No, Alternaria alternata is not contagious from person to person or from plants to people. However, exposure to Alternaria alternata spores can cause respiratory allergies in susceptible individuals. The spores can be found in the air, on contaminated surfaces, and in soil. It is important for individuals who are at risk for respiratory allergies to take steps to minimize their exposure to Alternaria alternata spores. These steps include good hygiene practices, wearing appropriate personal protective equipment, and avoiding outdoor activities during peak spore season.