H1N1 virus is sometimes mentioned in the news with reference to which

H1N1 virus is sometimes mentioned in the news with reference to which one of the following diseases?

AIDS
Bird flu
Dengue
Swine flu
This question was previously asked in
UPSC IAS – 2015
The H1N1 virus is the primary cause of swine flu.
H1N1 is an influenza A virus subtype that is the most common cause of human influenza (flu).
The 2009 swine flu pandemic was caused by a new strain of H1N1 that resulted from a mix of human, swine, and bird flu viruses. While H1N1 strains circulate in various animals, this particular strain was referred to as “swine flu” because genetic analysis showed it originated from pigs. Bird flu is typically caused by other influenza subtypes like H5N1. AIDS is caused by the Human Immunodeficiency Virus (HIV), and Dengue is caused by the Dengue virus, transmitted by mosquitoes.