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202 terms

Types of infectious agents

Lecture 001 I&D
STUDY
PLAY
Inanimate proteins able to cause pathology
What are prions?
It is inanimate - only a protein
It has no DNA
Why is a prion unable to replicate on its own? (2)
They can not replicate on their own (are inanimate)
Why can prions not be cultured?
Host derived glycoproteins (e.g. Cellular prion protein, PrPc)
What are prions derived from?
PrPc - Cellular protein prion
Give an example of a prion.
The abnormal form of PrPc - PrPsc
What is the infectious agent of a prion?
The abnormal, infectious form of PrPc
What is PrPsc?
Enzymes
Heat
Radiation
Disinfection
What is PrPsc resistant to? (4)
Phenol
NaOH
Hyperchlorite
What is PrPsc susceptible to? (3)
<100nm
What is the average size of PrPsc?
Induces the conversion of PrPc on a cell to PrPsc (acts as a template)
Cell replicates and precipitates more PrPsc
How does PrPsc replicate?
It induces a change in a cell protein to cause the cell to make more PrPsc rather than using DNA
Why is PrPsc replication non conventional?
Transmissible spongiform encephalopathies
Bovine spongiform encephalopathis - Mad cow
Ceutzfeldt-Jakob disease
What diseases does PrPsc cause? (3)
Brain tissue
Neural tissue
What main tissue groups does PrPsc affect? (2)
Tiny holes appear in cortex - causes mental and physical abilities to deteriorate
What is transmissible spongiform encephalopathy?
Degenerative neurological disorder
What is Creutzfeldt-Jakob disease?
Transmissible spongiform encephalopathy
What group of diseases is Creutzfelt Jakob disease a part of?
Illness that causes gradual deterioration of organs and cell
Leads to loss of function
What does degenerative mean?
Infectious agent made up of nucleic acid and a protein coat which is too small to be seen using a light microscope
What are viruses?
Protein
Nucleic acid
What types of molecule make up a virus? (2)
DNA or RNA in centre
Nucleic acid surrounded by protein coat
(Sometimes protein coat is surrounded by lipid envelope)
What are the components of a virus? (3)
The capsid
What is the protein coat of a virus called?
The protein coat that surrounds the nucleic acid of a virus
What is a capsid?
Nucleic acid type (RNA or DNA)
Single or double stranded
Presence of an envelope
Symmetry
What is the process of classification of viruses? (4)
Parvovirus
Give an example of a single stranded DNA virus.
Destroys RBC
How does the parvovirus cause pathology?
Severe diarrhoea
What is the main symptom of a child infected with rotavirus?
Faeco-oral route
How is rotavirus transmitted?
Herpes
Hep B
Adenovirus
Papilloma virus
Give an example of a double stranded DNA virus? (4)
Herpes simplex (HSV)
Varicella zoster (VZV)
Cytomegalovirus (CMV)
Epstein Barr virus (EBV)
Human Herpes Virus (HHV)
What are the 5 main types of herpes virus?
Genital herpes
What does type 2 herpes simplex virus cause?
Type 2 herpes simplex virus
What causes genital herpes?
Type 1 herpes simplex virus
What causes cold sores?
Cold sores
What does type 1 herpes simplex virus cause?
Chicken pox
Shingles
What does varicella zoster virus cause? (2)
Varicella zoster virus
What causes chickenpox?
Varicella zoster virus
What causes shingles?
Cold-like symptoms
What does cytomegalovirus cause in immunocompetent people?
Oesophagitis
Gastroenteritis
Retinitis
Pneumonia
What does cytomegalovirus cause in immunocompromised patients? (4)
Infection of the oesophagus
What is oesophagitis?
Infections of the stomach or intestines
What is gastroenteritis?
Infection of the eye
What is retinitis?
Infection of the lungs
What is pneumonia?
Infectious mononucleosis
What does the Epstein Barr virus cause?
Abnormally high number of mononuclear white blood cells in the blood
What is mononucleosis?
Fever
Malaise
Sore throat
Lymphadenopathy
Atypical lymphocytes
What are the symptoms of infectious mononucleosis? (5)
Infected blood
Hypodermic needles
Tattooing needles
Unprotected sex
How is Hepatitis B transmitted? (4)
Headache
Fever
Chills
General weakness
Jaundice (after 1-6month incubation period
What are the symptoms of a hep B infection? (5)
Interferon - and other antivirals
What is the main treatment of hepatitis B?
Infections of upper respiratory tract
What does adenovirus cause?
Rota virus
Give an example of a double stranded RNA virus.
Picorna virus
Rubella virus
Hep C virus
SARS
Influenza
Measles virus
Mumps virus
Give an example of a single stranded RNA virus. (7)
Cox sackie viruses
Polio viruses
Rhino viruses
What are some of the subtypes of picornaviruses? (3)
Respiratory diseases
Neurological diseases
Muscular diseases
What do coxsackie viruses cause in humans? (3)
In the GI tract
Where do cox sackie viruses multiply?
Poliomyelitis
What does polio virus cause?
Paralysis
Because it affect the CNS
What does poliomyelitis cause? ...Why?
German measles
What does the rubella virus cause?
Enlarged lymph nodes
Headache
Sorethroat
Slight fever
(Later) Rash with pink spots
What are the symptoms of german measles? (5)
Fatigue
Sore bones
Dryness of eyes
What are the symptoms of an infection with Hep C virus? (3)
Interferon
What is used to treat hepatitis C infections?
Severe acute respiratory syndrome
What does SARS stand for?
The respiratory system
What system does the influenza virus affect?
Coughing
Sneezing
How is influenza transmitted? (2)
Headache
Fever
Loss of appetite
Aches and pains
What are the symptoms of an infection with influenza? (4)
Blotchy pink rash
Koplicks spots
What are the main symptoms of measles? (2)
Small red spots with white centre on the inside of cheeks
What are koplicks spots?
Pneumonia
Middle ear infections
What are people infected with the measles virus susceptible to? (2)
Fever
Headache
Vomiting
Swelling of parotid salivary glands
What are the symptoms of mumps? (4)
Infectious parotitis
What us mumps also known as?
They are inanimate - so cannot replicate on their own
Wy do viruses need a living host?
Prokaryotic, single celled
What type of organism are bacteria classed as?
70S
What type of ribosome is found in bacteria
Cell wall
(Capsule)
Flagella
DNA in nucleid
Plasma membrane
Pili
Plasmid
What are the main components of a bacterial cell? (7)
The basal bodies they are attached to?
What causes the flagella of a bacterium to move?
Movement
Attachment
What are the main functions of pili? (2)
Movement - chemotaxis
What is the main function of flagella on bacteria? (1)
A nucleoid
What is the DNA of a bacterium found in?
Irregularly shaped region in a prokaryotic cells that
contains the genetic material
It is not surrounded by a nuclear membrane
What is a nucleiod?
Rods
Spheres
Spirals
What are the three general shapes of bacteria?
Cocci
What is another word for describing bacteria that have a spherical shape?
Spirochete
What is another word for describing bacteria that have a spiral shape?
Culture conditions
Shape
Staining reactions
Sensitivity to oxygen
Genetic similarity
What characteristics are used in bacterial classification? (5)
Streptococci
What is the most common gram positive cocci?
Listeria
What is the most common gram positive rod?
Neiserria
What is the most common gram negative cocci?
E. Coli
What is the most common gram negative rod?
Genus name
Speices name
What is the naming of bacteria based on? (2)
Organisms that feed on organic matter
What is a fungi?
The moulds
The yeasts
What are the 2 forms of funig?
The filamentous form of a fungi
What is a mould?
Myecelium
What do filamentous fungi form?
Networks of Hyphae
How doe filamentous fungi form a myecelium?
100 microns
What is the length of a hyphae?
2-8 microns
What is the diameter of a hyphae?
A unicellular form of mould
What is a yeast?
2-20 microns long
What is the range in size of yeasts?
Eukaryotic, unicellular or multicellular
What type of organism is a fungi?
Budding and division
How do yeast cells multiply?
Growth form
Type of infection
How are yeasts classified? (2)
Myocoses

Superficial and deep
What types of infections do fungi cause? ...What are the subtypes of this type of infection?
Epidermophyton
Microsporum
Trichophyton
Sporothrix
What types of fungi cause superficial mycoses? (4)
Aspergillus
Blastomyces
Canadida
Coccidiodes
Cryptococcus
Histoplasma
Paracoccidiodes
What types of fungi cause deep myocoses? (7)
Eukaryotic, single cellular
What type of organism are protozoa?
Free-living (extracellular)
Parasitic (intracellular)
What types of existences can protozoa have?
Active
Inactive
What are the two forms of free living protozoa?
Trophozoite
What is an active, free living protozoa called?
A cyst
What is an inactive, free living protozoa called?
Entameoba
Leishmania
Trypanosome
What are the three meain genera of protozoa that affect humans?
Infected food
Infected water
Insect vectors
What are the most common ways a protozoa is acquired? (3)
Malaria
What s the most common protozoan disease?
A parasitic worm
What is a helminth?
An organism that lives in or on another organism that benefits by depriving nutrients at the hosts expense
What is a parasite?
Eukaryotic, multicellular
What type of organism is a parasite?
Round worms
Flat worms
Tape worms
What are the three common shapes of parasitic worm?
Nematode
What are roundworms also known as?
Trematode
Fluke
What are flat worms also known as? (2)
Cestodes
What are tape worms also known as?
Acaris
Shistosoma
Teania
What parasites are particularly important in human disease? (3)
Organism with an exoskeleton made of chitin
What are arthropods?
Eukaryotic, multicellular
What type of organism is an arthropod?
Directly
As vectors - for other microorganisms
How do arthropods cause disease? (2)
Mites
Ticks
Bugs
Lice
Flies
Mosquitoes
What arthropods are important medically? (6)
Lyme disease
Malaria
Plague
Yellow Fever
What human diseases are spread via arthropods? (4)
An inflammatory disease
Tick borne
Caused by borrelia bacteria
What is Lyme disease?
Borrelia bacteria
What is Lyme disease cause by?
Via ticks
How is Lyme disease transmitted?
A tropical, viral, haemorrhagic disease that causes fever and jaundice (affects kidneys and liver)
What is yellow fever?
Kidneys
Liver
What organs does yellow fever affect? (2)
Fever
Jaundice
What are the main symptoms of yellow fever?
Through female mosquitoes
How is yellow fever transmitted
Accompanied/Produced by haemorrhage
What does haemorrhagic mean?
2 organisms living in close association without much interaction
What is commensalism?
2 organisms living in close association each benefitting from the other (reciprocal benefit)
What is mutualism?
2 organisms living in close association, one doing damage to the other for its own benefit - unilateral benefit
What is parasitism?
Symbiosis
What is another word for mutualism?
Toxin production
Invasion
Immune mechanisms
How do microbes causes disease? (3)
Travel to sites that are normally sterile
Why commensal organisms found the the human body sometimes cause disease?
On epithelial surfaces
Where are commensal organisms found int the body generally?
Ability to make toxins
Ability to invade cells/tissues
Ability to outcompete normal commensal organisms
What are the virulence characteristics of pathogenic organisms? (3)
Staph aureus
Staph epidermidis
Diptheroids
Streptococci
What normal commensal bacteria are found in the nose? (3)
Strep mutans
Becteroides
Fusobacterium
Streptococci
Actinomyces
What normal commensal bacteria are found in the teeth? (5)
Pneumocyctis jirovecii
What normal commensal bacteria are found in the lungs? (1)
Staph epidermidis
Diptheroids
Streptococci
Gram negative rods
What normal commensal bacteria are found in the urethra/vagina? (4)
Strep viridians
Strep pyogenes
Stre pneumoniae
Neisseria
Staph epidermidis
Haemophilis influenzae
What normal commensal bacteria are found in the throat? (6)
Strep mitis
Candida
Trichomonas tenax
What normal commensal bacteria are found in the mouth? (3)
Staph epidermidis
Staph aureus
Diptheroids
Streptococci
Pseudomonas
Aeruginosa
Anaerobes
Candida
Torulopsis
Pityrosporum
What normal commensal bacteria are found in the skin/feet/scalp/groin/perineum? (10)
pH
Humidity
Attachment/retention
Oxygen tension
Host inhibitors
Nutrients
What factors influence how many/which types of bacteria grow in certain areas of the body? (6)
A macrophage phagocytosing bacteria
What does this slide show?
Filamentous
'Mould'
What type of fungi does A show?
Budding
'Yeast'
What type of fungi does A show?
Budding
'Yeast'
What type of fungi is this?
Filamentous
'Mould'
What type of fungi is this?
Staphylococcus
What genus of bacteria is this?
Gram positive cocci - Streptococci
What type of bacteria is shown in A?
Gram positive rods - Listeria
What type of bacteria is shown in B?
Gram negative rods - E.Coli
What type of bacteria is shown in C?
Gram negative cocci - Neisseria
What type of bacteria is shown in D?
Spirochetes
What type of bacteria is this?
Rods
What type of bacteria is this?
Cocci (staphyl)
What type of bacteria is this?
Pili
What are the red arrows pointing at?
Infolding of plasma membrane
What is the red arrow pointing at?
Capsule
What is the red arrow pointing at?
Cell wall
What is the red arrow pointing at?
Nucleoid (DNA)
What is the red arrow pointing at?
Basal body
What is the red arrow pointing at?
Flagellum
What is the red arrow pointing at?
Ribosomes (70S)
What is the red arrow pointing at?
Plasmid
What is the red arrow pointing at?
Cytoplasm
What is the red arrow pointing at?
Plasma membrane
What is the red arrow pointing at?
Cytoplasmic inclusion
What is the red arrow pointing at?
Eukaryotic
What type of cell is this?
Prokaryotic
What type of cell is this?
Capsid protein
What is the structure indicated by the *?
Virus
What type of microrganism is this?
Lipid envelope
What is the structure indicated by the *?
RNA or DNA (Genetic material)
What is the structure indicated by the *?
Eukaryotic
Multicellular
What type of organism is this? (2)
Arthropod
Parasite
What is this organism? (2)
Protein
Lipid
DNA
RNA
What molecules make up this type of organism? (4)
Eukaryotic
Multicellular
What type of organism is this? (2)
Arthropod
Parasite
What is this organism? (2)
Protein
Lipid
DNA
RNA
What molecules make up this type of organism? (4)
Protozoa
What is this organism?
Protein
Lipid
DNA
RNA
What molecules make up this type of organism? (4)
Eukaryotic
Unicellular
What type of organism is this? (2)
Eukaryotic
Multicellular or Unicellular
What type of organism is this? (2/3)
Fungi
What is this organism?
Protein
Lipid
DNA
RNA
What molecules make up this type of organism? (4)
Prokaryotic
Single celled
What type of organism is this? (2)
Bacteria
What is this organism?
Protein
Lipid
DNA
RNA
What molecules make up this type of organism? (4)
Inanimate
What type of organism is this? (1)
Virus
What is this organism?
Protein
DNA OR RNA
What molecules make up this type of organism? (2)
Inanimate
What type of organism is this? (1)
Prion
What is this organism?
Protein
What molecules make up this type of organism? (1)
Light Microscope
What type of microscopy is indicated by the *?
Electron microscope
What type of microscopy is indicated by the *?