Public Health Exam #2

mechanical vector

carries a pathogen on its body without the pathogen developing inside it.

• Example: a fly carrying bacteria from garbage to food. 

biological vector

an organism in which the pathogen develops or multiplies before being transmitted.

• Example: a mosquito transmitting dengue.

zoonotic disease

can spread from animals to humans.

• Example: Lyme disease, which involves ticks and animal reservoirs.

anthroponotic disease

maintained primarily through human-to-human transmission, sometimes through a vector.

• Example: dengue, which commonly spreads between humans through mosquitoes.

Intrinsic incubation period

The time between a person becoming infected and developing symptoms. 

Extrinsic incubation period

The time a pathogen takes to develop inside a vector before the vector can transmit it.

 Identify common disease vectors.

• Mosquitoes transmit dengue, Zika, malaria, and West Nile virus. 

• Ticks transmit Lyme disease and Rocky Mountain spotted fever. 

• Fleas transmit plague. 

• Sand flies transmit leishmaniasis. 

• Some flies transmit pathogens mechanically.

 Identify commonalities and differences of dengue and Zika. 

Both are viruses transmitted primarily by Aedes mosquitoes, occur in tropical and subtropical regions, and can cause fever, rash, and joint pain.

• Dengue can cause severe bleeding, shock, and death. Zika is often mild but is especially concerning during pregnancy because infection can cause serious birth defects, including microcephaly.

Identify the vector that transmits dengue and Zika and list its key characteristics

• Vector: Aedes mosquitoes (Aedes aegypti and Aedes albopictus)

  • Biting behavior: Daytime biters (peak activity at dawn and dusk)

  • Appearance: Distinctive black-and-white striped markings

  • Breeding & habitat: Lay eggs in artificial containers with standing water; highly adapted to urban human dwellings

Describe how climate and weather affect vector-borne diseases.

• Warm weather helps vectors grow faster and allows germs to multiply more quickly.

• Rain creates more places for mosquitoes to breed.

• Drought can lead people to store water, which also creates mosquito breeding sites.

• Very hot or very cold temperatures can kill vectors or reduce their survival.

• Climate also determines where vectors can live and how long they are active during the year.

Describe mosquito vector control strategies.

• Personal protection: Use insect repellent, wear protective clothing, and avoid mosquito bites.

• Structural barriers: Install window and door screens and use bed nets where appropriate.

• Larval control: Target immature mosquitoes using approved larvicides or biological controls.

• Adult control: Use insecticides or targeted spraying to kill adult mosquitoes when appropriate.

• Physical source reduction: Empty standing water, clean gutters, and remove discarded containers and old tires.

• Biological source reduction/control: Use appropriate natural predators or biological agents, such as mosquito-eating fish in suitable water bodies, where environmentally appropriate.

Identify and describe agent, vector, reservoir, and other factors important for Lyme disease transmission. 

• The agent is the bacterium Borrelia burgdorferi. 

• The vector is an infected blacklegged tick (Ixodes species). 

• Reservoirs include small mammals, especially white-footed mice, that maintain the bacterium in nature. 

• Other factors:

  • Deer helps support adult tick populations but are not the main reservoir for the bacterium. 

  • Risk also depends on tick habitat, season, outdoor activity, and the duration of tick attachment.

Explain how urbanization and climate change affect dengue and Lyme disease risks.

• Urbanization can increase dengue risk through crowded communities, international travel, and standing water in containers. 

• Climate change may allow Aedes mosquitoes to survive in new areas or remain active longer. 

  • For Lyme disease, expanding suburban development into wooded habitats can increase contact between people, ticks, and wildlife. 

  • Warmer temperatures may expand tick ranges and lengthen tick activity seasons.

E.coli

Some strains cause severe diarrhea and abdominal cramps; certain strains can cause bloody diarrhea and kidney complications.

• Undercooked ground beef, contaminated produce, and unpasteurized products are possible sources.

Salmonella

A bacterium that commonly causes diarrhea, fever, and stomach cramps.

• Sources include raw or undercooked poultry and eggs, contaminated produce, and other foods.

Q fever

Caused by Coxiella burnetii. People commonly become infected by inhaling contaminated particles from infected animals, especially livestock; it is not typically acquired by eating contaminated food. Unpasteurized dairy is another possible route.

Listeria

Listeria monocytogenes can grow at refrigerator temperatures. It can cause severe illness, miscarriage, stillbirth, or newborn infection.

• High-risk foods include unpasteurized dairy, certain soft cheeses, and refrigerated ready-to-eat meats.

List industry-level risk factors for foodborne illness.

Problems during food production and processing include contaminated raw ingredients, infected animals, contaminated equipment, poor sanitation, unsafe processing temperatures, and inadequate pasteurization.

• Example: contaminated meat entering a processing facility.

List food-service-level risk factors.

Restaurants and cafeterias may contribute to illness through improper cooking, poor refrigeration, cross-contamination, inadequate handwashing, sick food handlers, and unsafe holding temperatures.

• Example: raw chicken contaminating a cutting board used for salad.

List individual/consumer-level risk factors. 

Consumers may eat undercooked food, drink unpasteurized milk, fail to wash their hands or produce, or improperly store leftovers.

Describe the role of local government in foodborne illness prevention. 

Local health departments inspect restaurants and food establishments, enforce food-safety rules, investigate complaints and outbreaks, educate food workers, and require corrective action when violations occur.

Identify steps in local foodborne illness outbreak investigations. 

• identify and confirm cases

• interview sick people about foods they ate

• look for common exposures

• collect clinical or food samples when appropriate

• identify the likely source

• implement control measures

• communicate findings to prevent further illness.

Define attack rate

The attack rate is the percentage of people at risk who become ill during an outbreak.

Attack rate = Number of new cases/Number of people at risk x 100

Ex: 40 people attended a picnic. 20 people ate the potato salad. 10 of those became sick. Attack Rate = (10 ÷ 20) × 100 = 50%

Describe the role of the federal government in foodborne illness prevention. 

Federal agencies set food-safety standards, inspect or oversee food production, monitor outbreaks, coordinate investigations, and issue recalls. 

• The FDA oversees most foods, the USDA oversees meat, poultry, and certain egg products, and the CDC tracks illnesses and helps investigate outbreaks.

Identify foods requiring the highest cooking temperatures and explain why.

• Poultry, Ground Meats, Whole cuts of beef, pork, & lamb.

• Proper cooking kills harmful pathogens; use a food thermometer rather than judging by appearance.

Describe the exposure pathway, list components in order, explain its purpose, and give examples.

The exposure pathway explains how a harmful substance reaches a person. 

The five components are: 

(1) Source — where the hazard originates

(2) Environmental medium and transport — how it moves through air, water, soil, or food

(3) Point of exposure — where a person comes into contact with it

(4) Route of exposure — how it enters the body, such as inhalation, ingestion, or skin absorption

(5) Receptor population — the people exposed. It helps public health workers identify where to interrupt exposure and prevent illness. 

• Example: lead pipes (source) contaminate drinking water (medium), which reaches a household faucet (point), is swallowed (route), and exposes residents (receptors).

Different dose-response relationships. 

Describes how the amount of a substance affects the body's response.

linear relationship

the response changes proportionally with dose.

threshold relationship

an effect generally does not occur below a certain dose.

A saturation curve

When the effect of a substance does not increase at the same rate as the dose. As the dose gets higher, the response may level off or stop increasing much.

Bioaccumulation

when a chemical builds up inside one organism over time because intake exceeds elimination.

Biomagnification

when chemical concentrations increase at higher levels of a food chain.

• Example: mercury can accumulate in a fish and reach higher concentrations in larger predatory fish that eat many smaller fish.

toxin

a poisonous substance that can harm an organism.

carcinogen

an agent that can cause cancer. Some chemicals can be both toxic and carcinogenic.

Explain how half-life relates to bioaccumulation. 

• A chemical's half-life is the time it takes for half of a substance to break down or be eliminated. 

• Chemicals with long biological half-lives may accumulate when exposure continues because the body removes them slowly.

Acute exposure

occurs over a short period, often as a single exposure. 

Subacute exposure

occurs repeatedly over a relatively short period. 

Subchronic exposure

occurs repeatedly over weeks or months.

Chronic exposure

occurs over a long period, often months or years.

Describe the exposure pathway for lead in the Flint, Michigan, crisis. 

• Flint changed its water source to the Flint River without adequate corrosion control. 

• The corrosive water caused lead to leach from aging pipes and plumbing into drinking water. 

• Residents drank or used the contaminated water, exposing them to lead through ingestion. 

• Children were especially vulnerable to its effects on brain development. 

  • The crisis resulted from infrastructure problems, inadequate corrosion control, and failures in public protection and response.

Identify health effects of lead exposure and previous and remaining sources of lead.

• Lead can damage the brain and nervous system, lower children's IQ, cause learning and behavioral problems, damage the kidneys, contribute to high blood pressure, and affect reproduction. No safe level of lead exposure in children has been identified.

• Historical sources include lead-based paint, leaded gasoline, and lead pipes. 

• Remaining sources include old paint and dust, contaminated soil, plumbing, some imported products, and certain occupational exposures.

Recognize historically significant air-quality events. 

• The Meuse Valley disaster (1930) involved severe pollution and respiratory illness.

• The Donora smog (1948) in Pennsylvania caused widespread illness and deaths during a severe pollution episode.

• The Great Smog of London (1952) caused thousands of excess deaths and helped drive stronger air-pollution controls.

  • These events demonstrated that air pollution can cause serious population-wide health effect

Explain the Air Quality Index (AQI) and how it is used

• The AQI is a scale that communicates how polluted the air is and the potential health risk.

  • Lower values indicate better air quality; higher values indicate greater concern. It helps people decide whether to limit outdoor activity and helps public health agencies issue alerts. 

Common categories are Good (0–50), Moderate (51–100), Unhealthy for Sensitive Groups (101–150), Unhealthy (151–200), Very Unhealthy (201–300), and Hazardous (301+).

 Identify legislation that established US air-pollutant monitoring and the criteria pollutants.

• The Clean Air Act of 1970 established the foundation of modern federal air-pollution regulation, including national air-quality standards and monitoring. 

• The six criteria pollutants are: carbon monoxide, ground-level ozone, particulate matter, sulfur dioxide, nitrogen dioxide, and lead. Remember "COPS NO"

List key sources and health outcomes associated with particulate matter (PM)

• Particulate matter (PM) comes from vehicle exhaust, wildfires, dust, construction, industry, and combustion.

• It can worsen asthma, harm the lungs and heart, and increase the risk of premature death. 

List key sources and health outcomes associated with ozone

Ground-level ozone forms when nitrogen oxides and volatile organic compounds react in sunlight.

• Sources of these precursor pollutants include traffic, industry, fuel vapors, and solvents.

• Ozone irritates airways, reduces lung function, and worsens asthma.

 Explain why children are vulnerable to air pollution. 

• Children's lungs and immune systems are still developing. They breathe more air relative to their body weight than adults and often spend more time being physically active outdoors. Air pollution can affect lung development and worsen asthma.

Explain the connection between PM particle size and health effects. 

• PM10 includes particles 10 micrometers or smaller that can enter the respiratory tract.

• PM2.5 includes particles 2.5 micrometers or smaller that can travel deeper into the lungs and may enter the bloodstream. Smaller particles are particularly concerning because they can contribute to cardiovascular and respiratory disease.

primary pollutant

released directly into the air, such as soot

secondary pollutant

forms through chemical reactions in the atmosphere; ground-level ozone is an example

A chemical vs physical hazard

• A chemical hazard involves harmful chemicals, while a physical hazard involves harmful physical agents or particles. 

Describe key prevention and control strategies for particulate matter in Washoe County. 

• Key strategies include monitoring air quality, controlling dust and emissions, promoting cleaner transportation, and issuing pollution alerts.

• Residents can reduce exposure by checking AQI reports, staying indoors during poor air quality, and using air cleaners.

Describe key prevention and control strategies for ozone in Washoe County.

Ozone control focuses on reducing nitrogen oxides and volatile organic compounds.

• Key ozone prevention and control strategies in Washoe County include reducing vehicle emissions, limiting idling, using public transportation or carpooling, controlling industrial emissions, and reducing fuel-vapor emissions. High-ozone alerts help people limit exposure on warm, sunny days.

Describe control strategies for occupational injury.

The hierarchy of controls ranks prevention strategies from most to least reliable:

• elimination removes the hazard

• substitution replaces it with something safer

• engineering controls physically isolate workers from hazards

• administrative controls change work practices or schedules

• personal protective equipment (PPE) protects individual workers. Eliminating a hazard is generally more effective than relying only on PPE.

Give examples of risk factors and control strategies from the Triangle Fire.

• Risk factors include locked or inaccessible exit doors, inadequate fire escapes, flammable materials, overcrowding, and poor emergency planning.

• Controls would include unlocked and accessible exits, sprinkler systems, fire-resistant materials, safe building design, inspections, and emergency training.

Identify key plot points and individuals involved in the Triangle Fire and policy response

• On March 25, 1911, a fire at the Triangle Shirtwaist Factory in New York City killed 146 workers, many of them young immigrant women. Locked doors and inadequate escape options contributed to the deaths. Owners Max Blanck and Isaac Harris operated the factory. Frances Perkins, who witnessed the aftermath, later became a major advocate for workplace safety. The tragedy led to investigations and stronger labor and fire-safety laws.

Identify how the fire influenced regulations and policy.

The tragedy increased public pressure for workplace reforms. New York strengthened fire codes, building safety requirements, factory inspections, and labor protections. It helped establish the importance of government oversight and safer working conditions.

Identify Frances Perkins' accomplishments

• Frances Perkins became the first woman to serve as a US cabinet secretary, as Secretary of Labor under President Franklin D. Roosevelt. She promoted workplace safety, labor rights, unemployment insurance, minimum-wage protections, and the Social Security Act. The Triangle Fire strongly influenced her commitment to reform.

Describe occupational disease control strategies and relate them to primary, secondary, and tertiary prevention. 

• Primary prevention: Prevents disease before it happens (e.g., reducing workplace hazards like dust or chemicals).

• Secondary prevention: Finds disease early through screenings and health tests.

• Tertiary prevention: Treats and manages disease to reduce complications and improve quality of life.

 Give examples of occupational disease controls from the black lung case study.

Black lung disease is caused by inhaling coal mine dust.

• Primary prevention includes reducing dust at its source, using water sprays and ventilation, and enforcing exposure limits.

• Secondary prevention includes screening miners for early lung disease.

• Tertiary prevention includes medical treatment, pulmonary rehabilitation, and support for workers with advanced disease.

Identify factors contributing to increased severe black lung cases in Central Appalachia.

Factors include

• exposure to very fine silica-containing dust from cutting rock

• mining practices that create more dust

• inadequate dust control

• long-term cumulative exposure.

Distinguish Years of Potential Life Lost (YPLL) from other epidemiology measures. 

• YPLL measures premature death by estimating the years a person would have lived if they had reached a chosen reference age. Deaths at younger ages contribute more YPLL.

  • Incidence measures new cases.

  • Prevalence measures all existing cases in a population.

  • Mortality rate measures deaths in a population over a period.

Identify leading causes of unintentional injury death overall and by age group.

Overall, major causes include drug poisoning/overdose, falls, and motor vehicle crashes

Identify leading causes of nonfatal injuries in children/adolescents, adults, and seniors.

Falls are a major cause of nonfatal injuries across age groups.

Describe injury data trends for leading causes of injury death

• Drug overdose deaths increased dramatically during the opioid crisis, although trends can vary by year.

• Falls have become an increasing concern as the population ages.

• Motor vehicle deaths fluctuate with driving exposure, behavior, and safety policies.

Identify risk factors for non-crash-related fatalities among children in and around cars. 

Risk factors include:

• being left unattended in a hot vehicle

• accidentally entering a vehicle and becoming trapped

• children being struck by vehicles in driveways or parking areas.

Identify causes and prevention strategies for other childhood injury topics. 

• Common childhood injuries are drowning, falls, burns, poisoning, and bike/pedestrian accidents.

• Prevention includes pool fences, supervision, safety gates, smoke alarms, safe storage of medicines, and wearing helmets.

Identify opioid abuse, overdose, and suicide risk factors using host, agent, and environment categories.

The host is the person, the agent is the substance or harmful exposure, and the environment includes surrounding social and physical conditions.

• Host factors: Medical conditions, prior substance use, mental health challenges, previous overdose, and social isolation.

• Agent factors: Opioid potency, unpredictable drug strength, and combinations with other substances that suppress breathing.

• Environment factors: Limited access to treatment, stigma, unstable housing, social stress, and barriers to emergency services.

Describe the three waves of opioid overdose trends. 

• First wave: Increased deaths involving prescription opioids beginning around 1999. 

• Second wave: Increased heroin-related deaths beginning around 2010. 

• Third wave: A sharp increase in deaths involving synthetic opioids, especially illicitly manufactured fentanyl, beginning around 2013.

These waves overlapped rather than replacing one another completely.

Identify programs and policies implemented to reduce opioid overdose risk.

Programs to reduce opioid overdose risk include naloxone, addiction treatment, prescription monitoring, Good Samaritan laws, medication take-back programs, and harm-reduction services.

What is naloxone?

A medication that can rapidly reverse an opioid overdose by blocking opioid effects. It is temporary, so emergency medical assistance is still needed.

What are safe injection sites?

Facilities where people can use previously obtained drugs under trained supervision, with overdose response and referrals to health services available.

Describe two laws that support naloxone intervention. 

• Good Samaritan laws may protect people who seek emergency help during an overdose from certain legal consequences.

• Naloxone access or standing-order laws allow naloxone to be dispensed or obtained without each person needing an individual prescription, depending on state law.

Define harm reduction and give an example.

• Harm reduction refers to practical strategies that reduce the negative health consequences of risky behaviors without requiring someone to stop the behavior first.

  • Examples include naloxone distribution, syringe-service programs, and fentanyl test strips where legally permitted.

Define means restriction in suicide prevention. 

• Means restriction means reducing access to highly lethal ways of causing self-harm during a crisis.

  • Examples include secure storage of firearms and medications, barriers at dangerous locations, and safer storage policies.

Define substitution in suicide and explain how it relates to means restriction. 

The concern that if access to one method is restricted, a person might switch to another method.

Explain what an Extreme Risk Protection Order is and how it relates to suicide prevention.

• An Extreme Risk Protection Order (ERPO) is a legal order that can temporarily restrict a person’s access to firearms when a court determines they pose a serious risk to themselves or others.

Define suicide magnet and give an example.

• A suicide magnet is a location that attracts repeated suicide attempts or deaths, sometimes because of its notoriety or visibility.

  • A well-known bridge associated with repeated suicide incidents is an example. Prevention strategies include physical barriers, crisis phones, monitoring, and connecting people with immediate help.