Infectious Disease Transmission/Host Defenses & Pathophysiology Flashcards
Describe Prions:
Structure and function?3
Examples?3
How can our body respond to these?
Transmission?3
- Protein particles without a genome
- Infectious and capable of producing disease
- (normal or altered host proteins)
Examples:
- Creutzfeldt-Jakob disease,
- Kuru and
- “mad cow” disease
We dont really have a response to this.
Eating humans
Unclean cervical instruments
Animals
What is a virus?
What is the structure of a virus?2
Intracellular pathogen/incapable of replication outside a living cell
- Consist of a protein coat (capsid), surrounding either RNA or DNA (never both)
- Some viruses have a lipoprotein envelope derived from the parasitized host cell
(make an envelope from host)
What must viruses have to live?
Viruses MUST penetrate a susceptible living cell & use the biosynthetic machinery of the cell to produce viral progeny (Latency)
What is the pathology of an oncogenic virus?
Examples?4
Some viruses have the ability to transform normal host cells into malignant cells during the replication cycle
HPV
CMV- hodgkins lymphoma
Herpes
Adenoviruses
Pathology of retro virus?
2
reverse transcriptase to turn their RNA into DNA
Transmit DNA into the host
What are the happy viruses?
DNA viruses
herpes
adenoviruses
STructure of bacteria?
5
- Autonomously replicating unicellular organisms—prokaryotes*
- Generally contain no organized intracellular organelles
- Genome consists of a single chromosome of DNA and RNA
- Does have reproductive and metabolic machinery in the cytoplasm of the cell (unlike viruses)
- unicellular-prokaryote
- no organelles
- single DNA or RNA chromosome
- does have reproductive and metabolic machinery unlike viruses
- Have cytplasmic membrane and cell wall-peptinoglycan (helps us kill them because we dont have it)
How do bacteria reproduce?
Most produce asexually be cellular division
What does gram pos stain?
Gram neg stain?
Gram-positive—PURPLE
Gram-negative—RED
How are some ways that bacteria reproduce?
3
chains (streps)
clusters (staff)
Pairs
What are fungi?
Free-living, eukaryotic saprophytes found in every habitat on earth
acid fast assciated with what?
TB
acid alcohol
How do fungi reproduce?
Reproduction is sexual or asexual (Involves production of spores)
What are the two groups of fungi we talk about?
yeasts
Molds
Describe structure of yeasts, reproduction and appearance of colonies?
Single-celled organisms
Reproduce by a budding process
Colonies are smooth with a waxy or creamy texture
What do molds produce?
3
- Produce long, hollow, branching filaments—hyphae
- Some produce cross walls which segregate the hyphae others do not
- Produce cottony or powdery colonies of mats of hyphae–mycelium
Types of parasites?
4
Athropods
Ectoparasites
Protozoa
Helminths
Examples of parasitic arthropod vectors?
3
ticks, mosquitoes, biting flies
What makes the arthropod parasitic?2
Actual infectious agent is carried by the arthropod
Usually a virus
Mechanism of infection for ectoparasites?
Infest external body surfaces and cause localized tissue damage or inflammation secondary to the bit or burrowing action
Some of the most prominant ectoparasites?
4
Mites (scabies)
Chiggers -
Lice
Fleas
What is a protozoa?
How do they reproduce?
Unicellular animals with complete eukaryotic machinery**
Reproduction may be sexual or asexual
Most are saprophytes but some can cause human disease
Examples of protozoa infectious to humans?
3
amebic dysentery, malaria, and giardiasis
What are helminths?
Examples?3
Collection of wormlike parasites
Include nematodes (roundworms), cestodes (tapeworms), & trematodes (flukes)
Helminths mechanism of reproduction and infection needs what?
Often an intermediate host is required for development & maturation of the offspring and then humans are infected and sexual reproduction occurs in the human host
Hemolinth infections often involve what?
multiple organ systems
For infectious diseases what should our epidemiology include?
6
- Incidence—number of new cases
- Prevalence—number of active cases at any given time
- Source of infection
- Port of entry, site of infection
- Virulence factors, signs & symptoms, and clinical course
- Endemic, epidemic, and pandemic
What are the goals of epidemiologic studies for ID?
2
- Interruption of spread of infectious diseases
2. Eradication of infectious diseases
Whats a vector?
Vector—organism that transmits a pathogen from a reservoir to a host
Forms of penetration for portals of entry of bacteria?
3
- any disruption in the body’s surface barrier Ex. stevens/johnsons breakdown of skin = massive infections
- Can be a result of accident, a wound, or a medical procedure
- May be a direct inoculation from a an animal or arthropod bite**