EPIDEMIOLOGY & BIOSTATISTICS
CHAPTER 2 : TERMS USED IN EPIDEMIOLOGY INVESTIGATION
MIND MAP
THE EPIDEMIOLOGY TRIANGLE
EPIDEMIOLOGY TERMS
Disease: a response by a living organism to form invasion by a foreign substance/injury which causes an alteration of normal functioning.
Pathogens : organisms such as bacteria, viruses, or parasites that are capable of producing diseases
Pathogenesis : the development, production, or process of generating a disease
Pathogenicity : the potential ability and strength of a pathogenic substance to cause disease
AGENT
The 4 factors contribute to the outbreak of a disease
- Role of the host
- Agent
- Environmental circumstances
- Time
HOST
The agent is the cause of the disease:
- Bacteria, virus, protozoa, fungi
- Chemicals (solvents), Radiation, heat, natural toxins (snake or spider venom)
There are 6 types of agents:
- Biological
- Physical
- Chemical
- Mechanical
- Nutritional
Social
The host is an organism, usually human or animal, which are exposed and harbors the disease
Different people may have different reactions to the same agent.
There are 4 factors of host:
- Demographic
- Biological
- Socio-economic
- Lifestyle
ENVIRONMENT
There are 3 factors of environment:
- Physical
- Biological
- Psycho-social
TIME
Most infectious diseases have an incubation period, between when the host is infected and when disease symptoms occur.
LEVELS OF DISEASE
Diseases have a range of seriousness, effect, duration, severity, and extent and are classified into 3 levels:
- Acute: severe of short duration, and often treatable. usually, the patient either recovers or dies.
- Subacute: intermediate in severity and duration, having some acute aspects to the disease for longer duration and with a degree of severity. The patient is expected to eventually heal.
- Chronic: less severe but long or continuous duration, lasting over a long time period, if not a lifetime. The patient may not fully recover and the disease can get worse over time. Life not immediately threatened, but maybe over the long term
MUHAMMAD SAIFUL ISLAM BIN BAHARUDIN
(012021071984)
KESAVAN SUPPIAH
(012021021498)