N251 exam 4: lecture 2

major viruses

Ebola, HIV, SARS

Ebola

RNA virus
-helical shape: can be quite long
-have envelope
-originated with bats: especially deadly to primates, other animals can also get it
-humans exposed through bush meat: animals from wild that contracted ebola, other ways as well
-a boy who went exploring in cave and came down with it


-serious in certain parts of world
-had here in US due to transporting people who were infected

spread by close contact
-unprotected healthcare workers: blood and body fluids
-as well as some traditional funeral practices
-kills between 25-90 percent of victims depending on strain
-no cure or vaccine
-people can be treated
-care needs to be quickly

early stage:
-headache
-fever
-fatigue
-muscle ache
-sore throat

later:
-liver and kidneys impaired
-diarrhea
-rash
-can bleed from any orifice
-a lot of internal and external bleeding

mysteries to ebola

Hot zone
-book that looks at what could of been the first major outbreak of ebola in US
-monkeys transported into Virginia
-monkeys were dying: people flying into look then flying out to leave
-monkeys had ebola type virus: thankfully the strain was only deadly to monkeys and not humans
-if was deadly to humans: could have been very serious

HIV

human immunodeficiency virus

-envelope with glycoproteins

-RNA

-retrovirus: with reverse transcriptase

-can lead to AIDS

-impact immune system

-infects helper t cells: activate b cells that produce antibodies and killer t cells that destroy infected cells

if t cells do not work, cannot effectively fight off infections

-HIV doesnt kill people but secondary infections do: pneumonia

SARS (severe acute respiratory syndrome)

-caused by SARS coronavirus

-outbreak in 2002-2003 resulting in 774 deaths in 37 countries and 8000 cases

-not seen since 2004

-flu like symptoms: fever above 100.4 was the only symptom all patients had in common

-chest x rays show atypical pneumonia, normally patchy infiltrates

covid 19

-a contagious respiratory disease that was first detected in China in December 2019 has spread worldwide
-the 2019 new coronavirus has been named SARS-COV2
-we learned that its easily transmissible and can spread easily from person to person even before a person develops symptoms
-carried by respiratory droplets when we talk, sneeze, and cough


when droplets land on surface we can pick them up with our hands and transfer them to our eyes, mouth, or nose
-hand hygiene is important
-respiratory secretions are also infectious

prions

A type of protein that can trigger normal proteins in the brain to fold abnormally

infectious proteins
-no genetic material
-major impact on animals and humans, sometimes spread to humans by infected meat protects
-COOKING DOES NOT EFFECT

Prion Theory:
-theory that proteins are able to come into contact with another protein and transform it into an infective prion protein
-change the protein and will make proteins grow abnormally and fold
-affect nervous tissue
-creates spongy areas in slide of brain tissue
-think of it like zombie disease

Viroids

infectious RNA
-no proteins

Types of prions found in animals

1. Bovine Spongiform Encephalopathy (BSE): mad cow disease

2. Chronic Wasting Disease (CWD)- disease of deer

3. Scrapie: impacts sheep

4. Transmissible Mink Encephalopathy: infects mink

5. Feline Spongiform Encephalopathy: felines

6. Ungulate Spongiform Encephalopathy: ungulate

BSE

bovine spongiform encephalopathy

-chronic degenerative disease affecting the CNS of cattle

-mad cow disease

-prion

-if eaten: can spread to us

-huge spreader of mad cow: feeding cows ground up parts of the cows own relatives: happened especially in Europe

-catal would start stumbling around and have trouble standing up

Chronic Wasting Disease (CWD)

deer
-big problems with putting deers in pens: putting a lot of deer in close contact, as well as shipping
-brings infective populations in contact with noninfected

stumbling and walking in circiles
-potential of spreading to humans

types of prions in humans

•Creutzfeldt-Jakob Disease (CJD)

•Variant Creutzfeldt-Jakob Disease (vCJD)

•Gertmann-Straussler-Scheinker Syndrome

•Fatal Familial Insomnia

•Kuru

CJD

Creutzfeldt-Jakob disease
-caused by abnormal proteins folding

those effected
-lose ability to think and move properly
-lose memory
-always fatal
-notice stumbling in animals
-brain will start to shrink

Forms
-sporadic: dont know cause, people over 50, ataxia, dementia, short course

-familial: inherited, younger age, longer coarse

-iatrogenic: through surgery: not age dependent, same as sporadic

-variant: exposure to BSE, younger age of onset, longer duration, daisy like plaques

no cure

for any prion disease
-always 100 percent fatal

BSE

in catal and showing up as variant CJD in humans

kuru

in humans
-spread amongst cannibals

-first identified by Robert and Louise Glasse in 50s
-worked with Flore tribe: 1 percent were afflicted: mostly women, few adults males

headache, joint pain, 6-12 weeks later difficulty walking then death usually within 12 months
-recent 1910-1920
-suggested endocannibalism
-not well accepted among medical community

women and children infected because brains and nervous tissue were reserved for them

Endocannibalism

the eating of human flesh from members of one's own society

viroids

-unlike viruses, only made of gentic material
-no protein coat
-only a little larger than prions
-mainly in plants
-spread through contact between plants
-example: potato spindle viroid

will be very misformed