Infectious and Noninfectious Disease Midterm 1 Flashcards
Infectious disease
Contagious- Illness caused by pathogens
(eg. Influenza)
Non-infectious disease
Illness caused by something that is not a pathogen
(eg. Cancer)
Pathogenicity
Level of ability of a pathogen to cause disease
Are bacteria bad?
Nope
Most of the time they’re very helpful.
Transmissible
Contagious - able to spread from one individual to another
- Applies to both direct and indirect transmission
Clinical Phase (incubation period)
Time of infection to first clinical symptoms
- varies with pathogen
- can vary with dose
Infectious period
Time where the infection is transmissible
Type A infection
Contagious prior to symptoms
Type B Infection
Contagious after symptoms start
When do you start to see symptoms?
When the immune system kicks in
What is the most abundant biological entity on Earth?
Viruses
By the way, most of them make you sick >:(
Can Viruses replicate by themselves?
No, they need a host cell
Latent period
The time from infection to the time where the infection is transmissible
Enveloped virus
Hard to make vaccines from, but easy to kill with alcohol (It destroys the envelope)
Non-enveloped virus
Hard to kill with alcohol, but easier than enveloped viruses to make vaccines for
5 steps of viral infection
- Get into the cell
- Release DNA or RNA
- Hijack host cell machinery for replication
- Latency period
- Shedding of viral particles
Example of DNA viruses
Pox virus
- many are zoonotic
Parvo viruses
Herpes viruses
Example or RNA viruses
Rhabdoviruses (Rabies)
Corona viruses
Why do RNA viruses suck?
-High mutation rate makes it very hard to make vaccines for
- immune cell memory is infected due to the antigen changing so often
Genome reassortment
RNA can be shared amongst viruses, making entirely new codes
Bacteria
Prokaryotic, single celled organisms
Most are very helpful
-Fewer than 100 species are known to cause disease
Shapes of Bacteria
Bacilli (rod)
Spirilla (spirals)
- cork screws
- comma
Cocci (spherical)
Generation time
Length of time it takes for a bacteria to reproduce
- some bacteria form spores
Gram staining
Distinguishes bacteria into gram negative and gram positive bacteria
Why is gram staining important?
Gram negative bacteria have largely impermeable cell walls and are more resistant to antibiotics
Antimicrobials (Antibiotics)
Treat or prevent bacterial infections
Antibiotic resistance
Bacteria can develop resistance to antibiotics
Fungi
Eukaryotes
eg. yeast, mushrooms, mold
Less than 100 cause problems
Many are commensal and only cause problems when they overgrow
Protozoa
Single celled Eukaryotes
Most cause diarrhea
Treatment:
Some antimicrobials
can develop resistance
Helminths
Parasites - often have intermediate hosts
- Cestodes: Tapeworms
- Trematodes: Flukes
- Nematodes: Roundworms
Nematodes
Roundworms
~50% are parasitic
- can infect almost any organ
- 2 separate sexes
Tapeworms
Endoparasites
- Has multiple segments
- no gut
Anthelmintic resistance
Worms can gain resistance
- this is due to too much dewormer being used
Arthropods
Ecto and endo parasites
- separate sexes
- lots of parasitic species
Ecto-parasite
Parasite that live in or on the skin, but not in the body
Endo-parasite
Parasite that lives in the body
mycotoxicosis
“the consequence of ingestion of grains or forage containing toxic metabolites produced by certain fungi”
Iowa State University
Mycosis
A fungal infection
-usually caused by the overgrowth of a fungus naturally found in the body
