Angst Today

**When data and models conflict, do we reason the data into agreement with the model or modify the models to fit the data? **
**In reality, we need to do some of each; remember that over-simplification is the surest way to get eaten.**

## What About Parsimony?

**Explanations that are as simple as the data allow (William of Occam)**
**NOT**
**Explanations that are as simple as we can imagine (Aristotle)**

## A Tale of Two Traditions

**Host-Centered Studies: **
**The host species ****IS**** the critical resource**
**Parasite Centered Studies: **
**The host species ****HAS**** the critical resource**

## Both Traditions Agree on One Thing

**Parasites are Ecological Specialists**
**Microhabitat preferences**
**Transmission dynamics**

## The Host-Centered View: Simple and Intuitive

**Parasites become more strictly adapted to their hosts through time**
**Pathogenic strains can only survive by switching hosts**
**Climate change creates more mutations, hence more switches and pathogenic strains**

## The Parasite-Centered View: Complex and Non-intuitive

**Increased specialization on a particular host at a particular place and time may enhance the ability to switch hosts and cause pathology without increased rates of mutation**
**How can this be?**

## A Thought Experiment

**How can extreme resource specialists host switch readily?**

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## Specialists and Host Switching: The Parasite-Centered View

**Phylogenetic conservatism in host resource evolution and geographic distribution results in a geographic mosaic of infected uninfected, yet susceptible, hosts, even when the parasites are extreme resource specialists. **
**This is called Ecological Fitting**

## An Exemplar: Brooks & Ferrao (2005) 

**Most species of parasites infecting humans have been acquired as a result of anthropogenic changes in trophic structure associated with the evolution of agriculture, domesticated livestock, and urbanization**
**Pinworms (*****Enterobius*****) and Hookworms (*****Oesophagostomum*****) infecting humans have been seen as exemplars of cospeciation**

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## Overview of Host Switching for Pinworms and Hookworms

**All but one host switch involved Great Apes and Cercopithecoids, thus likely to be due to ecological fitting. One case involved a switch from primates to rodents, likely due to the evolution of novel host utilization capabilities.**

## What Drives Ecological Fitting?

**Phylogenetic conservatism in host resource evolution and geographic isolation results in uninfected susceptible hosts**
**Changes in geographic range and/or trophic interactions bring the parasites into contact with those susceptible hosts**

## A Prediction: Host Switching is Mostly Episodic, not Stochastic

**All host switches resulting from ecological fitting were associated with episodes of climate change and biotic expansion.**

## Historical Biogeography

**In considering the geographic **
**distribution of organic beings **
**over the face of the globe... **
**[w]e see...some deep organic **
**bond, through space and time, **
**over the same areas of land and **
**water,independently of physical **
**conditions. ****The naturalist must **
**be dull who is not led to **
**enquire what this bond is.**

## NOW We Look at the Hosts

**Hominoids, Hynaenids and Proboscideans since the Miocene**

## Slide 29

## The Taxon Pulse

**The Taxon Pulse**

## Back to The Parasites

**Back to The Parasites**

## How “New” is this View?

**Parasites...are simultaneously the product of an immediate environment and of a long ancestry reflecting associations of millions of years. The messages they carry are thus always bilingual and usually garbled. Eventually there may be enough pieces to form a meaningful language which could be called ****parascript ****- the language of parasites which tells of themselves and their hosts both of today and yesteryear. -- Manter, 1966**

## How New is Parascript? 

**... ****there are two factors: namely, ****the nature of the organism**** ****and ****the nature of the conditions****. The former seems to be much more the important ... nearly similar variations ... arise ... under dissimilar conditions; and ... dissimilar variations arise under conditions which appear to be nearly uniform. -Darwin, 1872**

## The Jagger Principle

**You can’t always get what you want, but if you try sometimes, you just might find you get what you need**

## Why is it Hard to Let Go of the Simple View? 

**The neocortex allows us to accurately assess the complexity of our surroundings. ****(The simplicity view is dead)**
**The brainstem keeps us from believing the bad news. ****(It’s simpler to believe the simplicity view is alive)**
**Incomplete integration of the brain produces *****denial*****.**** (The simplicity view is not dead, it’s pining for the fjords)**

## Does Any of This Matter?

**If the host HAS the critical resource, the resource is a trait or trait set**
**If the trait or trait set is widespread and phylogenetically conservative, host switching will occur whenever allopatry and/or trophic structure break down**
**Such as global climate change or species introductions**

## EIDs are Evolutionary Accidents Waiting to Happen 

**The host associations for *****Enterobius***** and *****Oesophagostomum***** that arose through host switching associated with geographic dispersal were all emerging infectious diseases at the time the switches occurred**

## Global Climate Change: A Double-Edged Sword 

**Species that disperse well and species with large geographic ranges survive mass extinctions **
**Species that are most successful at surviving mass extinctions will be the primary source of EIDs.**

## Bad News for Bio-Control and Bio-Containment

**Extreme resource specialists may be able to host switch even when there are no “closely related” hosts available**
**Host range in the native ecosystem is a poor indicator of potential host range**
**The phylogenetic basis of host specificity must be taken into account when considering the introduction of species as bio-control agents**** **

## There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact. - Mark Twain 

**There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact. - Mark Twain**

## The Scope of our Ignorance

**We have named <10% of the species on this planet, analyzed <1% of those phylogenetically, and analyzed <5% of those in terms of coevolution and biogeography, mostly using anachronistic methods**

## The Dirty Harry Criterion

**Our ignorance of such **
**potentially important **
**aspects of the **
**world’s biodiversity **
**calls for massive **
**discovery efforts, **
**and extreme **
**skepticism about **
**existing models**

## Why Are We in This State of Affairs?

**Taking advantage of the human capacity for denial is good business and good politics**

## Two Corollaries of Denial: Fear and Despair 

**When we’re afraid and when we feel we have no control, we retreat into familiar patterns and avoid innovation.**
**We do not attempt bold actions to solve problems, we settle for managing them along, hoping things will get better by themselves.**

## The Medical-Industrial Complex’s Two Most Hated Words

***Prevention***** and *****Cure***
**Managing disease is more profitable than curing it. Responding to a crisis is always less cost- and time-effective than anticipating it. **
**Keep people afraid and in crisis response mode, and they won’t think to ask for prevention and cure.**

## The False Comfort of Models: More Denial

**“****You *****rationalize...*****You *****defend*****. You reject unpalatable truths, and if you can't reject them outright you trivialize them....****evidence is never enough for you.**** Temperatures rise, glaciers melt— species *****die*****—and you blame sunspots and volcanoes...You turn incomprehension into mathematics...”**
**"It served me well enough."**** **
**	****  ****- Peter Watts, *****Blindsight***** (2006)**

## “Well Enough” is not Good Enough

**[Women know that] ‘Be reasonable’ means ‘lower your expectations.’ **
**	****- Ursula Le Guin  **
**Do not lower your expectations - challenge the models, get more data**** **

## If There was Ever a Time to Think Outside the Box...

**If the climate change biodiversity and EID crises are real, time is critical**
**We can’t afford business as usual. We must transcend our biological heritage, and cooperate outside our kin groups.**

## A Religious Principle

**Then the Lord said to Cain, “Where is Abel your brother?” And he said, “I do not know. Am I my brother’s keeper?”- Genesis 4: 9**

**A Religious Principle**

## A Literary Principle

**Moving from **
***Pride & Prejudice***** **
**to **
***Sense & Sensibility***
**It is time for ecologists and evolutionary biologists to join forces with biomedical and biotech specialists in a spirit of enlightened mutual self-interest**

## A Sports Principle

**Never change a winning game**
**Always change a losing game**

## A Socio-Political Principle

**Do the right thing. It will gratify some people and astonish the rest. **
**-Mark Twain **

## What’s going to Happen?

**There is a certain inevitability about inaction. - Voltaire**

## Will We Make It?

**The most altruistic and sustainable philosophies fail before the brute brainstem imperative of self-interest.**
**- Peter Watts, *****Blindsight***** (2006)**