Modes of transmission of Infectious Diseases

• What is an infectious disease?

  An illness due to a pathogen or its toxic product transmitted to a susceptible host.
• How do infectious diseases impact global health systems?

  They create an immense burden that disproportionately affects vulnerable populations.
• What factors contribute to the global spread of infectious diseases?

  Economic integration, industrialization, urbanization, and mass migration.
• Name three examples of infectious diseases.

  Malaria, cholera, and tuberculosis,
• What are emerging infectious diseases?

  Diseases that have newly appeared or rapidly increased in incidence or geographic range.
• What does the term "modes of transmission" refer to?

  How an infectious agent can be transferred from one host to another.
• Why is understanding modes of transmission important?

  It helps to limit the spread of infectious diseases.
• What is the chain of transmission?

  The series of events that result in a new person becoming infected.
• What are vehicles in the context of infectious disease transmission?

  Inanimate objects that serve as intermediaries for pathogen transmission.
• What is a fomite?

  An object or surface capable of transmitting infectious agents.
• What is a vector in infectious disease transmission?

  A living organism involved in the indirect transmission of a pathogen.
• What is a portal of entry?

  The site at which an infectious agent enters a susceptible host.
• What is a portal of exit?

  The path through which an infectious agent leaves a host.
• What is a susceptible host?

  An individual at risk of infection following exposure to an infectious agent.
• What does the epidemiological triad model illustrate?

  Infectious diseases occur due to the interaction between an agent, a host, and the environment.
• What are the stages of interaction in the epidemiological triad?

  Infection, disease, and recovery or death.
• What is colonization in the context of infectious diseases?

  The adherence and initial multiplication of a disease agent at a portal of entry.
• How does infection differ from disease?

  Infection disrupts host tissues but does not always result in disease.
• What are latent infections?

  Infections where the agent remains quiescent in host cells and can reactivate later.
• Why are latent infections significant from a public health standpoint?

  They represent silent reservoirs of infectious agents for future transmission.
• What are the primary sources of infectious agents?

  Human sources, contaminated objects, and environmental sources.
• What is direct transmission?

  Transfer of the infective form of the agent directly from a reservoir to a host.
• What is indirect transmission?

  Transfer of the agent via a live or inanimate intermediary.
• What is direct physical contact in disease transmission?

  Contact between the skin or mucosa of an infected person and a susceptible individual.
• What is direct droplet transmission?

  Transmission that occurs through droplets projected from sneezing, coughing, or talking.
• In what settings do diseases spread by direct contact and droplet transmission commonly occur?

  Households, schools, and refugee camps.
• How does direct contact to an agent in the environment occur?

  Exposure to infectious agents maintained in environmental reservoirs.
• What is the most common means of infection with rabies virus?

  Animal bites through broken skin.
• What are the two types of transmission that occur during pregnancy and delivery?

  Transplacental and perinatal transmissions.
• What is biological transmission?

  Transmission requiring multiplication or development of a pathogenic agent within a vector.
• What is the extrinsic incubation period?

  The time necessary for a pathogenic agent to become infectious within a vector.
• What are some diseases transmitted by biological vectors?

  Lymphatic filariasis, Lyme disease, and schistosomiasis.
• What is mechanical transmission?

  Transmission that does not require pathogen multiplication within a living organism.
• Give an example of a disease spread by mechanical vector transmission.

  Shigellosis transmitted by flies.
• What is airborne transmission?

  Transmission associated with inhalation of droplet nuclei that remain infective over time.
• What size are droplet nuclei in airborne transmission?

  1. 5 µm.
• How does respiratory transmission differ from airborne transmission?

  Respiratory transmission is limited to within 3 feet of the source.
• What is the basic approach to preventing transmission from contaminated vehicles?

  Prevent contamination, decontaminate, or eliminate the vehicle.
• What is food hygiene?

  Conditions and activities employed to prevent microbial contamination of food.
• What are the four major categories of vector control strategies?

  Biological, chemical, environmental, and mechanical.