Which of the following lead to an outbreak of Influenza in China in 2013 –
**Core Concept**
The underlying principle being tested is the identification of the causative agent of an influenza outbreak. Influenza outbreaks are often caused by **influenza viruses**, which are classified into types A, B, and C.
**Why the Correct Answer is Right**
Although the specific correct answer is not provided, influenza outbreaks can be caused by new strains of the **influenza A virus**, such as H7N9, which was identified as the cause of an outbreak in China in 2013. This virus is a subtype of **influenza A virus** and can be transmitted from animals to humans.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific details of option A, it's challenging to provide a precise explanation for its incorrectness.
**Option B:** Similarly, without the details of option B, its incorrectness cannot be directly addressed.
**Option C:** And option C's incorrectness also cannot be specified without more information.
**Option D:** The same applies to option D, as the details are necessary to explain why it is incorrect.
**Clinical Pearl / High-Yield Fact**
It's crucial to remember that **influenza A viruses** are known for their ability to undergo **antigenic shift** and **antigenic drift**, leading to new strains that can cause significant outbreaks. The **H7N9 virus** is an example of an **avian influenza virus** that has caused concern due to its potential for human-to-human transmission.
**Correct Answer:** Correct Answer: D. H7N9.