W32/L8 Flashcards
(24 cards)
What is the common presentation of gonorrhoea in men?
Purulent & profuse urethral discharge
In which sites is gonorrhoea often asymptomatic?
Rectum
Pharynx
Cervix
What are some reasons that gonorrhoea has higher rates in indigenous communities?
Poor/slower access to testing & treatment = longer duration of infection
What symbol means the “basic reproductive rate”
R0
What does the basic reproductive rate mean?
The number of cases of an infection that will arise from a primary case
What values of R0 will cause an epidemic
R0 > 1
For which values of R0 will a disease die out?
R0 < 1
Why does prevalence of an infection level off, even when R0 is greater than 1?
As the prevalence of the disease increases, the number of susceptible people decreases
R0 =
Beta * c * D
What is Rt?
The effective reproduction rate
Rt =
Beta * c * D * x
What is “beta” in the reproductive rate expression?
Transmission probability per partnership
What is “c” in the reproductive rate expression?
Rate of partner change
What is “D” in the reproductive rate expression?
Duration of infection
What’s “x” in the reproductive expression?
The proportion of the population who are susceptible
What things will influence beta for an STI?
Condom use Types of sex Duration of sex Presence of other STIs How infectious their disease is currently (1" infections, high viral load etc)
Duration of partnership
What things will influence D for an STI?
Presence of symptoms
Access to screening & t’ment
What component of the reproductive rate is most straightforward to target as a pop health measure?
D - duration of infectiousness
What does assortative mixing refer to?
High risk people having sex with other high risk people
What does disassortative mixing refer to?
High risk people having sex with low risk people
What type of mixing is bad for population control of an infection
Assortative mixing
What does concurrency refer to?
Simultaneous partners
Even if the number of partners per year is the same, why is concurrency worse than serial monogamy for population control of infections?
There are more partners during a persons duration of infection
(And they presumably have multiple partners too)
What does the core group refer to in epidemiology?
The small portion of a population who have many partners
