Exam II: Lecture 4 Flashcards
Define pathogenesis
the process by which an infection leads to disease
What are the 6 forms of pathogenesis?
- Localized infections
- Systemic infection
- Latent infection
- Chronic infection
- Acute infection
- Slow infection
What is an example of a localized infection?
Influenza
https://www.ncbi.nlm.nih.gov/books/NBK8149/
What is an example of a systemic infection?
Variola Virus (smallpox)
https://www.ncbi.nlm.nih.gov/books/NBK8149/
What is an example of a latent infection?
HIV
https://clinicalinfo.hiv.gov/en/glossary/viral-latency
What is an example of a chronic infection?
Hepatitus C
https://www.sciencedirect.com/topics/immunology-and-microbiology/viral-pathogenesis
What is an example of an acute infection?
Poliovirus
https://www.virology.ws/2009/02/13/acute-viral-infections/
What is an example of a slow infection?
HIV
https://en.wikipedia.org/wiki/Slow_virus
What are the 3 basic principles of virology?
- Viruses must be able to spread from one infected organism to another
- The tissues infected and seriousness of disease determine the mechanism of spread
- Epidemiology influences replication and pathology
What are the 7 routes of entry for a virus?
- Respiratory Tract
- GI tract
- Genital Tract
- Conjunctiva = membrane of the eyes
- Skin
- Blood
- Iatrogenic = medical exam/treatment
What are the 5 routes of transmission?
- Oral-fecal
- Airborne
- Blood-borne (mosquitos, transfusion, needles)
- Sexual
- Congenital (present from birth)
Zoonosis
Viruses that hang out in animals and go through their life cycle and then jump back in humans
What is an example of an oral-fecal virus?
Rotavirus
Viruses that use oral-fecal transmission are spread by what?
The ingestion of contaminated food or water
Infection via oral-fecal transmission usually begins where?
The gut
Can spread to other organs
Gastroenteritis
Abdominal cramps, diarrhea, vomiting; inflammation of the gut
Where are the mature virions excreted in the fecal-oral transmission?
urine or feces
Are oral-fecal viruses usually stable or unstable? Why?
Stable
They have to persist in an infectious form outside of the body for long periods of time
Airborne viruses are expelled as what? (2)
- Aerosol
2. Mucus
Viruses that use airborne transmission are spread when? (2)
- When contaminated air is inhaled
2. Mucosal secretions > object > mucosa of mouth, nose, eyes
Are airborne viruses usually stable or unstable?
Unstable when outside the body
Airborne infections often begin where? (2)
Eye
Upper respiratory tract
What is an example of an airborne virus?
SARS - coronavirus
What is a defense our body has against airborne viruses?
Mucociliary elevator
What is a defense our body has against oral-fecal viruses?
???
Viremia
Viruses present in the bloodstream
How are blood-borne viruses transmitted? (2)
- Via the skin by blood-sucking insects
2. exposure to contaminated blood
Arboviruses
Arthropod Borne Viruses
Can blood-borne viruses replicate in arthropods and vertebrates?
Yes
Are blood-borne viruses stable or unstable?
Unstable outside of the host
Blood-borne viruses, because of their need to establish a significant viremia can cause serious disease. Why?
Every organ in your body is supplied with blood and therefore if there is a full-on infection in the blood every organ in your body has the potential to be infected
How much Ebola-infected blood does someone need to come into contact with in order to have a full-blown infection?
One drop
What is an example of a blood-borne virus?
Ebola virus
What is an example of a host defense against a blood-borne virus?
Our entire circulatory system is protected by endothelial cell linings, so blood to blood contact is very difficult
Sexual transmission requires ____ contact
Genital
Is sexual transmission a common or uncommon route for viruses?
Common route
Sexually transmitted viruses can be present in what 4 forms in the genital area?
- Warts
- Lesions
- Semen
- Vaginal secretions
Infection by sexually transmitted viruses begin where?
Begin in genital mucosa
May spread to other organs
Sexually transmitted viruses are not spread easily, what implication does this have?
They mush persist in their host for a long period of time = set up long term persistent infections with mild disease
What is an example of a sexually transmitted virus?
HIV
What is a host defense against sexually transmitted viruses?
Genital to genital contact does not happen with great frequency with multiple people in the population ?
Unnatural = condom
Congenital viruses are said to spread ______
vertically
Where does congenital infections occur? (3)
- In utero
- Perinatal =during passage of the infant through the birth canal
- During breastfeeding
What is an example of a congenital virus?
HIV
What is a host defense against congenital infections?
Placenta
Mom can be treated with heavy antivirals right before birth (HIV)
Iatrogenic virus example
Rabies
Rabies virus in animals is a good example of what?
How viruses can actually change the psychology of its host to prompt spread
Hantavirus is an example of what kind of unusual mode of transmission?
Inhaling dust and aerosols from the excreta of rodents
Rabies virus is an example of what kind of unusual mode of transmission?
Bite - contact of saliva with blood
Viruses take advantage of the unique lifestyle of the host to increase likelihood of spread. What are 4 examples?
- Density of human population
- Sexual habits
- Geographic location
- Diets (prions that cause Kuru) (mad cow disease)
What are some reasons why refugee camps and temporary shelters make for virus playground? (5)
- Poor Sanitation
- Crowding
- Lack of access to clean water
- Poor nutritional status
- Limited medical care
Tell me about the benefits of Xenotransplantation
Pigs have organs which closley match ours
If we genetically modify them we can decrease cell surface proteins which decreases the immune response
What is the concern about Xenotransplantation?
We can introduce pig viruses to humans