ZOONOSES

ZOONOSES

Suzanne R. Jenkins, VMD, MPH, Dpl. ACVPM

Office of Epidemiology

Virginia Department of Health

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

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

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

Fecal-Oral Bacterial DiseasesCommon examples

Organism

Salmonella spp. (> 1000 serotypes)

Campylobacter

E. coli O157-H7

Prevention

Good hygiene

Good hygiene

Good hygiene

Other issues

Eggs, reptiles

Raw milk

Undercooked ground beef

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

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

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

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

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.

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.

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.

FECAL-ORAL - Parasites

Conditions

• Cryptosporidiosis

• Giardiasis

• Toxoplasmosis

• Larva migrans

• Trichinosis

Prevention

Good hygiene

Good hygiene

Good hygiene

Good hygiene Treat animals

Cook pork

Other Issues

water, day care

water, day care

undercooked meat

raccoon roundworm

wildlife

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

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

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

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

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

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

INHALATION TransmissionPrevention

Treat birdsWear

mask/respirator

Avoid areasWear respiratorReduce dust

Eliminate rodentsDisinfectVentilate area

Sources

Parrot-like birds

Bat/bird guano(> 2 years old)

Rodent urine/feces

(fresh)

Disease

Psittacosis(chlamydiosis)

Histoplasmosis

Hantavirus

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

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

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

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

Sin NombreSin NombrePeromyscus maniculatus

Rio SegundoRio SegundoReithrodontomys mexicanusReithrodontomys mexicanus

El Moro CanyonEl Moro CanyonReithrodontomys megalotisReithrodontomys megalotis

AndesAndesOligoryzomys longicaudatusOligoryzomys longicaudatus

BayouBayouOryzomys palustrisOryzomys palustris

Black Creek CanalBlack Creek CanalSigmodon hispidusSigmodon hispidus

Rio MamoreRio MamoreOligoryzomys microtisOligoryzomys microtis

Laguna NegraLaguna NegraCalomys lauchaCalomys laucha

MuleshoeMuleshoeSigmodon hispidus

New YorkNew YorkPeromyscus leucopusPeromyscus leucopus

JuquitibaJuquitibaUnknown HostUnknown Host MacielMaciel

Necromys benefactusNecromys benefactus

Hu39694Hu39694Unknown HostUnknown Host

LechiguanasLechiguanasOligoryzomys flavescensOligoryzomys flavescens

PergaminoPergaminoAkodon azaraeAkodon azarae

OrOránánOligoryzomys longicaudatusOligoryzomys longicaudatus

CCañaño Delgaditoo DelgaditoSigmodon alstoniSigmodon alstoni

Isla VistaIsla VistaMicrotus californicus

Bloodland LakeBloodland LakeMicrotus ochrogasterMicrotus ochrogaster

Prospect HillProspect HillMicrotus pennsylvanicusMicrotus pennsylvanicus

New World HantavirusesNew World Hantaviruses

BermejoBermejoOligoryzomys chacoensisOligoryzomys chacoensis

CDC DVRD

DIVISION OF VIRAL AND RICKETTSIAL DISEASES

Deer mouse

Cotton rat

Prevention – Rodent Control

• Eliminate food sources and nesting sites

• Prevent mice from entering dwellings

• Encourage natural predators

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

DIIRECT CONTACT Transmission

Main Source

Urine

Blood, tissue

Afterbirth(cattle, dogs)

Disease

Leptospirosis

Tularemia

Brucellosis

Prevention

Wear glovesProtect woundsVaccinate animals

Wear glovesProtect wounds

Wear glovesVaccinate animals

Other sources

contaminated water

ticks

raw milk

VECTOR BORNE Transmission Reservoir

Birds

Ticks

White footed mice

Deer (?)

Vector

Mosquitoes

Dog tick

Deer tick

Lone star Deer tick

Disease

Arboviral encephalitis

Rocky Mountain spotted fever

Lyme disease

Ehrlichiosis

Prevention

repellents protective clothing

repellents protective clothing remove ticks

“

“

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.

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

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

West Nile Virus Transmission Cycle

West Nilevirus

West Nilevirus

Mosquito vector

Incidental infections

Bird reservoir hosts

Incidental infections

WNV hospitalized WNV hospitalized 62 persons in 1999 and seven of these died62 persons in 1999 and seven of these died. .

WNV was detected in 194 birds and 25 horses (8 horses died).WNV was detected in 194 birds and 25 horses (8 horses died).

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

9 3

145

1

1

15

21

2

1

WNV Activity Detected in Virginia in 2000WNV Activity Detected in Virginia in 2000In 2000, over 600 dead birds were tested for WNV. Starting in early 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 October, seven birds were found to be WNV positive. All were crows and were found in the following jurisdictions.and were found in the following jurisdictions.

AlexandriaAlexandria

Fairfax Co.Fairfax Co.

Spotsylvania Co.Spotsylvania Co.

Hanover Co.Hanover Co.Powhatan Co.Powhatan Co.

Pr. Edward Co.Pr. Edward Co.HamptonHampton

West West Nile Nile VirusVirus

in in 20012001

US WNV - 2001

• 5,190 birds

• 100 horses

• 38 humans

• 511 mosquito pools

VA WNV -2001

• 195 birds

• 4 horses

• 1 mosquito pool

Testing Virginia Birds for WNV in 2001Testing Virginia Birds for WNV in 2001As of mid October, a total of 1108 dead birds had been tested for WNV 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 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.least one bird tested. 180 birds have tested positive for WNV.

Percentage of Birds Tested, by LocalityVirginia, 2001

% Birds Tested

0.00% to 0.01%

0.01% to 1.01%

1.01% to 5.01%

5.01% to 10.01%

10.01% to 15.01%

15.01% to 20.00%

11

4

2

51

29

10

3

1

3

1

1

4949

1

1

1

516

1

1

Preventing Arbovirus Infection

• Personal protection– Clothing– Repellents (20 – 30% DEET, < 10% on

children)

• Reduce vectors– Eliminate standing water– Larvicides– Adulticides

Tick Borne Diseases

• Lyme disease

• Rocky Mountain spotted fever

• Human monocytic ehrlichiosis

• Human granulocytic ehrlichiosis

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

Lyme disease continued

• Transmission– usually nymph stage when tick is actively

feeding– adult tick can transmit disease– tick must be attached for > 24 hours

• Tick life cycle– 2 years from egg to adult

Adult female

Adult male Nymph Larvae

Borrelia burgdorferi

White Footed Mouse

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

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

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

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); <10% on children or 0.5% permethrin (clothes only).

Penetrating Wound Transmission

• Tetanus – soil with feces, especially equine; maintain immunity

• Cat Scratch disease

• Rabies

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

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

Cat Scratch Disease - Prevention

• Wash wounds well

• Control fleas on cats

• Kittens, especially strays or from shelters may not be appropriate for children, immunocompromised

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.

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

Disease Transmission• High risk animals

– Carnivores• Low risk animals

– Small rodents– Rabbits and Hares

• ??– Large rodents, especially groundhogs– Opossums– Exotic animals

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?

F o x

S k u n k R a c c o o n

C o y o t e

S k u n k

D i s t r i b u t i o n o f M a j o r T e r r e s t r i a l R e s e r v o i r so f R a b i e s i n t h e U n i t e d S t a t e s

F o xS k u n k

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F o xF o x

Fox

S kunkR accoon

C oyote

S kunk

Distribution of M ajor Terrestrial Reservoirsof Rabies in the United States

Fox

S kunk

Fox

Fox

Disease signs & symptoms

• Early - vague, nonspecific.

• Behavioral- more or less aggressive, vocalization.

• Physical - appetite loss, paralysis, seizures, coma.

• Abnormal, abnormal, abnormal - death

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

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

Human Rabies Trends:1980-1989 versus 1990-1998

DVRD / VRZB0

5

10

15

20

25

Bat

Acquired abroad

Dog/Coyote

Skunk

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

Control - Wildlife

• Population Control

• Wildlife Vaccination

• Public Education

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

Wildlife Vaccination

• Trap, vaccinate and release

• Oral vaccine – Foxes - Europe, Canada– Raccoons - US

• federal or state rabies program

– Most effective as barrier

Oral Wildlife Vaccination

• Vaccine?

– Genetic recombinant with Vaccinia virus

– Modified live virus – mutant, apathogenic

• Bait?

• Attractant?

• Biomarker?

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

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

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%

Control - Domestic Animals

• Vaccination

• Animal Control

• Postexposure Management

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

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

Domestic Animal Control

• Leash laws

• Eliminate stray animals

• Enforcement

• Cats

Domestic Animal Exposure

• Suspected or confirmed rabid animal could have bitten or had mouth to mouth contact

• A visible bite wound is not necessary.

Postexposure Management

• Vaccinated dog, cat, ferret, livestock

– Immediate booster

– 3 months confinement and observation

• Code vs. Compendium


• 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


• Unvaccinated Livestock

– Send to slaughter immediately

– Six months routine confinement and observation.


• 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.

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

Human Prevention

• Education

• Postexposure management

• Preexposure vaccination

Education

• Avoid wildlife

• Avoid stray animals

• Animal and bat proof home

• Remove wildlife attractants

• Report exposures to health department

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


• 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


• Wild carnivore bite

– Euthanize and test if available

– Initiate postexposure treatment if not available


• 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???

Human Postexposure Treatment

• Rabies Immune Globulin (if no previous vaccination)

• Rabies Vaccine– Day 0, 3, 7, 14, 28

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 1:5 or less

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

ZOONOSES

Documents

handling reptiles

reptileassociated serotypes

salmonella isolates

reptile cages

child care centerspet

examplesfecal oral bacterial

marinum isolates

fecesprevent young children