2-Rabies Flashcards
What disease has the highest case fatality proportion of any conventional infectious disease?
Rabies
What is an acute, typically fatal, rapidly progressive encephalomyelitis of humans and other mammals?
Rabies
The rabies virus present in saliva late in infection is usually transmitted to susceptible hosts in what way?
By the bite of diseased animals.
Rabies is the leading viral zoonosis in terms of what 2 things?
- Global public health
- Veterinary significance
Rabies is caused by what viruses?
RNA viruses in the family Rhabdoviridae, genus Lyssavirus
What is the type species of the genus for rabies?
Rabies virus (RABV)
How many other Lyssavirus species or “genotypes” cause rabies?
11
What is the host range for rabies?
Very broad - all mammals can be affected
T/F: RABV is not associated with bats outside of the Americas.
True
Sustained intraspecies maintenance of rabies is seen in what type of host?
Reservoir host
Inefficient transmission is seen in what type of host?
Spillover host
Biological susceptibility to an adapted virus variant that induces behavior changes that enhance viral transmission via saliva can be seen in what type of host?
Reservoir host
What are 2 orders of species that can act as reservoir hosts for rabies?
- Carnivora (canids, skunks, raccoons, mongoose)
- Chiroptera (bats)
Where is rabies distributed?
On all continents except Antarctica.
T/F: There are no areas considered “free” of rabies.
False - several areas are considered “free” of the disease, including many islands in Pacific Oceania
What threatens the disease-free status of many localities, due to he introduction of rabid animals?
Globalization
About how many humans rabies deaths are estimated per year?
60,000
How much is lost economically annually with rabies?
What are 2 causes of this loss?
- $8 billion US
- Premature death, post-exposure prophylaxis
Most of the burden of rabies falls on what countries?
Developing countries
What is the single most important global animal reservoir?
Domestic dogs
What percentage of human cases contract rabies form domestic dogs?
> 95%
What else is considered important concerning the burden of rabies,especially in developed countries, such as Europe and North America?
Wildlife
What are 4 countries where rabies can be seen in the Caribbean mongoose?
- Puerto Rico
- Cuba
- Dominican Republic (and presumably Haiti)
- Grenada
There is evidence of bat rabies on what 3 Caribbean islands?
- Cuba
- Grenada
- Trinidad
Do mongoose on Trinidad carry rabies?
No
Is human rabies common or uncommon?
About how many cases per year?
- Uncommon
- About 1 to 8 cases per year
Approximately how many cases of human exposures to rabies occur per year?
30,000 to 38,000
Approximately how many animal rabies cases are diagnosed per year?
5,000 to 10,000
T/F: Dog rabies virus transmission has been eliminated.
True
What are 5 examples of wildlife hosts of rabies?
- Raccoons
- Skunks
- Foxes
- Mongoose
- Bats
Rabies in the USA is distributed in every state except which one?
Hawaii
How good is rabies surveillance in animals?
Very good
Who publishes an annual summary of rabies surveillance (runs about 1 years behind real time data)?
CDC
In 2010, how many cases of rabid animals were reported?
6,154 rabid animals
What percentage of rabies cases are seen in wildlife?
What percentage in domestic animals?
- 92%
- 8%
What percentage of rabies cases are seen in raccoons?
Skunks?
Bats?
Foxes?
- 37%
- 24%
- 23%
- 7%
What percentage of rabies cases are seen in cats? Dogs? Cattle? Horses? Goats and sheep?
- 5%
- 1%
- 1%
- 0.6%
- 0.1%
What other country reports similar findings in wildlife and domestic animal rabies cases to the US?
Canada
Mexico only has surveillance of rabies in which animals?
What percentage of cases are seen in cattle?
- Domestic
- 83%
The majority of human rabies in the US is caused by what variants of the rabies virus?
Bat variants of rabies virus
What are 3 problems with detecting minor wounds from a bat bite?
- Difficult to detect
- May not recognize exposure
- May sleep through the bite
Most human rabies are diagnosed what?
Post-mortem
If symptomatic for rabies, what occurs in almost all cases?
Death
In 2012, how many animals were reported rabid in the US?
What percentage were wildlife?
How many human cases?
- 6,162
- > 90%
- 1
How is the rabies virus primarily transmitted?
Via bite
Are rabies agents mildly or highly neurotropic?
Highly neurotropic
Where does the rabies virus enter the nervous system?
Peripheral nerves
How does the rabies virus get to the CNS?
Centripetal travel by retrograde flow in axoplasm of nerves to CNS.
Where does the rabies virus replicate?
In the brain.
Where else can centrifugal flow spread rabies virus to in the body?
Innervated organs, including the portal of exit, the salivary glands.
Where is viral excretion seen in the body?
Saliva
What is the incubation period for rabies?
What is the average?
- Variable (range = weeks to years)
- 1 to 2 months
Non-specific signs can be seen during which phase?
Prodromal phase
What are 2 phases that can be seen with rabies?
- Prodromal phase
- Acute neurological phase
Rabies can lead to what 2 conditions?
- Coma
- Death
Encephalitis can lead to what?
Behavioral changes
Is “furious” rabies considered excitatory or depressive?
Excitatory
Is “dumb” rabies considered excitatory or depressive?
Depressive
Which form of rabies is excitatory?
“Furious” rabies
Which form of rabies is depressive?
“Dumb” rabies
What are 6 clinical signs seen with “furious” rabies?
- Anxious
- Restless
- Aggressive
- Vocal
- Hyper reactive
- Ataxic
Is the “furious” form of rabies seen more in cats or dogs?
Cats
How might the “furious’ form of rabies present in horses?
As colic
What are 4 clinical signs seen with “dumb” rabies?
- Somnolent
- Depressed
- Ataxic
- Ascending paralysis
Is the “dumb” form of rabies seen more in cats or dogs?
Dogs
Which form of rabies is seen more often in ruminants, “furious” or “dumb”?
“Dumb”
What are 3 clinical signs that can be seen with all forms of rabies?
What can this lead to in cattle?
- Paralysis of muscles in throat (dysphagia)
- Salivation
- “Hydrophobia”
- Cattle = “choke”
What is the official reference document for rabies prevention?
Compendium of Animal Rabies Prevention & Control