Infectious disease Flashcards
what is the definition of disease?
any condition that interferes with how an organism functions
what is the definition of infectious ?
if caused by a pathogen and can be transmitted from one host to another
what is a pathogen ?
a disease causing particle
what are the types of pathogens?
-viral
-bacterial
-fungal
-protist
what are zoonotic diseases ?
infectious disease that can be passed from one vertebrate group to another
what are the three phases of an infection ?
- infection
- incubation period
- symptoms of disease
what are the characteristics of bacteria?
-earliest life form
-unicellular or colonies
-prokaryotes - no membrane
-ribosomes and circular DNA chromosomes
-plasmids
-cell wall-murein
asexual reproduction
how does bacteria cause disease?
- toxin that disrupts cell functioning or kills cell
- damage to the host tissue
- may induce and immune response so strong that it damages the host cells
what is the invasion method of tuberculosis ?
enters through the mucous membranes
what is the transmission method of tuberculosis ?
direct
-droplets and zoonose
indirect
-droplet reservoirs
what is the impact of tuberculosis ?
-coughing
-chest pain
-coughing up blood
-fever
-night sweats
-headaches
what is the life-cycle of tuberculosis (MTB)?
- MTB enters the lungs
- MTB ingested by macrophages (WBC)
- MTB multiply in WBC
- WBC burst releasing MTB to enter more WBC
- tubercle form in the lung
- tubercle ruptures into the lung and MTB is coughed out
what is the invasion method of crown gall disease ?
attracted to open wound by sugars being released, flagellated bacteria enters root through open wound, attaches to cell plasmid DNA is inserted into plant DNA
what is the transmission method of crown gall disease ?
indirect
-contact from soil reservoir or fomite
what is the impact of crown gall disease ?
-gall (tumors) on the root and stem
-galls prevent the movement of water and nutrients
-stunt growth
-changes gene expression and hormone production
what is the treatment method of tuberculosis?
antibiotic
vaccination
what is the management strategies of crown gall disease ?
-disinfecting tools
-heat treat infected soil
-remove and burn infected plants
what is the life-cycle of crown gall disease?
- bacteria enters roots from soil via wounds
- bacteria transfer some DNA to plants cell
- Bacteria reproduce in roots forming galls
- gall detached and release flagellated bacteria into the soil
what are antibiotics used for?
treating bacterial infections
what is bactericidal ?
kills cells
what is bacteriostatic?
inhibits the growth of the bacteria
how do antibiotics work?
- rupturing cell membrane
- stop synthesis of new cell wall during cell division
- inhibit enzymes essential for transcription and translation
- inhibit enzymes essential for metabolism
what are the characteristics of fungi?
Eukaryotes
membrane bound organelles
cell wall of chitin
reproduce via spores
unicellular or multicellular
what do fungi effect?
mostly external
irritation of the skin
what is the invasion method of chytridiomyeosis?
enters skin cells
what is the transmission method of chytridiomyeosis?
indirect
- water Bourne
direct
-contact with infected individuals
what is the impact on the host of chytridiomyeosis?
-thickening of the skin affects gas exchange
-excessive skin shedding
-sitting out in the open
-lethargy
-legs spread out
-death
what is the life-cycle of chytridiomyeosis?
- single celled flagellated zoospores enters the skin cells
- thallus (body of the fungus) forms
- new zoospores are produced in the thallus as it matures asexually
- zoospores released into water where they swim to find a new host
what are the characteristics of viruses ?
-protein coats surrounding either DNA or RNA
- vaccination is the most effective prevention
how do viruses work ?
- virus injects nucleic acid into host cell
- cell creates more virus particles
- cell splits open releasing viruses which infect more cell
what is the invasion method of a virus ?
through a physical breach
direct inoculated
direct infection (mucous membrane )
what is the life-cycle of a virus?
- viral entry
- viral replication
- viral shedding
what is viral entry ?
- attaches to host cell membrane
- a hole forms in the membrane
- the virus particle or its genetic content are released into the host cell
what is viral replication ?
- virus takes control of the host cells replication mechanism
- begins to make copies of itself
- new viruses are assembled
what is viral shedding ?
cell ruptures virus progeny are released to find new host cell
what is viral latency ?
virus may remain dormant until conditions are favourable