Learning Objective
- Zoonoses, such as influenza, can be transmitted between vertebrate species (SU)
What is a Zoonose?
A zoonose is a disease which can be transmitted between vertebrate species.
An infectious disease caused by a pathogen that has jumped from a non-human animal (usually a vertebrate) to a human.
Typically, the first infected human transmits the infectious agent to at least one other human, who, in turn, infects others.
Major modern zoonoses:
Animal influenza viruses occasionally recombine with human strains of the flu and can cause pandemics. Examples include;
Of 1,415 pathogens known to infect humans, 61% are zoonotic.
Most human diseases originated in other animals.
Only diseases that routinely involve non-human to human transmission, such as rabies, are considered direct zoonosis.
Zoonoses have different modes of transmission.
Direct zoonosis:
Indirect zoonosis:
Reverse zoonosis or anthroponosis:
- The term is from Greek: zoon meaning"animal" and nosos meaning "sickness".
An infectious disease caused by a pathogen that has jumped from a non-human animal (usually a vertebrate) to a human.
Typically, the first infected human transmits the infectious agent to at least one other human, who, in turn, infects others.
Major modern zoonoses:
- Ebola virus disease
- Salmonellosis
- HIV was a zoonotic disease transmitted to humans in the early part of the 20th century, though it has now mutated to a separate human-only disease.
- Bird flu
- Swine flu
Animal influenza viruses occasionally recombine with human strains of the flu and can cause pandemics. Examples include;
- the 1918 Spanish flu (likely from birds)
- the 2009 Swine flu (likely from pigs)
- COVID-19 (suspected although the source animal species is unconfirmed)
Of 1,415 pathogens known to infect humans, 61% are zoonotic.
Most human diseases originated in other animals.
Only diseases that routinely involve non-human to human transmission, such as rabies, are considered direct zoonosis.
Zoonoses have different modes of transmission.
Direct zoonosis:
- the disease is directly transmitted from other animals to humans
- through air (influenza) or through bites and saliva (rabies).
Indirect zoonosis:
- intermediate species (referred to as a vector), carry the disease pathogen and pass it on to humans
Reverse zoonosis or anthroponosis:
- When human transfer a disease to animals.