Week 1: Infection as a Mechanism of Disease Flashcards
Why are infections still a major global concern despite advances in medicine?
Vaccine hesitancy
AMR (antimicrobial resistance)
Poor Healthcare
High threat pathogens (MDR-TB)
What are the key features of the bubonic plague?
Spread by bite from infected flea off rodent (vector borne)
Can be fatal within 24 hours
Causes painful swollen lymph nodes in groin and armpit
Can cause gangrene (lack of blood flow from narrowed/blocked/hardened arteries blackens tissue)
Highest rates in DRC, Madagascar and Peru
What pathogen causes bubonic plague?
Yersinia Pestis - zoonotic microbe with fleas as a vector
What are the key features of cholera?
Acute diarrhoeal disease
Fatal within hours
Endemic in many countries
Spread by contaminated food/water
What pathogen causes cholera?
Vibrio cholerae - bacteria
What is the pathogen responsible for the Spanish flu?
Influenza A virus
Common fever, sore throat and headache
Often developed pneumonia and died
What are the different types of microbes that can cause infection?
Bacteria
Viruses
Prions
Viroids
Fungi
Parasites
Helmiths
What are prions?
Give examples of diseases they cause
normal prion proteins to become abnormal and clump together causing brain damage
E.g CJD (mad cow disease), Kuru and FFI
What are viroids?
Examples?
Free RNA molecules (no viral coat)
Hepatitis D - which requires hepatitis B virus in order to replicate
What type of infection does Staphylococcus aureus cause?
Skin infections
What type of infection does E.Coli cause?
UTIs
Diahorreal
Neonatal meningitis
Pneumonia
What bacteria typically causes tonsilitis?
Streptococcus pyrogenes
What pathogen is normally responsible for a yeast infection?
Candida albicans - a fungi
Often caused by overuse of penicillin
What is a common parasite?
Malaria
What is a parasite?
Lives on or in a host, gets food at the expense of the host
What is a helminth?
What is a common example?
Cysticercosis - tape warm
Are a subset of intestinal macroparasites, typically cause abdominal pain, bloating and bloody stool
Define disease from a microbiology perspective
Suboptimal functioning of an organism due to infection or other causes
Define infection
When a foreign microbe invades and replicates in a host
What is an endogenously acquired infection?
Caused by microbes on or in us.
- alteration of microbiome by antibiotics
- commensal on skin enters by wound
What is an exogenously acquired infection?
Caused by pathogens in the external environment
- Food, air, water, objects, animal or insect bites
What are commensals?
A microorganisms that lives on/in a host, replicates. but does not interact with the host so rarely causes disease
What are some common examples of commensals?
Staphylococcus epidermis on the skin
Lactobacillus in the gut
Streptococcus salvarius - oral microbiome
What are opportunistic pathogens?
When microorganisms commonly found in the microbiome with causing disease, exploit compromised immunity to cause disease
What are some common opportunistic pathogens?
S, aureus if enters blood stream
Candida albicans - thrush in penicillin use
P.aeruginosa - serious infection in immunocompromised such as CF patients
Define apparent infection
An infection that causes symptoms
What is an acute infection?
Symptoms within 4 weeks (rapid) e.g Influenza
What is a subacute infection?
Slower onset of symptoms within4-12 weeks e.g endocarditis