Infectious diseases

Disease

Any disorder in a human that produces symptoms and is not simply a direct result of physical injury.

infectious disease

Diseases caused by the spread of pathogenic microorganisms, such as bacteria, viruses, fungi, or parasites.

How can infectious diseases be spread?

Directly or indirectly from one person to another, or from animals or the environment, such as food or water.

What is an infectious agent?

The pathogen responsible for causing a disease.

What are the four main groups of micro-organisms?

Bacteria, viruses, fungi, parasites

What is a spirochete shaped like?

spiral

where is spirochete found in?

can live in mud and sediments

What disease does Leptospira cause?

Leptospirosis

where can leptospira be found in?

animals and humans

What is Vibrio cholerae known for?

Causing Asiatic cholera

What does Escherichia coli (E. coli) cause?

Intestinal and urinary tract infections, and can lead to neonatal meningitis.

What are pyogenic cocci?

Spherical bacteria that cause suppurative (pus-producing) infections.

where does Staphylococcus epidermidis live

lives on the skin and mucous membranes

Staphylococcus aureus

A pathogen that can cause various infections and is a leading cause of hospital-acquired infections.

bacterial endospores

Dormant forms of bacteria that are highly resistant to physical and chemical agents.

Which bacteria can form endospores?

Bacillus and Clostridium.

What disease does Mycobacterium tuberculosis cause?

Tuberculosis

What does Corynebacterium diphtheriae cause?

Diphtheria.

What is the role of beneficial bacteria in the human body?

They aid in the digestive process and overall health.

What is the difference between pathogenic and non-pathogenic bacteria?

Pathogenic bacteria cause disease, while non-pathogenic bacteria can be harmless or beneficial.

How do pathogens typically enter the human body?

Through direct contact, bodily fluids, contaminated surfaces, air, food, and drink.

What is the significance of the NHMRC and ACQSHC in healthcare?

They produce guidelines for the prevention and control of infection in healthcare.

What is the role of actinomycetes in medicine?

They are used to produce antibiotics.

What are some examples of diseases caused by pathogenic bacteria?

Syphilis, whooping cough, anthrax, botulism, and tetanus.

What are multidrug-resistant (MDR) pathogens?

Pathogenic bacteria that mutate to become more virulent and resistant to antibiotic treatments.

MDR

multi-drug resistant

What is Methicillin-resistant Staphylococcus aureus (MRSA)?

A type of staph bacteria resistant to many antibiotics, causing serious infections.

MRSA

methicillin-resistant staphylococcus aureus

How are MRSA infections commonly transmitted?

Through unclean hands or contaminated surfaces

What is the primary function of a virus?

To invade host cells and reproduce using the host's cellular mechanisms.

What is the process called when a virus pushes against a host cell's membrane to form a viral envelope?

Budding.

What is lysis in the context of viral replication?

When a new viral particle bursts out of the host cell, damaging or destroying it.

What are enveloped viruses?

Viruses that have a lipid envelope derived from the host cell membrane.

What are non-enveloped viruses?

Viruses that lack a lipid envelope, making them more resistant to external stressors.

How do non-enveloped viruses typically transmit?

Via the fecal-oral route, contaminated surfaces, or fomites.

What is colonization in microbiology?

The process of an organism taking up residence on a host without causing harm.

What are asymptomatic carriers?

Individuals who carry a pathogen without showing symptoms but can still transmit it.

What are the five stages of the infection process?

Incubation, Prodromal, Illness, Decline, Convalescence.

What occurs during the incubation stage of infection?

Time from exposure to onset of symptoms; pathogens replicate during this period.

What happens during the prodromal stage?

symptoms appear as the infectious agent continues to replicate.

What characterizes the illness stage of infection?

The presence of specific symptoms of the infectious disease.

What occurs during the decline stage of infection?

The immune system successfully fights the pathogens, and symptoms begin to improve.

What is convalescence?

The stage where symptoms resolve, and the person returns to normal functions.

What is the role of the immune response during infection?

To combat the infectious agent and help the host recover from the infection.

What can happen during the decline stage if the immune system is weakened?

Secondary infections may develop.

What is the process called when a pathogen spreads from person to person?

The chain of infection

How many links are there in the chain of infection?

Six links

What is the first link in the chain of infection?

Causative agent

What is a causative agent?

The pathogen that begins the infection

What is the second link in the chain of infection?

Reservoir

What is a reservoir in the context of infection?

The habitat of the infectious agent where it lives, grows, and multiplies.

What are common reservoirs for infectious agents?

Environment, animals, and humans.

What is the third link in the chain of infection?

Portal of exit

What is a portal of exit?

The pathway by which the pathogen leaves the reservoir or host.

What is the fourth link in the chain of infection?

Mode of transmission

What are the three main modes of transmission in healthcare settings?

Contact, droplet, and airborne.

What is contact transmission?

Transmission by touch or contact with blood or body substances.

Indirect transmission

Transmission through contact with an intermediate contaminated object

What is vector transmission?

Transmission where a living organism carries the infectious agent to a new host.

What is vehicle transmission?

Transmission where a substance like soil, water, or air carries an infectious agent.

What is droplet transmission?

Transmission that occurs when an infected person coughs, sneezes, or talks, transferring infection with droplets.

What size are droplets in droplet transmission?

Larger than 5 microns.

What is airborne transmission?

Transmission via particles suspended in the air that remain infective over time and distance.

What size are aerosols in airborne transmission?

Smaller than 5 microns.

What is the fifth link in the chain of infection?

Portal of entry

What is the sixth link in the chain of infection?

Susceptible host

How can brucellosis infect humans?

Through direct contact with infected animal tissues or fluids, or consuming undercooked meat or unpasteurized milk.

What are fomites?

Objects or materials likely to carry infection.

What is the role of healthcare workers in infection transmission?

They can transmit infectious agents if proper hand hygiene is not performed.

What are aerosols?

Infectious particles smaller than 5 microns created during breathing, talking, coughing, or sneezing.

How do aerosols differ from droplets?

Aerosols are smaller than droplets (less than 5 microns) and can remain suspended in the air longer.

What is direct transmission?

Movement of infection from one host to another through direct physical contact.

What is the portal of entry?

The route through which infectious agents enter a susceptible host.

What factors can increase susceptibility to infections?

Age, immune status, co-morbidities, and presence of medical devices or implants.

What is an endogenous infection?

An infection caused by bacteria residing within the host's own body.

What is an exogenous infection?

An infection caused by pathogens from external sources.

What is an infectious disease?

An illness caused by the spread of pathogenic microorganisms.

What are pathogens?

Substances responsible for causing disease.

What is the incubation period?

The time from exposure to an infectious agent until the onset of symptoms.

What occurs during the prodromal phase?

The period after incubation before the characteristic symptoms of infection occur.

What happens during the illness phase?

The time when a person shows symptoms of an infectious disease.

What is the decline phase?

The time when the immune system successfully defends against pathogens, leading to symptom improvement.

What is the means of transmission?

The method by which an infectious agent is transferred to a susceptible host.

standard precaution

asic infection prevention measures applied to all patients, regardless of their infection status

transmission precaution

additional measures used when a patient has a known or suspected infectious condition

what are the nine foundational infection prevention practices

Hand hygiene

Personal protective equipment

Respiratory hygiene and cough etiquette 

Safe use and disposal of sharps

Aseptic technique

Routine environmental cleaning

Waste management

Safe handling of laundry and linen

Cleaning and reprocessing reusable medical equipment.

cross contamination: multiple site on the same patient

travelling from a site on a patient to another site on the same patient. ie. one eye to the other eye

cross contamination: healthcare worker to patient

worker transfering something my hand to the patient

cross contamination: the patient to the environment

patient making contact with objects while carrying an infectious disease

cross contamination: Healthcare worker and the environment

healthcare worker making contact with an object, making the object a reservoir

cross contamination: between two healthcare workers

nfections being transferred from one individual to another, rubbing an eye infection and then shaking a hand

hand hygene in terms with transmittion of infection

the act of removing or reducing micro-organisms on the hands in order to prevent transmission of infections

the five moments of hand hygene

1. before touching a patient

2. before a care procedure or body substance exposure risk

3. after a care procedure or body substance exposure risk

4. after touching a patient

5. after touching a patients surroundings

exogenous infection

an infection caused by an organism forren to the patient

procedure

an active care for a patient where there is a risk of direct introduction of a pathogen into the patient's body

what are the two hand hygiene techniques

hand rubbing and hand washing

hand rubbing hygiene technique

the use alcohol based hand rub on the surface of the hands

pathogens vs hand rubbing

it does not remove them it can only attempt to disable them.