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Chapter 4Epidemiology Prevention and Control of .docx
- 1. Chapter 4 Epidemiology: Prevention andControl of Diseases and Health Conditions Introduction • Diseases and other health conditions are classified in several meaningful ways • Classification can lead to prevention and control strategies Classification of Diseases and Health Problems • In community health, diseases are usually classified as: • Acute or chronic (<3 or >3 months)
- 2. • Communicable ornoncommunicable Communicable versus Noncommunicable Diseases • Communicable (infectious) diseases – those diseases for which biological agents or their products are the cause and that are transmissible from one individual to another • Noncommunicable (noninfectious) diseases – those illnesses that cannot be transmitted from one person to another • Identifying cause is difficult because many factors can contribute Acute versus Chronic Diseases and Illnesses • Diseases classified by duration of symptoms • Acute – diseases in which peak severity of
- 3. symptoms occurs andsubsides within 3 months • Can be communicable or noncommunicable • Chronic – diseases or conditions in which symptoms continue longer than 3 months • Can be communicable or noncommunicable Communicable Diseases • Infectivity: ability of a biological agent to enter and grow in the host • Agent: cause of disease or health problem • Host: susceptible person or organism invaded by an infectious agent • Environment: factors that inhibit or promote disease transmission • Pathogenicity: capability of a communicable agent to cause disease in a susceptible host
- 4. Biological Agents ofDisease Communicable Disease Model Chain of Infection • Step-by-step model to conceptualize the transmission of a communicable disease from its source to a susceptible host Chain of Infection • Pathogen: disease causing agent (virus, bacterium, etc.) • Reservoir: favorable environment for infectious agent to live and grow (human, animal, etc.) • Portal of exit: path by which agent leaves host Transmission: how pathogens are passed from reservoir to next host • Portal of entry: where agent enters susceptible host
- 5. New host: susceptibleto new infection being established Chain of Infection • Zoonoses – diseases for which the reservoir resides in animal populations • Anthroponoses – diseases for which humans are the only known reservoir Modes of Transmission • Direct transmission – immediate transfer of disease agent between infected and susceptible individuals • Touching, biting, kissing, sexual intercourse • Indirect transmission – transmission involving an intermediate step • Airborne, vehicleborne, vectorborne, biological • Vehicles – nonliving objects by which agents
- 6. are transferred tosusceptible host Chain of Infection Example • Agent (cold virus), leaves reservoir (throat of infected person), when host sneezes (portal of exit-nose and mouth). Direct transmission (saliva droplets) enter respiratory tract of susceptible host at close range (portal of entry-mouth). New infection possibly established. If one link is missing, chain is broken. Noncommunicable Diseases • Nation’s leading causes of death • Heart disease, stroke, cancer • Complex etiologies (causes) • Multicausation disease model • Host: inalterable, unique genetic endowment • Personality, beliefs, behavioral choices: impact host
- 7. • Complex environment:exposes host to risk factors Multicausation Disease Model Noncommunicable Disease Problems • Diseases of the heart and blood vessels • Coronary heart disease • Cerebrovascular disease (stroke) • Malignant neoplasms (cancer) • Chronic obstructive pulmonary disease • Diabetes mellitus • Chronic liver disease and cirrhosis Prioritizing Prevention and Control Efforts • Criteria used to judge importance of disease to a community • Number of people who will die from a disease
- 8. • Leading causesof death • Number of years of potential life lost • Captures issues affiliated with various groups • Economic costs associated with disease • Money spent at various levels of government; ex: alcohol and other drugs Prevention, Intervention, Control, and Eradication of Diseases • Prevention: planning for and taking action to prevent or forestall onset of disease or health problem • Intervention: effort to control disease in progress; taking action during an event • Control - Containment of a disease; prevention and intervention measures • Eradication: total elimination of disease from human population
- 9. Levels of Prevention •Primary prevention • Forestall onset of illness or injury during prepathogenesis period • Secondary prevention • Early diagnosis and prompt treatment before disease becomes advanced and disability severe • Tertiary prevention • Aimed at rehabilitation following significant pathogenesis; retrain, reeducate, rehabilitate Primary Prevention of Communicable Diseases • Strategies at each link in chain of infection • Individuals • Hand washing, using condoms, properly cooking food
- 10. • Communities • Chlorinatingwater supply, inspecting restaurants, immunization programs for all citizens, vector control, solid waste disposal • Individuals • Self-diagnosis, self-treatment w/home remedies • Antibiotics prescribed by a physician • Communities • Controlling or limiting extent of an epidemic • Carefully maintaining records; investigating cases • Isolation, quarantine, disinfection Secondary Prevention of Communicable Diseases • Individuals • Recovery to full health after infection; return to
- 11. normal activity • Communities •Preventing recurrence of epidemics • Removal, embalming, burial of dead • Reapplication of primary and secondary measures Tertiary Prevention of Communicable Diseases Primary Prevention of Noncommunicable Diseases • Individuals • Education and knowledge about health and disease prevention, eating properly, adequate exercise, driving safely • Communities • Adequate food and energy supplies, efficient community services, opportunities for education, employment, and housing
- 12. Secondary Prevention of NoncommunicableDiseases • Individuals • Personal screenings (mammogram, pap test, PSA test), regular medical and dental checkups, pursuit of diagnosis and prompt treatment • Communities • Provision of mass screenings for chronic diseases, case-finding measures, provision of adequate health personnel, equipment, and facilities Tertiary Prevention of Noncommunicable Diseases • Individuals • Significant behavioral or lifestyle changes, adherence to prescribed medications, following rehabilitation requirements after surgery
- 13. • Communities • Adequateemergency medical personnel and services: hospitals, surgeons, nurses, ambulance services Discussion Questions • Which components of the Multicausation Disease Model can communities most effectively impact? • Which level of prevention is most important for better community health outcomes and why? • Who plays a more significant role in preventing diseases, individuals or communities? Chapter 12
- 14. Alcohol, Tobacco, and OtherDrugs: A Community Concern Introduction • Use, misuse, and abuse of mind-altering substances predates recorded history • Chronic alcohol and other drug abuse or dependence is regarded as destructive behavior in most cultures • Affects individuals and the surrounding community Scope of the Current Drug Problem • More deaths, illnesses, and disabilities can be attributed to substance abuse than any other preventable health condition • Economic costs include direct costs (health
- 15. care, premature death,impaired productivity) and indirect costs (crime and law enforcement, courts, jails, social work) • Those abusing are threats to themselves, their families, and their communities Annual Cost in Lives and Economic Cost in $ Billions Drug Use Among High School Seniors Definitions • Drug • Psychoactive drugs • Drug use • Drug misuse • Drug abuse • Drug (chemical) dependence
- 16. • Psychological dependence Factorsthat Contribute to Alcohol, Tobacco, and Other Drug Abuse • Risk factors – factors that increase the probability of drug use • Protective factors – factors that lower the probability of drug use • Both can be genetic or environmental Inherited Risk Factors • Most research related to drug dependence and inherited risk is on alcoholism • Research has shown genetic and biological markers may predispose someone to increased susceptibility to develop alcohol-related problems
- 17. Environmental Risk Factors •Personal factors • Home and family life • School and peer groups • Sociocultural environment Types of Drugs Abused and Resulting Problems • Legal drugs • Alcohol, nicotine, nonprescription (over-the- counter) drugs, prescription drugs • Controlled substances and illegal (illicit) drugs • Marijuana, narcotics, cocaine and crack cocaine, hallucinogens, stimulants, depressants, club drugs and designer drugs, anabolic drugs, inhalants Legal Drugs • Can be legally bought and sold in the
- 18. marketplace • Includes drugsthat can be closely regulated, likely regulated, and not regulated at all Alcohol • Number one drug problem in the United States • Binge drinking • Underage drinking • Problem drinkers • Alcoholism • Blood alcohol concentration (BAC) • Fetal Alcohol Spectrum Disorders • Fetal Alcohol Syndrome Nicotine • Psychoactive and addictive drug present in tobacco products • Environmental tobacco smoke (ETS) or
- 19. secondhand smoke • SynarAmendment • Tobacco use is single most preventable cause of disease, disability, and death in the U.S. • Community efforts: tax increases on cigarettes Over the Counter Drugs (OTCs) • Legal drugs other than alcohol and tobacco that can be purchased without a physician’s prescription • Carefully regulated by the Food and Drug Administration (FDA) • Most only provide symptomatic relief, not a cure • Subject to misuse and abuse Prescription Drugs • Can be purchased only with a physician’s
- 20. prescription because theyhave serious side effects for some people • Regulated by the FDA • Subject to misuse and abuse • Risk of dependence and unintentional overdose • Development of drug-resistant strains of pathogens Controlled Substances and Illicit Drugs • Those regulated by the Controlled Substances Act of 1970 • Cannot be cultivated, manufactured, bought, sold, or used within the confines of the law • Schedule I – high potential for abuse; no accepted medical uses • Schedules II-V – have medical uses; scheduled based on potential for risk of dependence or
- 21. abuse • Drug EnforcementAgency (DEA) responsible for enforcing Controlled Substances Act Marijuana • Products derived from hemp plant • Most abused illicit drug in the U.S. • Often used in conjunction with other drugs – polydrug use • Acute effects – reduced concentration, slowed reaction time, impaired short term memory, impaired judgment • Chronic effects – damage to the respiratory system (if smoked), amotivational syndrome Synthetic Marijuana • Emerging cause for concern • Chemically produced with properties similar to
- 22. THC • Pose seriousthreat to communities – potential for abuse and other adverse health effects, long-term effects unknown • In 2011, five chemicals used to produce synthetic marijuana were added to Schedule I of the CSA • States have banned synthetic marijuana Narcotics • Opium and its derivatives, morphine and heroin, come from an oriental poppy plant • Narcotics numb the senses and reduce pain • High potential for abuse • Opium poppies do not grow in U.S.; drug trafficking problems • Heroin addiction leads to significant community health problems
- 23. Cocaine and CrackCocaine • Cocaine is the psychoactive ingredient in the leaves of the coca plant • Powerful and addictive euphoriant/stimulant • Purified forms – salt (white powder), dried paste (crack) • In 2012, annual prevalence of cocaine use among high school seniors at lowest reported level of 2.7% Hallucinogens • Produce illusions, hallucinations, changes in perceptions • Synesthesia – mixing of the senses • Both naturally derived and synthetic • LSD, mescaline, peyote, mushrooms Stimulants
- 24. • Drugs thatincrease the activity of the central nervous system • Amphetamines • Schedule II prescription drugs; widely abused • Methamphetamines often made in clandestine labs Clandestine Laboratory Incidents Depressants • Slow down the central nervous system • May lower anxiety and inhibitions • Tolerance develops • Strong physical dependence • Alcohol, barbiturates, benzodiazapines Club Drugs and Designer Drugs • Illicit drugs, primarily synthetic, most
- 25. commonly encountered atnightclubs and raves • MDMA (ecstasy) most popular club drug • Rohypnol – “date rape” drug • Designer drugs – synthesized by amateur chemists in secret labs • Constantly change design to stay ahead of law enforcement Anabolic Drugs • Protein-building drugs • Anabolic/androgenic steroids, testosterone, human growth hormone • Have some legitimate medical uses • Sometimes abused by athletes and body builders • Acute and chronic side effects Inhalants
- 26. • Collection ofpsychoactive breathable chemicals • Paint solvents, motor fuels, cleaners, glues, aerosol sprays • Easy availability • Low cost • Often drug choice of young • Acute and chronic effects Prevention and Control of Drug Abuse • Requires knowledge of: • Causes of drug-taking behavior • Sources of illicit drugs • Drug laws • Treatment programs • Community organizing skills • Persistence, and cooperation of various individuals and agencies
- 27. Levels of Prevention •Primary prevention aimed at those who have never used drugs • Secondary prevention aimed at those who have used, but are not chronic abusers • Tertiary prevention aimed at drug abuse treatment and aftercare, including relapse prevention Elements of Prevention • Education • Treatment • Public policy • Law enforcement • Education and treatment goals same: • Reduce demand for drugs • Public policy and law enforcement goals same:
- 28. • Reduce supplyand availability of drugs Governmental Drug Prevention and Control Agencies and Programs • Include a multitude of federal, state, and local agencies • Aim to reduce either the supply or demand for drugs Federal Drug Control Spending Federal Drug Control Spending Federal Agencies and Programs • Office of National Drug Control Policy • Department of Justice • Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF)
- 29. • Department ofHealth and Human Services • Substance Abuse and Mental Health Services Administration (SAMSHA) • National Institute on Drug Abuse • Department of Homeland Security State and Local Agencies and Programs • State departments of health, education, mental health, justice, and law enforcement all address drug abuse prevention and control issues • Some states have passed laws that conflict with federal laws • Local communities have individuals, task forces, or agencies to prioritize problems and decide approaches for solving them Nongovernmental Drug Prevention and
- 30. Control Agencies andPrograms • Community-based drug education programs • School-based drug education programs • DARE, student assistance programs, peer counseling programs • Workplace-based drug education programs • Employee assistance programs • Voluntary health agencies Discussion Questions • How can risk factors for drug abuse be utilized to aide in drug abuse prevention? • How should federal, state, and local funds be used to successfully deal with drug abuse problems?