week 4 part 1 Flashcards
pathogen
a micro-organism that can cause
infection
a pathogen has reproduced in the hosts body
pathogenicity
the capability of a microbe to cause disease
virulence
the degree of pathogenicity
infectious disease are caused by
pathogens (including bacteria, viruses, fungi , protozoa
bacteria
- contain DNA, ribosomes and RNA
- can survive and divide without a living host
- name is based on there shape
- prokaryotic single cell organsim have a rigid cell wall
viruses
- small intracellular parasite
- a protein coats with a core that contains DNA or RNA
- REQUIRES a living host to relipucate and spread through the body
virion
is a virus when it lives outside of the host cell
steps of viral infection
- virus
- attachment to host cell and penetration
- uncoating viral DNA or RNA enters host cell nucleus and takes control of host cell DNA
- host cell synthesizes viral component
- assemble new viruses
- releases of many new virus ands host cells
characertisic of Covid 19
contains a spike protein coat
RNA core
how can viruses intrefear with Cancer
some viruses may alter the host cell chromosomes– malignant cells develop
E.g. certain strains of HPV Increased risk of cervical cancer
how can you use a virus to treat cancers
Oncolytic Virus Therapy
* Engineer a known virion so that it targets and infects tumor cells and promotes their
destruction
(+) insert immune stimulating gene
(-) remove disease causing genes (selective targeting of tumors)
fungi
- found everywhere in the environment
- eukaryotic single cells or chain of cells
can produce spores that become air-bone
only certain fungi are pathogenic
protozoa
- parasites( the pathogenic protozoa)
- complex eukararyotic organism
- uni cellular motile
prions
- don’t not contain any genetic material
- infection is transmitted by protein particles that are able to self propagate
(Induces proteins in the brain to misfold nonfunctional neurodegeneration)
reservoir
the source carrying the infection
how an infection enters your system
- reservoir (human, animal…)
-portal of exit (nasal mucosa)
-mode of transmission(insect bite , nasal droplets, semen)
-portal of entry (nasal mucosa, skin punture, skin abrasion)
-susceptible victim (unimmunzied)
the bodies defence against a host
-first line -skin and mucous membrane, body secretions
-* Interferons are proteins made by human host cells
* Increase cell resistance to viral invasion, interfere with viral replication, stimulate the immune
response
incubation period
the period between exposure to an infection and the appearance of the first symptoms.
prodromal period
the period after incubation and before the characteristic symptoms of infection occur
acute period
having the short duration of the infection being present
local
pathogen confined to a specific location in the host
focal
pathogen spreads to other tissues
Systemic
infection spreads through circulatory system
* Bacteremia – bacteria in the blood
* Toxemia – toxins in the blood
* Viremia – viruses in the blood
Septicemia – multiplication of pathogens in the blood, causes sepsis
acute infection
rapid onset, more intense symptoms, short lived
chronic infection
persistent, often less sever symptoms
local signs of inflammation
pain, swelling, redness warmth
If bacterial—purulent exudate
* If viral—serous, clear exudate
