Zoonosis refers to the transfer of some diseases from animals to humans. Many animals carry the same pathogens that cause illnesses in us, though whether the animals show the same symptoms or suffer from any ailments themselves may differ.
The organisms are able to move from the carrier animals to humans in many ways. Some organisms are air-borne and can spread just by being in close contact with the carrier animal, some spread only when humans are bitten by the infected animal, some are spread by consuming the meat of infected animals which is not properly cooked at a high enough temperature for an adequate amount of time, others may be passed on by insects like ticks and fleas.
Whenever a disease in humans is detected which is zoonotic in nature it is important to identify the animal carrier so that others can be protected and a rapid spread of the illness avoided.