Flashcards in ID terms Deck (28):
Diagnostic test for flu/influenza
1. Viral cultures have to be sent to a specialized lab and take days to come back
2. Rapid antigen test can be done on site but has low sensitivity. So if negative, the employee could still have flu.
3. PCR: can be done rapid. The test is sensitive. Requires a nasopharyngeal swab, not nasal like the rapid antigen test. The advantage is that one can use the results to decide on need for treat and whether and when the employee can work.
Control of infectious diseases
1. Sanitation and hygiene
3. Antibiotics and other antimicrobial medicines
Agent infects host continuously without overt evidence of disease or infection.
Agent infects host, time-limited, without overt disease (majority of infection)
Infection with disease (minority of infection)
Ability to evolve/multiply in host
Does of agent necessary to infect 50% of host
Ability to be transmitted to other host
Ability to cause disease in a susceptible host; to produce clinical illness
Ability to produce severe clinical illness, including death
Dose of agent necessary to kill 50% of hosts
Ability to elicit an immune response.
Factors to the natural history of infectious disease
Time between infection and the creation of overt disease.
Period between infection and maximal communicability.
Resistance of a population to the spread of disease based on prior immunity of the population.
Secondary attack rate
Measures the rate of spread of disease within an exposed group
= ( # of new cases - # of initial cases)/(# of susceptible - # of initial cases)
Type of infections in a population
Occasional cases at irregular interval
Low level(usual), expected frequency of disease occurrence, the constant presence of a disease within a given geographical area (usual prevalence)
A gradual increase in the frequency of disease occurrence above endemic level
A sudden increase in the frequency of disease occurrence above endemic level (clearly in excess of expected level)
An epidemic occurring across continents
Plot of # of. Cases against time
Epi curve for point source
A single jumped with rapid rise and slower return to baseline
Epi curve for ongoing source
Rapid rise at onset of exposure to persistent epidemic level
Propagated cure with multi- hump
1st peak: Primary attack rate for those exposed to the index case
Subsequent peaks represent 2ndary and beyond attack rates as those in the 1st peak infect others.