Week 11- Quiz 6 Flashcards
What are some mechanisims of defense for the respiratory tract
- Mucus made by goblet cells is sticky and traps microorganisms
- cilia beat rythymically to move mucus to oropharynx to then spit out mucus
What in the respiratory tract is an important part of the innate immune system
The mucociliary escalator
What produces whooping cough
bordetella- cocobacillus, produces pertussis(whooping cough) in children
If the pathogen can create diarrhea, is this advantageous or disadvantageous?
It has an additional advantage because now you spread it to other people
What is the single most common cause of UTI’s
E coli (gram negative rod)
Which host action leads to the most respiratory droplets spread
Sneezing- leads p to 20,000 respiratory droplets being shed
- Coughing only leads to 100’s
- Talking only has a few
What are 3 reasons respiratory pathogens spread more easily indoors?
- Air indoors is warmer and more humid than air outside, and moisture and warmth allow them to survive
- people crowd together indoors
- in summer, air conditioning can dry out air and lead to impaired cilia, increasing infection too.
What are 3 different mechanisms for pathogens to pass through the GI mucous layer
-Motile pathogens like e coli, salmonella, v. cholerae can propel themselves through mucous layer
-Have a special attachment to epithelial cells so they don’t get expelled (can then establish an infection)
-V. cholerae produces mucinase
What public health circumstances previously lead to the spread of GI pathogens
- No sewage disposal and contaminated drinking water which lead to the spread
- Underground disposal systems and seperation between sweage and water helps today
- Fecal-oral routes and contaminated water are still present in poorer countries
Why are UTI’s more common in Women than men?
Much shorter urethra in women (1.5 inches, 4.5 inches from anus) than men (5 inches, 7.5 inches from scrotum to urethra)
What factors in women increases the presence of pathogens?
-More glucose and protein in urine increases bacterial growth
- Progesterone decreases smooth muscle tone in ureters
- Uterus blocks flow from ureters to urethra
What factors in men increase presence of pathogens
- Enlarged prostate gland can cause dysuria
- Prostate gland can compress urethra, urine retained in bladder
What factors can decrease pathogens in women
-Vagina secretes glycogen
- Lactobacillus (protective normal part of microbiome) ferments glycogen, produces pH of 4
- Lactobacillus makes H2O2 and bacteriocins, prevents pathogen binding and growth
What was the bubonic plague caused by and how was it transmitted
Caused by yersinia pestis bacteria, transmitted through the bite and vomiting of the rat flea
What are the sources and types of things you can get from a congenital infection
Blood is the source of infection in maternal fetal transmission (transplacental)
HIV, CMV, Hep B, Syphilis
Most common way someone would get Hep B, Hep C, and HIV
Transmissible by needles in a shared IV drug use setting
Syringes are used more than once without sterilization in resource-poor countries
Contributed to Hep C virus outbreak in egypt– treated s. helminth infections with reused syringes
- Transfusions with contaminated blood
How are virulance and pathogen transmission related
The ability of a pathogen to be transmitted varies independently of their ability to do damage
What actions of the host benifit the pathogen and improve transmission
Coughing and sneezing
- Pathogens that increase secretions in respiratory tissue induce more coughing and sneezing
- Pathogens that increase fluid secretions in GI tract induce more diarrhea and are transmitted more effectively
What are the 3 factors that determine successful transmission of a pathogen
- Number of pathogens shed
- Stability of the pathogen in the environment (Ability for them to withstand dehydration and temperatures)
- Number of pathogens needed to infect the host
What is the primary factor that causes pathogen death
Dehydration
- Related to temperature– Pathogens that are dehydrated are more likely to resist thermal inactivation
How many gonorrhea are needed to cause an inefction in the urethra vs rectum or oropharynx
10 gonorrhea in the urethra, 1000s in the oropharynx
What are the primary factors that kill pathogens after they are shed from their host
- Drying and dehydration is the primary cause of death
- Hot or cold temperatures
- Chemicals on surfaces
- Sunlight/UV radiation
How are respiratory and sexual transmission of pathogens controlled
difficult to control- use sexual protection or wear masks
How do you control fecal-oral transmission
washing hands and public health fecal matter disposal
