Deck 31: Epidemiology Part Sixapplications of Biotechnology Introduction to Biotechnology

Question 1

What is the definition of index case ?

Answer 1

Index Case:
On the epidemiological study, the earliest or the first case in a disease outbreak is called as Index Case. The index case can be otherwise called as "Patient zero".
On the epidemiological study about the communicable diseases, the identification of the first case (index case) is essential to evaluate the disease outbreak. If, the index case is identified means, the travel and peoples whom he/she contacted (direct transmission), will alerts the epidemiologist, to prevent the further transmission of disease. In addition, the index case is also provides the information about, how fast the disease is transmitted.

Question 2

On your agar plates, there may be other bacteria growing on them that are not pigmented. What is the likely source of the non-pigmented bacteria?

Answer 2

Serratia marcescens is a bacteria belonging to family Enterobacteriaceae. The non pigmented strain of this bacterium due to the presence of a cytotoxin producing mechanism is more virulent. Non pigmented bacteria cause many serious and difficult infections.
Normally, the non pigmented bacteria that are produced may be due to contamination as the subject has shaken the hand with more than one person. The non pigmented bacteria that could be identified on the nutrient agar medium can be Escherichia coli which are gram negative bacteria, K lebsiella pneumonia which is one more gram negative strain, Pseudomonas aeruginosa is a gram negative rod shaped bacteria which causes diseases to both plants and animals.

Question 3

Is this lab a model of direct transmission or indirect transmission of a disease agent?

Answer 3

Direct Transmission of disease occurs due to the person to person contact, by direct contact on the infectious lesions or by handshaking. For example: an individual, with diarrhea, does not follows the proper hand washing means, he/she can able to transfer the diarrhea disease to others through handshaking. In addition, the improper preventions of herpes lesions can transmit the herpes infections to the others, through the direct contact while handshaking.
The indirect transmission of disease occurs through the respiratory droplets while sneezing, or touching the innate objects includes the doorknobs, pen, etc.
According to the given exercise, about the disease transmission by the "Candy experiment", is belongs to the Direct transmission. Because, transmission of disease occurred by handshaking; the handshaking gives the direct contact to the pathogenic organisms.
Hence, the given model in the lab describes the direct transmission of disease.

Question 4

In your class, who was the index case? Briefly explain how you determined the index case.

Question 5

Why are we using the organism S. marcescens in this exercise?

Question 6

In this lab, we are assuming that everyone who comes into contact with the disease agent is infected. Is this a model of what happens in "real life"? Explain your answer