Transcript Rabies powerpoint

Current Issues in Rabies
Mira J. Leslie, DVM, MPH
April 6, 2009
Todays Objectives
• Rabies:
– Overview of rabies disease
– Understand the current epidemiology of rabies
in animals and humans
– Describe the role of public health in rabies
detection, prevention and policy
– Consider the impact of importation of animals
on local animal and human health
Rabies Virus
• Rabies is caused by RNA viruses
in the family Rhabdoviridae, genus
Lyssavirus
• At least 7 Lyssavirus species or
genotypes cause rabies (disease)
• Recently, 4 new Lyssaviruses
collected from Eurasian bats have
been described
Rabies Disease
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Acute, progressive viral encephalitis
Highest case fatality of any infectious disease
One of the most ancient diseases described
Model zoonosis
ZOONOSES
Inoculated virus moves in
nerve tissue, not blood.
Rabies infection
• Long incubation period: usually 3-12 weeks
– Dogs: 2weeks-6m
– Humans: 2 weeks- 6 years (1-4 months usually)
– Wildlife: unknown
• Contagious period (viral shedding in saliva)
– Dogs: 1-10 days before death
– Humans: ?
– Wildlife: ?
Signs of rabies in animals
Abnormal Behavior :
• Nocturnal animals acting sick or
active during daylight hours.
• Staggering, trembling, weakness,
paralysis, agitation, confusion,
hypersalivation, unprovoked
aggression, abnormal
vocalization, glazed eyes,
choking….
• **Grounded bats.
• Variable symptoms
Rabies
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Estimated >55,000 deaths
annually
Global Disease
Encephalitis Caused by a Lyssavirus in Fruit Bats in
Australia
Graeme C. Fraser,* Peter T. Hooper,† Ross A. Lunt,† Allan R.
Gould,† Laurence J. Gleeson,† Alex D. Hyatt,† Gail M. Russell,† and
Jaqueline A. Kattenbelt†
EID, Volume 2, No 4, Oct-Dec 1996
Characterization of a novel lyssavirus isolated from
Pteropid bats in Australia.
Gould AR, Hyatt AD, Lunt R, Kattenbelt JA, Hengstberger S,
Blacksell SD.
Virus Res 1998;54:165-87
Rabies
• Animal reservoirs maintain and transmit
different rabies virus variants
• TerrestrialCarnivora (canids, skunks,
raccoons, mongoose, etc.) and nonterrestrialChiroptera (bats)
Source: http://www.rbe.fli.bund.de/About_Rabies/Epidemiology.aspx
United States confirmed rabid animals
wildlife
domesticated
• In the U.S., wildlife reservoirs maintain rabies and
infection is transmitted from wildlife to other species.
Animal Rabies in
North America
Reportable disease
N=273
N= 7258
•US: 6500-9500 rabid animals
recognized annually in all states
except Hawaii; 93% wild
•Canada: 220-280 rabid animals
reported annually
Terrestrial** and
non-terrestrial rabies
reservoirs
2007: N=2658
1980:
translocation
by hunters
started
epizootic
Raccoons and Rabies
• Raccoons efficiently
transmit rabies to:
skunks, beaver, fox,
groundhogs, cats, deer
dogs, goats, deer,
horses, pigs, sheep,
cattle, rabbits, …
2007: N=1478
Skunks and Rabies
• Skunks transmit
rabies to :
badgers, raccoons,
other wild animals,
cats, dogs, humans,
cattle, horses, …
Foxes transmit rabies to
coyotes, bobcat, dogs,
horses, etc
Skunk
Raccoon
Skunk
Skunk
Fox
Fox
Fox
Coyote
3 different variants
What accounts for this?
Bats and Rabies
• > 1900 rabid bats reported
in US during 2007
• Widespread distribution
• Many species affected
• Most bats are healthy- not
rabid
• No ‘carrier’ state
• Predominant cause of
human infections in US.
Bats with rabies
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Appear injured
Found flapping or dead on ground
Flying during the day
When in urban area, often expose
human and/ or pets
– Found in pets mouth
– Child finds bat
Rabies in Cats and Dogs
• Spillover infection
from wildlife reservoirs
• 2007:
– 274 cats
– 84 dogs in US
• for > decade 3:1
• Why?
Rabid cats
Walla, Walla: 2002
British Columbia: 2007
All pets including
cats SHOULD BE
VACCINATED!
Rabid puppy: Tucson 2002
• 3-4 month old stray
• Given to Humane
Society 3/11
• Animal Rescue 3/17
• PETsMART 3/22 &
3/24
• Euthanized March 29
• Rabies test April 2
Rabid Puppy: Follow up
• Count back 14 days from
death.
• Identify all human and animal
exposures.
• Press release, hotline, …
• Emergency room notification.
• 105 human exposures, 1
unvaccinated animal contact
Cost of PEP: $250,000?
Rabid puppy
• This pup was
vaccinated 2weeks
before it became ill:
what happened?
Contagious
Rabies
Exposure
Feb/
March
(virus shedding)
period = 0-10 days
Symptomatic
Vaccination at
Humane society Petsmart
& Rescue
Euth/test
April
Incubation period = weeks
Vaccinate pets before exposure
–A dog, cat, ferret receiving an initial
rabies vaccine will take about 28 days to
develop immunity. Subsequent vaccines
are “boosters”.
–After being exposed to a rabid animal a
vaccinated pet should have an immediate
booster rabies vaccine (to mount optimal
virus neutralizing antibody) .
Rabies Vaccines- Animals
• Domestic: parenteral vaccines for
dog, cat, ferret, horse, cattle,
sheep (see Compendium).
• Wild: Oral recombinant DNA
bait vaccine for raccoon, coyote,
fox (not used in WA)
• Exotic/wild: No licensed vaccine
for bats, monkeys, llamas, wolfhybrid…(off- label use by
veterinarians)
Pacific Northwest
(OR, WA, BC) Bat reservoirs of rabies
• So far, no terrestrial
rabies reservoirs
• Spillover infection
from bats into other
mammals including
humans
Other wildlife and pets
Rabies Surveillance
• Rabies surveillance is mostly passive and
not standardized among states or counties.
• In 2007, the range of rabid animal
reports/state is 0 (Hawaii) to 969 (Texas)
• # reported cases is only fraction of actual
cases- no accurate incidence or prevalence
http://www.cdc.gov/rabies/docs/rabies_surveillance_us_2007.pdf
Rabies: Evolving Epidemiology
Human factors:
1. Importation of foreign
dogs, exotic animals,
livestock
2. Interstate movement of
rabies reservoirs
3. Better diagnostics
4. Improved surveillance of
wildlife
5. Canine vaccination
Animal factors
1. Evolutionary adaptation
of virus in new hosts
2. Population density
3. Susceptibility
4. Reservoir range
Spit Happens
•History: Veterinarian
examined, sedated and
euthanized a llama that was
exhibiting abnormal
behavior.
Brain tissue sent to veterinary
diagnostic lab.
• Laboratory confirmed
rabies.
Site visit to small ranch;
5 llamas; 2 have wounds.
Investigation
• Another llama from
same pen died 2 weeks
earlier of undiagnosed
acute illness.
• Exhume for testing.
Investigation
• Brain tissue from
exhumed llama tests
positive for rabies
One week later:
Wounded llama dies.
Rabies Confirmed.
30 days later:
Three llamas remained healthy
Three llamas died of fox variant of rabies
One llama was euthanized due to wound/exposure
Three rabid llamas in 30 days
• Unusual for rabies to affect group of animals
• Llama to llama transmission? Not likely.
• What happened?
– River/Wildlife corridor adjoining ranch
– Probable single attack by rabid fox on the three male
llamas sharing one pen;
– Variable incubation according to amount of viral
inoculum and proximity to nerve–all died within one
month.
Human Rabies
• Worldwide, rabies causes an estimated 30,000-70,000
human deaths annually.
– Asia, Africa,…
• “… the patient can neither stand nor lie down;
like a madman he flings himself hither and
tither, tears his flesh with his hands, and feels
intolerable thirst. This is the most distressing
symptom for he so shrinks from water and all
liquids that he would rather die than drink or
be brought near to water; it is then that they
bite other persons, foam at the mouth, their
eyes look twisted, and finally they are
exhausted and painfully breath their last.”
– Girolamo Francocastro, 16th century
Human Rabies, U.S.
1980- 2006
N=59
9
8
7
6
5
4
3
2
1
0
Transplant
WA cases
Raccoon
Bat
ForeignDog
200
200
200
2
4
6
20
98
96
94
92
90
88
86
84
82
80
Temporal Trends in the Diagnosis of Rabies in the United States, 1944 to 2002
Rupprecht C and Gibbons R. N Engl J Med 2004;351:2626-2635
Human Rabies
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Minnesota
46 year old male
Paresthesia RH
Unsteady gait
Fever, resp failure
Steady neuro decline- death 22d
Handled bat with bare hands 2
months prior
Rabies
• 10 year old died Sept. 27,2005
(post hurricane) Mississippi
• No history of sick pets, no animal bite
• Bats in and around home
• Post mortem history; bat in bedroom
released outdoors by the child
Exposure of hospital staff and family
• 23 family members (including one who was
bitten by case)
• 32 of 79 health care workers (19 nurses, 4
physicians, 5 resp therapists, 2 XR techs, 2
lab staff)
Human Rabies Cases, U.S.
1980-2005
• 36/56 (64%) associated with insectivorous
bat rabies virus variants
• Most do not have history of bat bite
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Unreported minor bites
Hard to get history from rabies infected people
Unrecognized bites?
Teeth are small- no large wounds
Human rabies exposure/transmission
• Not all animal bites are rabies
exposures. However all bites
should be evaluated.
• Potential rabies exposure:
infectious saliva into skin or
on mucous membrane.
Post exposure prophylaxis
• Rabies is preventable if
vaccine is administered
before the virus gets into
nerve tissue.
• Administration of PEP is
not reportable. Approx
30,000? series/year in US.
Potential Human Rabies Exposures
• International travelers can
be exposed to canine rabies
– Some areas are HIGH RISK.
– (2008 Oaxaca exposed case)
• Bites in U.S.= risk varies
with species, test status, and
location
• “Cryptic” human exposure
(unknown history of rabid
animal contact)
Rabies Post-Exposure Prophylaxis (PEP)
• Vaccine supply has been limited: reserve for
truly exposed
• Cleanse wound immediately.
• When needed, administer PEP as soon after
exposure as possible.
• Rabies immunoglobulin: one dose
• 5 doses of rabies cell culture vaccine
Rabies and Public Health
• PH (federal, state, local) is involved in every aspect of
rabies
– Investigation of animal and human cases
– Laboratory testing
– Disease reporting: Surveillance, epidemiology
– Animal control: may be health or law enforcement
– Provide expert consultation to medical and veterinary
community
– Media and public education
– Policy, guidelines for control and preventionanimals/humans
– Vaccine supply
Rabies in animals and in humans is a
nationally reportable condition
• All suspected animal and human cases are tested
by Public health labs and affiliates (some vet
universities for animal)
• Reporting system: clinician (vet, medical) to
local ph state ph  CDC
• Complete investigations (to find exposed people
and animals) are done on every case.
Rabies is preventable
Medical/ public health evaluation of animal bites
• Species?
• Bite? Non-bite?
• Place of exposure
– Foreign travel?
– Other US, local
• How was the animal
acting?
• Provoked/unprovoked?
• Is animal available for
observation- (domestic
animal)or testing (wild)?
Encephalitis of unknown origin
• Medical consultation
• Physicians often have ruled out
many common etiologies
• Rapid, progressive, compatible
with rabies- transport of test
samples to CDC
Public Health
Rabies Control and Prevention
Coordination/partnership
Animal Bites: Wash wounds and seek
medical consultation - especially those
from bats, wild animals and foreign
dogs
Control rabies in pets:
• Vaccinate pets
• Keep pets away from wildlife (bats,
raccoons..)
• Follow leash laws
• Control strays
Wildlife:
• Avoid contact with sick
and injured wild animals.
• Don’t feed, handle or translocate
wildlife
•Health Care Providers
•Veterinarians
•Animal Control
•Wildlife officials and rehabilitators
•Schools, Public, Media….
Example of a rabies surveillance and control system
Citizen finds sick or dead
bat or wild carnivore; calls
animal control agency
Animal control picks up animal
and submits brain tissue to
public health laboratory.
Veterinarian suspects rabies in a domestic
animal; animal is euthanized or dies; requests
public health laboratory rabies test
Public health laboratory
performs rabies test
Results provided to state and local public health agencies and
the submitter (animal control, veterinarian)
Rabies virus not detected
Rabies virus detected
Public health calls citizen to assess
any potential human exposure(s).
No further
follow-up
No
Local, state and national
rabies databases updated
Animal control evaluates and
regulates management of pet
animal exposure(s).
Potential human exposure to rabies
Yes
Refer to healthcare provider
Public Health: Rabies Testing
•Direct Fluorescent antibody: Gold standard
diagnostic- very reliable test. [Only
performed at Public Health and few
university labs]
•Cross sections of fresh brainstem,
hippocampus, cerebellum.
Molecular: monoclonal antibody and PCR
to identify rabies virus variant.
Local, State, National
Regulation, policy and guidance
• Local and state regulations- pet
vaccination, disease reporting, animal bite
reporting, rabies exposed pets
• U.S.: Animal import regulations
• Guidelines
– Compendium of Animal Rabies Prevention
and Control
– ACIP- Human Rabies Prevention
Global Health
tragic fact that every day approximately 100 children die of rabies.
www.rabiescontrol.net - Alliance for Rabies Control
Importation of Animals
March 2007
• New Delhi, India
• Veterinarian from WA state: volunteer at animal
shelter
• Adopts 2 street puppies
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Unvaccinated (> 12 weeks old)
Unknown health histories
Acting normally at time of rescue
Reports of puppy being “picked on” by other street dogs
Source: http://www.rbe.fli.bund.de/About_Rabies/Epidemiology.aspx
Timeline
Bites vet & 2nd
puppy
Taken to
Olympic
Penninsula
2 pups and vet
arrive in Seattle, Pup 1 begins to
regurgitate
pass through
US Customs
14
15
16
19
Pup 1 gnaws on
kennel,
breaking/losing
deciduous teeth
Pup 1 adopted &
certified for
interstate travel
20
March, 2007
Dies. Rabies test
positive
Neuro signs
noticed
Flown to
Juneau
21
22
23
Imported rabid puppy, 2007
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Second pup euthanized and tested
8 people received PEP
Customs protocols reviewed
Health certificate for interstate
travel should not have been given
Importation of rabid dogs/cats to US
• 1986 – New York – Dog, 4 months old, West Africa
(http://www.cdc.gov/mmwr/preview/mmwrhtml/00000874.htm)
• 1987 – New Hampshire – Dog, 5 months old, Mexico
(http://www.cdc.gov/mmwr/preview/mmwrhtml/00001275.htm)
• 1987 – California – Cat, unknown age, Mexico
(http://www.cdc.gov/mmwr/preview/mmwrhtml/00001275.htm)
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1995 – California – Dog, 4 weeks old, Mexico
2004 – California – Dog, 3 months old, Thailand
2004 – Massachusetts – Dog, 3 months, Puerto Rico
2007 – WA and Alaska –Dog, 3 months, India
• There is a thriving international trade in exotic pets,
birds, and puppies (>280,000 dogs and 183,000 wild animals
imported to US annually).
• Imported pets may be infected with diseases that put animals
or the public at risk.
• Current federal regulations are inadequate for preventing the
introduction of animal-borne diseases.
• Veterinarians and others must remain vigilant so they can
recognize potential threats quickly.
• The public and health care costs of combating rabies once it
is established in a new area are very high.
Deriengue
Imported cases of Bovine Paralytic Rabies transmitted
by vampire bats in Central America
ARIZONA
MEXICO
Rabies translocation/exportation events
Coyote RVV: Texas to Florida 1994
Raccoon RVV: Florida to Virginia, 1978
Hunters
Coyote RVV: Texas to Alabama (1993)
E. fuscus Canada to Germany (1986)
E. fuscus Massachusetts to Denmark (1994) Researchers
E. fuscus MI/CA car container to Hawaii, (1991)
Rupprecht CE, Smith JS, Fekadu M, Childs JE. The ascension of wildlife rabies: a cause for public
health concern or intervention? Emerg Infect Dis 1995;1:107--14.
[1995-2000: AZ- 2 steers with deriengue (Mexico-separate
incidents); Dairy cow, horse from midwest]
Summary
• Rabies is an important zoonoses worldwide
– Global reservoirs: dogs, wildlife, bats
– North America reservoirs: raccoon >bat>skunk>fox
– Spillover: Cats= #1
• Public health has a primary role: laboratory testing,
surveillance, investigation, prevention, education,
control, regulation, and policy.
• Movement of animals globally and nationally
presents constant risk of introduction of rabies virus
variants to new geographic areas.
http://www.cdc.gov/ncidod/dvrd/rabies/