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45 Cards in this Set
- Front
- Back
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What is a prion? |
They are proteinaceous infectious agents |
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Explain the process of how you get transmissible spongiform encephalopathies |
We have structural and regulatory components in our brain made up of proteins called prion proteins that function as alpha helix (the are not prions) Prions are abnormal proteins that are configured in to beta pleated sheets. The prion links to the alpha help prion protein and reconfigures it into a waffle iron beta pleated sheet and it stops its functioning. Once you get enough of these converged from alpha helix into beta pleated sheets you start getting serious neurological diseases and once alpha helix prion proteins stop working you get transmissible spongiform ecephalopathies |
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What are transmissible spongiform encephalopathies? |
they are infectious non living proteins that you can catch from other species. Tough, insoluble, and cause vacuolation of neurons |
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What are the four prion proteins? What do they do? |
PrPc - a normal suface component of neutrons and glial cells (alpha helix) PrPc - highly conserved between species PrPsc - is infectious form of prion (beta pleated sheet) PrPsc - is very resistant to inactivation |
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What are examples of Human transmissible spongiform encephalopathies? |
1. Kuru (extinct) - catabolism (eating human flesh) 2. Cruetzfeldt-Jacob disease 3. Gerstmann Straussler Schnieker syndrome 4. Fatal Familial Insomnia (psychotic behaviour) |
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What are examples of animal transmissible spongiform encephalopathies? |
1. Scrapie (sheep) - sheep scrap against fence 2. Bovine (cattle), feline (cats), and ungulate (mammals) spongiform encephalopathies 3. Chronic wasting disease (deer and elk) - especially bad in Michigan 4. Transmissible mink encephalopathy |
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What happens in Kuru? How do you get it? |
Infectious and it causes spasticity and ataxia (loss of full control of body movements) Extinct |
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What happens in Creutzfeldt Jacobs Disease? How do you get it? |
it is infectious and/or inherited It causes dementia, spasticity (hard time moving), seizures |
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What happens in Gertsmann Straussler Scheinker syndrome? How do you get it? |
it is inherited It causes ataxia (loss of movement) |
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What happens in fatal familial insomnia? How do you get it? |
Inherited Causes ataxia (loss of body movements) and insomnia (loss of sleep) |
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What are some common characteristics of Retroviruses? |
ssRNA, positive polarity and use DNA intermediate |
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Explain how a virus gets a host cells to replicate its virus |
Virus will bring viral RNA dependant DNA polymerase (reverse transcriptase) to synthesize dsDNA Then the dsDNA will integrate into the host genome Then the viral dna uses host RNA polymerase to firstly synthesize mRNA to manufacture viral proteins and secondly synthesize reverse transcriptase to incorporate into virions. |
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What are two examples of Retroviruses?
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1. Oncoviruses 2.Lentiviruses (prototype lentivirus is visnavirus in sheep) - is in the HIV family |
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Where can HIV like viruses occur? |
They can occur in cattle, lions, sheep, goats and simians (monkeys) - this causes simian immunodeficiency virus |
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Where was SIV first isolated from? |
Japanese Macaques (old monkeys) |
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SIV is mostly.... |
it is mostly benign but can cause disease in equines (horses) and house cats |
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what does SIVgm, SIVcpz, SIVsm mean? and what two are close to HIV 1 and HIV 2 |
SIVgm =simian immunodeficiency virus in green monkeys SIVcpz = simian immunodeficiency virus in chimpanzees - close to HIV 1 SIVsm = simian immunodeficiency virus in sooty mangabey - close to HIV 2 |
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Where was HIV-0 discovered in? |
it was discovered in 1990 in Cameroon and Gabon |
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When was HIV 1 discovered and what are the two variants? Explain them |
HIV 1 was discovered in 1983 and has a rapid global spread the two variants are HIV 1A - spread is heterosexually HIV 1B - spread via anal intercourse, the dominant strain is in Europe and North America |
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How is HIV 2 spread, lethality? Location? |
HIV 2 is spread heterosexually, low lethality, confined mostly to West Africa |
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Explain the origin of Human HIV |
Started in the 1880s when Europe separated Africa into colonies This causes turmoil so they migrated from West Africa to East Africa By the end of World War 1 German colonies redistributed among victors and HIV 1A established in Lake Victoria Area - cachexia resulted Then some germans stayed in Cameroon and when WW2 began there land was confiscated and 300 Germans repatriatiated to Germany by Ship via Danzig in 1939 and they were carrying HIV 1B |
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How did HIV spread? |
There were 81 cases of Pneumocystis caring pneumonia in children at the Limberg Midwife Training School - outbreak Global sexual spread Spread to Haiti via vacationing Americans Canadian Flight Attendant Geatan Dugas spread HIV to many North American Cities |
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What cities had Aid like cases? |
Danzig 1939, Switzerland 1941, Austria 1942, Scandinavia late 1940s |
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How did they discover HIV? |
epidemiologist from CDC noticed increasing requests for pentamidine to treat PCP (pneumocystis carinii pneumonia) which was a previously rare opportunistic pathogen. - Many of these patients were from Dr Michael Gottleib at UCLA, Dr. Gottleibs patients fit not fit the usualy description of immunosuppressed profile: they were instead young homosexual males Then in New York and San Francisco there were cases of Kaposis Sarcoma noted in young homosexual males -- They then names it GRID |
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Explain the naming of HIV |
First when CDC and Dr. Gottleib and the many cases of Kaposis sarcoma came to light they names it GRID (gay related immune deficiency) then they renamed it AIDS However the first name of HIV was HTLV -3 (human t leukocyte variant 3) then it was renamed HIV |
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where is HIV pandemic predominant? |
Africa |
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How long do you need to treat aids for? |
60 years in order to try to fully get rid of the virus - long treatment course |
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How long is the incubation period for the HIV virus? |
10 years |
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What happens soon after you have been infected with HIV? |
Soon after infection there is a flu like illness which is associated with seroconversion - often goes unnoticed |
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After a period of years having this infection of HIV what happens? |
the disease causes deletion of CD4 cells resulting in opportunistic infections and dementia secondary to direct infection of CNS Immunosuppression correlated inversely to the CD4 count |
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What is "AIDS" |
Is noe reserved as the end stage of the disease, CD4 <200 (normal is 500) - it causes the highest mortality of any infectious disease |
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What is the average time without therapy from infection to an AIDS developing illness? |
For HIV 1- it is 10 years For HIV 2 - longer |
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What are the three things that can happen when you get infected? |
you can be a rapid Progressor - get AIDS within 2-3 years after infection Non progressor - Catch it but don't get sick HIV resistant people - HIV negative regardless of how many times you have been exposed to it |
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What has vastly increased the time to the onset of AIDS in developed Countries ? |
HAART (highly active antiretroviral therapy) |
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What is normal immunity? |
CD4 count >500/mm3 |
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What might you have if your CD4 count is 200-499/mm3? |
strep pneumonia, pulmonary tuberculosis, kaposis sarcoma, shingles, mucutaneous candida (vaginitis, thrush, yeast infection), oral hairy leukoplakia |
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What might you have if your CD4 count is <200/mm3 |
pneumocytosis jirovecii pneumonia (aka pnemocytosis canine pneumonia), chronic herpes simplex, extra pulmonary TB, toxoplasmosis, progressive multi focal leukoencephalopathy |
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What might you have if your CD4 counts are <50/mm3 |
Reactivated cytomegalovirus and Mycobacterium avid complex infection |
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How is HIV transmitted? |
Heterosexual activity, needle sharing, iv drug users, hemophilia reaction, blood transfusions, vertical transmission |
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What decreased seroconversion rate? |
PEP -post exposure prophylaxis (combivir and Kaletra) |
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How can you HIV? |
Antibody based: ELISA - looks for whole virus or synthetic HIV peptides Viral component Based: PCR of viral RNA or pro virus DNA |
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What are a few things to know about treating HIV? |
HIV mutates frequently and it is very drug resistant therefore you need to hit hard and hit early. |
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What is HAART? |
high active antiretro therapy -best to start when the CD4 count is >500/mm3 Expensive |
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Is there a vaccine for HIV? |
not yet there ahem been many failed attempts however there is one vaccine that is looking promising |
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