rthropods typically serve as which mechanism of transmission for viruses?
fomite
biological vector
both as fomites and as vectors
Question 2
4 / 4 pts
Which of the following would be considered a symptom and which would be considered a sign? Label each using the drop down.
blood pressure reading of 150/90 mm Hg sign
body ache and chills symptom
fever of 39 °C sign
heart rate of 120 bpm sign
blurry vision symptom
body ache and chills symptom
burning sensation during urination symptom
gross hematuria (visible presence of blood in urine) sign
Answer 1:
sign
Answer 2:
symptom
Answer 3:
sign
Answer 4:
sign
Answer 5:
symptom
Answer 6:
symptom
Answer 7:
symptom
Answer 8:
sign
Question 3
1 / 1 pts
Identify which pathogen is the least virulent on the basis of ID50.
a pathogen with an ID50 of 50 cells
a pathogen with an ID50 of 1000 cells
a pathogen with an ID50 of 1 cell
pathogenicity cannot be determined from ID50 values
Question 4
1 / 1 pts
________ are extracellular structures in bacteria that are involved in conjugation and can be used as adhesins.
Pili
Question 5
1 / 1 pts
What is true of adhesion proteins (referred to as adhesins)?
are molecules, receptors, or surface structures necessary for attachment to a host cell.
help pathogens block immune cells and antibodies.
help destroy host cells so bacteria can consume host nutrients.
help bacteria by eliciting systemic inflammation in host.
Question 6
1 / 1 pts
Endotoxin is produced only by gram-negative bacteria.
True
False
IncorrectQuestion 7
0 / 1 pts
All contacts with a pathogen will result in infection.
True
False
Question 8
1 / 1 pts
The prodromal period is when the maximum number of pathogen particles or organisms are present in an infected host.
*Review lecture notes. We covered a graph that shows # of pathogens in host vs. each period.
True
False
Arthropods typically serve as which mechanism of transmission for viruses? Group of answer choices
- fomite
- biological vector
- both as fomites and as vectors
The correct answer is: biological vector
Explanation: Arthropods, like mosquitoes and ticks, often transmit viruses by actively carrying the virus inside their bodies and transferring it to a new host through biting. This makes them biological vectors, not fomites (which are non-living objects like doorknobs or utensils).
A biological vector is a living organism (usually an arthropod like a mosquito, tick, or flea) that carries a virus or other pathogen inside its body and transmits it to a new host through a bite or other direct contact.
Simple Example:
A mosquito bites a person who has dengue virus
→ the virus multiplies inside the mosquito
→ the mosquito bites another person
→ that person becomes infected.
So the mosquito is a biological vector for the dengue virus.
Key Point:
The pathogen often reproduces or develops inside the biological vector before transmission.
Identify which pathogen is the least virulent on the basis of ID50.
Group of answer choices
- a pathogen with an ID50 of 50 cells
- a pathogen with an ID50 of 1000 cells
- a pathogen with an ID50 of 1 cell
- pathogenicity cannot be determined from ID50 values
The correct answer is: a pathogen with an ID50 of 1000 cells
Explanation:
-
ID₅₀ (Infectious Dose 50%) is the number of microbial cells needed to infect 50% of a test population.
-
Higher ID₅₀ = less virulent (it takes more cells to cause infection).
-
Lower ID₅₀ = more virulent (it takes fewer cells to cause infection).
So:
-
1 cell = very virulent
-
50 cells = moderately virulent
-
1000 cells = least virulent
✅ Therefore, the pathogen with an ID50 of 1000 cells is the least virulent.
- Pili are extracellular structures in bacteria that are involved in conjugation and can be used as adhesins.
- The correct answer is: Pili (specifically sex pili)
- Explanation:
- Pili are extracellular structures found on the surface of some bacteria.
- Sex pili are involved in conjugation, a process where bacteria transfer genetic material to each other.
- Pili can also act as adhesins, helping bacteria attach to host cells or surfaces.
- So the complete sentence would be:
- Pili are extracellular structures in bacteria that are involved in conjugation and can be used as adhesins.
What is true of adhesion proteins (referred to as adhesins)?
Group of answer choices
are molecules, receptors, or surface structures necessary for attachment to a host cell.
- help pathogens block immune cells and antibodies.
- help destroy host cells so bacteria can consume host nutrients.
- help bacteria by eliciting systemic inflammation in host.
The correct answer is:
are molecules, receptors, or surface structures necessary for attachment to a host cell.
Explanation:
- Adhesins are special proteins or structures on the surface of pathogens (like bacteria or viruses).
- They allow the pathogen to stick to specific receptors on host cells, which is often the first step in infection.
- Without adhesins, many pathogens cannot attach and cannot cause disease effectively.
✅ So, adhesins are important for attachment, not for immune blocking, destroying cells, or causing inflammation directly.
❌ False
Correct Explanation:
The prodromal period is the early stage of an infection, when the host begins to show mild and nonspecific symptoms (like fatigue or low-grade fever), but it is not the stage with the maximum number of pathogens.
The maximum number of pathogen particles is typically present during the illness period, which follows the prodromal stage.
That’s when symptoms are most severe and the pathogen load is highest.
Summary:
-
Prodromal period = early, mild symptoms
-
Illness period = peak symptoms and highest number of pathogens ✅he prodromal period is when the maximum number of pathogen particles or organisms are present in an infected host.
❌ False
Correct Explanation:
The prodromal period is the early stage of an infection, when the host begins to show mild and nonspecific symptoms (like fatigue or low-grade fever), but it is not the stage with the maximum number of pathogens.
The maximum number of pathogen particles is typically present during the illness period, which follows the prodromal stage. That’s when symptoms are most severe and the pathogen load is highest.
Summary:
-
Prodromal period = early, mild symptoms
-
Illness period = peak symptoms and highest number of pathogens ✅
all contacts with a pathogen will result in infection. true or false❌ False
Explanation:
Not all contacts with a pathogen lead to infection.
Whether an infection occurs depends on several factors, including:
-
The virulence of the pathogen (how strong it is)
-
The dose (how many pathogens enter the body)
-
The immune status of the host (how strong your immune system is)
-
The route of entry (how the pathogen enters the body)
For example, if a small number of a weak pathogen enters through a route it's not suited for, your immune system may destroy it before it causes an infection. ✅
-
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