Lecture 3: Rabies

what are the animals that are most commonly infected with rabies?

wild terrestrial carnivores - raccoons, skunks, foxes

what are not considered reservoirs for rabies?

rodents

true or false: the US has been declared free of canine rabies virus variant transmission.

true

since 2000, what animal has been diagnosed more with rabies?

cats

when do dogs, cats, and ferrets shed rabies virus?

a few days prior to, and during, clinical signs

incubation period for rabies

• highly variable

• 3-12 weeks in domestic animals

rabies transmission

dogs usually shed rabies in their saliva for up to 5-10 days before clinical signs develop

latent period for rabies

from infection to shedding, up to 6 months

incubation period for rabies

infection to clinical signs, usually 5-10 days longer than latent period

clinical presentation of rabies in animals

inappetance, dysphagia, cranial nerve deficits, abnormal behavior, ataxia, paralysis, altered vocalization, seizures

case definition of rabies requires lab confirmation by

positive direct fluorescent antibody test or isolation of rabies virus (cell culture or lab animal)

what are the 2 main categories of animal-to-human exposures of rabies?

bite and non-bite

bite exposure to rabies

any penetration of the skin by teeth

non-bite exposure to rabies

• surgical recipients of corneas, solid organs, vascular tissue

• people exposed to large amounts of aerosolized virus

• contact of open wounds with saliva from a rabid animal

true or false: indirect contact of rabies constitutes rabies exposure.

false - it does not

what exposure to rabies deserves special consideration?

bat exposure

organ transplantation has resulted in

16 rabies cases

true or false: caring for a human rabies patient is not an exposure.

true

what are the 2 rabies vaccines that are licensed for human use in the US?

human diploid cell vaccine (HDCV) and purified chick embryo cell vaccine (PCECV)

rabies immune globulin (RIG)

provides rapid passive immunity for about 21 days

pre-exposure prevention for rabies in humans

• 2 doses of RV on days 0 and 7

• follow up with serologic testing to ensure protection 1-3 years later or booster after 3 years without titer testing

high-risk groups for rabies exposure

vets and staff, animal handlers, rabies researchers, certain lab workers

post-exposure prophylaxis for rabies in humans

• wound treatment

• local infiltration of RIG

• vaccination (RV)

post-exposure regimen for rabies in humans if not previously vaccinated

• thorough wound cleansing with soap and water

• RIG (half at bite site and other half IM)

• 4 doses of RV on days 0, 3, 7, and 14

post-exposure regimen for rabies in humans if previously vaccinated

• thorough wound cleansing

• RV on days 0 and 3

post-exposure prophylaxis is considered a

medical urgency NOT emergency

management of rabies exposures in humans

• 16,000-39,000 people receive post-exposure prophylaxis each year in the US

• pre-exposure prophylaxis alone may not be sufficient to protect without post-exposure prophylaxis

• costs of post-exposure rabies prophylaxis can be significant

rabies prevention in domestic animals

• all dogs, cats, and ferrets be vaccinated

• remove strays and unwanted animals

rabies prevention in wildlife

• no licensed parenteral vaccines used in wild animals or wild hybrids

• states are encouraged to enact laws to prohibit importation, distribution, translocation, and private ownership of wild species

true or false: adverse events from rabies vaccine are rare in animals.

true

do licensed vaccines exist for wild or hybrid animals?

no

human contact with animal rabies vaccines

• injectable: does not constitute rabies exposure

• vaccinia-vectored oral: should be reported to health department

pre-exposure prevention of rabies in animals

• dogs, cats, ferrets, horses, and livestock with frequent human contact

• wild animals or hybrids should not be kept as pets

• vaccination by licensed DVM with approved vaccine

• animal should be boostered in one year regardless of age at initial vaccine

typical vaccination schedule for dogs, cats, and ferrets

• initial vaccination at 3 months of age

• booster one year later regardless of initial vaccine type

• booster every 3 years

rabies control and prevention in carnivores

• oral rabies vaccines for mass vaccination is considered in select situations

• labeled for use only in raccoons and coyotes

rabies control and prevention for bats

• rabid animals reported form all 48 contiguous states

• caused at least 43 human deaths in USA

• reducing bat populations is neither feasible nor desirable

wild mammalian carnivores and bats that are unavailable for rabies testing should be

considered rabid

management of dogs, cats, and ferrets that are exposed to a rabid animal

• unvaccinated animals should be euthanized immediately

• current vaccines should be revaccinated immediately and observed by owner for 45 days

• those overdue for booster also should be boostered immediately and kept under owner control for 45 days

management of livestock exposed to rabid animal

• unvaccinated livestock should be euthanized immediately

• current vaccines should be revaccinated and observed for 45 days

• multiple exposures in herd are uncommon

• exposed animal can be immediately custom-slaughtered

• cooking and pasteurization inactivate rabies virus

management of dogs, cats, ferrets that bite humans

• confined and observed for 10 days regardless of vaccination status

• strays or unwanted animals should be euthanized and tested immediately

testing for rabies in animals

• accomplished for those animals potentially exposing humans or domestic animals

• for all animals except bats, submit only the head or brain to diagnostic lab

international and interstate movement of animals

• CDC regulates the importation of dogs and cats into the US

• prior to interstate movement for dogs, cats, ferrets, and horses, they should be current on rabies vaccination and accompanied by valid rabies certificate