Pathogens & Stages of Infection Flashcards
(24 cards)
How do pathogens spread?
- Direct Physical Contact
- Indirect Contact Through Air
- Indirect Contact By Object
- Disease Vectors
How do pathogens cause disease
- Rapid Multiplication
-Toxins - Cell Destruction
- Competition
Rapid Multiplication
multiply rapidly and crowd and kill healthy cells. eg. salmonella
Toxins
produce toxins that interfere with normal cell activities. eg. tetanus
Cell Destruction
take over cells to replicate itself, destroying the cell. eg. influenza
Competition
competes with body for nutrients, causing malnutrition. eg. tapeworm
How pathogens enter the body?
- open wounds, cuts, or bites
- inhaling airborne droplets
- drinking contaminated water
- eating contaminated food
- direct physical contact
- sexual activity
Types of Pathogens
- Bacteria
- Viruses
- Fungi
- Protoza
- Rickettsia
- Helminthus
Bacteria
- single celled, prokaryote
- genetic material is not contained in cell membrane
- four main types based on shape: bacilli (rod), cocci (sphere), spirochetes (spiral), vibrio (curve rod)
How does bacteria transmit/infect?
- mostly reproduce through binary fission
- release toxins harmful to host
- invade body, reproduce and grow tissues
- treatement: penicillin, antibiotics, amoxicillin
- examples: food poisoning, pneumonia, strep throat
Viruses
- tiny particles
- replicate only inside living host cells
- composed of DNA/RNA and protein coat used to recognise suitable host ells
How do viruses transmit/infect?
- enters a cell nucleic acid inserted into host cell and produces new virus cells which are then released and attack other host cells
- transmitted easily - airbone, direct, bodily fluids
- treatement: vaccines
- examples: ebola, influenza, AIDS
How does the immune system respond to viruses?
- produces pryrogens which raise body temps slowing down chemical reactions - WBC produce antibodies to stop virus replication; other cells detect this and kill
Fungi
- rigid cell wall
- saphrophytes- live on dead organic matter
parasites live on host tissue
long, fine branching hyphae form mycellum web - treatment: antifungal creams, spreays and tablets
- examples: tinea, asthma
How does fungi transmit/infect?
- produces microscopic reproductive spores that are spread through air, water and direct contact
humans are mostly infected on skin,
How does the immune system respond to fungi?
- Immune system can react to fungi spores through an allergic reaction (sneezing and coughing)
Protozoa
- single celled eukaryotic cell
- genetic material in cell membrane
- get food from environment including water, soil, and human body
- treatment: malaria antibiotics or suplhur medications
- examples: malaria, sleeping sickness
How are do protozoa transmit/infect?
- cyst stage infect humans
- trophozoite stage - (active feeding reproducing) disease develops
- plasmodia spread by anopheles like mosquitos
Prions
- most recently discovered
- no nucleic acids
- composed of a protein in cell membrane
- distorted shape which induces distortion of normal proteins
- treatement: N/A
- examples: CJD pr mad cow disease
How do prions transmit/infect?
- pathogen prions infect lining of neural cells, which are destroyed and lead to the infection of others
How does the immune system respond to prions?
- there is no immune response as prions resemble proteins normally found in the body
Macroparasites
- parasites that are visble to the naked eye
How do macroparasites transmit/infect?
How does the immune system respond to macroparasites?
- high temps sometimes develop
