Does the flu have environmental causes?

Answer 1

Not a direct cause. However, the virus that does cause flu is present in the environment and that is one way it spreads by our contact with the virions (virus particles) on objects and surfaces in the environment from others' coughs and sneezes (along with direct contact with infected individuals).

There is another link between the environment and the incidences of influenza infections, too. That is that the flu likes the environment dry. In the northern hemisphere, our flu season occurs in the fall and winter. The latest info has it that there is a flu season because, at that time of year, the absolute humidity is low, making the type of dry environment that allows more activity by the viruses that cause the flu.

See the related question about why flu has a season on this page.

Answer 2

The flu is primarily caused by the influenza virus which is transmitted from person to person through respiratory droplets. While environmental factors such as temperature and humidity can influence the survival and transmission of the virus, the primary mode of transmission is person-to-person contact.