Zoonosis Flashcards

1
Q

What is zoonosis?

A

Infectious disease transmitted naturally between humans and animals wild or domestic
Zoonotic in animal reservoirs and transmits to humans with little onward spread

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2
Q

Describe zoonotic spread to humans

A

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

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3
Q

How are zoonotic diseases transmitted?

A

Airborne
Vectors - infected agents from animals
Close proximity to animals - faecal/ oral transfer
Food-borne
Direct contact from animals - bites from infected animals

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4
Q

What is needed for spill over from zoonotic pool to human infection?

A

Ecological contact
Phylogenetic distance
Viral traits

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5
Q

What are risks for zoonosis?

A

Human living environments
Natural ecosystems
Food and agriculture
All can cause disease emergence, re-emergence and persistence

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6
Q

Can reservoir be predicted?

A

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

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7
Q

What are common UK zoonosis?

A

Salmonella
Campylobacter
Toxoplasma
Ringworm/ dermatophytosis

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8
Q

What are uncommon UK zoonosis?

A

Anthrax, rabies, bubonic plaque, tularaemia and acute brucellosis

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9
Q

What is not zoonosis?

A

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

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10
Q

What is anthroponosis?

A

Reverse zoonosis in that humans are infecting animals
Ex. influenza, step throat, leishmaniasis and chytridiomycosis

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11
Q

What are some complex interacting reasons for pathogen emergence?

A

Changing land use
Human population growth
Globalisation and air travel
Changing human behaviours - travel, meat eating, exotic pets and closer interaction to wildlife

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12
Q

Describe the connection of food security and zoonosis

A

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

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13
Q

What is Lyme disease?

A

Spirochete found in wild dear
Transmitted by tick - lxodes ricinus
Commonest in summer months
Borrelia Burgdorferi

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14
Q

What is the Lyme vector?

A

Lxodes genus - ricinus (Europe), scapilaris and persulcatus

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15
Q

What is erythema migrans?

A

Classic presentation mark of Lyme disease
3-90 days after the bite
Mainly single lesion but can have multiple

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16
Q

What are some Lyme disease symptoms?

A

Fever, chills, fatigue, fatigue and erythema migrans
Later - facial palsy, irregular heartbeat and dizziness

17
Q

Describe neuroborreliosis

A

Triad of facial nerve palsy, radicular pain and lymphocytic meningitis
Onset of symptoms 2-6 weeks after bite
Preceded by EM in 30-50%

18
Q

How is Lyme disease diagnosed?

A

If erythema migrans rash present - offer antibiotics
If not then offer ELISA test
Positive then offer immunoblot test
If positive then offer antibiotics and negative then alternative diagnosis

19
Q

What is the treatment for Lyme disease?

A

First line is Doxycycline
Then amoxicillin if child
Neuro Lyme - Ceftriaxone

20
Q

Describe Leptospirosis

A

Spirochete
One of the most widespread zoonosis
Many reservoir hosts
Survive in the environment for weeks to months
Penetrate abraded skin or mucous membranes to cause systemic illness

21
Q

What are the symptoms of leptospirosis?

A

Undifferentiated fever, myalgia, headaches and abdominal pain
Severe disease - Weil’s disease and pulmonary haemorrhage

22
Q

How is leptospirosis spread?

A

Human is incidental host - direct contact with animal
Contact with environment contaminated with their urine
Incubation is 20-30 days

23
Q

What are the investigations for leptospirosis?

A

Clinical suspicion
Serology - IgM and IgG
Microscopic agglutination test

24
Q

What is the treatment for leptospirosis?

A

Doxycycline
Amoxicillin or azithromycin as second line
Severe disease - ceftriaxone

25
Describe rabies
Viral infection transmitted from bite of an infected animal Wide range of wild animal transmitters - dogs, bats, monkeys, foxes, racoons... Incubation is 1-3 months but may be years
26
Describe the pathogenesis of rabies
Virus enters tissue from saliva of biting animal Virus replicates in muscle near bite Virus moves up peripheral nervous system to CNS in spinal cord Virus reaches brain and causes fatal encephalitis Enters salivary glands and other organs
27
What are the symptoms of rabies?
Furious - hydrophobia, insomnia, confusion, agitation and coma Paralytic - ascending flaccid paralysis, fever, confusion and coma
28
What is the investigations for rabies?
PCR of skin biopsy and saliva Often post mortem confirmation - brain biopsy
29
What is the treatment for rabies?
Nil effective Milwaukee protocol
30
What is the post-exposure treatment for rabies?
Fully immunised - 2 doses on day 0 and 3-7 Not immunised and immunocompetent - HCG and 4 doses Not immunised and immunocompromised - HRIG and 5 doses
31
Describe Ebola
Filovirus West and central Africa 5 species Numerous outbreaks Most recent was 2014-16
32
How is Ebola transmitted?
Animal to animal transfer - bats are host Spill over event Human to human transmission Survivor - has tiredness and muscle aches
33
What are the symptoms of Ebola?
Dry - fever, fatigue and aches + pains Wet - vomiting, diarrhoea and haemorrhage
34
What is the incubation period for Ebola?
2-21 days Average - 8-10 days
35
What are the investigations for Ebola?
PCR Serology - IgM and IgG
36
What is the treatment and vaccination for Ebola?
INMAZEB - 3 monoclonal antibodies EBANGA - 1 monoclonal antibody Vaccine - Ervebo - 1 dose during outbreak. Zabdeno and Mvabea - 2 doses of each
37
What type of infection can zoonosis be?
Bacterial, viral, fungal and priron