IB 361- exam 2
Climate change and food production: Mediated by changes in what?
"climate envelope" for different crop species and cultivars
Paragonimiasis (Lung Fluke Disease) in Missouri
- "Outbreak" (4 cases) in Missouri during 18 month period - Young males ages 18-25 - All victims had recently been on canoe trips on Missouri rivers - All had eaten a raw crayfish (or two) on a dare while drunk
Total Deaths Due to Food-Borne Diseases in the U.S. by Infectious Agent
- 16% viral - 54% bacterial - 30% parasitic
Total Hospitalizations Due to Food-Borne Diseases in the U.S. by Infectious Agent
- 68% viral - 25.5% bacterial - 6.5% parasitic
Total Cases of Food-Borne Diseases in the U.S. by Infectious Agent breakdown
- 80% viral - 13.5% bacterial -6.5% parasitic
Zoonotic Spillover from Wet Markets
- A wet market is a market selling farmed and wild animals for human consumption or traditional medicine - Result in novel combinations of species and close contact with humans - Considered the likely source of SARS and COVID-19 outbreaks The SARS epidemic likely started in November, 2002, in Guangdong Province, China -Genetic evidence linked the origin of SARS to horseshoe bats, and a possible connection to palm civets as an intermediate host in the spillover chain -Both species encountered in wet markets
Models proposed for core microbiome:
- A) Substantial core - B) Minimal core - C) No core - D) Gradient - E) Subpopulations
Listeria monocytogenes and Unpasteurized Milk
- Accounts for over 25% of deaths/year in the U.S. from food-borne disease - Primarily affects pregnant women, newborns, and the immuno-compromised - Outbreaks frequently linked to consumption of raw milk
US Trichinellosis Incidence 1947-2007
- Caused by roundworms in the genus Trichinella - Trichinellosis historically associated with the consumption of pork - Proposed by religious scholars to be the reason some religions ban the consumption of pork
US-Mexico Border- Differences in disease incidence entirely attributable to socio-economic factors:
- Central air conditioning - Presence of intact window screens - Residential density
Factors Contributing to Emergence
- Changing Human Demographics - Increasing Antimicrobial Resistance - Changes in Food Production
Analytic techniques of microbiota
- Community indices - Principal Component Analysis
Causes two primary disease syndromes leishmaniasis
- Cutaneous Leishmaniasis (CL) - Visceral Leishmanisis (VL)
Human Demographics
- Demographic changes in industrialized nations have favored emergence - Increasing segment of the population immunocompromised:
Wolfe et al. 2007- What were the major goals of this article?
- Determine the origins of major infectious diseases that currently (or historically) placed a large burden on human health - Compare the origins and ecologies of temperate vs. tropical infectious diseases
What is a potential mechanism by which seasonality could impact a directly transmitted disease? What is a mechanism by which seasonality could impact an indirectly (e.g., vector-borne) transmitted disease?
- Directly: Effects on human behavior based on the weather. For example, in the winter humans are indoors since it is cold. This can transmit more human to human diseases. - Indirectly: In the summer, we may see humans outside more. With that being said, it can help aid the spread of vector-borne diseases. - Also impacts water/moisture levels (which then impacts diseases that are spread in areas of higher moisture).
Changes in Food Production: Fish Farming
- Due to declines in wild stocks, fish and other aquatic/marine organisms are increasingly farmed for food production - "Aquaculture" has increased 10% annually over the last decade - Include both freshwater and saltwater species
Industrial Livestock Production
- Due to overuse of antibiotics, potential for antibiotic resistant microbes to develop In confined animal operations is high - Recent efforts to ban use of antibiotics as growth promoters may help stem this tide...
Increasing segment of the population immunocompromised include:
- Elderly - Individuals with chronic or long-term diseases
Salmon Farms Cause 'Epizootics' in Wild Salmon
- Epizootics are disease outbreaks in wildlife - One advantage of salmon life-cycle is the decoupling of adult and juvenile life-stages - reduces parasite load - Adult salmon farms increase juvenile wild salmon mortality from "sea lice" (ectoparasitic copepods) 9-95%
The costs of pandemic prevention:
- Estimate that discovery of all viral threats and characterization of their risk for spillover, would be extremely costly at over $7 billion - Yet recent analyses suggests that strategies to mitigate pandemics would provide a 10:1 return on investment
Biofilms allow for:
- Evasion of host defenses - Decreased susceptibility to antibiotic therapy - Deliberate release of bacteria "propagules"
Small-Scale Aquaculture, SE Asia
- Fish for global markets may also be farmed in small-scale operations - Small family farms in SE Asia produce a significant portion of freshwater fish for global export, including Tilapia
Three primary diseases of poverty (in total # of cases)
- HIV/AIDS - Tuberculosis - Malaria
Two major anthropogenic changes to ecosystems that influence disease invasion, persistence and spread:
- Habitat destruction - Biological invasions
Oral microbiome is highly ecological:
- High species diversity - Characterized by succession - Subject to disturbance - Numerous potential niches
Two man-made "habitats" that strongly select for antimicrobial resistance:
- Hospitals/nursing homes - Confined animal operations
Psittacosis outbreak in customs officers in Antwerp, Belgium
- In 1994, several customs officers in Antwerp developed psittacosis - Caused by a bacterium in the genus Chlamydia associated with birds - Result of exposure to illegally imported parakeets -In 2004, two Crested Hawk-Eagles (Spizaetus nipalensis) smuggled into Europe from Thailand were seized at Brussels International Airport -Tested positive for a new, highly pathogenic strain of H5N1 avian influenza -The isolated virus was denominated A/crested eagle/Belgium/01/2004
Changes in Food Production: Egg Production
- Industry consolidation of egg production and distribution favors certain infectious agents - Primary factor in the emergence of Salmonella Serotype Enteritidis (SE)
Pathobionts
- Inhibit bodily processes - Cause inflammation - Cause infectious disease
feedback in to terrestrial systems issues:
- Less water for domestic and agricultural use - Greater frequency of droughts and forest fires
Potential reasons flu transmission increases in winter:
- Low humidity - Indoor air circulation - Reduced immunity and/or exposed mucous membranes - Increased contact indoors
Disaster Preparedness includes:
- Maintain an emergency supply kit - Develop a family disaster plan, including evacuation - Know how to respond to a disaster
Poverty can facilitate disease emergence via numerous pathways
- Malnourished and immuno-compromised individuals living in unsanitary conditions more susceptible to infection - Low incomes cause treatable diseases to go untreated or under-treated - Poor healthcare infrastructure (e.g., overcrowding, inadequate hygiene) - Increased "risky" behaviors (poor hygiene, consumption of high-risk foods, etc.)
Water-related problems for human health examples:
- Malnutrition - Water-borne diseases (kill ~3,900 children/day) - Vector-borne diseases - Obstacles to economic development - Death and injury due to catastrophic events (e.g., floods and droughts)
Understanding the function of the gut microbiome will require a synthesis among:
- Medical researchers - Public health experts - Microbial ecologists
Why study the microbiome from an ecological perspective?
- Multispecies interaction - Hosts as habitat - Independent communities occur in unique "ecosystems" of the body - Many ecological phenomena occur (e.g., 'priority effects')
Nasal microbiome poorly understood microbiome, but:
- Nasal tissues highly sensitive to inflammation - Microbiome is genetically distinct from other regions of the body
H1N1, 2009:
- Origin: zoonotic - Transmission: respiratory - Cases: 43-89 million (US) - Deaths: 9-18,000 (US) - Mortality rate: <1% - R0: 1.2-1.6 (higher in public schools: ~2.7)
SARS, 2002-2003:
- Origin: zoonotic - Transmission: respiratory - Cases: 8,422 (global) - Deaths: 916 (global) - Mortality rate: 10.9% - R0: ~3
What has changed from 1800 to 2019 in terms of life expectancy relative to income? What is the most striking pattern to you in these data?
- Overall, both saw a significant increase. Life expectancy increased nearly triple and income has increased over 50x the original (dollar amount has also changed). - It was surprising just how much of an increase there was in life expectancy regardless of income. I thought that there would be a greater deviation between them.
Paragonimiasis (Lung Fluke Disease)
- Paragonimiasis is a chronic inflammatory disease of the lungs - Caused by trematodes in the genus Paragonimus - Use crustaceans as intermediate hosts and carnivores as terminal hosts -Human illness associated with consumption of raw or undercooked crustaceans - Generally occurs in cultures with a diet that includes the consumption of raw crustaceans - Very rare in the U.S. until recently...
Due to four years of warm winters and low precipitation, California experienced worst drought in 1200 years:
- Reduced food production and increased prices - Increased water stress and wildfire risk - Estimated economic cost of 5+ billion USD
Other major diseases associated with poverty
- Respiratory diseases (e.g., pneumonia) - Diarrheal diseases (e.g., Cholera) - Childhood diseases (e.g., Measles) - "Neglected tropical diseases" (e.g., Chagas, Leishmaniasis)
Widespread Infection of SARS-CoV-2 in other Species
- SARS-CoV-2 now has been detected in animals traded in wet markets, domestic cats, wildlife in zoos, farmed mink, and now white tailed deer in the U.S. - Suggests a virus highly facile at invading new host species
Many types of infectious agents have reached epidemic/ pandemic proportions in human history:
- Schistosomiasis in ancient Egypt trematodes - The Black Plague bacterium Yersinia pestis - HIV/AIDS in the 20th century virus
Climatic factors expected to be influenced by climate change with potential consequences for infectious disease dynamics:
- Seasonality - Temperature - Precipitation - Hydrology
Changes in Food Production: Unpasteurized Milk
- Some evidence that it also reduces the health benefits of consuming dairy products - Resurging interest in "raw" (unpasteurized) milk
Evidence that the microbiome of the vagina has a significant impact on health:
- Susceptibility to STIs - Bacterial infections - Pregnancy and preterm birth - Infant microbiome
What these gut microbes "do" depends on what functional group they occupy:
- Symbionts - Commensals - Pathobionts
Surveillance Challenges in preventing food-borne diseases
- Underreporting - mild cases often go undiagnosed/ unreported - Many food-borne pathogens are "opportunistic" and have multiple modes of dispersal - Large percentage of food borne pathogens remain unidentified
From Modest Origins to Pandemic Proportions- Questions that need to be addressed:
- What type of infectious agent is most likely to cause a pandemic? - What will be its transmission mode? - Where will it come from (both geographically and biologically)? - What will be the extent and mortality rate?
Food-borne Illnesses Due to the Consumption of Wild Foods in the U.S.
- Wild foods can also be a source of pathogens & parasites - In the U.S., tends to be associated with the consumption of wild game meats and other nontraditional food sources
Two transmission modes
- Zoonotic: transmitted from animals (e.g., domestic dogs, rodents) to humans - "Anthroponotic": transmitted from human to human via sandfly
Dysbiosis of the gut
- a common cause of disease in developed nations, rare in developing nations - Likely an interaction between lifestyle and genetic predisposition to inflammatory diseases
Challenges to understanding linkages between climate change and infectious diseases:
- absence of an appropriate comparison group - long time period over which human actions affect climate - large number of health outcomes potentially affected by climatic change - numerous non-climatic influences on infectious disease dynamics that may also interact with climate
Climate change is already having substantial impacts on what?
- efficiency - stability of global food production
Climate change is expected to affect the frequency and intensity of precipitation
- less frequent - more extreme
'priority effect'
- the competitive advantage conferred to an early colonist in ecological communities that tend to assemble randomly - First used to describe community assembly in marine tide pools
Urbanization
- the process by which human populations increasingly congregate in developed areas at higher densities - is driven by a combination of rural flight and intrinsic growth - Historically associated with disease emergence, especially among the urban poor (e.g., measles and pertussis in London during the 19th century)
For what types of infectious diseases (transmission mode, host breadth, etc.) would you expect socio-economic status to strongly influence human incidence? For what types would you expect it to matter less?
- those who have a higher socioeconomic status are significantly less susceptible to water-borne pathogens due to having safe and clean water. Diseases that are often caused by dirty water are Cholera and Giardia. However, I think that overall zoonotic diseases would be less likely I think due to the fact that it depends on where you live regardless of status. I suppose if you have access to healthcare it may help your chances of preventing certain zoonotic illnesses.
Landscape Structure and Disease Invasions equation
- 𝑃 = 1 − 1/𝑅0 -P = probability of establishment
Influenza A viruses
-"multi-host" pathogens -move between humans and domestic livestock by gene reassortment
Monkeypox Outbreak in US
-2003 outbreak in the central Midwest (Wisconsin, Illinois and Indiana) first reported outside of Africa -~81 human cases, most of which reported contact with pet prairie dogs (and a few cases of human-to-human transmission) -Traced to a pet dealer in Milwaukee, WI -Prairie dogs were housed next to African rodents, including a Gambian giant rat that later tested positive for monekypox -Considered a "reemerging" disease in central Africa causing an increasing number of outbreaks -Linked to the disuse of smallpox vaccine after the eradication of smallpox
Antimicrobial Resistance
-Antimicrobial resistance represents an excellent example of short-term evolutionary change -Two man-made "habitats" that strongly select for antimicrobial resistance
what is the root cause of inflammation characteristic of CRS?
-Bacteria from sinonasal cavities of CRS patients more likely to form biofilms -Bacterial biofilms likely contribute to the persistence of chronic CRS infections as well
Bushmeat trade
-DEFINITION: the unsustainable, often illegal, and unregulated commercial harvesting of wildlife for meat -generally a problem in tropical rainforests -Congo basin rainforest of central Africa is the epicenter of trade
Emerging Food-borne diseases
-Food-borne pathogens and parasites include some of the most rapidly emerging infectious agents - In the U.S., cause 6-80 million illnesses/year and ~9,000 deaths
Potential impacts of climate change on human health
-Freshwater and natural disasters - Global food supply
Pathogen Introductions Due to the Pet Trade
-Global pet trade in illegal wildlife poses a considerable threat to biodiversity -US is second largest importer of wildlife for the pet trade -- $6 billion dollar industry - Important source of infectious disease outbreaks
Diversity and Invasion Resistance
-In many ecological systems, high diversity tends to confer resistance to invasion by new species -One of the functions provided by biodiversity
Huanan Wet Market and COVID-19
-In mid-December 2019, an outbreak of viral pneumonia was detected among workers of Huanan wet market in Wuhan, China -Causative agent was named SARS-CoV-2, the third coronavirus to spillover since 2002 -Like SARS-CoV, strong evidence that it was of bat origin
Evidence for Zoonotic Emergence
-In three separate studies, 33-66% of initial cases detected were associated with Huanan Market -Earliest confirmed case of COVID-19 is a seafood vendor with illness onset of Dec 10, 2019 -Huanan Market was closed and disinfected on Jan 1, 2020; no live mammal collected at Huanan has been screened for SARS- CoV-2-related viruses
First reports of Lyme disease seem to synchronize with first reports of the blacklegged tick early in the invasion. Later in the invasion, Lyme disease starts to appear "everywhere" in the Midwest including counties without the tick. What factors might explain this pattern?
-It could be possible that humans could have been exposed to lyme disease without realizing it. They could have been infected by a tick while hiking or traveling somewhere else (different than where you are from. With that being said, once they seek treatment it is reported in a different area than it originally occurred in.
So if loss of microbial community diversity makes us more susceptible to infection by pathogens, what can be done to protect against diversity loss? What can be done to protect against pathogens when diversity is lost?
-It is important for doctors to work on reducing their reliance on antibiotics, as they can kill beneficial bacteria in our gut. As well, possibly find a more targeted antibiotic. -It is important that individuals take probiotics and also work to cultivate microbes through the use of a healthy diet.
Global Trends in Infectious Diseases
-Most human pathogens are of Old World origin -A higher proportion of pathogens of humans emerged from more closely related species (shorter phylogenetic distance) -An "origins initiative" is needed to understand the origins of many important human pathogens
"Worst" Food-Borne Pathogen in the U.S., 1983-1997 (top 3-viral, bacterial, parasitic)
-Norovirus -Nontyphoidal Salmonella (most deadly) -Toxoplasma gondii
Gut Microbiota's Role in Diarrhea
-Recurrent patients have a variable microbial community -Recurrent patients have a low diversity microbial community
Bushmeat and HIV/AIDS
-SIV have been found in 26 species of nonhuman primates in Africa -SIVcpz and SIVsm are the progenitors of all HIV in humans -result of at least seven different cross-over events -has undergone substantial subsequent evolution hosts -all introductions presumed to be due to the handling or consumption of primate bushmeat -considerable potential for additional cross-over events and subsequent evolution of new human pathogens
Forest fragments less than 2 ha in area exhibit much higher Lyme disease risk. Based on this knowledge, what are some practical solutions to reducing human risk of exposure to Lyme disease due to forest fragmentation?
-Small neighborhoods with larger forest areas could help to reduce human risk of exposure. -It is important for individuals to be aware of the risks of ticks within that area.
Climate Change and Human Health
-The world is confronted with an impending era of profound climate change, the consequences of which remain uncertain -Growing concern that human health will be affected by a variety of complex pathways
Scenarios for Zoonotic Emergence?
-There are several possible scenarios for zoonotic emergence: -- Direct bat to human spillover, possibly in a cave due to tourism, mining, or scientific research -- Direct bat to human spillover, or indirect via an intermediate host, in a wildlife farm or wet market
What might make "invasive species" so successful outside of their native ranges? In other words, what features might make an invasive species invasive?
-They can have high reproductive success -They might not be under the same pressures they were back in their native habitats (pathogens and predators). -They could be a generalist predator (can eat a variety of things)
Besides antimicrobial resistance, how might confined animal operations select for more virulent pathogens? What are some of the potential biological trade-offs?
-They reduce contact between domestic birds and wild animals (prevent spillover). -The use of antibiotics in animals can influence the virulence of pathogens (only those strong enough can survive to spread to hosts). -Trade-off: Worse conditions to live in. For example, small spaces which can allow disease to spread quickly between animals within that area.
What might be the advantages and disadvantages to being an early colonizer? A late colonizer?
-advantages: might be that the early colonizers don't experience a lot of competition in comparison to later ones. -disadvantages: early colonizers are also not good at competition later on. -advantages: late colonizers are not primary producers, others are around to make things. Also, they are good at competition. -disadvantages: late colonizers have a lot of competition.
symbionts
-aid bodily processes -prevent inflammation -strengthen immune system
What are some potential "disturbances" that could alter the gut microbiota and tip the balance towards pathobionts?
-antibiotics can kill helpful bacteria in our gut -immunodeficiencies can make an imbalance in our microbiota -stress and mental health can play a role in altering our microbiota due to the fact that high levels of stress over time increase the intestine's permeability -genetics can play one of the biggest roles.
Monkeypox
-causes a rash-like illness in humans very similar to smallpox (and closely related virus in the same genus, Orthopoxvirus) -primarily associated with rodent reservoir hosts -mortality rate 1-10%
What is most global water use devoted to?
-devoted to agriculture
Bushmeat and Ebola
-ebola virus first identified DRC -about 24 outbreaks of Ebola hemorrhagic fever in central Africa -80-90% lethal -outbreaks are common in apes (conservation threat) -spillover event from sharing food with bats
factors that exacerbate bushmeat trade in what ways:
-extraction activities (timber, oil, and gases) -transportation -human population growth -absence of alternative sources of protein
Bushmeat and logging towns
-extraction activities in tropical forests often lead to the development of temporary towns/cities in natural areas -services such as the importation of protein sources are limited -bushmeat industry developed to meet the needs of workers in logging towns -serves as an export base to global commercial industry
The Human Microbiome
-genomic technology has increased research on the human microbiome -Numerous chronic and infectious diseases are now known to be caused, or exacerbated, by an unhealthy microbiome
Examples of human activities that increase chances of host jumping
-hunting and consumption of bushmeat -wet markets -wild animal pet trade
Subsistences Hunting in Rural Villages in Cameroon
-hunting for "home use" is common and widespread for people living in rural villages -primary source of protein for many rural Africans
Paramyxoviruses
-include some of the most significant human and livestock viruses (measles, mumps, distemper, etc.) -Include numerous agents with "pandemic potential" (e.g., Hendra & Nipah viruses)
What landscape features appear to associate with, and be predictive of, invasion by the black-legged tick?
-land use and fragmentation can influence black-legged tick amounts (increased fragmentation). -areas along rivers can influence black-legged tick populations.
Host-Jumping Due to the Bushmeat Trade
-multi-billion dollar international industry -in Africa it is currently the most significant threat to wildlife populations, especially great apes
Many crops are limited at what?
-northern latitudes by short growing seasons and cold temperatures -Increased temperatures at lower latitudes will increase heat and water stress
Global causes of host jumping
-occurs naturally when hosts come in to contact -certain human activities greatly enhance the opportunities for pathogens/parasites to jump to new hosts
Irritable Bowel Syndrome (IBS)
-periodic disturbances of bowel function, such as diarrhea and/or constipation, usually associated with abdominal pain - Prevalence in U.S. 14-15% - Significant cause of reduced productivity
Global limits of freshwater are driven by what two things:
-population growth -climate change
Host jumping requires what 3 things?
-some form of contact occurs between host species (direct or indirect) transmission -adaption on the part of infectious agent to cause infection in the new host -ultimately leads to sustained transmission within the new host species
The Gut Microbiome
-the most complex and important microbiome of humans
The field of epidemiology was discovered as a result of what?
-urban disease outbreaks -Cholera outbreaks in London in mid-19th century led to the use of maps to understand the source of disease
Microbes include
-viruses -bacteria -fungi -arthropods
Three Hypotheses for the Emergence of SARS-CoV-2 (COVID-19)
-zoonotic emergence hypothesis -lab leak hypothesis -genetic engineering hypothesis
Supported Hypotheses for lyme
1) Bordering or being intersected by one or more major rivers is positively correlated to a county's likelihood to be invaded by I. scapularis 2) Neighboring a previously invaded county is positively correlated to a county's likelihood to be invaded by I. scapularis 3) Increasing forest cover is positively correlated to a county's likelihood to be invaded by I. scapularis
microbiota of the human body have how many genes?
2,500,000 genes
human body has how many genes?
25,000 genes
human body has how many cells?
80 trillion cells
microbiota of the human body have how many cells?
800 trillion cells
what percentage of cells in your body belong to other organisms?
90%
Influenza Definition
A viruses are often perceived to be the greatest pandemic disease threat to humankind
Influenza A virus reservoir host
Aquatic wildfowl, many of which are migratory
Matrix
Background cover type in a landscape
Superbugs Found in House-flies From Poultry Farms
Bacteria carrying genes that confer antibiotic resistance abound in confined poultry farms
Formation of Biofilms
Bacterial biofilms comprise a complex, organized community of bacteria that attach to both biotic and abiotic surfaces
Disaster Preparedness purpose
Because services may be disrupted, federal and state agencies recommend individuals prepare for disasters
What are some potential "disturbance events" that reset the successional clock?
Brushing your teeth and mouthwash may reset the successional clock. As well, stomach acid and antibiotics can also damage teeth.
The hydrology of the Chicago area appears to determine the distribution of WNV risk. What steps could be taken to mitigate future WNV risk under climate change in this region?
Building retention ponds would be a great way to minimize contact with mosquito populations in these lower areas (prone to flooding).
Metagenomics
Compare millions of microbes using sequencing, not cultures
Oral Bacterial Colonization: Formation of Biofilms
Early colonizers bind to tooth enamel by co-aggregations into biofilms • Late colonizers bind to previously bound bacteria • Collectively, these interactions represent the formation of dental plaque
What is the "Core" Oral Microbiome?
Extent of overlap between three individual oral microbiomes for: A) unique gene sequences, B) "species-level" phylotypes (sequences that clustered at 3% genetic difference) C) higher taxonomic diversity (genus, family, etc.)
Changes in Precipitation
Extreme precipitation events (extreme rainfall or drought) often affect disease dynamics
Genomics
Genome of a single organism
Should raw milk laws be determined at the state or federal levels of government? Should raw milk be banned entirely?
I think it should be left to state levels to decide whether or not raw milk sales should be occurring. If people know there is a chance they can get sick, I suppose they are consenting to this risk when buying it. However, one thing that would be important to consider is whether or not it is negatively impacting our hospitals for example. With that being said, each state has a different prevalence of food-borne illnesses so it should be left to the state to decide.
Do you think the monitoring activities being conducted by Wolfe and his team will have the potential to prevent the emergence of new viruses in humans? What obstacles remain?
I think that the activities being conducted have great potential to help the emergence of new viruses. However, there are a few obstacles that still stand in their way: funding and manpower are going to be the hardest part of handling these activities and the prevention of new emerging viruses. In the end, if they can find a way to educate individuals in some way that may help this (find cheaper methods).
Water scarcity may become a major environmental problem of the 21st century. We in the Midwest sit on one of the world's largest supplies of freshwater. Everyone is going to want some. Should we share?
I think yes in moderation. If we don't I believe that this could lead to violence and war unfortunately. In the end, we are all humans and deserve access to safe water. If that means we have to share that is fine. However, we need to be careful as in general this will have a huge impact on our environment.
There was ultimately compelling epidemiological evidence that UN peacekeepers caused the cholera outbreak in Haiti, further contributing to instability. How can we better prepare for outbreaks of infectious diseases following natural/climate disasters?
If vaccines are available, ensure that peacekeepers are given them. Besides that, while in a given area have screening available for the population of individuals (not just peacekeepers). For example, proper sanitation and food preparation.
Seasonality of disease
In both temperate and tropical climates, many infectious diseases follow patterns in prevalence driven by seasonal changes
Demand for Freshwater is Increasing
In the 20th century, human water-use increased at twice the rate of increase in the human population - principally to grow food in areas that require irrigation.
What do these data suggest about the resiliency of different crops and in different regions? What should be grown where?
In the US we have really seen a decrease in our crops. Maybe the crops we are growing are more resilient. If we want to be proactive, we should try to find out what future climates will be and start growing them in those areas
If we can predict the time and place where these spillover events occur, is an H5N1 pandemic avoidable? Consider the complicating factors.
It is difficult to know human movement completely. It can help us to prevent human contact with domestic birds, through the use of education. However, preventing spillover from wild birds to domestic birds would be difficult.
Knowing the role of storm water catch basins in disease incidence, how could storm water management be modified to reduce human illness?
It is important that stormwater management finds a way to prevent water from sitting still. As we discussed in class, this is when we see the greatest emergence of mosquitoes. For example, putting the water overflow area lower. This will allow for more flushing to occur.
The Sacramento Valley produces about 1/4th of the U.S. food supply (and over 40% of fruits and nuts). What can be done to enhance the stability of the domestic food supply under climate change?
It is important that we work to create an incentive to plant more trees, prevent excessive water use, and urban rooftop gardens. All of these can help to fight the effects of climate change.
Average # of host switches for known and newly discovered Paramyxoviruses:
Most are of bat origin: - Most originate in Africa - Noteworthy: for humans, livestock are the second greatest source of novel viruses
Salmonella in the U.S
Nontyphoidal Salmonella serotypes (including SE) account for 10% of food-borne illnesses and 31% of deaths in the U.S.
Lab Leak Hypothesis
One or more researchers studying SARS-CoV-2 (or its immediate progenitor) in a lab accidentally became infected and spread the infection beyond the lab
Future of the Gut Microbiome
Possibly one of the most important, and poorly understood, ecological components of human health
What is the most effective tool for containing a pandemics initially?
Quarantine
If the majority of species' functions are unknown, what are the potential medical applications from describing the microbiomes of healthy and sick individuals?
Researchers could work to find a way to transplant "healthy" or missing microbes into individuals who are sick or unhealthy. Harmful microbes need to be identified first in order to know what to replace it with.
Population Growth and Climate Change Interaction
Rising water demands outweigh climate change in defining state of global water to 2025
Zoonotic Emergence Hypothesis
SARS-CoV-2 spilled over from bats to humans either directly (bat-->human) or indirectly (bat --> intermediate host--> human)
Genetic Engineering Hypothesis
SARS-CoV-2 was intentionally created in a lab setting and then accidentally or intentionally released to the public
Connectivity
Spatial continuity of a habitat or cover type
Patch
Surface area that differs from its surroundings in nature or appearance
In addition to accepting reduced yields and selecting for salinity-tolerant crops, what else could we do to adapt agriculture for climate change?
The main thing that can be done is to manipulate the way we grow things. For example, heat resistant crops that can handle the longer warmer summers, genetic modifications specific crops. As well, reducing food waste is essential for reducing water use.
Landscape structure (or configuration)
The specific arrangement of spatial elements in a landscape
How much do the climate conditions change for the location you selected? What do you think are the implications for life there?
The temperature would triple if there is warming of 3 degrees. This can cause huge issues when it comes to agriculture, water, and technology. Things will need to be made in order to cool us and provide water for us.
What are some potential health consequences, considering the maternal microbiome dominates during the first ~6 months of life?
There might be infections that get passed on to infants from mothers depending on the type of delivery mode.
Why might the relationship with temperature be more complicated than: "warmer weather means more disease because pathogens develop faster"?
Warmer weather is around longer than the colder temperatures. This means that overall the season is just longer, which can allow for disease transmission to continue (in comparison to cold weather). As well, there are pathogens within the permafrost that have been buried for a long time. With that being said, warmer weather could cause there to be new diseases appearing.
Sources of water stress and scarcity
Water stress and scarcity result from an imbalance between water use and water resource availability
Cessation of smoking leads to a rapid return of the non-smoking microbiome, a point the authors of this study offered as further evidence to convince smokers of the dangers to their health. Do you think the connection with CRS is sufficiently compelling for a public health campaign focused on the nasal microbiome? Why or why not?
Yes, I think that the connection with CRS is sufficiently compelling for a public health campaign focused on the nasal microbiome. Studies show improvement in the nasal microbiome. I do think more research should be done in order to provide more information to the public. It is important that we show why it is so important to focus on our nasal microbiome.
Listeria monocytogenes
a bacterial agent of Listeriosis
Prebiotic
a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon
Probiotic
a preparation containing viable, defined microorganisms in sufficient numbers, which alter the microbiota (by implantation or colonization) in a compartment of the host and result in beneficial health effects in this host
Synbiotic
a product that contains both pro- and prebiotics
lyme disease is caused by what?
bacterium "Borrelia burgdorferi"
Habitat destruction
decreases connectivity and isolates populations
Host Jumping
describes the process by which infectious agents adapt to a new host
Low connectivity
disease burns out before it can spread
Diseases of poverty
diseases for which poverty is the primary risk factor
there is one changing climate factor that determines change in disease incidence: true or false
false, interacting changes between numerous climate factors acting simultaneously will determine changes in incidence
Draw a graph depicting the relationship between connectivity (range = 0-1, x-axis) and probability of disease persistence (range = 0-1, y-axis) based on the theory we just discussed
graph is a negative/inverted parabola. As well, I believe that there would be a peak somewhere near the middle/center of connectivity
Higher R0
higher probability of establishment in a naïve population
Microbiome
includes all of the microbes , including their genetic elements, that occur within a host
Nasal Microbiome
includes the microorganisms characteristic of the nasal cavity
Concern that corridors will do what?
increase disease prevalence in threatened and endangered populations
biological invasions
increases connectivity and contact between populations)
inflammatory bowel disease (IBD)
inflammation of the colon and small intestine - Crohn's Disease - Ulcerative colitis
On Palmyra Atoll, the removal of one invasive species unintentionally led to the eradication of another. What might be the linkages in invasions of multiple nonnative species and what might be the implications for management of invasions?
invasive species can give us an idea of how to manage a multitude of invasive species. For example, a new invasive species can settle into a new area and could result in new species to invade. In the end, it could lead to an overall change in all organisms' environments (and those within it).
Using the graph you drew for Q1, indicate the portion of the connectivity gradient where you would expect conservation corridors to increase disease prevalence. Label the portion of the graph where corridors should reduce disease prevalence.
it would have an increase in the part of the graph that is left of the highest point and it will decrease in the other half of the highest
Commensals
just along for the ride
Connectivity between suitable habitat patches often determines what?
long term disease persistence
a healthy gut should exhibit a consistent community of what?
microorganisms at "immunological equilibrium"
Hydrology
movement and distribution of water across a landscape
Landscape change
natural or human mediated alterations to landscape structure
Potential mechanism of resistance
niche space is fully occupied
Public health consequences of climate and disease changes
not only will some diseases increase in incidence, but will also decrease in predictability
common cause of CRS
not yet defined
A large proportion of the Earth's population lives along coasts (~44% within 150 km). Under the most severe climate change scenarios many of these areas will become uninhabitable. What are some potential strategies for dealing with the projected rise in sea levels?
one of the main strategies that should be used in order to deal with the projected rise in sea levels is improving drainage systems. This can help prevent worse floods from happening. As well, governments should work to regulate companies that are significantly increasing global warming.
what microbiome is one of the best described human microbial systems?
oral microbiome -- historically accessible to traditional bacteriological investigation techniques and now metagenomic techniques
Visceral Leishmanisis (VL)
organ invasion (visceralization), particularly spleen, leading to death if left untreated
what does the correlation of H5N1 and and duck populations mean for outbreak predictions?
outbreaks may be predictable, if not preventable
Disease of the digestive system is likely due to what?
perturbation of community composition favoring pathobionts: "immunological disequilibrium" or "dysbiosis"
Microbes digest what?
polysaccharides that you normally cannot digest, release monosaccharides that are digested by you
Results from this meta-analysis suggest what?
probiotics and synbiotics reduce the rate of infective complications following major abdominal surgery
Pasteurization
process of heating and then quickly cooling foods and liquids to kill harmful microorganisms (invented by Louis Pasteur)
Increasing climate extremes (drought, flooding, severe weather events) reduce what?
production
High connectivity
rapid epidemic spreads to all suitable patches
Synbiotics appear to be most effective at what?
reducing the incidence and severity of infectious complications and a shorter length of antibiotic treatment
Chronic rhinosinusitis (CRS)
represents a spectrum of inflammatory and infectious processes concurrently affecting the nose and sinuses
Distribution of H5N1 cases and ducks in SE Asia
researchers have found a strong correlation (spatially and temporally) between the distribution of human H5N1 cases and densities of domestic ducks
The Draining of the Aral Sea
s once the 4th largest lake in the world, but diversion of the rivers that fed it by the Soviet Union for agriculture destroyed the lake's ecosystem and local economy.
Cutaneous Leishmaniasis (CL)
skin infection, non-fatal but disfiguring
Invasion biology
studies the colonization and establishment of organisms into new habitats, ecosystems or regions in which they did not occur previously • Rich area of study, as humans have introduced species to new areas for millennia
From the perspective of opportunities for infectious diseases to to emerge in humans, what might be some differences between subsistence vs. commercial bushmeat hunting?
subsistence bushmeat hunting will be more local and isolated. This could be more easy overall to contain, whereas, commercialization would result in a higher risk of infectious diseases emerging in humans (more vastly spread out).
Urogenital microbiome
the communities of the vagina and urethra
Challenge to analysis of microbiota
the functional role of most microbial species is unknown!
Which hypothesis for the origin of COVID-19 (zoonotic emergence, a lab leak, or a genetically engineered virus) do you believe and why? Indicate what evidence you find most compelling.
the most likely cause for the COVID-19 emergence was due to a zoonotic emergence. This is because we have seen similar events occur at wet markets within Huanan.
dilution effect
the reduced, or diluted, probability of predation to a single animal when it is in a group
Of the food-borne illnesses listed, which do you think is the worst and why?
the worst food-borne illness is salmonella due to the fact that it is very common and how deadly it is (in comparison to the others).
What do you think these predictions suggest for disease management for threatened/ endangered species in fragmented landscapes?
this needs to be a part of disease management in order to protect endangered species within a fragmented landscape. If it becomes a part of management, we may be able to cause diseases to not stick around for too long (trying to prevent killing off the whole populations).
Climate change predicted to impact what?
timing and duration of seasons
Different microhabitats lead to what?
to different microbial communities
Poverty, Urbanization, and Disease Emergence
• 2007 marked the first year that over half the global population lives in cities • Expected to increase from 3.2 to 4.9 billion in the next 25 years - 1.7 billion more people will move in to urban areas • Mostly in the developing world as a result of demographic shifts associated with emerging economies • Urbanization has been linked to outbreaks of numerous human-tohuman transmitted diseases • Can facilitate the emergence of vectorborne diseases as well
Mammals, Wildlife Trade, and the Next Global Pandemic
• 26.5% of mammals in wildlife trade host 75% of known zoonotic viruses - much higher than domesticated and non-traded mammals • Primates, ungulates, carnivores and bats are the major zoonotic reservoirs - host 132 (58%) of 226 known zoonotic viruses present in wildlife trade
The Health Challenges due to not having access to fresh water
• Access to clean drinking water is heterogeneous and strongly affected by poverty • 1.1 billion people lack access to safe drinking water • 2.6 billion people lack access to adequate sanitation
Impacts of Climate Change on Agriculture
• Adequate irrigation is often the limiting factor in agricultural development • Irrigation demands will continue to increase in the developing world as a result of population growth • Water demand for irrigation may increase globally as transpiration/evaporation increase due to higher temperatures and more frequent droughts under climate change
Freshwater is essential why?
• All life requires water • Fresh water is essential for metabolic processes in all terrestrial organisms (photosynthesis, respiration, enzyme function, cell division, etc.) • Freshwater determines the distribution and abundance of humans on the Earth
Potential Impacts of Climate Change on Human Health
• Altered distribution and prevalence of infectious diseases • Non-infectious impacts on human well-being (droughts, floods, crop failure, etc.) • Combinations of the two
Obesity
• Among the most serious public health concerns in the 21st century • Leads to type 2 diabetes, cardiovascular disease and cancer • Recent research suggests an "obesity-associated" microbiome
Increasing "Extreme Flood" Frequency
• Analyzed frequency of extreme floods: floods that are only expected to happen every 100 years • Provide strong evidence that the frequency of extreme floods has increased since the mid- 20th century
Adaptive Crop Selection
• As freshwater becomes more limited it may become too valuable to use for irrigation • For most crops, yield goes down as soil salinity increases • Agriculture under climate change may need to select for salinity-tolerant crops
Intensity and Frequency of Extreme Novel Pandemics
• Assembled and analyzed a global dataset of large epidemics spanning four centuries, 1600 - present • Due to an increase in disease emergence from zoonotic reservoirs caused by environmental change, yearly probability of occurrence of extreme epidemics increases up to threefold in the next decade
Bats and Zoonotic Diseases
• Bats are hosts of some of the most significant recently emerging zoonoses • Since 1994, four novel human pathogens have emerged from bats in genus Pteropus (fruit bats, a.k.a flying foxes)
Disease and Global Poverty
• Burden of infectious diseases is much higher in developing countries • A large proportion of these illnesses are avoidable or treatable with existing medicines or interventions • Globally, poor are unable to access these treatments due lack of individual or national resources
Leishmaniasis
• Caused by ~20 spp. of Leishmania parasites • Results in up to 2 million new cases/year • Second largest parasitic killer after malaria • No prophylactic drugs or vaccines, treatment inadequate • Transmission mode depends on sandfly spp., Leishmania spp., and even relative proportion of human to nonhuman hosts
Influenza
• Caused several major pandemics in the 20th and 21st centuries • Remain a persistent threat (e.g., H5N1 circulating in Egypt and southeast Asia)
The Ecology of Vibrio cholerae
• Cholera is caused by strains of V. cholerae • Persists along the full aquatic salinity gradient • Only two strains from relatively rare serogroups cause epidemic disease
Changes in Temperature
• Climate change generally expected to increase temperatures • Temperature is a fundamental determinate of biological processes • Most infectious agents and arthropod vectors reproduce more rapidly at higher temperatures
Impacts of Climate Change on Precipitation
• Climate change is generally decreasing frequency but increasing intensity of precipitation • Results in greater peak runoffs but less groundwater recharge • Ultimately results in less available freshwater for human consumption
The Future of Food (In)Security
• Climate change will have heterogeneous impacts on food production both by region and by crop • Maps of the 1980- 2008 linear trend in temperature (A) and precipitation (B) for the growing season of the predominant crop (among maize, wheat, rice, and soybean) • Estimated net impact of climate trends for 1980- 2008 on crop yields for major producers and for global production
Effects of Climate Change on Fish Harvests
• Climate change will likely impact the harvest of wild foods such as marine fisheries • Model-predicted change in national catch potential based upon redistribution of global fish stocks (under two different climate scenarios)
Are There Solutions to climate change and food production?
• Climate change will likely present an increasingly difficult barrier to global food production • Ecological farming approaches that take advantage of the climate regulating effects of natural ecosystems may become increasingly important
Sustainable Coffee Production
• Coffee is an example of a crop that can be grown "ecologically" • Less-domesticated cultivars can be grown under a canopy of native trees species (i.e. shade-grown) • Increases soil fertility, reduces need for fertilizers and pesticides, and conserves local biodiversity • Shade-grown coffee appears to be more resilient to climate change • In high shade (60-80% cover) daily soil evaporation rates and transpiration demand significantly less than low shade (10-30%)
Declines in Coffee Production
• Coffee plants require a balance of moderate temperatures, rainfall and periods of dryness for beans to ripen • Coffee pests thrive in warmer, wetter weather • Production has declined globally due to changes in climate • Columbia produces ~1/2 of coffee grown in Latin America • Exports of coffee have declined despite increased production effort
Rosacea and Demodex folliculorum
• D. folliculorum often occur in much greater numbers in patients with rosacea • Carry the pathogenic bacterium Bacillus oleronius • Exposure stimulates an immune system response in 79% of patients with rosacea, compared with only 29% of patients without the disorder
Deforestation and Malaria in the Amazon
• Deforestation for agriculture and timber inflicts a profound change in landscape structure • Generally a direct cause of enormous biodiversity loss • Some species thrive in these altered landscapes • Logging activities create many small aquatic habitats which receive direct sunlight-ideal breeding area for An. darlingi
Poverty and the Emergence of Dengue Along the US-Mexico Border
• Dengue is a mosquito-borne virus re-emerging in the southern U.S. • Human incidence is higher in Mexico, even in cities immediately across the border from US cities • Reiter et al. 2003 conducted a comparative study of two cities on the US-Mexico border to understand risk factors associated with Dengue incidence • Human incidence of Dengue was higher in Nuevo Laredo (IgM prevalence 16% vs. 1.3%) • Despite lower incidence, mosquito vectors were more abundant on US side of border
Impacts of Climate Change on Timing of Water Resources
• Earlier springs and changes in precipitation from snow to rain alter timing and reduce volume of seasonal flows • Can feedback in to terrestrial systems
The Microbial Ecology of Chronic Rhinosinusitis (CRS)
• Estimated prevalence in the U.S. of 16% with an annual cost of $6 billion • Tobacco smoke is an important risk factor • Abundant bacterial presence within the nasal and paranasal sinuses believed to be contributory • CRS patients may respond to aggressive antibiotic treatment
Impacts of Climate Change on Floods
• Floods are the most consistently destructive form of natural disaster on Earth • Floods in Pakistan in 2010 were rated the greatest humanitarian crisis in modern history by the U.N. with ~13.8 million people affected
Identify Microbes Using Databases
• Generate library of all microbes in sample • Use 16S ribosomal RNA genes for ID • Ribosomal genes that are common in all life • Involved in general protein synthesis • Very conserved • Use online databases of known sequences to identify microbial community
Poverty and the Emergence of H5N1
• H5N1 influenza (bird flu) one of the infectious agents with greatest potential to cause a global pandemic • Must first genetically adapt for human-to-human transmission • Currently transmitted bird-bird & bird-human (& a little human-human) • Education campaigns have failed to prevent the slaughter and consumption of sick chickens in impoverished rural areas
Spillover via Domestic Animals
• Hendra and Nipah viruses • Cause sporadic outbreaks in domestic animals and people, with extremely high case-fatality rates • Emergence of 4 novel human pathogens from single host genus in short period of time suggests changes in host ecology
The Corridor Controversy
• Human fragmentation of habitats is the #1 conservation threat for large carnivores • Increasing effort to use "conservation corridors" to reconnect fragmented habitats • In North America, considered crucial for the conservation of the Florida panther, grizzly bear, reptiles & amphibians in the Everglades, etc. • Small populations highly susceptible to extinction due to infectious disease outbreaks
The Microbiome: Human Studies
• Identify two groups: healthy and sick • Collect sample of microbes • Genomics • Metagenomics
Drought-Induced Mosquito Outbreaks
• In urban ecosystems, storm water catch basins (CBs) are often the most productive habitats for mosquito larvae • In CBs, mosquito production may be negatively associated with precipitation, counter-intuitively leading to mosquito outbreaks during droughts • The Chicago metro region is a WNV hotspot
Delivery Mode Shapes Infant Microbiome
• Infants delivered vaginally acquire bacterial communities in their skin, oral cavity, and nose that resemble their mother's vaginal microbiota • Infants delivered by Cesarean section harbor microbial communities similar to those found on mother's skin
How do you get your internal bacteria?
• Initial microbiome inherited maternally via several pathways • Communities change as additional microbes colonize body and interact with established species
Changes in Hydrology
• Interacts with precipitation, temperature and seasons and will likely be altered by climate change • Also affects disease dynamics
Burmese Pythons in the Everglades
• Introduction of the Burmese python to southern Florida has caused massive declines in medium/large-sized mammals in the Everglades • Subsequent increase in small mammals, including reservoir hosts of mosquito borne 'Everglades virus': - Hispid cotton rat (Sigmodon hispidus) - cotton mouse (Peromyscus gossypinus)
Examples in the Invasion Biology of Infectious Diseases
• Large-scale patters in the invasion of Lyme disease in the Midwest • Species invasions with unintended consequences • Mosquito-borne diseases invading the Americas
Gut Microbiome Influences Obesity
• Mice genetically engineered not to produce leptin adopt an obese phenotype (and gut microbiome) • Confirmed by transplantation of lean and obese caecal microbiotas into germfree mice • Recipient mice rapidly adopt obese phenotype following transplant from obese donor
Bacterial Vaginosis (BV)
• Most common vaginal infection in women of childbearing age • Pregnant women may deliver premature or low birth-weight babies • Associated with atypically high diversity of the vaginal microbiome
Adaptive Irrigation
• Most irrigated agricultural systems use "full irrigation" (i.e., no water stress) to maximize yields • Increasing yield can come at a cost of reduced water use efficiency • Agriculture under climate change may need to accept reduced yields as water becomes the most expensive or limiting resource
The Dangers of Bad Irrigation
• Most irrigation schemes around the world are extremely inefficient (less than half the water reaches crop roots) • Over-irrigation and inadequate drainage causes an accumulation of salt which reduces yield • Can carry enormous ecological costs
S. epidermidis and Would Healing
• Normal microflora of the skin includes many bacteria species • Staphylococcus epidermidis modulates the inflammation response necessary for wound healing • Prevents both over- and under-expression of inflammation
Costs of Biological Invasions
• Often occur at higher densities than native species • In the U.S., economic cost of invasive species exceed $120 billion/year • Biological invasions impose an enormous environmental cost -- #2 cause of species loss after habitat destruction • Also impose a human health cost via the introduction of infectious agents into new areas
Timeline UN Peacekeepers in Haiti
• Outbreak starts downstream from a Nepalese peacekeeper camp on the Artibonite river • Adjacent communes experience rapid outbreak • Distant communes experience a delayed outbreak as infected individuals flee from epidemic areas
Drought-Induced Mosquito Outbreaks: West Nile Virus
• Precipitation particularly important for the ecology of mosquitoes • Main vectors of West Nile Virus (WNV) are Culex spp. mosquitoes, which breed in human-made habitats in urban ecosystems • Mosquito abundance and infection rates strongly affected by precipitation
Impacts of Climate Change on Coasts
• Rising sea levels will have serious effects on coastal aquifers, which supply substantial water to many cities and other users • Severe impacts on food production in major delta regions, which are the "food bowls" of many countries
Disease Emergence
• Some disease vectors highly adapted to urban environments • Mosquitoes that transmit non-zoonotic viruses (Dengue, Yellow Fever, Chikungunya, Zika, etc.) adapted to breed in small aquatic habitats common in urban environments • High human densities ensure transmission rates maintain R0 > 1
Landscape Structure and Disease Invasions
• Spatial structure often causes organisms to 'cluster' • Some degree of clustering usually necessary for disease establishment • Some degree of connectivity usually necessary for disease spread
Global Instability in Food Production
• The FAO Food Price Index is a measure of the monthly change in international prices of food commodities • Cost of food has greatly increased across the globe early in the 21st century • Changes in food production can be due to social factors • Reduced interest in agricultural livelihoods as economies developGlobal Population (in millions) of Middle Class Affluence • Increasing global demand due to rising middle classes in emerging economies
Malaria Over Time
• The distribution has decreased dramatically over the last century • Enormous interest in the effect of climate change on malaria prevalence • The relationship is very complex - increases and decreases
Oral microbiome
• The human mouth provides a habitat for ~700 "species" of bacteria • 100-200 different species are present in the healthy mouth of any individual • The oral cavity presents a broad palette of environmental conditions
Pathogens of Pandemic Potential
• The next pandemic may be caused by a known pathogen or by "disease X" • These agents follow (sometimes) predictable patterns of host associations and transmission modes
Impacts on Oceans and Sea Level Rise
• The oceans take up more than 90% of the heat trapped by greenhouse gasses • Absorbed more heat in the first part of the 21st century than the previous 130 years • Rapid melting of sea ice may represent a global 'tipping point'
Ecological Succession
• The process by which an ecological community undergoes orderly and predictable changes in species following disturbance or initial colonization of new habitat • Among the first theories advanced in ecology
The Globalization of Infectious Diseases
• The species-area relationship is one of the foundational principles of ecology • Often repeated pattern: as area increases, so does species diversity • Log transformation of the equation generates a linear relationship
A Tale of Two Pandemics
• Timing of symptoms vs. infectiousness critical • Vaccines remain the most proven technology for preventing viruses • In the recent past, process of vaccine discovery could take decades • Technologies to quickly discover and mass produce vaccines will change how we respond to pandemics in the future
The Ecology of Lyme Disease
• Transmitted by the blacklegged tick (Ixodes scapularis) • White-footed mouse (Peromyscus leucopus) is a primary reservoir for B. burgdorferi • White-tailed deer (Odocoileus virginianus) is a crucial host for adult ticks
UN Peacekeepers in Haiti
• UN Peacekeepers were brought in due to the collapse of government services and security • Accused of starting the cholera outbreak • Major source of tension between the peacekeeping troops and the public
Managing Uncertainty
• Uncertainty should not be a reason for inaction • Adaptive management allows for adjustments, as additional and better information becomes available • Requires continuous feedback and adjustments based on the information provided by monitoring networks
Cholera: The Disease
• Upon entering the human host, attach to wall of small intestine via a "pilus" • Begin cell division to produce many new bacterial cells • Release an enterotoxin called "cholera toxin" causing severe diarrhea • Results in the shedding of many bacterial cells back into the environment
Climate Change
• Water is the primary medium through which climate change influences Earth's ecosystem and thus the livelihood and wellbeing of societies • Mediated via impacts on the hydrological cycle and water management
Multiple Healthy Microbiomes study
• conducted across 396 healthy patients divided by ethnic group demonstrated five consistent microbial communities • All five communities dominated by a few species responsible for producing lactic acid, which lowers the pH of the vagina and plays a key role in defense against pathogens
Paramyxoviruses: Drexler et al. (2012)
• investigated the prevalence and evolutionary history of Paramyxoviruses in rodents and bats • Discovered 66 new species of virus (more than doubled the known # of species) • Phylogenetic reconstruction of host associations shows many host switches from bats to other animals
The Global Virome Project
• launched in 2018 to identify the global diversity of viruses capable of causing pandemics • Estimated global viral diversity in wildlife hosts to be 1,607,837 virus species! And between 631,000 and 827,000 of these unknown viruses have zoonotic potential.
Skin Microbiome
• most variable • Shaped by extrinsic (e.g., climate, occupation, hygiene) and intrinsic (e.g., physiology, genotype, disease) factors • Skin microbiome of individuals is so distinct that it could be used in forensic pathology
Recurrent diarrhea
• severe, persistent form of diarrheal disease caused by the bacterium Clostridium difficile • Usually associated with use of antibiotics and acquired in hospitals • Example of an ecological 'priority effect'
