"Instances of transmission can be divided into direct or indirect, where a pathogen is transferred through an intermediate object or medium e.g. a contaminated ultrasound probe. Understanding the types of transmission possible for a specific disease is critical to control disease spread. The mode of transmission does not always imply the specific portal of entry in the affected person e.g. in vertical transmission, a disease may pass from mother to child during childbirth, by skin to skin contact or blood."
"NB: When epidemics of emerging diseases occur all the modes of transmission may not be apparent."