Julia Murphy, DVM, MS, DACVPM - PowerPoint Presentation

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Julia Murphy, DVM, MS, DACVPM

State Public Health VeterinarianOffice of EpidemiologyVirginia Department of Health2014

Rabies in Virginia: Overview

of Epidemiology and

Exposure ResponseSlide2

Rabies HistoryA recognized disease as early as 2300 BCAristotle wrote about rabies in 322 BCSaliva of rabid dogs was recognized as “venomous” in the 1st

century ADSlide3

Rabies History, USFirst documented case in USVirginia, 1753Colonial times-1950s

Dogs highest vector risk1960s-todayWildlife greatest reservoirSlide4

Rabies History, VARaccoon rabies:Noticed in FL in mid 50sSpread to VA in 1970s

Seen everywhere but sw VASkunk rabiesPresent in low levels in sw VA since 1960sSlide5

Why rabies?20,000 – 40,000 people exposed to rabies each year in USInfection is almost always fatal

Public health costs (detection, prevention, control) > $300,000,000 annually in U.S.Rabies is endemic in VirginiaSlide6

Rabies - OutlineVirusDisease and diagnosisAnimal epidemiology – US and VA

Human epidemiology – US and VARabies control and exposure responseRabies laws in the Code of VirginiaSlide7

Rabies VirusOnly affects mammalsInactivated by drying, high temperatures, sunlight, most disinfectants

Survives freezingFound in wet saliva and central nervous system tissue of infected mammalsSlide8

Rabies Virus - TransmissionMost commonly through the bite and virus-containing saliva of an infected animalVirus can not

enter intact skinOther possible routesContamination of mucous membranes Scratches - only if contaminated with wet saliva or CNS materialAerosolTransplantation Slide9

Rabies virus-PathogenesisVirus enters the bodyVirus enters NM junctionsTravels via peripheral nerves to

spinal cordThen to brain stem and forebrainSlide10

Rabies – signs and symptoms in animalsClinical presentation is variableEarly – vague, nonspecificBehavioral – more or less aggressive, vocalization

Physical – appetite loss, paralysis, seizures, coma, deathBehavior or physical signs or symptoms that are clearly abnormalSlide11

Rabies-Symptoms in HumansInitial clinical symptoms include anxiety, headache, mild fever, irritation at bite siteProgresses to muscle spasms, difficulty swallowing, hydrophobiaClinical course is typically shortSlide12

Rabies Diagnosis in AnimalsPostmortem testResults available in about 24 hours

Results reported to local health departmentSlide13

How is testing performed?No accurate test exists for examining live non-primate animals for rabies infectionAnimal necropsy of optimal parts:

Brain stem or medulla oblongata,Cerebellum,Hippocampus or Ammon’s HornSlide14

Direct Fluorescent Antibody Test for Rabies VirusMay be used on fresh or decomposed tissue

Produces sensitive and rapid resultsConsidered the most reliable of all available technologiesDaily quality control steps assure accuracySlide15

Rabies virus variants, USRaccoonFox3 variants

Skunk3 variantsBatMultiple variantsMongoose

Any variant can infect any speciesMajority of animals diagnosed with the raccoon variant each yearSlide16

Rabies Virus - VariantsAssociated with certain animal speciesAssociated with certain geographic areas (except bats)Spillover to other species

Vaccines protect against all variantsSlide17

Distribution of Major Terrestrial Reservoirs of Rabies in the United States and Puerto Rico, 2010Slide18

Rabies Virus Variants, VATwo terrestrial wildlife rabies variants – raccoon and skunkSpillover to other wild and domestic animals

Raccoon – endemic in most areas with cyclingSkunk – confined to southwest VA Multiple bat variants Occasional spilloverSlide19

Dogs, cats, ferretsThe time between when a dog, cat or ferret is bitten and when that animal will show signs of disease has been establishedTypically 1-2 months, but can be as short as 10 days or as long as 6 monthsSlide20

Dogs, cats, ferretsThe time between when a dog, cat or ferret starts shedding virus in its saliva and when that animal starts acting sick and then dies is also well establishedTypically a dog, cat or ferret will start shedding the virus in its saliva the same day it starts acting sick and will only live for a couple of days after that (may live as long as 8 days)Slide21

Rabies Shedding-Other AnimalsFor animals other than dogs, cats and ferrets, we do not know a definitive time period between when they start shedding the virus and when they start acting sickThis is why the only definitive observation times we have are for dogs, cats and ferrets Slide22

Rabies – risk of transmission by animal typeHigh riskCarnivores (raccoons, skunks, foxes)

Large rodents (e.g., groundhogs in raccoon variant areas)Opossums (in raccoon variant endemic areas)BatsLow riskSmall rodents (e.g., squirrels, chipmunks)

Rabbits, haresEvaluate circumstancesExotic animals/hybrids

LivestockSlide23

Rabies Risk by Animal TypeFor those animals for which no observation time has been established and do not fit into either a distinctly high risk or low risk category, the response is based on consideration of a number of factors including the scientific family of the animal, circumstances of exposure, how the animal is housed and/or health of animal.Slide24

Rabies - Animal EpidemiologySlide25

Rabies - Animal EpidemiologySlide26

Rabies – Wild Animal Epidemiology, U.S.Slide27

Wild Animal Rabies EpidemiologyWildlife have accounted for > 80% of reported rabid animals in the United States since 1975Raccoons, skunks, foxes and bats make up the bulk of rabid animals reported each yearSlide28

Rabies - Domestic Animal Epidemiology, U.S.Slide29

Domestic Animal Rabies EpidemiologyDomestic animals typically make up less than 10% of the total number of animals diagnosed with rabies each year in the USCats are the domestic animal most commonly diagnosed with rabies Slide30

Rabies Animal Epidemiology, VATwo terrestrial wildlife rabies variants – raccoon and skunkSpillover to other wild and domestic animalsRaccoon – endemic in most areas with cycling

Skunk – confined to southwest VA Multiple bat variants Occasional spilloverSlide31

Animal Rabies Statistics in Virginia, 2011-2013*

*Statistics typically also include < 5/yr = beaver, coyote, deer, donkey, goat, horse, otter, mink, rabbit, rat, opossum

Animal

2011

2012

2013

Raccoon

281

258

248

Skunk

190

166

115

Fox

70

52

56

Bat

20

19

16

Groundhog

6

7

2

Cat

30

28

37

Cow

10

15

9

Dog

3

3

1Slide32

Human Rabies Epidemiology, US33 cases, 2001–1121 infected with a bat variant

Many with exact exposure unknownForeign travel to countries where domestic animal rabies is more common is also a risk factorSlide33

Human Rabies EpidemiologyVirginia Cases1953 – veterinary hospital workerUnknown exposure1998 – prisoner in work program

Unknown exposurePipistrel/silver-haired bat variant2003 – office workerUnknown exposureRaccoon variant2009 – traveler to IndiaExposed to dogSlide34

Rabies Control – Domestic Animals and HumansAnimal and human vaccinationAnimal controlPre- and

postexposure managementSlide35

Rabies Control – Domestic Animal VaccinationVirginia code requires dogs and cats to be vaccinated by 4 months of ageBooster dose given 1 year after initial vaccinationThereafter, should vaccinate every year or every 3 years, depending on vaccine type

Encourage use of 3 year vaccineSlide36

Rabies Control – Domestic Animal VaccinationVirginia code requires vaccine administration by currently licensed veterinarian or licensed veterinary technician under direct supervision

Veterinarians must practice in a licensed facilityException – rabies clinics outside licensed facilityLocality must approve clinic Slide37

Rabies Control – HumanWhat constitutes an exposure?Any bite, scratch, or other situation where saliva or central nervous system tissue from a potentially rabid animal enters an open fresh wound or contacts a mucous membrane by entering the eye, mouth, or nose

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Rabies Control – HumanBat ExposureSmall bites; may go unrecognizedAlways ideal to test bat if available

PEP indicated in response to: 1. Known bite2. Direct contact and bite cannot be ruled out3. Situations where exposure may have gone unrecognized like bat found in the same room as a sleeping or mentally impaired or very young personSlide39

Rabies Control-HumanScratches:A scratch should be evaluated like any other open wound, i.e. did saliva or some other virus containing material (cerebral spinal fluid, brain) contaminate the wound while it was fresh.  A scratch in and of itself

is not an exposure unless the paws were soaked with saliva, e.g., cat is salivating/drooling profusely or paws are visibly wet.Slide40

Rabies Control – Domestic AnimalsWhat constitutes an exposure?Any circumstance where saliva or central nervous system tissue from a potentially rabid animal did have or could have had direct contact with mucous membranes or a break in the skin of a domestic animal

Note: The actual witnessing of a bite or attack by a potentially rabid animal is not required for an exposure to have occurred, however, a suspect needs to be witness in close proximity….Slide41

Rabies Control Guidelines for HumansHuman exposed to a dog, cat, or ferretAny dog, cat, or ferret (vaccinated or unvaccinated) that bites a person must be confined for 10 days observation

Veterinary evaluation at first sign of illnessIf thought to be rabies, euthanize and testDo not vaccinate during confinementSlide42

Rabies Control Guidelines for HumansPre exposure seriesHigh risk occupations: DVMs, ACOs, LVTs

Antibody measurement every 2 yearsBoosters if exposed or low titer (routine boosters not recommended)Should not receive RIGPost exposure series (for those

with no prior vaccination)RIG plus four vaccinationsSlide43

Rabies Control Guidelines for Domestic Animal ExposureConfinement House animal in a building, pen, or other escape-proof method or enclosureDo not remove animal unless on leash and under control of responsible adult

Owner should notify Health Department at first sign of illness and take to veterinarianSlide44

Rabies Control Guidelines for Domestic Animal ExposureStrict isolationHouse animal in a kennel at a veterinary hospital, animal control facility, commercial boarding establishment, or pen at home

Pen design should prevent direct contact between animal and human or other animalPen design should allow for feeding, watering, cleaning (see example in Guidelines)District Health Director or designee should approve penSlide45

Rabies Control Guidelines for Domestic Animal ExposureVaccinated dog, cat, or ferret exposed to proven or suspected rabid animalShould receive immediate booster of vaccine Confine for 45 days observation

Veterinary evaluation at first sign of illnessIf thought to be rabies, euthanize and testSlide46

Rabies Control Guidelines for Domestic Animal ExposureUnvaccinated dog, cat, or ferret exposed to proven or suspected rabid animalIf available, test exposing animal

If exposing animal unavailable or tests positive, euthanize exposed animal or place in 6 months strict isolationVeterinary evaluation at first sign of illnessIf thought to be rabies, euthanize and testVaccinate exposed animal before release from 6 months isolationSlide47

Rabies Control Guidelines for Domestic Animal ExposureDog, cat, or ferret with expired vaccination exposed to proven or suspected rabid animalImmediate booster to exposed animal (unless euthanized)

If available, test exposing animalIf exposing animal unavailable, 6 months strict isolation for exposed animalContact Office of Epidemiology to discuss situations where vaccination is recently expiredSlide48

Rabies related lawsCode of Virginia sections:3.2-6521. Rabies inoculation of companion animals

3.2-6522. Rabid animals3.2-6562.1 Rabies responsibility plan18.2-313.1 Withholding information about a possibly rabid animal54.1-3812. Release of recordsSlide49

Rabies Control Messages for the PublicKeep rabies vaccinations up-to-date on dogs, cats, and ferretsSupervise pets so they do not come into contact with wild animals

Call animal control to remove straysTeach children never to handle unfamiliar animalsSlide50

Rabies Control Messages for the PublicEnjoy wild animals from afarNever adopt wild animals

Do not encourage wild animals to come close to/into your houseAvoid leaving pet food outsideKeep trash inside or use lids on trashDo not relocate wildlifeCall DGIF or licensed rehabber for supportSlide51

Rabies Control Messages for the PublicIf you’ve been bitten…Decrease the chance of infection by washing the wound with soap and water

Capture the animal if this can be done SAFELYCall animal control or local hdSlide52

Rabies Resourceswww.vdh.virginia.govRabies Control

pagehttp://www.cdc.gov/rabies/www.nasphv.orgCompendium of Animal Rabies Prevention and Control, 2011Slide53

Questions?