Causative agent of Farmer's lung is:

Ans. (a) Themophilus actinomycetes(Ref: Robbins 9th/pg 689; 8th/pg 687)In farmer's lung, inhalation of proteins, such as thermophilic actinomyces bacteria and fungal spores that are present in moldy bedding and feed, are most commonly responsible for the development of Hypersensitivity pneumonitis.