Introduction to Infection Flashcards
What is an infection?
An invasion of a host’s tissue by micro-organisms
What is disease caused by?
- Microbial multiplication
- Toxins
- Host response
What is the importance of the host response causing a lot of damage?
When looking at managing patients, need to take into account what the host is doing
How can people get infections?
- Directly from source
- Through an intermediary
- From the environment
- From animals
- Themselves
Give an example of an intermediary that can cause disease
Mosquito
What environmental sources are there of disease?
- Water
- Food
- Air
- Surfaces
What is the importance of disease transmitted through water?
Many young children killed by diarrhoea every year, mostly as a result of ingesting contaminated water
What diseases are particularly caused by ingested of contaminated food?
Gastroenteritis
How can air transmit disease?
If it is contaminated by environmental organisms
Give an example of a surface that can become contaminated by pathogens
Medical devices
What is the importance of the contamination of medical devices?
Potentially very important/dangerous infections, e.g. viral hepatitis, HIV
What is it called when a disease is transmitted by an animal?
Zoonosis
How can animals get infections?
From the environment, or infect the environment which then infects the patient
How can a person get an infection from themselves?
Organisms that the patient has in one place can spread to another place
What is meant by microbiota?
An ecological collection of microorganisms that are carried on the skin and mucosal surfaces
Are microbiota harmful?
They are normally harmless, or even beneficial, but can be harmful if they transfer to other sites
Give an example of where transfer of the microbiota can cause disease?
E. Coli from the large bowel getting into the urinary tract can use a UTI
What is true of many organisms considered to be pathogenic?
Many organisms considered to be pathogenic are only so when they’re in the wrong place
What is meant by microbiome?
It is a description of the entire ecosystem, including the host
Give an example of a group of infections that require physical contact for transmission
Sexually transmitted infections
Give an example of an infection where airborne spread is sufficient for transmission
Chickenpox
What are aerosols?
Small particles that can suspend in air
What do aerosols allow?
Air can remain infectious from some hours after someone infected has been in a room
Give an example of an infection where a vector is required for spread
Malaria
What are the modes of horizontal transport?
- Contact
- Inhalation
- Ingestion
What kinds of contact can transmit infection?
- Direct
- Indirect
- Vectors
What can be inhaled to spread infection?
- Droplets
- Aerosol
What kind of transmission is common through ingestion?
Faecal-oral transmission
What are the modes of vertical transmission?
Mother to child
When can infection be spread from mother to child?
Before or after birth
Give an example of an infection that be transmitted mother to child?
HIV