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1

Define:
Zoonosis

An infectious disease that is transmitted between species from animals to humans

2

T/F

Zoonosis can be passed only directly

F
Both

Directly: ex. Rabies or Avian Influenza

Indirectly Via a vector intermediate (ex: WNV and mosquitos)
Via food (ex: campylbacteriosis)
Contaminated environment (Q fever)

3

Define:
Reverse zoonosis (anthroponosis)

Diseases transmitted from humans to animals

4

Example of reverse zoonosis (anthroponosis)

Human to Gorillas (ex: Measles)

5

What is Conservation medicine

An emerging, interdisciplinary field that studies the relationship between human and animal health, and environmental conditions.

6

What are some criteria for zoontic disease ****

1) a vertebrate reservoir exclusive of humans

2) transmission of the agent directly to people or from products derived from the host animal or through an arthropod intermediate

3) a recognized infectious disease syndrome in susceptible individuals

7

T/F

As animals became domesticated and a close bonds developed between animals and humans, the occurrence of zoonotic diseases decreases

False

It increased

8

Why are emerging zoonoses are a growing concern?

1. Novel diseases that current medical system is not prepared to handle (Ex: SARS, mad cow disease)

2. Outbreaks are unpredictable (Ex: Avian influenza)

3/ Outbreaks are increasing in recent times
(70% of all infectious outbreaks are zoonotic in origin)

4. Outbreaks can occur anywhere and spread quickly throughout the globe

5.Have a significant impact on global and country’s economies

9

Define
Enzootic
Epizootic

Enzootic: refers to a disease that is endemic (i.e. present at stable levels) among animal populations
Ex: Lyme disease in ticks and mice and plague in rats


Epizootic: and “epidemic” in animals
If in a specific locations, it an “outbreak”
If widespread it is “panzootic”

10

Define panzootic

Widespred epidemic in animals

11

Define:
Epidemic

Refers to human disease spread to a large number of people within a defined short amount of time

12

T/F

Of 1415 species of human pathogens recognized, 800 are known to be zoonotic

True

over half are zoonotic

13

T/F

Discovery of new human pathogen species is at a rate of 3-4 species /year

True

14

Types of zoonotic infections (5)

Bacterial
Viral
Fungal
Parasitic
Prions

15

List of viral diseases

Rabies

Rift Valley Fever
West Nile virus
Yellow Fever
Dengue
Monkeypox
Lassa Fever

16

List of Bacterial Diseases

Brucellosis
Leptospirosis
Plague
Q fever

Rat bite fever
Lyme

17

List of Parasitic Diseases

Echinococcosis

Angiostrongliasis
African and American Trypanosomiasis
Babesiosis
Chagas
Clinorchiasis
Cryptosporidiosis
leishmaniasis

18

Risk Factors for zoonotic diseases

1. Household pets
2. Increased contact between humans and wildlife
3. Increased human activity into wilderness areas
4. Wild animals encroaching into human civilization


19

How Diseases Spread

1. Through feces
2. Fecal-oral
3. Direct contact
4. Insect vectors

20

What diseases can be passed through feces?

- Parvo
- Feline panleukopenia
- Salmonella
- Toxoplasma
- Worm eggs (rounds, whips, hooks)
- Giardia and Coccidia

21

What diseases can be passed through direct contact?

- Ringworm
- Scabies
- Ear mites
- Hookworm larvae

22

What diseases can be passed through insect vectors?

Mosquitoes - heartworms and encephalitis
Heartworm in humans extremely rare, but few reports can be found

Fleas - tapeworms, cat scratch fever, plague, typhus.

Ticks - Lyme disease and RMSF

23

List some agricultural exposures

1. Frequent contact with domestic animals
2. Overlap with wildlife habitat
3. Large scale livestock production
4. Poor animal sanitation and personal hygiene

24

T/F

Salmonella is a part of the normal gut flora in turtles and is shed in their stool, heavily contaminating whatever environment they are in

True

25

What happened after turtle/aslmonella outbreak

Small turtles (<10cm) were banned specifically to protect children as these are often purchased for children

Federal ban is difficult to enforce, many locally owned or independent pet shops still sell small turtles

26

T/F

Rabies has been used as an attempted weapon

True

Some attempted to use it as a weapon
DaVinci : terror-bomb created from Sulphur, arsenic, tarantula venom, toxic toads, and the saliva of mad dogs

27

T/F

Rabies remains endemic throughout the world

True

2/3 of the world’s population lives in a rabies endemic area

28

T/F

Rabies virus has the ability to infect and replicate in a wide host range

True

29

Historically, _________ transmission was more common until wide scale canine vaccine programs

canine-to-human

30

______ are important reservoir for rabies virus

Bats

31

T/F

Rabies deaths are predominately in the developing world

True

50,000/year
Main reservoir associated deaths are canines

32

Rabid dog exposures to rabies is responsible for

>_____% of human exposures
>______% of human deaths

>90% of human exposures
>99% of human deaths

33

Rabies is member of the order _____________

Mononegavirales

34

Other members of this order, Mononegavirales, are ______ and ________

filoviridae (ebola) and paramyxoviridae (measles)

35

Rabies
Family
Genus

Family Rhabdoviridae, genus lyssavirus

36

Rabies has a ________________ genome

Non-segmented negative strand genome

37

Rabies virions are ______ shaped with ______ appearance

“bullet” shaped, with “spiky” appearance

38

Majority of rabies cases occurring in which countries

Asia and Africa

39

Where has rabies never been endemic

New Zealand and Australia

40

Two main types of spread/maintenance for rabies

Urban: through dogs

Sylvactic (forest): through wildlife

41

What is the main reservoir for rabies worldwide? And why?

Main reservoir worldwide is dogs
Main reason for spread is lack of rabies control programs and lack of vaccinations

42

What is the main reservoir for rabies in the US? And why?

Main reservoirs in US are wildlife, due to successful dog vaccination programs

43

T/F

From 2003 to 2013 there were only 34 cases of human rabies in the US

True

Due to animal control and vaccination

44

What wild animals in the US have rabies?

1. Raccoons
2. Skunks
3. Foxes
4. Coyotes
5. Bats

45

What wild animals in the US have bever transferred rabies to humans?

1. Squirrels/chipmunks
2. Rats/mice/hamsters
3. Rabbits

46

In the US which wild animal accounted for most of the rabies cases?

1. Bats
2. Raccoons
3. Skunks
4. Foxes

47

In the US which domestic animal accounted for most of the rabies cases?

1. Cats

48

Rabies in:
Europe

Successful control but fox and raccoon populations continue to pose a threat to complete elimination

49

Rabies in:
Asia

Grossly underreported

In India alone, estimated 20,000 people die of canine rabies.
Dramatic rise of rabies in China.

50

Rabies in:
Africa

Primarily canine in origin
Jackals, bat-eared foxes and mongoose are involved in rabies transmission in Africa

51

Rabies in:
Central & South America

Thru PAHO rabies vaccine programs, over the past 20 years has led to an almost 90% decrease in dog and human cases.

52

Rabies disease transmission

1. Bite of an infected animal that contains virus in the saliva (Infection may occur at exposed mucous membranes (conjunctiva, oral mucosa….)

2. Inhalation of aerosolized virus in bat caves has been reported. (extremely rare)

3. Organ transplantation has been reported

4. After the bite, the virions may enter the CNS directly or after initial replication within muscle tissue
Enters motor nerves through neuromuscular junctions
Can stay at inoculation site for days to months

53

T/F

After the bite, the virions may enter the CNS directly or after initial replication within muscle tissue

True

Enters motor nerves through neuromuscular junctions
Can stay at inoculation site for days to months

54

T/F

Non-Bite Exposure of rabies is common

False

- Aerosol exposure: laboratory accidents, caves with high concentrations of bats
Open wounds or mucus membranes must come into contact with infectious material like saliva or brain tissue

- Organ transplant

55

Rabies Virus remains at inoculation site for ___________ before ascending up the nervous system

weeks to months

(incubation period)

56

T/F

Patient is asymptomatic during incubation phase for rabies

True


Length of phase determined by amount of virus and how close the site is to the CNS

1. Virus inoculated through bite
2. Replicates locally in muscle near bite

57

Prodrome phase of rabies

1. Enters peripheral nervous system (nerves not in the brain or spine)
2. Ascends up via sensory fibers
3. Replicates in Dorsal Root Ganglia
4. Rapidly ascends into spinal cord

58

Neurologic phase

the infection of the brain is rapid as is the spread to the tissues

1. Infects CNS (spinal cord, brainstem, cerebellum, other parts of brain)
2. Infection descends into eye, salivary glands, and skin

59

T/F

Little histologic change can be seen in post mortem brain tissue

True

Classic finding is the “Negri Body”

60

T/F

Rabies infection elicits an antibody response early before the beginning of the neurologic stages of the disease

False

Rabies infection does not elicit an antibody response until the late neurologic stages of the disease

However, antibody is effective at stopping the disease prior to the neurologic phase

61

T/F

Exogenous antibody can block rabies

True

The long incubation period allows for the vaccine to be administered as post exposure treatment

62

Length of Incubation period for rabies is determined by 5 factors

1. The concentration of the virus in the inoculum
2. The proximity of the wound to the brain
3. Severity of the wound
4. Host’s age
5. Host’s immune status

63

Incubation period for rabies is typically ______ days but may be as long as _____ years

20-90 days
14-19 years

64

Entry virus at a _______ innervated site often leads to swift progression (ex: hands vs calves)

highly

(Also factors, the dose delivered, the subtype of rabies virus, and types of nervous tissue at bite site, depth of the bite, closer to the head)

65

Mortality rates for rabies due to location/type/extent of wound highest to lowest

1. Face/bite/deep
2. Face/nite/single
3. Fingers/bite/severe
4. Trunk+legs/scratch/mutiple
5. Skin covered by clothes/wound/superficial

66

5 clinical stages of rabies


Incubation Period
Prodrome
Acute Neurologic Phase
Coma
Death

67

Prodrome- Early symptoms may be difficult to appreciate
and may resemble

tetanus, typhoid, malaria, and other viral encephalitis

Fever, nausea, vomiting, headache, lethargy

68

Describe the ACUTE NEUROLOGICAL DISEASE of rabies

-80% develop “furious” rabies
1. Hyperactivity, disorientation, bizarre behavior, hypersalivation, sweating
2. Hydrophobia is actually dysphagia

- 20% develop paralytic rabies (“dumb”)
1. Ascending symmetric paralysis with flaccidity and decreased tendon reflexes

69

T/F

No tests are available to diagnose rabies infection in humans before the onset of clinical disease

True

Unless the rabies-specific signs of hydrophobia or aerophobia are present, the clinical diagnosis may be difficult.

Antibodies in blood are not present until neurological disease starts

70

Post mortem, the standard diagnostic technique is to detect rabies virus antigen in brain tissue is ______________

by fluorescent antibody test

71

Diagnosising rabies

1. Histopathology
2. Antigen detection - brain/spinal fluid
3. VIrus isolation (takes a long time)
4. Nucleic Acid based PCR

72

Diagnosis of rabies:
Histopathology

Negri bodies-consist of reticulogranular matrix containing tubular structures

Found in the cytoplasm of undamaged nerve cells, particularly in the hippocampus

73

Diagnosis of rabies:
Antigen detection- brain/spinal fluid

Fluorescent antibody test, recommended by OIE and WHO as the “gold” standard
95-99% accurate, results within hours

74

Diagnosis of rabies:
Virus Isolation

Takes too long

Mouse inoculation test-Used for confirmation, tissue sample is injected into weanling mice
In-vitro isolation-inoculation into a neuroblastoma cell line and FAT test used

75

Diagnosis of rabies:
Nucleic Acid based-PCR

Increasingly used

Serology antibody testing not done, since rabies infection is uniformly fatal

Allows for strain typing which allows for identification of the likely source of infection and geographic location
Various strains are adapted to specific animal reservoir hosts
Instrumental for CA- told us risk of bat

76

T/F

We have had an effective vaccine for rabies has been available for over 100 years

True

Invented by Pasteur in 1885
100% effective

77

T/F

Rabies vaccine may be given pre-exposure or post exposure

True

Pre-recommended for those working with the virus or have potential of contact

Post-key point is timing
Should be administered rapidly
Expensive and in short supply
RIG-Injected surrounding the wound and any left over injected into the intramuscular + rabies vaccine given


78

T/F

Animals can be vaccinated for rabies

True

Estimated that at least 50 million dogs are vaccinated each year against rabies.

However, in many parts of Asia and Africa the vaccination coverage established in the dog population (30% to 50%) is not high enough to break the transmission cycle of the disease


79

Considerations for rabies prophylaxis

- Epidemiology of rabies in the region
- Type of exposure
- Whether it was provoked or unprovoked
- The species and vaccination status of the animal

80

Data shows that animals like dogs, cats, and ferrets begin to sicken and die within _______ days of exposure to rabies

10 days of exposure

81

If a domestic animal with rabies bites a person, then they should be observed for ______ days

r 10 days

-If they show any illness, then they should be euthanized and the head should be shipped to a laboratory for rabies testing
- If animal is healthy for 10 days, then no rabies
- If bit around head, prophylaxis immediately as the incubation period can be as short as four days

82

Post Exposure Rabies Prophylaxis

1. After bite, wash area with soap and water and use virucides such as povidone-iodine if possible
2. Requires both active and passive immunity
3/ Must be given ASAP
4. Rabies vaccine = active immunization (body will produce its own antibodies)
5. Rabies immunoglobulin= passive immunization (provides a shot of immediate antibodies to fight virus)

83

Pre-Exposure Rabies Vaccine

1. Vaccine only
2. Travelers in whom rabies pre-exposure prophylaxis should be encouraged include:
3. The following groups should be vaccinated as well: animal workers, lab workers who handle potentially infected tissue, and travelers

84

Rabies Prevention

1. Estimated public health costs assoc. w/ disease detection, prevention, & control have risen, >$300 million annually.
2. Surveillance is important in the US
3. In the US, domestic animals are continuously vaccinated
4. National mass dog vaccination campaigns are the most cost-effective strategy for preventing rabies globally
5. WHO program to eliminate rabies world wide

85

T/F
Culling is effective in preventing rabies

False

86

WHO Tanzania Rabies
Unique Approach (3)

1. Data collection - mobile phoe syrvveillance system
2. Human post-exposure prophylaxis
3. Canine vaccination (aiming for 70%)

87

WHO Tanzania Rabies
Achievement

1. Animal bites halved in areas
2. Human rabies death decreased
3. Established mobile phone survellance system
4. Canine vaccination campaign

88

WHO has been collecting rabies data electronically through ______

“Rabnet”