Answer: A. A disease that can spread. A communicable disease can spread from one host to another, directly or indirectly.
What is a pathogen?
A A health behavior
B A disease-causing agent
C A screening method
D A symptom report
Answer: B. A disease-causing agent. A pathogen is an agent capable of causing disease, such as a virus, bacterium, fungus, or parasite.
Where can a pathogen live and multiply before transmission?
A A portal of entry
B An incubation period
C A reservoir
D A symptom
Answer: C. A reservoir. A reservoir is a place where an infectious agent normally lives and may multiply.
Which term describes how an agent leaves its source?
A Susceptible host
B Incubation period
C Immune response
D Portal of exit
Answer: D. Portal of exit. A portal of exit is the route by which an infectious agent leaves its reservoir or source.
How is the route from an infectious source to a host described?
A Mode of transmission
B Portal of exit
C Clinical symptom
D Disease outcome
Answer: A. Mode of transmission. The mode of transmission describes how an infectious agent moves from a source toward a susceptible host.
Which chain link describes how a pathogen enters a new host?
A Reservoir
B Portal of entry
C Incubation period
D Vector population
Answer: B. Portal of entry. A portal of entry is an opening or route through which an agent can enter a host.
What does the term susceptible host mean?
A A cleaned surface
B A disease-causing microbe
C A person at risk
D A protective barrier
Answer: C. A person at risk. A susceptible host is a person who can be infected by a particular agent.
What does a vector do in disease transmission?
A Measures blood pressure
B Produces every vaccine
C Removes all reservoirs
D Carries pathogens between hosts
Answer: D. Carries pathogens between hosts. A vector is a living organism that carries an infectious agent from a reservoir to a host.
Which item could act as a fomite?
A Contaminated doorknob
B A healthy immune cell
C A clean drinking glass
D A mosquito species
Answer: A. Contaminated doorknob. A fomite is an inanimate object that can carry an infectious agent, such as a contaminated surface.
Direct transmission can occur through which route?
A A distant food shipment
B Person-to-person contact
C A mosquito vector only
D A contaminated instrument only
Answer: B. Person-to-person contact. Direct transmission can involve close contact between people, depending on the infection.
What is indirect transmission?
A Only inherited genes
B Only direct skin contact
C Via a vehicle or vector
D Only a person’s symptoms
Answer: C. Via a vehicle or vector. Indirect transmission occurs through an intermediary such as a contaminated object, food, water, or vector.
What does the incubation period measure?
A Treatment until recovery
B Diagnosis until vaccination
C Infection until immunity
D Exposure until first symptoms
Answer: D. Exposure until first symptoms. The incubation period is the time from exposure to an infectious agent until symptoms begin.
Does an incubation period always equal an infectious period?
A No, they are different intervals
B Yes, they always match
C Only in bacterial illness
D Only after recovery
Answer: A. No, they are different intervals. Incubation describes time to symptom onset; the infectious period describes when transmission can occur. Their timing depends on the disease.
Which person may transmit an infection without noticeable illness?
A A clean-surface monitor
B Asymptomatic carrier
C A vaccine recipient only
D A non-susceptible host
Answer: B. Asymptomatic carrier. Some people can carry and transmit an infectious agent without noticeable symptoms, depending on the infection.
What does an outbreak describe?
A One unrelated symptom
B A single laboratory test
C More cases than expected
D A normal seasonal pattern
Answer: C. More cases than expected. An outbreak is an increase in cases above what is normally expected in a defined place and time.
How are people exposed in a point-source outbreak?
A Separate exposures over years
B Only inherited susceptibility
C No common exposure
D Shared brief exposure
Answer: D. Shared brief exposure. A point-source outbreak often follows exposure to the same source over a relatively short period.
Which measure helps estimate a likely exposure window?
A Incubation period
B Blood pressure range
C Vaccine brand
D Recovery preference
Answer: A. Incubation period. Public health investigators use the disease’s incubation period when estimating when exposure may have occurred.
When contaminated food spreads an agent, which route is involved?
A Inherited transmission
B Common vehicle transmission
C Direct genetic transmission
D Airborne-only transmission
Answer: B. Common vehicle transmission. Food can act as a common vehicle that carries pathogens to multiple people.
How do mosquitoes transmit some infectious diseases?
A As mineral reservoirs
B As vaccines
C As biological vectors
D As disinfectants
Answer: C. As biological vectors. Some mosquitoes carry pathogens between hosts and are called biological vectors.
Which type of pathogen causes malaria?
A A bacterium
B A fungus
C A prion
D A parasite
Answer: D. A parasite. Malaria is caused by Plasmodium parasites and is transmitted by infected Anopheles mosquitoes.
Which mosquito genus transmits dengue viruses?
A Aedes
B Anopheles
C Culex-free
D Simulium
Answer: A. Aedes. Dengue is primarily transmitted by Aedes mosquitoes, especially Aedes aegypti.
What does zoonotic transmission involve?
A Food-to-surface transfer
B Animal-to-human spread
C Person-to-person inheritance
D Water-to-soil filtration
Answer: B. Animal-to-human spread. Zoonoses are infections that can spread between animals and people.
Which practices can reduce respiratory infection spread?
A Share used tissues
B Touch the face often
C Cover coughs and wash hands
D Ignore respiratory symptoms
Answer: C. Cover coughs and wash hands. Respiratory hygiene and hand hygiene help reduce the spread of infectious respiratory secretions.
How can good indoor ventilation reduce airborne exposure?
A Creates new pathogens
B Replaces every vaccine
C Prevents all contact transmission
D Dilutes indoor infectious particles
Answer: D. Dilutes indoor infectious particles. Ventilation can reduce the concentration of infectious particles in indoor air, although it does not remove every risk.
When hands are visibly soiled, what is appropriate in healthcare?
A Wash with soap and water
B Wipe on clothing
C Use gloves instead
D Skip hand hygiene
Answer: A. Wash with soap and water. CDC guidance recommends soap and water when hands are visibly soiled.
What are standard precautions in healthcare?
A Rules for one pathogen
B Minimum practices for all care
C Optional practices after diagnosis
D Measures used only in outbreaks
Answer: B. Minimum practices for all care. Standard precautions are basic infection prevention practices used for all patient care, regardless of known infection status.
Do standard precautions apply only when infection is confirmed?
A Only to known infections
B Only in intensive care
C They apply to all patients
D Only during outbreaks
Answer: C. They apply to all patients. Standard precautions apply to all patients because infectious status may be unknown.
When should personal protective equipment be selected?
A Only after an infection spreads
B For every home activity
C Only when symptoms are visible
D When exposure risk is expected
Answer: D. When exposure risk is expected. In healthcare, PPE is selected based on anticipated exposure to infectious material and the task being performed.
What is the main purpose of surface disinfection?
A Reduce harmful microbes on surfaces
B Remove every possible spore
C Replace hand hygiene
D Clean inside the bloodstream
Answer: A. Reduce harmful microbes on surfaces. Disinfection reduces many harmful microorganisms on surfaces; it is not the same as sterilization.
What does cleaning primarily remove from a surface?
A All microorganisms permanently
B Dirt and organic matter
C A person’s immune response
D Every airborne particle
Answer: B. Dirt and organic matter. Cleaning removes dirt and organic material and can lower the number of microbes present.
Why are patient-care instruments cleaned and reprocessed?
A Increase pathogen growth
B Replace diagnosis
C Prevent transfer between patients
D Make gloves unnecessary
Answer: C. Prevent transfer between patients. Proper reprocessing helps prevent contaminated equipment from transmitting microorganisms between patients.
What do safe injection practices help prevent?
A Seasonal allergies
B Inherited disorders
C Air pollution exposure
D Bloodborne pathogen transmission
Answer: D. Bloodborne pathogen transmission. Safe injection practices reduce risks of bloodborne infection and medication contamination.
How can safe drinking water reduce infectious disease risk?
A Limits waterborne pathogen exposure
B Removes all respiratory viruses
C Prevents every vector bite
D Replaces food hygiene
Answer: A. Limits waterborne pathogen exposure. Safe water reduces exposure to pathogens that spread through contaminated water.
Which public service helps limit faecal pathogens entering the environment?
A Air filtration
B Safe sanitation
C Routine vaccination
D Noise reduction
Answer: B. Safe sanitation. Safe sanitation helps prevent human waste from contaminating water, soil, and food pathways.
Handwashing is especially important after which activity?
A Reading a book
B Walking outdoors
C Using the toilet
D Opening a window
Answer: C. Using the toilet. Handwashing after using the toilet and before preparing food helps reduce pathogen transmission.
What can happen when a link in a transmission chain is interrupted?
A Every disease disappears
B All hosts become immune
C The pathogen changes species
D That transmission route is interrupted
Answer: D. That transmission route is interrupted. Breaking a necessary link in the chain can interrupt that route of transmission.
What must be present for an infectious agent to reach a new host?
A A transmission route
B A visible symptom
C A treatment failure
D A confirmed outbreak
Answer: A. A transmission route. The agent must have a route from its source to a susceptible host.
How can contaminated surfaces contribute to infection spread?
A Surfaces create antibodies
B Hands transfer microbes to mucosa
C Microbes teleport between people
D Touch always causes infection
Answer: B. Hands transfer microbes to mucosa. A person may transfer microbes from a contaminated surface to the eyes, nose, or mouth; transmission depends on the agent and exposure.
What does fecal-oral transmission involve?
A Pathogens enter through hair
B Infection spreads through genes
C Pathogens enter through the mouth
D A vector injects saliva
Answer: C. Pathogens enter through the mouth. Fecal-oral spread occurs when pathogens from fecal contamination are ingested, often through unsafe water, food, or hands.
What can careful food handling help prevent?
A Inherited diseases
B Airborne pollen exposure
C Noninfectious injuries
D Foodborne infections
Answer: D. Foodborne infections. Clean handling, safe preparation, and proper storage can reduce foodborne infection risk.
Does every infection cause noticeable symptoms?
A No, some are asymptomatic
B Yes, symptoms are required
C Only children have symptoms
D Only viruses are asymptomatic
Answer: A. No, some are asymptomatic. Some infections cause no noticeable symptoms, although transmission potential varies by disease.
What is an infectious disease?
A Any inherited trait
B Illness caused by a pathogen
C A nutrient requirement
D A physical injury only
Answer: B. Illness caused by a pathogen. An infectious disease results from infection by a pathogen, though not every infection produces illness.
Why might a susceptible host face greater infection risk?
A More protective barriers
B No possible exposure
C Less effective defense against agent
D Complete immunity to pathogens
Answer: C. Less effective defense against agent. Host factors such as age, health, and immune status can affect susceptibility.
Which group may need tailored infection precautions?
A People with no exposure
B Only healthy adults
C People with clean hands
D Immunocompromised people
Answer: D. Immunocompromised people. People with weakened immune defenses can face greater risk from some infections and may need individualized precautions.
What is personal protective equipment designed to do?
A Create exposure barriers
B Diagnose an infection
C Replace vaccination
D Eliminate every pathogen
Answer: A. Create exposure barriers. PPE such as gloves, gowns, and masks can reduce exposure when used appropriately.
When are transmission-based precautions added in healthcare?
A For every household visit
B When specific spread risk warrants
C Only after recovery
D Instead of standard precautions
Answer: B. When specific spread risk warrants. Additional precautions are selected when a known or suspected pathogen requires measures beyond standard precautions.
Why is hand hygiene performed after removing gloves?
A Gloves produce antibodies
B Hands become sterile
C Gloves can contaminate hands
D Gloves replace handwashing
Answer: C. Gloves can contaminate hands. Hands can become contaminated during glove removal, so hand hygiene remains important.
What role does outbreak surveillance serve?
A Guarantees a pathogen source
B Replaces laboratory testing
C Prevents all infections
D Detects unusual case increases
Answer: D. Detects unusual case increases. Surveillance helps public health teams notice unusual patterns and investigate possible outbreaks.
Who may investigate a suspected outbreak source?
A Public health investigators
B A product advertiser
C A random bystander
D An unrelated retailer
Answer: A. Public health investigators. Public health investigators use case information and exposure histories to assess likely sources and transmission.
When a communicable disease is suspected, what should guide precautions?
A Unverified social media posts
B Current public health guidance
C Someone else’s prescription
D A guess based on symptoms
Answer: B. Current public health guidance. Precautions depend on the disease and setting, so people should follow current guidance from qualified health authorities.