e.g. HIV, passed from mother to child via the blood from the placenta other examples: hepatitis B and hepatitis C
horizontal transmission (from one person to another)
droplet infection from coughs and sneezes e.g. flu, cold, TB
direct contact, or via bodily fluids e.g. hepatitis (in blood), STIs (sexually transmitted infections: syphilis, gonorrhoea, HIV), SARS
Indirect contact involves a carrier mechanism
vehicle-borne diseases are spread by means of inanimate (non living) objects
e.g.
food poisoning such as that caused by Salmonella - in food!,
typhoid spread by (flood?) water,
athlete’s foot and verrucas spread by wet conditions in shower rooms etc
vector-borne diseases are spread by means of living organisms
e.g.
malaria is spread by the bite of a mosquito (specifically of the genus Anopheles)
sleeping sickness is spread by the bite of a tsetse fly
rabies, spread by dog (or bat) bites
This knowledge can be put to good use in preventing or controlling the spread of these diseases.