From an epidemiological point of view, is consumption of raw milk or meat considered as indirect or direct transmission ? Let's take the example of bovine TB. Is consumption of unpasteurized milk considered as direct or indirect ? IMO since milk is a tissue (liquid tissue but still), it is part of the cow, then how could you go more direct than eating the infected animal ?
Direct transmission is through direct contact with the infected person with no intermediary or vector. The Ebola virus and AIDs virus are examples. Indirect would be malaria spread through mosquitos, plague via rats, etc. The common cold spread through droplets in the air could seem indirect, but because of the proximity required, the CDC website lists it under direct. The CDC will provide reliable information for a lot of questions regarding infectious disease.