Zoonoses Flashcards
Zoonosis
any disease or infection that is naturally transmissible from vertebrate animals to humans
Infectious agent
The agent that causes infection and/or disease including viruses, bacteria, fungi, protozoa, and helminths
Horizontal: direct transmission
The transfer of infectious agent through an intermediate biological host or can be food-borne, water-borne, via transfusions or aerosol transmission (large distances)
Vector
A vector is an organisms, usually an arthropod, which transmits an infectious agent to a new host. Arthropods which act as vectors includes houseflies, mosquitoes, lice and ticks. Biological vectors: An infectious agent either replicates here or undergoes a necessary part of its life cycle i.e. Dirofilaria immitis in mosquitoes Mechanical vector: An arthropod that carries an infectious agent to its primary host. I.e. Mosquitoes and fleas transmitting myxomatosis virus to rabbits
Vertical transmission
Transmission via infection of the embryo or fetus while in utero or ovo
Airborne or aerosol transmission
Inhalation of small respiratory droplets that travel large distances Coxiella burnetii., SARS CoV-2
Droplet
Inhalation of large droplets that travel shorter distances than aerosols. SARS CoV- and mycobacterium tuberculosis
Reservoir host
In which an infectious agent normally lives and multiplies and is thus a common source of infection to other animals Eg. cattle as reservoirs for blue tongue virus Birds as reservoirs for WNV, EEE
Amplifier host
Host animals, such as pigs, that can become infected with the virus and produce a higher viral load, potentially leading to increased transmission to other hosts including humans
Incidental host or dead end hosts
Host animals, like humans or horses that don’t support significant replication of the agent or concentration in their bloodstream, making them unlikely sources of further transmission. These are hosts that are not integral to the infectious agents’ transmission cycle.
