proteinaceous infectious particles that cause disease
what are TSEs?
family of rare progressive neurodegenerative disorders that affect humans and animals
what are characteristics of TSEs?
long incubation periods
cause spongiform changes associated with neuronal loss
rapidly progressive and always fatal
what are 2 prion human diseases?
creutzfeld jakob disease and kuru
what are 2 prion animal diseases?
scrapie in sheep and mad cow disease in cattle
what are the ways that humans can acquire a prion disease?
protein misfolding that occurs spontaneously
eating meat that is contaminated with brain material with misfolded proteins
what is the size of viruses?
10-400nm
what type of entities are viruses?
acellular
what are viruses enclosed by?
a protein coat
what type of genetic material do viruses have?
DNA or RNA
what is a VIRION?
a complete viral particle of nucleic acid and protein coat
what is human virolution?
about 10% of the human genome is comprised of genetic information from viruses
what are retrotransposons?
pieces of DNA(virus like) that make copies of themselves
what is the process of endogenization
viral genetic information can be included in the genome when retroviruses incorporates into the host's germ line
how are viruses classified?
capsid symmetry
nucleic acid
genetic relatedness
what are the ways that viruses can be transmitted?
airborne
arthropod borne
direct contact
food and water borne
what are the airborne viral diseases?
chickenpox/shingles
measles
mumps
rubella
smallpox
influenza
what are the characteristics of smallpox (variola) virus
large brick shaped complex virus
linear dsDNA
what are characteristics of influenza?
negative sense RNA
disease of the respiratory system
high frequency of genetic changes
what is the incubation period for influenza?
1-2 days
how is the influenza subtypes classified?
based on hemagglutinin (HA) and neuraminidase (NA) membrane surface glycoproteins
how does antigenic shift happen in flu virus?
due to reassortment of genomes when 2 different strains of flue viruses from humans and animals infect the same cell and are incorporated into a single new capsid
how does antigenic drift happen in flu virus?
due to accumulation of mutaions in a strain within a geographic area
often the result of point mutations that lead to amino acid substitutions
what are characteristics of HIV?
positive sense ssRNA virus
enveloped retrovirus: RNA genome is copied into DNA and integrated into the host cell genome
mutates rapidly
how does HIV proliferate?
the retrovirus undergoes reverse transcription to generate DNA from RNA. The DNA is then integrated into the host genome as a provirus
what is a provirus?
virus genome that is integrated into the DNA of a host cell