Infectious diseases

disease

Any condition that impairs normal bodily functions.

disease transmission

The process through which an infectious agent is spread from one host to another.

transmission cycle

The series of steps through which an infectious agent passes from one host to another.

pathogen

Any microorganism that can cause disease in a host.

host

An organism that provides a suitable environment for a pathogen to live and multiply.

exit of pathogen

The process by which a pathogen leaves its host to enter a new host.

transmission of pathogen

The manner in which a pathogen is spread from one host to another.

environment of pathogen transmission

The specific conditions that facilitate the spread of pathogens.

entry of pathogen

The way in which a pathogen enters a new host.

susceptible person/animal

An individual vulnerable to infection due to a lack of immunity.

Infection

The process by which a pathogen establishes itself in a host.

Viruses

Infectious agents that replicate only inside living cells.

bacteria

Microorganisms that can be pathogenic or non-pathogenic.

rickettsia

A genus of bacteria transmitted primarily by arthropod vectors.

Fungi

Eukaryotic organisms that can be pathogenic, often in immunocompromised individuals.

Protozoa

Single-celled eukaryotic organisms that can be pathogenic.

helminths

Multicellular parasitic worms that can infect human tissues.

Lag phase

The initial period where the pathogen adapts to its environment.

Log phase

A period of rapid cell division in pathogens.

Stationary phase

The growth rate slows as resources become limited.

Death phase

The number of viable pathogens decreases as nutrients are depleted.

pathogen consolidation

A stabilization of the population size as pathogens adapt to their environment.

change of pathogen structure

Involves genetic mutations that enhance evasion of host defenses.

pathogen multiplication / reproduction

Pathogens replicate rapidly, leading to increased numbers.

pathogen spread

The dissemination of pathogens from one host to another.

infection of new host

Establishment of infection in a new host following transmission.

latency

The dormant state of a pathogen within the host.

persistance

The ability of a pathogen to survive in the host or environment over time.

persistant pathogen

A pathogen that remains in the host for prolonged periods.

non-persistent pathogen

A pathogen eliminated from the host or environment more rapidly.

non-latent pathogen

A pathogen that actively replicates and causes disease.

active immunity

Immunity developed as a result of exposure to a pathogen.

definitive host

An organism in which a parasite reaches maturity.

intermediate host

An organism that supports the immature forms of a parasite.

zoonoses

Infectious diseases transmitted between animals and humans.

virus

A small infectious agent that replicates inside living cells.

asymptomatic carriers

Individuals infected with a pathogen but showing no symptoms.

transient carrier

A person who temporarily harbors a pathogen without showing symptoms.

chronic carrier

A person who continues to harbor a pathogen for an extended period.

incubating carrier

An individual in the incubation period of an infectious disease.

convalescent carrier

A person who has recovered from an infectious disease but still harbors the pathogen.

pathogen reservoir

A natural host in which a pathogen lives and multiplies.

vectors

Organisms that transmit pathogens from one host to another.

food-borne infections

Illnesses caused by consuming contaminated food or beverages.

vector-borne infections

Infections transmitted through the bite of infected vectors.

water-borne infections

Illnesses caused by ingestion of contaminated water.

water-washed infections

Infections that occur when hygiene is compromised due to lack of clean water.

direct transmission

Spread of infections through direct contact with an infected individual.

fecal-oral infections

Infections that occur when pathogens in fecal matter are ingested.

leptospirosis

Bacterial infection caused by exposure to contaminated water.

infections of direct contact

Infections transmitted through skin-to-skin contact or contaminated surfaces.

infections with indirect transmission

Infections transmitted through an intermediary like air or vectors.

soil transmitted helminths

Parasitic worms transmitted through contaminated soil.

entrance by penetration of the skin

Infections occurring when pathogens enter through skin breaks.

entrance by ingestion

Infections that occur through contaminated food or water.

water-based helminths

Parasitic worms transmitted through contaminated water sources.

beef/pig tapeworm infection

Infections from consuming undercooked beef or pork.

guinea worm

A parasitic infection from drinking contaminated water.

vector-borne diseases

Infections transmitted by vectors like mosquitoes and ticks.

environment

Surrounding conditions influencing the spread of infectious diseases.

climate

Long-term patterns of temperature and weather affecting disease transmission.

landscape

Physical features of an area that influence the spread of infectious diseases.

human surroundings

The social and built environments impacting health behaviors.

human behavior

Actions of individuals that influence the transmission of infectious diseases.

future host

Potential organisms that can harbor pathogens.

infectious dose

The minimum number of pathogens required to establish an infection.

barriers of the body against pathogens

Defenses that protect hosts from infection.

infection over time

The progression and changes in an infection within a host.

Endemic disease

A disease that occurs regularly in a group of people

Epidemic disease

A widespread occurrence of a disease in a group of people, beyond what is normally there

Pandemic disease

An epidemic disease that is impacting multiple countries at the same time

Important terms for pathogens

• life cycle

• Latency

• Persistence

• Infectivity

• Mode of transmission

• Immunity

Important terms for transmission cycle of disease

• definitive host

• Zoonosis

• Disease vector

• Carrier

transmission cycle of disease: Important terms for exit, transmission, and entry

• food borne infection

• Water borne infection

• Vector borne infection

• Direct contact infections

• Fecal-oral contact

• Trachoma

• Scabies

• STD