Pathogens and Diseases Test

Pathogens

Pathogens are infectious agents that cause disease or illness to a host (the host is an organism in which the parasite does damage.

Parasite

A type of pathogen which needs a living host to survive.

(Bacteria, Viruses, and Fungi can live outside the body so they are not considered parasites)  

Ex.  Tapeworms, Hookworms, other unicellular (eukaryotic) organisms which cause infections.

Vector

A vector is an organism which does not cause an infection but carries an infection from one organism to another.

Ex.  Rats, mice, flies, mosquitoes.

Gram Positive Bacteria

Thick protein layer on their cell wall and stain purple

Ex.  Listeria

Gram Negative Bacteria

Thin protein layer on their cell wall and stain purple

Ex. Salmonella

Chronic Disease

Gradual onset and tends to worsen over time.

May be permanent or last for an extended period of time.

Ex. Dementia, Diabetes, Cancer.

Foodborne Transmission

Illnesses from foods contaminated with pathogens.

Symptoms range.

Raw foods are the most common source of these diseases, as they are not sterile.

Ex. Salmonella, botulism, E.coli, Shigella.

Aetiology

Study of the causes of diseases - Looks at the environmental, biological, and genetic factors.

Protista

Unicellular and eukaryotic (have a nucleus).

Classified based on how they look and feed.

Can reproduce sexually and asexually.

Most do not bother us but a few are pathogenic.

Prion

Misfolded proteins that cause other proteins to misfold as well.

Unlike pathogens, prions do not have any genetic material, DNA/RNA.

Brain eating amoebas.

Discovered in the last 15 years.

Build ups in the central nervous system.

Can lead to serious neurodegenerative diseases such as mad cow disease and Creutzfelds-Jakob disease.

Humans can get mad cow disease from contaminated beef - causes depression, loss of coordination, dementia, brain abnormalities.

Endemic 

A disease present in a particular area, remains at a constant low rate in that population.

Ex. Malaria is endemic in central Africa.

Sporadic

A disease which pops up occasionally.

Ex. Botulism.

Epidemic

A widespread occurrence of an infectious disease in a particular community at a given time.

Ex.  An unexpectedly high number of people in Niagara will get the flu this year.

Pandemic

An outbreak of a particular infectious disease throughout the whole world.

Ex. Covid-19, SARS.

Acute Disease

Rapid onset and recovery.

Ex. Influenza, Strep throat.

Giardia

Parasites that can cause giardiasis.

Causes diarrhea, stomach issues.

Spreads through contaminated water or food.

Treated through medicine.

Flagella

Long, whip-like structures that help certain cells and organisms to move.

Made up of protein and can be found in many types of cells, including bacteria, protozoa, and some plant cells.

Rotate to propel the cell through its environment, essential for mobility.

Bacteria

Prokaryotic (No nucleus) unicellular microorganisms.

A few micrometers to half a millimeter.

Found in almost every ecosystem in the world.

Airborne Transmission

Illnesses spread through droplets of pathogens from sneezing, coughing, and talking.

Prominent in schools, nursing homes, places with a lack of hygiene.

Spreads fastest in small quarters.

Ex. Mumps, Whooping cough, Influenza, Smallpox, and Covid-19.

Ringworm

Fungus.

Feeds on Keratin in the skin, nails, and hair.

Loves warm, moist skin.

Itchy ‘ring’ on skin.

Common transmission is contact.

Not fatal.

Contagious

“Pathogenic”

A Spreadable disease from one organism to another.

Binary Fussion (Asexual)

The bacterial DNA, which is circular, is replicated and the bacteria cell undergoes cytokinesis, producing two daughter cells, they are completely identical to the original cell.

The cell number increases this way - the infection grows.

Sexual Reproduction

This allows bacteria to share their DNA but it does not produce any new bacterial cells.

CONJUGATION: Direct transfer of genetic material, plasmids, from one cell to another by a sex pilus, (bridge), only one cell receives the DNA.

TRANSDUCTION: Bacteriophages (viruses that attack the bacteria) carry bacteria genes from one host to another.

TRANSFORMATION: Alteration of bacterial cells genotypes.  Specifically, recognize and transport DNA from closely related species of bacteria.

Virulence

Degree of pathogenicity or the ability of the microorganism, such as bacteria or virus, to cause a disease.

Encompasses factors contributing to the severity of the disease, including the organism's ability to invade host tissues, evade the immune system, and produce toxins.

Virulent pathogens can lead to more severe illnesses, compared to less virulent ones.

Local Infection

Infections confined to a specific area of the body.

Ex. Ear infection, skin infection, UTI.

Waterborne Transmission

Illness from consuming or touching contaminated water.

Usually from sewage.

Ex. Cholera - Intestinal illness causing diarrhea, dehydration, and vomiting.

Infection 

When pathogens enter the body and reproduce/replicate.

To lead to a disease, the pathogen must be able to find the correct site in the host, attach to the site, and resist the hosts defence mechanism.

Transduction

Sexual bacterial cell reproduction, one of three ways.

Transduction is the process by which a virus, called a bacteriophage, transfers genetic material from one bacterium to another.

Bacteriophages are able to infect bacterial cells and use them as a host to make more viruses.

Toxin

Naturally occurring poison produced by living cells or organisms such as plants, bacteria, and animals.

Toxins can cause harm to humans through contact or absorption with the skin. 

Severity of reactions can vary.

Tinea Pedis

Aka Athletes foot fungus.

Causes skin to flake off.

May be passed onto other parts of the body.

General transmission is contact.

Likes moist areas.

Not fatal but can be painful.

Hookworm

Parasitic worm that enters through the skin.

Comes from soil; walking barefoot outside.

Causes Diarrhea, abdominal pain, and anemia due to blood loss.

Viruses and Bacteria

Microorganisms.

Bacteria - Single celled, can be beneficial or harmful.

Viruses - Smaller, need a host to reproduce, can cause diseases like the flu.

Epidemiology

The study of how diseases spread to infect populations.

When diseases occur, who is affected, how to control outbreaks.

Use data to develop strategies to prevent or treat.

African Sleeping Sickness

Protista: Unicellular, Eukaryotic.

Trypanosoma species.

Move in a spiral motion.

Animal-like protozoa (type of protista).

Transmitted through the bite of Tsetse Flies

Affects people like sub-saharan Africa.

Severe neurological symptoms such as sleep disturbances, confusion, ultimately a coma if left untreated.

Viruses

NON-LIVING

Extremely small

Pathogenic

No cytoplasm / No organelles

No waste

Genetic material takes control of other living cells.

DNA/RNA encased in a capsid.

Systemic Infection

Infections which infect the whole body.

Occurs when bacteria or viruses enter the bloodstream or lymphatic system.

Ex. Sepsis, Infectious diseases such as influenza.

Pathogenesis

The step by step development of a disease from infection by a pathogen to termination of either pathogen or host.

Yeast Infection

Candida Species - Candida overgrowth (fungus).

Likes warm, moist areas such as mouth, groin, skin folds.

Symptoms such as itching, burning, unusual discharge.

Treated with antifungal medication.

Biology

The study of life and living organisms

Lytic Cycle

Rapid Viral Replication, no pause between steps. 

Ex. Bacteriophage, influenza, Ebola.

1. Ex Attachment + Penetration  - Virus spits DNA into host cells.

2. Biosynthesis/Replication - Cell reads viral DNA and replicates.

3.  Assembly of Viral Parts 

4. Lysis - New viruses break through cell membranes to infect more cells and the host cell dies.

Lysogenic Cycle

Viral replication with a dormant phase.  Pathogenesis is triggered by environmental change.

1. Attachment + Penetration - Virus spits DNA into host cells

2. Integration - Viral DNA becomes a part of host DNA.

3. Latency - Cell divides and produces more cells with dormant viral DNA

4. Induction - Environment change has the viral DNA excise itself from the host to prepare for lytic cycle.

The viral DNA then proceeds to the Lytic cycle.