ID: 1-10 Flashcards
Infectious Diseases
(communicable diseases) illnesses caused by pathogens that can spread from organism to organism
epidemiology
the branch of medicine which deals with the incidence, distribution and possible control of diseases and other factors relating to health
virulence
the ability of an agent of infection to produce disease. The virulence of a microorganism is a measure of the severity of the disease it causes
contagious
easily transmitted from one host to another
what does an infectious disease require to spread
an infectious agent (pathogen), a host and a mode of transmission (vector)
zoonoses
describes the example of the spread of a disease from animals to humans (eg. rabies)
pathogen
anything that is able to cause a disease within a host (eg. bacteria and viruses)
host
an organism that a pathogen infects
mode of transmission
how a disease is spread from host to host
indirect contact transmission
airborne disease, food and water, vectors (anthropods, mammals and birds) contaminated articles, non-sterile procedures, across the placenta
airborne
inhalation of bacterial spores or droplets containing pathogens from coughing, sneezing or speaking
food and water transmission
eating or drinking contaminated food (caused by a lack of proper sewage treatment of water supplies or poor hygiene)
vector transmission
transmission through other organisms that carry the pathogen from one person to another or from an infected animal to another person
across the placenta transmission
pathogens move across the placenta from the mother to enter the foetal circulation
pattern of infection
pathogen enters the body, incubation period, symptoms, crisis, convalescence
infection
detrimental colonisation of a host organism by a foreign species
variables involved in becoming infected
route of entry, virulence of the organism, quantity of the initial inoculant, immune status of host
fomite
any inanimate object that when contaminated can transfer disease to a new host
initiation
existence of a reservoir or source of infection
source
the person, animal, object or substance from which an infectious agent passes to the host
reservoir
any person, animal, anthropod, plant, soil or substance which an infectious agent lives and multiplies (on which it depends primarily for survival and where it reproduces itself in such a manner that it can be transmitted to a host)
endemic disease
a disease condition that is normally found in a certain percentage of a population
epidemic disease
a disease condition present in a greater than usual percentage of a specific population
pandemic disease
an epidemic affecting a large geographical area often on a global scale
reverse zoonoses
when humans infect animals
cross-species transmission
the phenomenon transfer of viral infection from one species, usually a similar species, to another. one species transfers to another which in turn transfers to humans
antigenic shift
the genetic change that allows a flu strain to jump from one animal species to another
toxigenesis
ability to produce toxins
microbial toxins
toxins produced by micro-organisms, including bacteria and fungi
exotoxins
are immediately released into the surrounding environment, they are generated and actively secreted and act at a site removed from bacterial growth
endotoxins
are not released into the surrounding environment until the bacteria is killed by the immune system, they remain a part of the bacteria
tinea
refers to a skin infection from a dermatophyte (ring worm) fungus
protozoans
diverse group of mostly mobile unicellular, heterotrophic eukaryotic organisms that were in the protista kingdom
apicomplexans
protist parasites of animals. most have life cycle stages that help them to survive in different environments
types of protists
protozoans, apicomplexans, amoebozoans, diplomonads
phage
a virus that infects bacteria
virion
the complete, infective form of a virus outside a host cell. have a core of RNA and a capsid
antibiotics
chemicals that kill or inhibit the growth of bacteria
capsule
aid disease progression, can protect the bacteria against hosts immune system
fibriae
hair-like appendages that help the bacteria stick to their substrate or to one another
plasmid
ring of DNA that may have antibiotic resistance genes
endospores
a dormant, tough, non-reproductive structure to ensure the survival of a bacterium through periods of environmental stress
conjugation
when two bacteria cells are temporarily joined and commonly transfer DNA
Gram staining
distinguishes bacteria based on the properties of their cell wall
mycosis
fungal infection
sporangia
fruiting body of fungi
plant rust
plant disease caused by a pathogenic fungi Puccinales
chytridiomycosis
caused by chytrid fungus, affects amphibians
fungi
heterotrophic, cell wall, eukaryotic, uni or multicellular
bacteria
prokaryotes, single strand of DNA, cell wall
capsid
protein coat that surrounds a virus
features of a virus
have DNA or RNA and a capsid, can be crystallised, lack metabolic enzymes, host range
host range
limited number of host species that each particular virus can infect
vial diseases
measles, mumps, chickenpox, AIDS
virus
very small infectious particles with either a DNA or RNA genome surrounded by a protein coat (capsid)
Tuberculosis
a disease caused by infection with the bacteria M. tuberculosis
how is tuberculosis transmitted
when a person with TB in the lungs or throat coughing, sneezes or speaks, sending the bacteria into the air (airborne)
tetanus
infection characterised by muscle spasms
chytridiomycosis
amphibian chytrid fungus disease
how is chytridiomycosis transmitted
waterbourne zoospores spread from place to place in water or wet materials, or found in the skin of infected individuals
transmission of phytophthora dieback
spores easily spread through stormwater and drainage . water, or human activities
zoospore
has a flagella
factors that increase spread of disease
fast life-cycle, exponential growth, high density, high population, direct contact, travel of people/goods, drug resistance, mutation, climate, social unrest/civil wars, lack of health care
attack rate
proportional number of cases developing in the population that was exposed to thee infectious agent
communicable disease
infectious disease that can be transmitted from one host to another
herd-immunity
a phenomenon that occurs when a critical concentration of immune hosts prevents the spread of an infectious agent
incidence
the number of new cases of a disease in a population at risk during a specific period of time
index case
the first identified case of a disease in an outbreak or epidemic
outbreak
a cluster of cases occurring during a brief time interval and affecting a specific population
conditions needed for bacterial growth
plenty of food, suitable temp and pH, no build-up of poisonous waste products, oxygen is needed
bacterial reproduction
asexual - binary fission
phases of bacteria growth
1 - lag phase, 2 - log phase, 3 - stationary phase, 4 - death phase
antimicrobial resistance
occurs when a microbe evolves to become more or fully resistant to antimicrobials which could previously treat it
Methicillin-resistant Staphylococcus Aureus (MRSA)
a bacteria that causes infections in different parts of the body
antigenic variation (drift)
when an influenza virus creates mutated copies that promote drug resistance
antigenic shift
an abrupt, major change in the human influenza A virus, by which two or more different types combine to form a virus that is radically different from the ancestor strains
quarantine
is used to separate and restrict the movement of persons; it is a ‘state of enforced isolation’
border controls
measures taken by acountryto monitor or regulate itsborders
biosecurity
A set of preventive measures designed to reduce the risk of transmission ofinfectious diseasesin crops and livestock, quarantined pests,invasive alien species, and living modified organisms
immunisation
when your immune system is stimulated, so that it can recognise a particular disease and protect you from future infections from that disease
chain of infection
name of the model that describes the way infections spread through a population. agent - reservoir - portal of exit - means of transport - portal of entry - susceptible host
antibiotics
a type ofantimicrobialdrugused in thetreatmentandpreventionofbacterial infections
bactericidal antibiotics
kill bacterial pathogens by targeting their outer cell walls
bacteriostatic antibiotics
do not kill the bacteria but inhibit their growth and reproduction by targeting their ribosomes, which interferes with their protein synthesis
higher temperatures will affect? (for mosquito vector)
geographical range, breeding patterns, feeding patterns
increase in rainfall and humidity will? (for mosquito vector)
increase mosquito breeding habitats, increase moquito survival
decrease in rainfall and humidity will? (for mosquito vector)
create habitat by rivers drying into pools, increase container breeding
increase in sea level will? (for mosquito vector)
create new water habitats for breeding
