HSC Ch 4 Notes

Methods of classification of diseases and health problems include by organ/organ system, ot by causative agent

• Biological agents include viruses, bacteria, protozoa, rickettsiae, fungi

• Chemical agents include drugs, pesticides, food additives, pollutants

• Physical agents include radiation, heat, noise, falling objects

Communicable disease: Disease for which biological agents or their products are the cause and is transmissible from one individual to another

• Infection: Establishment of a communicable disease agent in a host

• Acute example: Pneumonia

• Chronic example: AIDS

• Host: Any susceptible organism to be invaded by an infectious agent

• Host environment: Includes physical, biological, social factors that inhibit or promote disease transmission

• Infectivity: Ability of a biological agent to enter and grow in a host

• Pathogenicity: Infectious disease agent’s ability to produce disease

• Chain of infection: Step by step process by which communicable disease spread from an infected person to an uninfected person in the community

  • Pathogen > Reservoir > Portal of Exit > Transmission > Portal of Entry > Est. of infection in new host

• Case: Person who has the disease

• Carrier: A well person who is still infected and capable of infecting others

• Zoonosis: Disease for which the reservoir resides in animal populations

  • Ex. Rabies

• Direct transmission: immediate transfer of the disease agent between the infected and susceptible individuals by direct contact

  • ex. Kissing and then getting mono

• Indirect transmission: airborne, vehicleborne (contaminated materials/objects), or vectorborne (living organism) transmission of a disease agent to a susceptible individual

Noncommunicable disease: Disease that cannot be transmitted from one person to another

• Contributing factors can be genetic, environmental, or behavioral

• Acute example: Appendicitis

• Chronic example: Diabetes

• Eitology: cause of a noncommunicable disease

• Diseases of the Heart/Blood vessels

  • Nearly 1 in every 4 deaths in the US can be attributed to heart disease

  • Coronary heart disease: Leading cause of death in the US

    • Characterized by damage to the coronary arteries which usually evolves from atherosclerosis (narrowing of blood vessels due to fatty buildup)

    • Lifestyle contributing factors: Smoking, high blood pressure, high cholesterol, obesity, stress

    • Non-lifestyle contributing factors: Age, sex, race, genetics

  • Cancer/malignant neoplasm: Occurs when cells lose control over growth/division

    • Metastasis: spread of cancer cells to distant parts of the body by circulatory or lymphatic system

    • Cancer sites with the highest # of new cases are the prostate and breast

    • Lung cancer is the leading cause of cancer deaths in both sexes

      • Smoking is an important risk factor

    • Highest cancer mortality rates are seen in non-Hispanic black men and women

    • Skin cancer is the most commonly diagnosed cancer in the US

  • Other noncommunicable disease

    • Alzheimer’s

    • Epilepsy

    • Cerebral palsy

Prevention and control

• Use of the YPLL statistic to focus on all ages

• Estimating the economic cost of the impact of a disease/health problem to a country or community

• Prevention: planning for and taking of action to prevent or forestall the occurrence of an undesirable event

• Intervention: taking of action during an event

• Eradication: uprooting or total elimination of a disease from the human population

  • Rarely achieved in public health (ex. Smallpox)

• Primary prevention: To forestall the onset of illness or injury during the prepathogenesis period

  • Ex. health education, immunization, use of face masks

• Secondary prevention: early diagnosis and prompt treatment of diseases before a disease becomes advanced and severe

  • Health screenings (ex. pap smears, diabetes screenings)

  • Isolation: seperation for the period of communicability of infected persons or animals from others to prevent direct/indirect transmission

  • Quarantine: limitation of the freedom of movement of well persons or animals that have been exposed to a communicable disease until the incubation period has passed

  • Disinfection: killing of communicable agents outside the host, use of antibiotics

• Tertiary prevention: to retrain, reeducate, rehabilitate a patient that has already acquired a disease or disability

  • Ex. therapy for someone with a heart condition

• Use of the chain of infection to prevent communicable diseases

  • Weakening each link using preventative measures

  • Ex. for Human Reservoir - using quarantine measures and drug treatment in a carrier

  • Active immunity: when a person is exposed to an organism that causes diseases and their body develops antibodies that know how to fight off that disease

  • Passive immunity: when people recieve the antibodies rather than their own body making them

    • Ex. a baby receiving antibodies from breast milk, vaccinations