ZOONOSES

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ZOONOSES

• Suzanne R. Jenkins, VMD, MPH, Dpl. ACVPM
• Office of Epidemiology
• Virginia Department of Health

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Introduction

• Focus on prevention
• Hundreds of zoonotic diseases
• Using method of transmission as outline,
  highlight some more common zoonotic diseases as
  examples
• Fecal Oral bacterial, parasitic
• Inhalation
• Direct Contact
• Vector Borne mosquitoes and ticks
• Penetrating Wounds

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Animal Benefits

• Food, fiber, leather
• Guards and hunters
• Recreation/Entertainment
• Companionship
• Improve physical and mental health
• Must weigh risks/benefits for immunocompromised,
  children, the elderly

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Fecal-Oral Transmission

• Organism passed in feces and then ingested
• Human to Human
• Animal to Human
• Through food or water
• May or may not cause disease in animals

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Fecal-Oral Bacterial Diseases Common examples
Organism Salmonella spp. (gt 1000
serotypes) Campylobacter E. coli O157-H7
Prevention Good hygiene Good hygiene Good
hygiene
Other issues Eggs, reptiles Raw
milk Undercooked ground beef
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Clinical Features

• Incubation hours to days
• GI signs diarrhea (can be bloody), cramps,
  vomiting
• Fever
• Usually self limiting days to weeks
• Salmonella sepsis, especially old/young
• E. coli 0157-H7 hemolytic uremic syndrome

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Foodborne Prevention

• Do not eat raw or undercooked eggs, poultry or
  meat
• Do not consume raw/unpasteurized milk or other
  dairy products
• Produce should be thoroughly washed
• Avoided cross-contamination of foods
• wash hands, utensils, cutting boards, counters

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Pet Associated Prevention

• Wash hands after handling animals and cleaning up
  feces
• Prevent young children from exposure to pets with
  diarrhea
• Use special care with puppies from animal
  shelters and crowded kennels
• Make sure petting zoos and other animal exhibits
  provide handwashing facilities

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Reptile-associated Salmonella

• Approximately 93,000 (7) cases per year of
  Salmonella spp. infections are attributable to
  pet reptile or amphibian contact
• increase in human isolates of rare Salmonella
  serotypes, such as Java, Marina, Stanley, Poona,
  and Chameleon
• During 1989-1998, 516 (24) of 2150 Salmonella
  isolates with reptile-associated serotypes were
  from children aged less than 4 years

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Case Reports

• Infants being cared for in homes with iguanas
• No direct contact
• Matching S. marinum isolates from infants and
  iguanas and environmental cultures
• Iguana was in same tub that baby bathed in
• Aquarium and other objects washed in sink where
  baby bottles washed.

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Prevention of Reptile Transmission

• Pet store owners, veterinarians, and
  pediatricians should alert owners
• Wash hands thoroughly with soap and water after
  handling reptiles or reptile cages.
• Persons at increased risk, e.g., children aged
  less than 5 years and immunocompromised persons
  should avoid contact with reptiles and should not
  have them in same house.

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Prevention of Reptiles Transmission

• Pet reptiles should not be kept in child care
  centers
• Pet reptiles should not be allowed to roam freely
  throughout the home or living area.
• Pet reptiles should be kept out of
  food-preparation areas.

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FECAL-ORAL - Parasites

• Prevention
• Good hygiene
• Good hygiene
• Good hygiene
• Good hygiene
• Treat animals
• Cook pork

• Conditions
• Cryptosporidiosis
• Giardiasis
• Toxoplasmosis
• Larva migrans
• Trichinosis

Other Issues water, day care water, day
care undercooked meat raccoon roundworm wildlife
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Protozoans Cryptosporidia, Giardia

• Most common transmission via water (Milwaukee)
• Less sensitive to chlorine than bacteria,
  especially Cryptosporidia
• Contamination from wild animals, livestock
• Person to person - giardiasis in diapered day
  care
• Animal to person especially pound and kennel
  pups

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Cryptosporidiosis and Giardiasis Prevention

• Do not drink from streams, rivers or lakes
• Surface water used for drinking should be
  filtered
• Wash hands after changing diapers, cleaning up
  after pets, handling livestock or wild animals
• High level of suspicion in pound/kennel pups
  treat accordingly

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Toxoplasmosis (another protozoan)

• Woman infected in early pregnancy severe damage
  or death of fetus
• Immunocompromised primary or reactivated
  disease is serious and can result in death
• Healthy individuals asymptomatic or mild
  illness
• Reservoir cats that eat rodents, birds
• Oocysts in cat feces only 10-20 days
• Intermediate hosts may carry oocysts in muscle

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Toxoplasmosis Prevention

• Cook meat well
• Clean litter box daily (takes 1-5 days for
  oocysts to be infective)
• Feed cats prepared food and discourage hunting
• Wear gloves while gardening
• Wash hands well

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Toxocara and Ancylostoma

• Larva migrans visceral, ocular, etc.
• Roundworm egg ingestion
• Hookworm egg ingestion or larval penetration of
  skin
• In foreign host (human) animal round worm larvae
  do not mature in GI tract, instead travel through
  tissue and cause damage
• Baylisascaris procyonis raccoon roundworm
• Affinity for brain children, rabbits, rodents,
  birds

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Larva Migrans Prevention

• Worm puppies and kittens at 2, 4, 6 and 8 weeks
  of age
• Educate owners about good hygiene
• Prevent soil contamination roundworm eggs can
  survive in soil for extended periods

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INHALATION Transmission

• Prevention
• Treat birds
• Wear mask/respirator
• Avoid areas
• Wear respirator
• Reduce dust
• Eliminate rodents
• Disinfect
• Ventilate area

• Sources
• Parrot-like birds
• Bat/bird guano
• (gt 2 years old)
• Rodent urine/feces
• (fresh)

Disease Psittacosis (chlamydiosis) Histoplasmosi
s Hantavirus
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Psittacosis Issues

• Infected birds can be asymptomatic
• Shed intermittently in feces and respiratory
  secretions
• Inhaled from desiccated droppings/secretions,
  dust from feathers
• Stress initiates shedding/ illness
• Some strains more pathogenic for birds/humans
• Requires 45 day treatment of bird

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Histoplasmosis

• Mold in soil and yeast in animals and humans
• Technically not a zoonoses not transferred from
  infected animals
• Fungus occurs naturally in highly organic soil or
  collections of bird or bat droppings
• Takes several years to become infective
• Spores are inhaled when disturbed, e.g.,
  cleaning out buildings with bird or bat roosts

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Histoplasmosis, continued

• Most adults have been exposed and are immune,
  especially in midwest
• Five clinical forms from asymptomatic to chronic
  disseminated or pulmonary
• Can reactivate when immune system depressed
• Prevent by dampening area and wearing respirator
  - best to have professional clean up, e.g.,
  asbestos

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Hantavirus Pulmonary Syndrome

• Many different hantaviruses found worldwide
• Some pathogenic, HPS or other organs, especially
  kidneys
• Rodent hosts Genus/species specific
• Transmission via aerolization of rodent excreta

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New World Hantaviruses
New York Peromyscus leucopus
Sin Nombre Peromyscus maniculatus
Prospect Hill Microtus pennsylvanicus
Muleshoe Sigmodon hispidus
Bloodland Lake Microtus ochrogaster
Isla Vista Microtus californicus
Bayou Oryzomys palustris
Black Creek Canal Sigmodon hispidus
El Moro Canyon Reithrodontomys megalotis
Rio Segundo Reithrodontomys mexicanus
Caño Delgadito Sigmodon alstoni
Laguna Negra Calomys laucha
Juquitiba Unknown Host
Rio Mamore Oligoryzomys microtis
Orán Oligoryzomys longicaudatus
Bermejo Oligoryzomys chacoensis
Andes Oligoryzomys longicaudatus
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Deer mouse
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Prevention Rodent Control

• Eliminate food sources and nesting sites
• Prevent mice from entering dwellings
• Encourage natural predators

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Prevention - personal

• Air buildings before cleaning
• Dampen area with Clorox and water solution
• Wear gloves to clean up and dispose
• Avoid sleeping in areas inhabited by mice
• Buildings
• Burrows and nests at campsites

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DIIRECT CONTACT Transmission
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VECTOR BORNE Transmission
Reservoir Birds Ticks White footed
mice Deer (?)
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Mosquito Borne Encephalitis

• Group of acute inflammatory viral diseases of
  short duration involving parts of the brain,
  spinal cord and meninges.
• Signs and symptoms similar, but vary in rate and
  progress.
• Most infections asymptomatic.
• Usually fever, headache and if severe, stiff
  neck, stupor, confusion, coma.

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Arboviral Encephalitis

• Each disease caused by a specific virus (EEE,
  SLE, LaCrosse, West Nile)
• Virus usually maintained in animal reservoir.
• Transmitted by vector infected mosquito.
• Species varies with disease and geography
• Amplification and bridge vectors

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Human Arboviral Disease in Virginia

• Eastern Equine Encephalitis
• Tidewater - 1975 (2), 1998 (1) Henrico -1990 (1)
• St. Louis Encephalitis
• Richmond area - 1976 (4)
• La Crosse Encephalitis
• southwest Virginia - several cases yearly since
  1994

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West Nile Virus Transmission Cycle
Mosquito vector
Incidental infections
West Nile virus
West Nile virus
Incidental infections
Bird reservoir hosts
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WNV hospitalized 62 persons in 1999 and seven of
these died. WNV was detected in 194 birds and 25
horses (8 horses died).
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US WNV - 2000

• From New Hampshire to North Carolina,
  concentrated around New York City
• 21 humans, 2 deaths
• 4,323 birds (87 crows)
• 59 horses
• Over 500 mosquito pools

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WNV Activity Detected in Virginia in 2000
In 2000, over 600 dead birds were tested for WNV.
Starting in early October, seven birds were
found to be WNV positive. All were crows and
were found in the following jurisdictions.
Alexandria
Fairfax Co.
Spotsylvania Co.
Hanover Co.
Powhatan Co.
Pr. Edward Co.
Hampton
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West Nile Virusin 2001
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US WNV - 2001

• 5,190 birds
• 100 horses
• 38 humans
• 511 mosquito pools

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VA WNV -2001

• 195 birds
• 4 horses
• 1 mosquito pool

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Testing Virginia Birds for WNV in 2001
As of mid October, a total of 1108 dead birds
had been tested for WNV in Virginia. All but 39
of the 120 local health departments had had at
least one bird tested. 180 birds have tested
positive for WNV.
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Preventing Arbovirus Infection

• Personal protection
• Clothing
• Repellents (20 30 DEET, lt 10 on children)
• Reduce vectors
• Eliminate standing water
• Larvicides
• Adulticides

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Tick Borne Diseases

• Lyme disease
• Rocky Mountain spotted fever
• Human monocytic ehrlichiosis
• Human granulocytic ehrlichiosis

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Lyme Disease Clinical Symptoms

• Erythema migrans
• 3 to 32 days after tick exposure
• Malaise, headache, fever, stiff neck
• Muscle aches and joint pain
• Swollen lymph nodes
• Chronic arthritis, heart and nervous system
  complications if not treated early

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Lyme disease continued

• Transmission
• usually nymph stage when tick is actively
  feeding
• adult tick can transmit disease
• tick must be attached for gt 24 hours
• Tick life cycle
• 2 years from egg to adult

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Adult female
Adult male
Nymph
Larvae
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White Footed Mouse
Borrelia burgdorferi
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Rocky Mountain Spotted Fever

• Sudden onset
• High fever
• Severe headache
• Maculopapular rash starts on extremities
• Case fatality rate 13 15 without treatment
• American dog tick is vector and reservoir

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Ehrlichiosis

• Ranges from subclinical to life threatening
• Nonspecific symptoms, often with decreased WBCs
  and thrombocytes also may be elevated liver
  enzymes
• Human monocytic (HME) Lone Star tick
• Human granulocytic (HGE) deer tick
• Potential for other human and animal diseases

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Diagnosis and Treatment

• LD, RMSF, Ehrlichiosis all respond to antibiotics
  in tetracycline family
• Treat on suspicion
• Definitive diagnosis relies on acute and
  convalescent serum samples
• LD requires confirmation with Western Blot

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Prevention

• Avoid areas with tall grass and dense vegetation
• Wear light-colored clothing
• Tuck pant legs into socks and boots, wear
  long-sleeved shirts buttoned at the wrists
• Conduct tick checks and removal every 4-6 hours
• Apply tick repellent containing 20-30 DEET (skin
  or clothes) lt10 on children or 0.5 permethrin
  (clothes only).

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Penetrating Wound Transmission

• Tetanus soil with feces, especially equine
  maintain immunity
• Cat Scratch disease
• Rabies

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Cat Scratch Disease - Humans

• Bartonella henselae
• Usually cat scratch
• Healthy self limiting lymphadenitis does not
  respond to antibiotics
• Complications encephalopathy, liver and spleen
  abscesses
• Immunocompromised disseminated does respond to
  antibiotics

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Cat Scratch Disease - Cats

• Asymptomatic
• Chronic bacteremia often in presence of
  antibodies
• Fleas may play role in cat to cat transmission
• Seroprevalence varies, but can be as high as 55
  in certain areas

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Cat Scratch Disease - Prevention

• Wash wounds well
• Control fleas on cats
• Kittens, especially strays or from shelters may
  not be appropriate for children, immunocompromised

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Rabies Disease Transmission

• Almost always by a bite.
• Virus cannot enter intact skin.
• Virus can cross mucous membrane less efficient.
• Scratches are risk only if wet saliva gets in
  wound.
• Secondary transmission rarely a risk.

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Virus in body

• Travels nerve pathways
• To spinal cord
• To brain
• To salivary glands (and other organs)
• Multiplies in
• Brain
• Salivary glands
• Shed in saliva

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Disease Transmission

• High risk animals
• Carnivores
• Low risk animals
• Small rodents
• Rabbits and Hares
• ??
• Large rodents, especially groundhogs
• Opossums
• Exotic animals

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Virus Variants

• Associated with certain species
• Associated with certain geographic areas
• except bats
• Spillover to other species occurs
• Vaccines protect against all variants
• Role of variants in disease?

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Disease signs symptoms

• Early - vague, nonspecific.
• Behavioral- more or less aggressive,
  vocalization.
• Physical - appetite loss, paralysis, seizures,
  coma.
• Abnormal, abnormal, abnormal - death

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Diagnosis - Postmortem

• Impression smears of 3 to 4 parts of brain
• brain must still have good architecture
• Immunofluorecent antibody
• very sensitive and specific
• false positives rare
• unsatisfactory manage as positive

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Human Epidemiology - US

• From 1990 to present, 32 human cases
• Dog exposures 2 Texas, 6 overseas
• 24 attributed to bat exposure
• 17 pipistrelle/silver haired bat variant
• only 3 bites reported
• bites probably unrecognized and unreported

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Human Epidemiology - VA

• 1953 - unknown exposure, worked in veterinary
  hospital
• 1998 - unknown exposure, infected with
  pipestrelle/silver haired bat variant
• prisoner in work program
• opportunities for exposure

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Control - Wildlife

• Population Control
• Wildlife Vaccination
• Public Education

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Wildlife Population Control

• Usually not cost effective
• Not acceptable to portions of public
• Trapping and euthanasia may be appropriate to
  remove animals posing threat, e.g. tame raccoons
  in park
• Translocation not acceptable illegal across
  county lines

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Wildlife Vaccination

• Trap, vaccinate and release
• Oral vaccine
• Foxes - Europe, Canada
• Raccoons - US
• federal or state rabies program
• Most effective as barrier

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Oral Wildlife Vaccination

• Vaccine?
• Genetic recombinant with Vaccinia virus
• Modified live virus mutant, apathogenic
• Bait?
• Attractant?
• Biomarker?

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Oral Wildlife Vaccination

• Distribution method
• density
• plane, helicopter, vehicle, hand
• Timing?
• Time of year?
• Frequency?
• Duration?
• Cost Benefit?????
• Fairfax proposal reduce risk in endemic area

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Fairfax Oral Vaccine Program

• May 5-24, 2000
• 819 parcels
• 17,598 acres
• 18,108 doses
• ? person hours

• October 9-20, 2000
• 1,402 parcels
• 22,690 acres
• 20,046 doses
• 434 person hours

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Fairfax Results Rabies Titers

• Baseline Fall, 1999 1/52 2
• First baiting June/July, 2000 33/89 37
• Second baiting November/December, 2000 30/67
  45

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Control - Domestic Animals

• Vaccination
• Animal Control
• Postexposure Management

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Domestic Animal Vaccination

• Code
• Dogs and cats
• Required by 4 months of age
• Vaccines labeled for 3 months or 8 weeks
• Booster 1 year after initial vaccination
• Encourage 3 year vaccines after that

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Blood Tests vs. Vaccinations

• Tests on blood (serum) measure antibodies
• Antibodies indicate body responded to vaccine (or
  virus)
• Antibody titer does not measure protection
• If protective titer was known, would not need
  challenge studies for vaccine approval

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Domestic Animal Control

• Leash laws
• Eliminate stray animals
• Enforcement
• Cats

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Domestic Animal Exposure

• Suspected or confirmed rabid animal could have
  bitten or had mouth to mouth contact
• A visible bite wound is not necessary.

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Postexposure Management

• Vaccinated dog, cat, ferret, livestock
• Immediate booster
• 3 months confinement and observation
• Code vs. Compendium

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Postexposure Management

• Unvaccinated dog or cat
• Euthanasia
  
• Six months strict isolation
• No opportunity for direct human or animal
• contact
• Vaccinate one month prior to release
• Postexposure regimen

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Postexposure Management

• Unvaccinated Livestock
• Send to slaughter immediately
• Six months routine confinement and observation.

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Postexposure Management

• Dog or cat with expired vaccination
• Euthanize OR
• Immediate booster and six months strict isolation
• Vaccinate again one month before release to
  comply with Code.

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Postexposure Management

• Recently expired vaccination
• May be handled as currently vaccinated depending
  on
• Severity of exposure
• Vaccination history
• Consult with Office of Epidemiology if unsure

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Human Prevention

• Education
• Postexposure management
• Preexposure vaccination

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Education

• Avoid wildlife
• Avoid stray animals
• Animal and bat proof home
• Remove wildlife attractants
• Report exposures to health department

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Human Postexposure Management

• Wash wound well with soap and water (10 minutes)
• Confine animal or remember identifying marks
  (domestic animals)
• Call health department or animal control

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Human Postexposure Management

• Dog, cat or ferret bite- confine and observe
  animal 10 days
• Begin treatment within 3 days or earlier if
  animal not available
• Euthanize and test if signs compatible with
  rabies - veterinary exam

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Human Postexposure Management

• Wild carnivore bite
• Euthanize and test if available
• Initiate postexposure treatment if not available

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Human Postexposure Management

• Small rodent, rabbit, squirrel bites - rarely
  require testing or treatment of bitten person
  unless animal abnormal
• Groundhog, other large rodent bites - risk in
  raccoon rabies areas
• Livestock observe if negative history
• Opossum, etc. bites???

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Human Postexposure Treatment

• Rabies Immune Globulin (if no previous
  vaccination)
• Rabies Vaccine
• Day 0, 3, 7, 14, 28

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Human Preexposure Vaccination

• May protect against mild, inapparent exposure
• Reduces postexposure treatment to two doses of
  vaccine and NO RIG
• 3 doses IM or ID on day 0, 7, 21 or 28
• Titer every 2 years booster if 15 or less

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Resources

• www.cdc.gov
• www.vdh.state.va.us
• Control of Communicable Diseases Manual, James
  Chin, Ed., American Public Health Association,
  17th edition
• Zoonoses Updates from JAVMA