You and your exercise buddy decide to go to Yosemite National Park to hike the famous El Capitan trail. You book your trip through a well known agency but before you leave for your vacation, you learn that there have been two cases of plague reported in people who recently visited a different area of the park. Your friend is anxious and tells you he thinks that plague is really dangerous and kills people everyone who gets it. He points out that this disease killed a lot of people during the Middle Ages, and says he doesn't want to do the trip after all. You decide to do some research on the plague and its causative agent before making a decision about your trip.
-Yersinia pestis is transmitted by fleas. The organism forms biofilms in the digestive tract of infected fleas, often blocking the tract. This prevents the flea from feeding properly, causing bacteria to be regurgitated into the bite wound that the flea has made. In this situation, the flea is a
A) mechanical vector.
B) biological vector.
C) mechanical host.
D) biological host.
E) dead-end host.

Question

You and your exercise buddy decide to go to Yosemite National Park to hike the famous El Capitan trail. You book your trip through a well known agency but before you leave for your vacation, you learn that there have been two cases of plague reported in people who recently visited a different area of the park. Your friend is anxious and tells you he thinks that plague is really dangerous and kills people everyone who gets it. He points out that this disease killed a lot of people during the Middle Ages, and says he doesn't want to do the trip after all. You decide to do some research on the plague and its causative agent before making a decision about your trip.
-Yersinia pestis is transmitted by fleas. The organism forms biofilms in the digestive tract of infected fleas, often blocking the tract. This prevents the flea from feeding properly, causing bacteria to be regurgitated into the bite wound that the flea has made. In this situation, the flea is a
A) mechanical vector.
B) biological vector.
C) mechanical host.
D) biological host.
E) dead-end host.

Quizplus · Accepted Answer

A biological vector is an organism that transmits a pathogen and is also involved in the pathogen's life cycle. Yersinia pestis forms biofilms in the digestive tract of infected fleas, which directly affects the flea biology and allows for the transmission of the pathogen into the bite wound. Therefore, it is a biological vector rather than a mechanical vector (which just carries the pathogen on its body) or host (which harbors the pathogen for reproduction). Dead-end hosts do not allow the pathogen to complete its life cycle, so they are not involved in transmission.

You and Your Exercise Buddy Decide to Go to Yosemite