Infectious agents Flashcards
what is a virus?
- obligate intracellular parasites
- sub-microscopic infectious agents
- can infect all lifeforms
what are the two types of antiviral drugs?
- viristatic
- viricidal
what are the four different shapes of virus?
- helical
- polyhedral
- complex
- spherical
what are the two components of a virus?
- genome
- capsid
how does a virus replicate?
- virus attaches to a cell with a compatible receptor
- virus is taken into cell by endocytosis or fusing of the envelope
- replicated for new virus cells
- released from the cell, intact or destroyed
what are the two types of transmission?
- direct
- indirect
what is the incubation period?
- period of time between initial infection and development of symptoms
- caused by the time it takes for the virus to reach the cells, invade and replicate
what are some treatment for viral infections?
- isolation
- supportive care
- vaccination
- antivirals
- interferon
what is bacteria?
- organism often consisting of one biological cells
what are the three types of prokaryotes?
- bacilli - cylindrical
- cocci - spherical
- spirochaetes - spiral
what are some components of a bacteria?
- fimbrae
- flagellae
- bacterial chromosome
- plasmid
- ribosomes
- cytoplasm
- capsule
- cell wall
- cell membrane
what colour does gram positive bacteria stain?
purple
what colour does gram negative bacteria stain?
pink
what are endospores?
- dormant forms of the bacteria
- formed to survive inhospitable conditions
what are the conditions for bacterial growth?
- supply of nutrients
- correct temperature
- correct pH
- water
- correct gaseous environment
what is an obligate aerobe?
need oxygen for growth
what is an obligate anaerobe?
need absense of oxygen for growth
what is a facultative anaerobe?
grow with oxygen, but do not need it to function
what is a microaerophile?
grow best with a concentration of oxygen that is lower than atmosphoric air
what is binary fission?
- reproduce asexually by dividng into two daughter cells
what is conjugation?
passage of DNA from one genetic cell to another
what is an exotoxin?
proteins secreted by gram-positive bacteria during their metabolism which are released into the surrounding environment
what is an endotoxin?
part of gram-negative cell envelope
what are some characteristics of moulds?
- multicellular
- direct or indirect transmission
what are some characteristics of yeasts?
- unicellular
- can appear as ulcers or white growth in mouth
what are prions?
- very small protein particles that may or may not be infections
- causes infections to brain or nervous system
what are protozoa?
- single celled eukaryotes
- unicellular
what is coccidia?
causes watery diarrhoea and can be life threatening
what is eimeria?
parasites that can cause infection in rabbits’ liver/intestines
what is giardia?
- a binucleated intestinal flagellate
- zoonotic
- water borne spread
