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120 Cards in this Set
- Front
- Back
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What is first severe and readily transmissable disease of the 21st century?
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SARS
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Does SARS have an animal reservior?
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Yes civets or bats
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How is the virus transmitted?
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The virus is relatively hardy, easily spread by droplet secretions, person to person contact or fecal contamination
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How long is the SARS incubation period?
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two to seven days
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What is the mortility rate of SARS?
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10%, but in the elderly it can reach 50%
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How did SARS initiially spread
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First appeared in Guandong province in Nov. 2002, by Feb 2003 it was in 32 countries, by July 774 were dead
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What caused the spread of SARS?
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Global travel caused the spread of the virus
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What is the problem if there is an animal reservior?
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You can never get rid of virus because its always lurking in the population
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What can you do for animal reservior?
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change behavior or consider vaccinating the animal population
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What is zoonosis
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animal rerservior
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Who is really important on the frontline with disease?
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Vets!
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How did the doctor start this whole thing?
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Doctor from Guandong attends a wedding and infects 16 people, one guest returns to canada, doctor in hanoi sees this is a new disease and names it SARS, in March its a worldwide threat and quarantine/isolation are instituted
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What types of virus is SARS
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coronovirus
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How did they prove it was SARS?
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through koch's postulate using a monkey
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Describe the SARS virus.
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single-stranded, positive RNA stranded virus (it can be used directly for translation) that causes unusually severe respiratory illnesses
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Herd Immunity
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certain percentage of population must vaccinated to prevent the spread to others
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What percent of the pop must be immunized for polio?
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70%
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What is another way the diseases can be spread (ie happens in birds) and food
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migration and trade
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What do we normally link to common source epidemics
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food and water
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What is the hot zone?
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a highly infectious deadly virus from central African rainforest suddenly appears in the suburbs of Washington DC (true story)
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What factors that increase assurance and economy in the food industry also spread disease when sanitation measures fail? What is an example?
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transportation, bulk processing, central distribution
ecoli |
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What is the disease causing version of ecoli
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ecoli O157
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What is the difference between common source epidemics and others?
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Causes very fast outbreaks, hosts will take more time
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is ecoli always bad?
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nope, its in us right now
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describe ecoli as a pathogen
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its ecoli O157:H7 as an emerging pathogen, also called enterohemorrhagic
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What is the O antigen of ecoli?
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on LPS serogroup (negative), H+ antigen+flagella=serotype
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What is the leading cause of foodborne illness?
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ecoli
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When was ecoli first recognized as a sourcce of disease?
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in 1982 when during an outbreak of severe bloody diarrhea whih was traced to hamburgers
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Can the government recall meet?
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Nope!
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What do we do about madcow?
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we can ban imports
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How long does it take us to become sick after ingesting bad ecoli?
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3 to 4 days
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Where do cattle carry ecoli
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in their intestine
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How can ecoli from cows spread?
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direct or indirect contact with the cow manure, it's used as fertilizer, polluted irrigation water, defacation near vicinity of produce of foods of animal origin, ie spinach
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Why has ecoli recently become such a problem
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We've changed how we raise cattle, feeding grain has more acidic ph which may have created an acid resistant strain
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What barrier in the cow would kill ecoli usually?
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acid barrier in the tummy
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How does ecoli make you sick? Why don't cows get sick?
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It has a toxin, but cows have a do not receptor for it
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Describe the ecoli toxin.
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shigalike toxin also called verotoxin, AB toxin, carried on lambdoid bacteriophage, functions as an N-glycosidase cleaving several nucleobases frm the RNA the compriises the ribosome thereby halting protein synthesis
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Where are the toxin receptors?
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intestinal cells and kidney cells
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How do AB toxins work?
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The B-Subunit is a pentamer that binds to specific glyolipids on the host cell, specifically gb3, following this the A subunit is internalized and cleaved into two parts, the A1 component then binds to the ribosomes, disrupting protein synthesis
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What does the toxin require?
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highly specific receptors on the cells surface in order to attach and enter the cell, species such as cattle, swine, deer can carry them any ill effect and shed them in their feces
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What are other AB toxins?
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cholera, diptheria, tetanus, botulism
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What are type III secretions?
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inject their own receptor, bind intimin, cause changes to the actin cytoskeleton
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What else uses type three secretions?
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yersinia pestis
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What is a pathogenicity island?
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region of genomic dna that we believe has been horizonttally transferred probably through transposable element, could start out with nice ecoli and get shitty ones
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define Lambdoid
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temperate viruses, has own DNA
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What is the difference between Lytic and Lysogenic pathway?
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Lysogenic can integrate host genome into the actual DNA, transduction
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What kind of DNA does ecoli have?
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circular
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Can the prophage ever exit the cell?
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yes it can jump out of the DNA if conditions aren't favorable
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What kind of virus is the influenza virus?
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envelope, negative stranded, has reverse transcriptase
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How long does it take for influenza?
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Replication takes about 6 hrs and kills the host
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What are other negative stranded RNA viruses?
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rabies, hanta, ebola, measles,
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What is the structure of the virus?
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pleomorphic (helical/ovoid), enveloped, two viral proteins extrude from the surface, the nucleocapsid houses eight segments of negative stranded RNA, RNA dependent rna polymerase, rna endonucleases
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Why do we see much diversity with influenza?
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genome is segmented
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How many proteins do the 8 segments code for?
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11
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What are the most characterized viral proteins on influenza
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hemagluttin and neruminidase, two large glyoproteins on the outside
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What is Neraminidase?
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an enzyme involved in the release of progeny virus from infected cellsby cleaving sugars that bind the mature viral particles
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What is Humagluttinin
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a lectin that mediates binding of the virus to the target cell and entry of the viral genome into the target cell
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What are some methods of detecting viruses
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antibody based detection systems, PCR based systems, culturing the virus from infected tissue
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Can we always culture a virus? What do we use to culture it?>
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No we can't, but if we do its down with chicken eggs
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How does PCR work?
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PCR 1. Initialization step the DNa is heated to denature it it (pull it apart by breaking the hydrogen bonds, annealing step: temp lowered so primers can attach, elongation step: new DNA is synthesized
You have to use an RNA polymerase Need DNA |
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Why do epidemics and pandemics occur?
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antigenic variation and antigenic drift
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Antigenic drift
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a slow process attributed to the tendency for RNA viruses to acquire mutations, RNAP lacks proofreading causing slight alteration that may result in the ability to escape the immune system-causes epidemics
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Antigenic shift
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a fast process due to a segmented genome, if two genitically and antigenetically distinct viruses infect the same cell then thier genome segments can reassort to form unique progeny-this causes pandemics
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How many HA serotypes?
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16
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How many NA serotypes
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9
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How much of the population needs to be vaccinated to get herd immunity for influenza?
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90 to 95%
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Why is the rhesus moneky used for animal studies?
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their response to infectious disease
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What is now an issue with polio?
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people don't want to immunize their children
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What killed more Spanish flu or WWI
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spanish flu
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How many people did the flu kill worldwide
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50 million
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What part of the human body does influenza dispay high growrth ability in?
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lung cells
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Why did they think swine flu is related to the 1918 flu?
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we had antibodies against swine flu
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What animal do we use to test the flu?
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ferrets-we used for dog distemper first
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What is Avain flu?
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H5N1
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When and what were the three pandemics of the last century?
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1918: H1N1
1957: H2N2 1968: H3N2 |
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How many mutations make 1918 a big bad killer.
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two point mutations and it cannot be transmitted from place to place
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What happened in 1976 with swine flu?
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we went a little crazy
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Why couldn't people make a vaccine for everybody?
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Nobody wanted the liability
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Why was the specimen that was frozen good?
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she was obese
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Whats not so hot about killing chickens to produce bird flu?
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we need them for eggs
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What disease was linked to the flu vaccine?
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Guillai-Barre, a nervous system disorder
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how many biosafety level 4s are there?
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10 in USA
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What are the two sources for sequence info
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tests in chicks and mice
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How does HA bind to host cell?
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Through alpha 2,6 in humans and in alpha 2,3 in birds
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how does microarray analysis work?
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if gene is highly expressed you'll have lots of it, there is a corresponding oligonucleotide corresponding to a sequence, If hybridize green and red you see yellow if they’re equal, red genes are more in n=known control
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What might have actually caused?
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immune system is overreacting, doesn't let normal course happen, die of overactive immune response
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Who has a better immune system?
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Healthy people
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Abberant immune response
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overactive immune response
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What are intervenetions we can make for the flu?
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vaccination, antiviral, neuraminidase inhibitors such as tamiflu which is fed to chickens, non drug methods such as masks, social distancing
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Why did St. Louis have lower infections?
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St Louis did early social distancing
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How fast is our population increasing?
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faster than exponential
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How must we consider population?
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in terms of number and denisty
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What is density?
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population size/ area
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what do density models define?
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how much people come into contact with each other
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What does the united nations define as an urban area? us? iceland?
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more than 20,00 residents, Us 2500, iceland 200
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What are megacities? How many will there be in 2015?
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more than 10 million, 23 by 2015 with 19 in developing countries
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what was the first country to exceed 1 million people?
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Peking
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How much of an increase does the Un predict will occur in the next 30 years
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2 billion more people
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how much of the worl'd resources does the US use?
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30%
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What is the difference between developed and developing countries?
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in developed people are living in smaller cities
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How many megacities will Europe add by 2015?
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zero
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What was the first megacity?
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NYC
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What is a major issue in cities?
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water
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What fraction of people lack safe water?
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1/6
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What percent of the world lacks feasible means of sanitation?
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50%
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What is water most of the time?
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65 to 70% for irrigation
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How many gallons does it take feed a person for one day?
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528
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Are bigass cities a new thing?
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tikal is an old city
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Where were the earliest settlements?
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The fertile crescent of Mesopotamia
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why did large urban areas develop?
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trade and commerce
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do cities have ecology?
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yes
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Why are urban areas heat islands?
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because of asphalt absorbs heat and releases it
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When does heat island mainly effect?
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at night
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Why is baltimore hotter and phoenix cooler?
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because phoenix sweats when they irrigate grass and it secretes water
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Where is precipitation higher?
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in and downwind of cities
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What is the diffference in percipitation in cities vs rural?
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43% of precipitation exits cities via storm sewers vs towns where 50% of it ends up in groundwater
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What are two problems from cities?
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Cause atmosphere to dump water at higher rate also immediately gets swept away
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How do city forests differ?
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fewer species, lower density, and more species that are adapted to wet soil
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What happens to all the bigger predators?
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They go away
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What animals do cities have
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feral, cats, and dogs, lots of midsized predators, scavengers
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