Disease transmission

Disease transmission is the way that an infectious disease or pathogen is “passed on” or “communicated” from one individual to another in a population of humans, or in groups of other animals. Disease can be transmitted in two ways:

• Horizontal disease transmission – from one individual to another in the same generation (piers in the same age group).^[1] Horizontal transmission can occur by either direct contact (licking, touching, biting), or indirect contact (vectors or fomites that allow the transmission of disease without physical contact).^[2]

• Vertical disease transmission – passing a disease causing agent vertically from parent to offspring. Typically the mother transmits the disease by means of bodily fluid, and sometimes breast milk.^[1]