EEBioLect8 Ecology and Evolutionary Biology 100
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Ecology and Evolutionary Biology 100
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This 9 page One Day of Notes was uploaded by Marissa Mayeda on Monday February 2, 2015. The One Day of Notes belongs to Ecology and Evolutionary Biology 100 at University of California - Los Angeles taught by Dr. Johns in Winter2015. Since its upload, it has received 107 views. For similar materials see Introduction to Ecology and Behavior in Behavioral Sciences at University of California - Los Angeles.
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Date Created: 02/02/15
Ecology and Behavior EEB 100 Philip Johns philipjohns1uclaedu Disease Ecology Office hours Philip Johns philipjohns1uclaedu Tue HH 316 1100 1200 Wed HH 328 1100 1200 Fri HH 31611OO 12OO Comments on test The mid term is on Thursday 05 February from 5 7 PM Last names beginning A N Moore 100 Last names beginning O Z Humants A51 Test comments Exam format Some multiple choice Some short answer with strict word limit 1 Essay choose from a few possibilities Hints for studying Go through slides amp practice problems Use readings including discussion to supplement lecture Use readings to clarify gures amp examples Study with someone else practice explaining concepts Anticipate questions Ecology amp disease Transmission is both Within population biology problem Across population problem metapopulation dynamics May amp Anderson 1979 Disease can be become an epidemic when Birth rate infection of new hosts gt Death rate demise of current host R0 gt 1 disease can spread httpwwwnaturecomnaturejournalv280n5721abs280361a0html httpwwwmathunmedusulskymathcampAndersonMav1979pdf Network theory and dynamics Disease amp distribution of organisms Can view disease as exploitative relation akin to parasites Disease in uences spatial distribution of organisms Caribou migrate 1000 s of km y parasites popular wisdom Ming Dynasty amp Vietnam amp malaria httpphysorgnews2015 01 mosquito borne diseases stymied ming dynastyhtml Ecology amp disease R0 sometimes called the basic reproduction number affected by how many people die D What in uences disease spread death of individuals those who live carrying disease D Probability of infection given contact C tau D Average rate of contact between infected and uninfected individuals C D Duration of infection d R0 C X c X d What kinds of diseases are most likely to spread disease that lingers airbome disease when you have a cold measles only infectious for about 8 days whereas infectious disease that don39t kill host right away are most likely to spread Diseases amp R0 Common diseases amp their R0 refer to table in slides if R0 greater than 1 disease can spread why is R0 for ebola so low It kills you so quickly so it usually doesn39t spread that effectively In uenza of 1918 killed 20 100 million people Disease amp networks 1 Spread within a population diffusive dispersal 2 Spread across populations jump dispersal Disease amp networks Spread of SARS in Taiwan Nodes of transmission shown in picture Connectedness R0 gtgt 1 epidemic different people who went to different hospitals lines show connections between nodes only about 6 links can trace transmissions through these kinds of maps Ecology amp Disease Networks Transmission of HIV amp sexual behavior Morris 2011 100 monogamy no transmission 4555 1 partner 2 or 3 partners 2 of population at risk 3565 1 partner 2 or 3 partners 64 of population at risk RAPID increase in risk HIV and networks Phylogeny of pandemic M group HIV Estimated times based on mutations amp key sample specimen ZR59 ZR59 first person recorded to die of HIV late 50s can see how HIV spread through South Africa through transporttravel function of networks Traveled along railways amp waterways httpwwwsciencemagorgcontent346620556fullhtml Ecology amp disease Chytridiomycosis in amphibians Chytrid fungus Batrachochytrium dendrobatidis many frogs die from fungal infection in past 30 years aquatic spores frogs infected have thick skin whereas normally get oxygen through skin so essentially suffocate Infects through motile swimming spores Ecology amp disease 0 Chytridiomycosis in amphibians Batrachochytrium dendrobatidis fungus 325 of amphibians are listed as threatened Kilpatrick et a1 2010 0 httpkilpatrickeebucsceduwpcontentuploads20l304Kilpatricketal20lOTREEpdf 925 of critically endangered species are undergoing enigmatic declines possibly due to Bd fungus Ecology amp disease 100 mortality in some species gt200 species extinctions already Bd linked to extinction of possibly 30 of harlequin toads in the tropics Ecology amp disease Phylogeny of Bd Rosenblum et a1 2013 Ancient group long history with amphibians Present and diversi ed on every continent Bd not a novel pathogen but a former Brazilian or African endemic transported worldwide Mortality due to lack of coevolution between introduced strain and local populations Likely vectored by transport of Xenopus or bullfrogs carriers but not highly affected disease on toad due to people keeping them as pet or used to be studied in research source of fungus is us drive to extinction in just a year or two httpwwwpnasorgcontentl 10239385fu11 Ecology amp disease White nose syndrome in North American bats Pseudogymnoascus Geomyces destructans fungus don39t need to know official fungal name just know white nose syndrome bats nocturnal and hibernate tightly together in roosts wings have large surface area so it is easy to lose heat and hard to stay warm spread this white nose fungus Spread primarily by females Spread by contact in roosts httpnewssciencemagorgbiology201405scienceshotfemalebatsdictatespread whitenosesyndrome Ecology amp disease Causes bats to wake from torpor during winter Depletes energy reserves to the degree that mortality results Maher et a1 2012 usually when hibernate don39t expend much energy whereas waking up cause bats to loose energy quickly especially in cold httpwwwnaturecomncommsjoumalv3n12absncomms2301html 0 Est 5767 million deaths up to 95 mortality lst observed in NY in 2006 By 2012 in 20 states over 2000km from initial infection Pd is likely a strain imported from Europe Unknown as to how it was introduced in North America Ecology amp disease North American bats at risk Bigeared bat Little brown bat used to be very common and dense pops drop hugely from fungus 34 remain Pallid bat Indiana bat bats are 14 of all mammals abundant and many species Ecology amp disease 1 Spread within a population diffusive dispersal may go among roosts 2 Spread across populations jump dispersal White nose syndrome in North American bats Ecology amp disease Data of past and future spread of WNS in bats Maher et a1 2012 shown in figure in slides by what year it spread in different areas Ecology amp Disease White nose syndrome in North American bats Ecological and economic costs Bats eat 100 s of tons of insects One little brown bat 6 grams insects night 150 foraging nights 900 grams bat year 14 million dead little brown bats from WNS white nose syndrome 12600000 kilograms of insects not eaten ecosystem trophic cascade Save farmer s 37 Billion per year in pesticide costs 0 512137 in pesticide costs acre Ecology amp Disease Chytridiomycosis in amphibians amp White nose syndrome in bats No obvious treatment for either No obvious way to prevent further spread No cure only hope is that some individuals will be disease resistant and be able to repopulate Species extinctions are likely inevitable 1 Mortality from disease 2 Allee effects in low density populations 3 Stochastic events affected small populations Some good news bats amp resistance WNS P destructans disrupts torpor patterns Big brown bat Ef has some immunity big brown bat have more fat whereas small brown bat doesn39t have much fat so when it wakes up mid hibernation it shivers and losing small fat reserves httpwwwplosoneorgarticleinfo3Adoi2F1013712Fjoumalpone0113958 Lyme disease distribution Lyme disease bullseye rash is defining factor mostly common in the east has only been around for about 40 years fever and chills can get chronic joint pain when you39re 20 can get neurological disorders can have for decades Full disease first described in 1975 in Lyme CT Nearly worldwide phenomenon Caused by spirochete Borrelia burgdorferi Lyme disease amp black legged tick Spirochete transferred by Ixodes ticks young ticks are not carriers pick up disease by suck on animals when ticks bite you transfer parasite Larvae rarely infected pick up infection from host reservoirs some hosts more likely to transfer Transfer infection as nymphs or adults Fragmentation amp Lyme disease Fragmentation increases in nymphs carrying Lyme as area increases patches of forests cut off by cities lower incidence of lyme big patches higher incidence of lyme think of forest patches as islands why would this lead to higher risk of lyme Look at graphs in slide httpon1ine1ibrarywileycomdoi1 0 1046j 1523 1739200301260Xfull Activity fragmentation amp Lyme disease Activity fragmentation amp Lyme disease What happens when forests are fragmented How will that affect species compositions How might this in uence disease white footed mouse in these fragmented forests if you have smaller fragments lower biodiversity and if some animals are better hosts for the disease then ticks that live in these small forests have to bite these animals passing it then onto humans patches of forests have less big predators some middle species more common like White footed mice White footed mice Very competent reservoir of spirochete As frequency of other mammals decrease Ticks concentrate on White footed mice more mammals increase ticks don39t focus on mice With fewer other mammals ticks concentrate on these White footed mice Dilution effect Diversity dilutes vector concentration on a species Sq squirrel Sts Ss shrews O opossum Ch chipmunk D deer B bird R raccoon Sk skunk look at graph in slides some species highly decrease risk of lyme huge dilution potential increase biodiversity and decrease chance of disease in theory httpWWWpnasorg content 1 002 5 67 full Dilution vs rescue effect Loss of diversity D disease risk is a controversial idea Dilution effect depends on species involved Diversity can rescue infection birds If there are multiple competent reservoirs if tick doesn39t get disease from first host might get it from another bird goes against dilution theory Species at risk amp disease outbreaks Look at graph on slides more species at risk of extinction at the right side of graph usually When species are at risk of extinction means there is little biodiversity as number of species at risk increases risk increases as forest cover decreases vector borne outbreaks increases all support idea that biodiversity can help decrease risk of disease Asian Pacific countries Zoonotic outbreaks and frequency of threatened vertebrates A amp B And forest cover C Fragmentation loss of diversity amp increase in disease pattern may be general httpWwwplosoneorgarticleinfo3Adoi 2F1013712Fjoumalpone0090032 Human ecology amp disease New diseases continue to appear HIV SARS West Nile Bird u Managing the response 1 Controlling contacts from infected individuals 2 Preventative vaccinations Ecology amp Disease In uenza vaccination in Japan Reichert et al 2001 look at graph on slides kids vaccination don39t really affect death however vaccinating school children helps seniors children mainly immune but infect others in the population Herd Immunity if some in the herd are immune can create barrier this barrier of immune individuals can protect the whole herd Primate networks behavior amp disease Chimpanzee groups with a no b 1 and c 2 estrus females Pairwise associations as function of estrus females What if we target certain individuals for immunization when females in heat increase in ties of all classes even among juveniles increase in contact when there are two females in heat even though juveniles are not the ones mating everyone affected what if we target who we vaccinate for ebola httponlinelibrarywileycomdoi 101 1 111365265612088full Primates amp network based vaccination Simulated disease outbreak in primates R0 30 large risk Strategies based on immunizing some individuals base on networks or traits reduces number of vaccinations required suggests that certain vaccination strategies will be more effective Either based on networks centrality or traits rank sex amp reproductive status reduces number of vaccinations required httprsifroyalsocietypublishingorgcontent 1 19720140349short httpnewsugaedureleasesarticlenetworkbasedvaccinationsdiseaseoutbreakschimps 0614 Human Ecology amp Disease Zoonoses and emptyvacated niches Zoonosis is a disease that has evolved in one species is transmitted to a second species and successfully replicates there Of 1415 pathogens known to infect humans 61 are likely zoonotic in origin Taylor et al 2001 0 httprstbrovalsocietvpublishingorgcontent 356 141 1983short Sources for human zoonoses 1 Domesticated animals 2 Bushmeat Human Ecology amp Disease Domestic Pigs fowl and cows Bushmeat Ebola Ebola outbreak in 2014 Dead people on oor of hospital in Liberia In one clinic 23 of 25 healthcare workers died of Ebola 60 mortality 5 authors died on big paper published on 2014 outbreak httpwwwwashingtonpostcomsfnationa120141004howebolaspedoutofcontrol httpnewssciencemagorghealth20l408ebolasheavytollstudyauthors Ebola cases 2014 Ebola outbreak in 2014 Orders of magnitude higher than previous outbreaks Worstcase scenario was 277000 deaths usually in rural areas small pops so dies out or kills host too fast and dies out this recent outbreak first true spread httpblogsplosorgspeakingofmedicine2014111 1factorsmightledemergenceebolawest africa httpwwweurosurveillanceorgNiewArticleastArticleld20894 Ebola amp R0 Ebola R0 relatively low 1525 why Where is it from how did it spread so actively duration is short because so deadly and also only spread through bodily uids blood vomit and species usually affects families who deal with the body httpblogsplosorgspeakingo nedicine20 l4103 lsocialpathwaysebolavirusdisease ruralsierraleoneimplicationscontainment Ebola spread through West Africa Ebola outbreak in 2014 Large percentages of people in communities born or work elsewhere httpblogsplosorgspeakingo nedicine20 l4 103 lsocialpathwaysebolavirusdisease ruralsierraleoneimplicationscontainment Ebola networks in Sierra Leone Ebola outbreak in 2014 spread through travel social networks between villages for marriage and work Large percentages of people in communities born or work elsewhere httpblogsplosorgspeakingofmedicine20 l4 103 lsocialpathwaysebolavirusdisease ruralsierraleoneimplicationscontainment Ebola reservoir Phylogeny of virus bats in the Zaire clade Bats Hypsignathus monstrosus horse jawed monster blue Epomops franqueti red and Myonycteris torquata Asymptomatic in bats live in forests of West Africa reservoirs for ebola are bats bats immune but carry http wwwnaturecomnature j ournalv43 8n7068full43 85 75ahtml Source of current outbreak Single hollow tree in Ginea Where outbreak started Bats roosting in tree children playing in hollow of tree httpnewssciencemagorgafrica20 14 l2bat filled tree may haVe been ground zero ebolaepidemic Ebola Bats a reservoir of Virus Outbreaks affect non human mammals Human contact With bats amp non human primates D human outbreak Reservoir in Asia Fruit bat Rousettus leschenaultii Widespread in Asia Antibodies found in bats from Bangladesh Other Ebola Viruses found in bats in China Indonesia httpwwwnccdcgoveidarticlel92pdfs12 0524pdf httpWWWVirologyj com content 9 1236