Zoonosis Flashcards
What is zoonosis?
Infectious disease transmitted naturally between humans and animals wild or domestic
Zoonotic in animal reservoirs and transmits to humans with little onward spread
Describe zoonotic spread to humans
Now established human transmission with no/ little ongoing zoonotic transmission - HIV
Both typically cause stably endemic disease with localised outbreaks
Efficient transmission once transmitted from host - typically rapidly spreading sizeable outbreaks
How are zoonotic diseases transmitted?
Airborne
Vectors - infected agents from animals
Close proximity to animals - faecal/ oral transfer
Food-borne
Direct contact from animals - bites from infected animals
What is needed for spill over from zoonotic pool to human infection?
Ecological contact
Phylogenetic distance
Viral traits
What are risks for zoonosis?
Human living environments
Natural ecosystems
Food and agriculture
All can cause disease emergence, re-emergence and persistence
Can reservoir be predicted?
Largely found to be host neutral
Bats and rodents carried no higher prediction than for their size of groups
Largely predictable without need for invoking special ecology or immunological relationships
What are common UK zoonosis?
Salmonella
Campylobacter
Toxoplasma
Ringworm/ dermatophytosis
What are uncommon UK zoonosis?
Anthrax, rabies, bubonic plaque, tularaemia and acute brucellosis
What is not zoonosis?
Malaria
Schistosomiasis
Onchocerciasis
Elephantiasis
Because they are transmitted from animals by depend on human host as part of their life cycle - not an accidental spill over
What is anthroponosis?
Reverse zoonosis in that humans are infecting animals
Ex. influenza, step throat, leishmaniasis and chytridiomycosis
What are some complex interacting reasons for pathogen emergence?
Changing land use
Human population growth
Globalisation and air travel
Changing human behaviours - travel, meat eating, exotic pets and closer interaction to wildlife
Describe the connection of food security and zoonosis
Increasing global meat consumption and production
Intensification of livestock production
Substandard animal welfare
Inadequate disease surveillance
Improper preparation or slaughter
Incomplete understanding of pathogen lifecycles
What is Lyme disease?
Spirochete found in wild dear
Transmitted by tick - lxodes ricinus
Commonest in summer months
Borrelia Burgdorferi
What is the Lyme vector?
Lxodes genus - ricinus (Europe), scapilaris and persulcatus
What is erythema migrans?
Classic presentation mark of Lyme disease
3-90 days after the bite
Mainly single lesion but can have multiple