5.1: Microbial infection Flashcards
What is the classification of viruses?
not cells in their own right
What is the classification of bacteria?
prokaryotes
What is the classification of fungi?
eukaryotes- single cell
What is the classification of protozoa?
eukaryotes- single cell
What is the classification of helminths
eukaryotes- multi-cellular
What is another word for viruses?
obligate parasites
What is the genetic material contained in viruses?
RNA or DNA
Do viruses show host specificity?
yes
How do viruses divide?
by budding out of host cells or cytolysis
What are the routes of infection of a virus?
various routes
faecal-oral, airborne, insect vectors, blood borne
What is an example of a retrovirus?
HIV– enveloped virus
‘DNA makes RNA makes protein’
RNA genome requires reverse transcriptase
What is the only infectious disease to be eradicated by vaccination?
smallpox (variola virus)
What is the human papilloma virus?
virus that causes cervical cancer
What is the structure of prokaryotes?
they do not have internal membranes
photosynthetic bacteria are an exception
How is the genetic material contained in prokaryotes?
single copy of a chromosome
(haploid)
eukaryotes can be haploid or diploid
Do prokaryotes have a cytoskeleton?
yes
but it is poorly defined unlike eukaryotes where it is well developed
What does prokaryote cell wall contain?
peptidoglycan
How do prokaryotes divide?
binary fission
What are the key structures of bacteria?
pilus, capsule, cell wall, plasma membrane, nucleoid (DNA), cytoplasm, ribosomes
What are pili used for?
determine how cells interact with and adhere to surfaces
What is the role of the capsule?
can prevent desiccation or hinder phagocytosis
What is the role of the flagella?
important for swimming
What is shigella?
an invasive pathogen
faecal-oral transmission
What is neisseria meningitidis?
a commensal pathogen that lives without causing harm in the naso-pharynx of about 20% of population
causes: rash, septicaemia
penetrates cerebrospinal fluid- meningitis
What are hospital acquired infections?
antimicrobial resistance (AMR) c. difficile and MRNA
What is helicobacter pylori
causes peptic ulcer and gastric cancer
How do pathogens evolve so quickly?
mutation rates
Mutations in viruses
have error-prone replication and they dont correct the errors they make with very high efficiency
mutations in bacteria
are haploid so only one gene needs to be mutated to have any phenotypic effect
- much shorter replication times (genes can be selected and spread in a population much more rapidly than in humans)
What are the 3 groups of fungi?
cause cutaneous, mucosal and/or systemic m
What do fungi occur as?
yeasts, filaments or both
filaments have cross walls or septa
How do fungi replicate?
bud or divide
What are protozoa?
unicellular eukaryotic organisms
intestinal, blood and tissue parasites
How do protozoa replicate?
by binary fission or by formation of trophozoites inside a cell
How is infection by protozoa acquired?
ingestion or through a vector eg insect or invertebrate vector
What are examples of protozoa?
malaria and laishmaniasis
What is malaria?
plasmodium species
- infection is acquired via a mosquito vector
- blood and tissue parasites
- formation of trophozoites inside a cell
What is leishmaniasis?
Leishmania species
- infection is acquired via a sandfly vector
- blood and tissue parasites
- formation of trophozoites inside a cell
What are helminths?
metazoa with eukaryotic cells ( they contain cells that are differentiated into tissues and organs)
- multi-cellular
What is the life cycle of helminths?
outside the human host
What are some examples of helminths?
roundworms
flatworms
tapeworms
some flukes require hosts for life cycles
schistosomiasis
What does effective treatment of infectious disease require?
knowledge of causative agent
- its source and means of transmission
- how they cause damage
- how the human body reacts
prevent
vaccination
treat
drugs
