The correct answer is option 2: III and IV.

Let`s dissect each statement to better understand why they are correct or incorrect:

Statement I: "The agent of infection is not well identified." This statement is not mentioned in the question, so it is incorrect.

Statement II: "The risk is higher in those who consume pork." This statement is not mentioned in the question, so it is incorrect.

Statement III: "It has a propensity to spread from contact with an infected person." This statement is mentioned in the question and is correct. Swine flu, like other types of flu, can be spread through contact with an infected person.

Statement IV: "Absence of an effective treatment or vaccine makes it a risk for a global pandemic." This statement is mentioned in the question and is correct. The absence of an effective treatment or vaccine for swine flu increases the risk of it becoming a global pandemic.

Therefore, the correct answer is option 2: III and IV.