Swine flu is a highly contagious, yet generally low-mortality viral respiratory disease that occurs when a mutated variant of the H1N1 subtype of the Influenza A virus infects humans. Symptoms include fever, cough, sore throat, and fatigue. The name "swine flu" originated because the virus was initially prevalent in pig populations and could be transmitted to humans through direct contact.

Among the groups at highest risk of contracting swine flu are farmers, slaughterhouse workers, and veterinarians who have close contact with pigs. Additionally, individuals living in or traveling to regions where swine flu cases are widespread are also at high risk.

Common symptoms of swine flu include high fever, cough, sore throat, headache, body aches, fatigue, chills, runny nose, and red eyes. This highly contagious disease spreads from person to person through respiratory droplets released by coughing and sneezing. The virus can also be transmitted by touching surfaces where infected droplets have landed (e.g., doorknobs or sinks) and then touching the mouth, nose, or eyes.

The most effective ways to protect against swine flu include vaccination and adhering to personal hygiene rules such as regular hand washing. As a respiratory disease, the virus can directly affect the lungs and lead to serious complications, especially in individuals with weakened immune systems. High-risk groups include kidney and liver patients, children under two years old, individuals over 65, diabetes and heart patients, those with chronic lung conditions like asthma, bronchitis, COPD, and individuals who have experienced lung damage due to tuberculosis.

Treatment for swine flu typically involves rest, antiviral medications, and pain relievers to alleviate symptoms, usually under medical supervision.