Detecting Viruses, Viruses in Other Kingdoms, and Prions Flashcards
How do we study and detect animal viruses?
cell cultures
some types of host cells can be grown in the lab using media
How do we study and detect animal viruses?
primary cell lines
used for viral growth, die after only a few generations
How do we study and detect animal viruses?
diploid cell lines
developed from human embryos, can be maintained for 100s of generations
How do we study and detect animal viruses?
continuous (immortal) cells lines
transformed (cancerous) cells that can be maintained indefinitely
How do we detect animal viruses?
serology
detection of the presence of antibodies specific to a pathogen of interest in a patient’s serum
How do we detect animal viruses?
Enzyme-Linked Immunosorbent Assay (ELISA)
detection of a pathogen using an indicator antibody that is linked to an enzyme that induces a color change in the presence of its substrate
How do we detect animal viruses?
Indirect ELISA
- purified pathogen antigens are used to detect the presence of antibodies specific to the pathogen of interest
- the indicator antibody binds to any human antibody
How do we detect animal viruses?
Direct ELISA
- purified antibodies specific to the pathogen are used to detect antigens in the patient serum
- indicator antibody is specific to the antigen of interest
How do we detect animal viruses?
Lateral flow/Rapid antigen assays
detection of the presence of antigens specific to a pathogen using labeled and unlabeled antiviral antibodies
How do we detect animal viruses?
Polymerase chain reaction (PCR)
amplification of target DNA using complimentary primers
How do we detect animal viruses?
multiplex PCR
multiple primers are used in the same reaction to determine the casual agent associated with symptoms that many pathogens cause
How do we detect animal viruses?
real-time PCR
relies on fluorochromes that bind to amplified DNA and a machine that detects fluorescence, no longer need to run a gel
How do we detect animal viruses?
reverse transcriptase PCR
used for RNA viruses, RT enzyme is used to first make cDNA which is then amplified using typical PCR cycle
influenza virus
- antisense (-) RNA genome comprised of 8 segments
- enveloped
- HA and NA spikes are often used to designate type
antigenic drift
accumulation of point mutations resulting from error-prone RdRp making mistakes during genome replication
antigenic shift
reassortment of influenza genomes in a ‘mixing vessel’ due to coinfection of two different flu strains in the same cell
prions
infectious protein that induces progressive degeneration of the brain and eventual death
PrPc (cellular prion protein)
protein localized in neuron plasma membrane, tied to brain development and function
PrPsc (scrapie-associated cellular prion protein)
has the same amino acid sequence as PrPc byt has been irreversibly misfolded and cause PrPc but has been irreversibly misfolded and can cause PrPc to misfold following direct contact
History of Prion Diseases
scrapie
prion caused disease first described in sheep
- intense itching caused sheep to scrape against fences
History of Prion Diseases
Variant Creutzfeldt-Jakob disease
first observed by Hans Gerhard Creutzfeldt and Alfons Maria Jaokb in humans in 1920
- transmitted by ingesting infected cows (bovine TSE, mad cow disease)
History of Prion Diseases
Kuru
described in 1959 amongst the Fore tribe in Papua New Guinea
chronic wasting disease
affects deer, elk, reindeer, sika deer, moose
- prolonged incubation period of 1 year
- symptoms = weight loss, stumbling, listlessness
- not treatments/cure; always fatal after symptoms
- transmitted through feces, saliva, blood, or urine
- shown to persist in soil, water and food
