Week 11- Quiz 6

Question 1

What are some mechanisims of defense for the respiratory tract

Answer 1

• Mucus made by goblet cells is sticky and traps microorganisms
• cilia beat rythymically to move mucus to oropharynx to then spit out mucus

Question 2

What in the respiratory tract is an important part of the innate immune system

Answer 2

The mucociliary escalator

Question 3

What produces whooping cough

Answer 3

bordetella- cocobacillus, produces pertussis(whooping cough) in children

Question 4

If the pathogen can create diarrhea, is this advantageous or disadvantageous?

Answer 4

It has an additional advantage because now you spread it to other people

Question 5

What is the single most common cause of UTI’s

Answer 5

E coli (gram negative rod)

Question 6

Which host action leads to the most respiratory droplets spread

Answer 6

Sneezing- leads p to 20,000 respiratory droplets being shed
- Coughing only leads to 100’s
- Talking only has a few

Question 7

What are 3 reasons respiratory pathogens spread more easily indoors?

Answer 7

1. Air indoors is warmer and more humid than air outside, and moisture and warmth allow them to survive
2. people crowd together indoors
3. in summer, air conditioning can dry out air and lead to impaired cilia, increasing infection too.

Question 8

What are 3 different mechanisms for pathogens to pass through the GI mucous layer

Answer 8

-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

Question 9

What public health circumstances previously lead to the spread of GI pathogens

Answer 9

• 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

Question 10

Why are UTI’s more common in Women than men?

Answer 10

Much shorter urethra in women (1.5 inches, 4.5 inches from anus) than men (5 inches, 7.5 inches from scrotum to urethra)

Question 11

What factors in women increases the presence of pathogens?

Answer 11

-More glucose and protein in urine increases bacterial growth
- Progesterone decreases smooth muscle tone in ureters
- Uterus blocks flow from ureters to urethra

Question 12

What factors in men increase presence of pathogens

Answer 12

• Enlarged prostate gland can cause dysuria
• Prostate gland can compress urethra, urine retained in bladder

Question 13

What factors can decrease pathogens in women

Answer 13

-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

Question 14

What was the bubonic plague caused by and how was it transmitted

Answer 14

Caused by yersinia pestis bacteria, transmitted through the bite and vomiting of the rat flea

Question 15

What are the sources and types of things you can get from a congenital infection

Answer 15

Blood is the source of infection in maternal fetal transmission (transplacental)
HIV, CMV, Hep B, Syphilis

Question 16

Most common way someone would get Hep B, Hep C, and HIV

Answer 16

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

Question 17

How are virulance and pathogen transmission related

Answer 17

The ability of a pathogen to be transmitted varies independently of their ability to do damage

Question 18

What actions of the host benifit the pathogen and improve transmission

Answer 18

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

Question 19

What are the 3 factors that determine successful transmission of a pathogen

Answer 19

1. Number of pathogens shed
2. Stability of the pathogen in the environment (Ability for them to withstand dehydration and temperatures)
3. Number of pathogens needed to infect the host

Question 20

What is the primary factor that causes pathogen death

Answer 20

Dehydration
- Related to temperature– Pathogens that are dehydrated are more likely to resist thermal inactivation

Question 21

How many gonorrhea are needed to cause an inefction in the urethra vs rectum or oropharynx

Answer 21

10 gonorrhea in the urethra, 1000s in the oropharynx

Question 22

What are the primary factors that kill pathogens after they are shed from their host

Answer 22

1. Drying and dehydration is the primary cause of death
2. Hot or cold temperatures
3. Chemicals on surfaces
4. Sunlight/UV radiation

Question 23

How are respiratory and sexual transmission of pathogens controlled

Answer 23

difficult to control- use sexual protection or wear masks

Question 24

How do you control fecal-oral transmission

Answer 24

washing hands and public health fecal matter disposal

Question 25

How do you control arthropod-borne infections and zoonoses

Answer 25

Control vectors or animal infection