HSC Ch 4 Notes

Methods of classification of diseases

By organ/organ system or by causative agent.

Biological agents

Microorganisms causing disease, including viruses, bacteria, protozoa, rickettsiae, and fungi.

Chemical agents

Substances such as drugs, pesticides, food additives, and pollutants that can cause health problems.

Physical agents

Factors like radiation, heat, noise, and falling objects that can lead to health issues.

Communicable disease

A disease caused by biological agents that can be transmitted between individuals.

Infection

The establishment of a communicable disease agent in a host.

Host

Any susceptible organism that can be invaded by an infectious agent.

Host environment

Includes physical, biological, and social factors influencing disease transmission.

Infectivity

The ability of a biological agent to enter and grow in a host.

Pathogenicity

The capacity of an infectious agent to produce disease.

Chain of infection

The process by which a communicable disease spreads: Pathogen > Reservoir > Portal of Exit > Transmission > Portal of Entry > Establishment of infection.

Case

A person who has the disease.

Carrier

A healthy person who is infected and can spread the disease to others.

Zoonosis

A disease where the reservoir resides in animal populations, such as rabies.

Direct transmission

Immediate transfer of a disease agent between infected and susceptible individuals via direct contact.

Indirect transmission

Airborne, vehicleborne, or vectorborne transfer of a disease agent to a susceptible individual.

Noncommunicable disease

A disease that is not transmitted between individuals.

Eitology

The cause of a noncommunicable disease.

Coronary heart disease

The leading cause of death in the US, characterized by damage to coronary arteries.

Lifestyle contributing factors

Factors like smoking, high blood pressure, and obesity that increase disease risk.

Cancer

Occurs when cells lose control over growth and division.

Metastasis

Spread of cancer cells to distant parts of the body.

Smoking

An important risk factor for lung cancer.

Primary prevention

Measures to prevent the onset of illness or injury before it occurs.

Secondary prevention

Early diagnosis and treatment to prevent disease progression.

Tertiary prevention

Rehabilitation efforts for patients with existing diseases.

Active immunity

Immunity developed by the organism after exposure to disease.

Passive immunity

Immunity gained by receiving antibodies from another source.