concepts of infectious diseases

infection: occurs when ___

-most don’t cause symptoms & go unnoticed

-ex: asymptomatic but PCR positive for covid

pathogen/ parasite enters/ begins to grow in/ on host

disease: disruption of ___

-specific signs & symptoms

-ex: HIV infection progresses to AIDs disease

normal structure/ function of any body part, organ or system

pathogenicity: ____

think: “___“

pathogen’s ability to make host sick, CAN it make host sick

virulence: _____

think: “__”

level of harm caused by pathogen following infection, HOW sick can it make host

types of pathogens

-primary pathogens: disease-causing microbes that ______

-opportunistic pathogens: cause disease only in hosts that are ____

break defenses of healthy hosts, immunocompromised

virulence can be measured by:

-lethal dose 50% (LD50)

-infectious dose 50% (ID50)

-# of pathogens needed to kill (LD) or infect (ID) of hosts

-the lower the LD50 & ID50, the ___ (higher/ lower?) the virulence

higher

latent infections: ____ (sympatomatic/ nonsymptomatic?) when virus is undetectable?

chronic infections: _____ (symptomatic/ nonsymptomatic?)

-symptoms that gradually develops & may resolve ___ (quickly/ slowly?)

-some infections have a latent state: pathogen can’t be found in culture (bc they’re in dormant state) but persist in body & can reactivate

acute infection: symptoms develop & resolve rapidly

ex: common cold

nonsymptomatic, symptomatic, slowly

primary infection: new infection in __ ___ ___

secondary infection: another infection w/ a diff ____ that follows ___ infection (due to weakened immune system from primary infection)

-ex: damaged tissues more succeptable to infection by diff organism; bacterial lung/ ear infection following primary infection with flu virus

-ex: ear infections after respiratory viruses, and skin infections like cellulitis following boils or other breaks in the skin

previously healthy individual, pathogen, primary

signs: ____

ex: fever, rash,

symptoms: ____

ex: pain, fatigue, dizziness

observable & measurable, experienced only by the patient

syndrome: collection of ___ & ___ that occur together & collectively _________ (can be multiple diseases)

sequelae: pathological consequences after ____

ex: immune response to strep infection can cause heart damage after infection

signs, symptoms, characterize a condition, a disease resolves

phases of disease

-incubation: between ___ & ___ of disease, host may/ may not be ___ & pathogen trying to ___

-prodromal: ___ symptoms of general ___, similar to most diseases

-illness: typical __ & __ develop & are most severe: _____ battle at its peak
-decline: # of __ decreases and __ & __ decline

-convalescent: symptoms have disappeared, __ at its peak, host is recovering

-long-term: immunity (memory of pathogen) ___ over time

-infection, signs, infectious, replicate quickly

-vague, discomfort

-sign, symptoms, pathogen-host

-pathogen, signs, symptoms

-immunity

-wanes

modes of transportation

direct

infected → uninfected host through: skin contact, air (aerosols, droplets, etc)

-from __ to new host

-vertical transmission: ___ → ___

indirect

through , ___ which means LIVING carrier

through ___ (fomite, food, water, aerosols)

-reservoir, mom, offspring

-vector, vehicle

reservoir: _____

-asymptomatic carrier harbors ___ ___ agent by doesn’t have the disease

• ex: Neisseria meningitidis is an important cause of meningitis. It has no animal reservoir and is maintained in the human population by asymptomatic hosts.

-animal (including humans) or environment that normally harbors & maintains pathogen

-potential disease

reservoir vs vector

.