Zoonotic Diseases

Website ReferencesCDPH Veterinary Public Healthhttp://www.cdph.ca.gov/programs/vphs/Pages/default.aspxCDC http://www.cdc.gov/healthypets/browse_by_diseases.htmIowa State Center for Food Security & Public Healthhttp://www.cfsph.iastate.edu/Zoonoses/zoonotic-disease-resources.phpCDFA Animal Health Branch www.cdfa.ca.gov/ahfss Grey Book http://www.aphis.usda.gov/emergency_response/downloads/nahems/fad.pdfOIE http://www.oie.int/WHO http://www.who.int/topics/zoonoses/en/

Words• Zoonosis– CDC definition: Infections and infestations

which are shared in nature by man and lower vertebrate animals

– WHO definition: Diseases and infections naturally transmitted between vertebrate animals and man

Words• Host– Reservoir: the host of an infection in which the infectious

agent multiplies and/or develops, and on which the agent depends for survival in nature; the host essential for the maintenance of the infection during times when active transmission is not occurring.

– Dead-end (Incidental): an intermediate host that does generally not allow transmission to the definitive host

– Amplifying: a host in which the level of pathogen can become high enough that a vector such as a mosquito that feeds on it will probably become infectious

Words

• Vector – Agent (person, animal, organism) that carries & transmits

an infectious agent• Mechanical: they carry the disease agent on their body

(legs, feet pads) rather than taking it into their body. • Biological: they take the disease agent into their body

and then inject it into a person

Center for Food Security and Public Health Iowa State University 2006

Zoonotic Disease Transmission

• Animals may not show obvious signs of illness

• Awareness of all routes of transmissionis essential– Develop strategy to

minimize disease risk

Center for Food Security and Public Health Iowa State University 2006

Aerosol Transmission

• Infected droplets passed through the air from an animal to a person– Sneeze/cough– Birthing tissues– Fecal material– Urine– Contaminated soil

Center for Food Security and Public Health Iowa State University 2006

Direct Contact Transmission

• Pathogen in animal (blood, saliva, body fluids) or environment

• Contact with open wounds, mucous membranes, skin

Center for Food Security and Public Health Iowa State University 2006

Fomite Transmission

• Contaminated inanimate object

• Carries pathogens– Brushes, needles,

clothing, bedding

Center for Food Security and Public Health Iowa State University 2005

Vector Transmission

• Insect • Acquires pathogen

from one animal• Transmits to

a person– Biological vectors

• Ticks, mosquitoes– Mechanical vectors

• Flies, cockroaches

Center for Food Security and Public Health Iowa State University 2005

Vector Transmission

• Anthrax– Flies

• Q Fever– Ticks

• Rift Valley Fever*– Mosquitoes

Horsefly

Tick

Mosquito

* Denotes Foreign Animal Disease

Tuberculosis• Gram positive acid-fast bacteria• Mycobacterium bovis– Unpasteurized milk, cheese most likely source

• Mycobacterium tuberculosis– CDC, 2010: 11,182 cases in US– WHO, 2010: 8.8 million cases worldwide; estimated

prevalence of 650,000 cases of multidrug-resistant TB (MDR-TB)

Center for Food Security and Public Health Iowa State University 2005

Tuberculosis in Cattle

• Bacterium: Mycobacterium bovis• 1917: U.S. eradication

program began– Less infection,

but still present• Signs of illness

– Slowly progressive disease– Early stage: Asymptomatic– Late stage: Weight loss, anorexia,

cough, difficulty breathing

Center for Food Security and Public Health Iowa State University 2005

Tuberculosis in People

• Ingestion (oral)• Inhalation (aerosol)• Direct contact• Symptoms

– May not be sick– Disease of the lungs: Fever,

cough, chest pain– Disease can spread: Kidney,

spine and brain

TB Case Rates,* United States, 2010

*Cases per 100,000.

< 3.6 (2010 national average)

>3.6

D.C.

>50%25%–49%<25%

2000 2010

DC

*Updated as of July 21, 2011

Percentage of TB Cases Among Foreign-born Persons, United States*

DC

Brucellosis• Brucella abortus (cattle), Brucella suis (swine),

Brucella melitensis (goats)• Heifers are required to be vaccinated for

movement (regulatory REPORTABLE disease)• Undulant fever • Direct contact with secretions and excretions

of infected animals and by ingesting UNPASTEURIZED milk or milk byproducts.

Center for Food Security and Public Health Iowa State University 2005

Brucellosis in Cattle

• Bacterium: Brucella abortus• Third trimester abortions

– Up to 80%– Inflammation of placenta

• Birth of dead/weak calves• Retained placenta• Low milk yield• Temporary sterility• Shed bacteria in milk for life

Identification of Brucellosis (Bangs) Vaccinate

• Tattoo in right ear (R 7)– R, shield, last number in year– +/- orange metal ear tag

Center for Food Security and Public Health Iowa State University 2005

Brucellosis in People

• Ingestion (oral)• Inhalation (aerosol)• Direct contact• Variable (undulant) fever• Headache, weakness, joint

pain, depression, weight loss, fatigue, liver problems

Brucellosis in People

• Incubation 5 days to several months• Onset sudden and acute• Chills, fever, severe headache, lethargy• Intermittent symptoms• Treatment is combination of antibiotics• Caution when handling suspect animals and

vaccines.

Center for Food Security and Public Health Iowa State University 2005

Listeriosis in Cattle

• Bacterium: Listeriosis monocytogenes• Poor quality silage with a high pH • Signs of illness

– Facial paralysis, drooling

– Lack of coordination– Circling, head pressing– Abortions, stillbirths – Death

Center for Food Security and Public Health Iowa State University 2005

Listeriosis in People

• Ingestion (oral)• Inhalation (aerosol)• Symptoms

– Pregnant women: Death of the fetus

– Newborns, elderly, weak immune system: Infection of the blood stream, brain inflammation

Center for Food Security and Public Health Iowa State University 2005

Q Fever in Livestock

• Bacterium: Coxiella burnetii, gram negative pleomorphic coccobacillus

• Most do not show any signs• May cause abortions• Large number of bacteria shed

– Lambing/Calving • (placenta, fetal fluids, fetus)

– Milk– Urine– Feces

Center for Food Security and Public Health Iowa State University 2005

Q Fever in People

• Inhalation (aerosol)• Ingestion (oral)• Symptoms

– Sudden onset: flu-like, pneumonia,liver disease

– Long term: heart complications, bone inflammation

– Pregnant women: premature delivery, death of the fetus

• Direct contact• Ticks (vector)

Leptospirosis

• Leptospira interrogans, a spirochete bacteria with many serogroups/serovars: L. grippotyphosa, L. pomona, L. canicola and L. icterohaemorrhagiae (these serovars are commonly Vx for)

• Direct contact with infected animal, contaminated water and soil

• Multiple species may be affected: dogs, horses, cattle, humans

• Skin break / mucous membranes route of entry• Incubation 2 to 26 days

Center for Food Security and Public Health Iowa State University 2005

Leptospirosis in People

• Ingestion (oral)• Inhalation (aerosol)• Direct contact• Symptoms

– Flu-like signs: Fever, body aches, headache

– Weakness, vomiting, mental confusion– Jaundice, stiff neck– Liver, kidney or central nervous

system damage

Leptospirosis• Early signs: fever, headache, chills, muscle aches, vomiting,

jaundice, anemia, and sometimes a rash• As dz progresses: patient could develop kidney damage,

meningitis, liver failure, and respiratory distress. • Serious icteric form: Weil’s Dz - hemorrhage, hepatomegaly,

pulmonary hemorrhage, ARDS, and jaundice are among the severe features. Case fatality rate is 1 to 5%.

• Treat with antibiotics: amoxicillin/ampicillin, doxycycline

• Highest incidence of cases in U.S.: Hawaii• Current cases in Thailand, related to flooding

Lyme Disease• Borrelia burgdorferi, spirochete bacteria• Carried by ticks (deer tick, Ixodes)• Seen more in Coastal areas in CA; high prevalence

in NE U.S.• Symptoms (days to years to mainifest) – bulls eye

rash at bite site & flu-like symptoms (3-30d); Bell’s palsey, arthritis , cognitive defects,

• Treatment, early most beneficial, antibiotics• Prevention – remove ticks quickly, tick collars, monthly topical

• Tick must be attached for 24-48 hours to transmit dz

Tularemia (Rabbit Fever)• Francisella tularensis (gram negative coccobacillus)• Reservoir: rodents, rabbits/hares• At most risk: Hunters, butchers, farmers, fur handlers and

laboratory workers• Transmitted by: direct contact with infected animals, tick

bites, biting flies, contaminated water, aerosol• Cats can be susceptible & source of human infection • Incubation 4 to 5 days – sudden onset• Lesion at bite site, chills, fever, headache, vomiting,

drenching sweats, prostration

Plague (Bubonic, Pneumonic, Septicemic)• Yersenia pestis (gram negative rod)• Bubonic: 88% of cases, Septicemic: 10%• Prevalent in wild rodents; cats also potential

source of infection for humans• Vector borne: transmitted by fleas, aerosol or

direct contact with infected• Incubation 1 to 6 days• Lesion at site: buboe, enlarged lymph nodes, fever, confusion• Prompt tx necessary

Rat Bite Fever

• Streptobacillus moniliformis, gram neg rod• 48% of wild and pet rats are carriers• Transmission by: bites, scratches, handling

of infected animals, consuming contaminated food/drink

• Incubation 3-21 days• Symptoms – rash, fever, vomiting, chills,

headache, muscle/joint pain• 7-13% fatal if untreated

Cat Scratch Fever

• Bartonella henselae (gram negative bacillus)• Usually from kittens with fleas present: inoculation of

infective flea feces at time of scratch • Asymptomatic infection with Bartonella henselae (and B.

clarridgeiae) is common in cats; 40-70% with seropositivity and 9-90% with bacteraemia.

• Incubation 3 to 10 days• Enlarged lymph nodes, red crusty sore at site, fever & headache,

heat at site of scratch• Severe in immune suppressed (Bacillary angiomatosis, peliosis

hepatitis)

Psittacosis (Ornithosis, Parrot Fever)• Chlamydophilia psittaci, gram negative cocci• REPORTABLE DZ• Most often found in poultry & bird workers• Infected birds shed organism in feces &

nasal/ocular discharges• Birds can be healthy carriers• Contracted by inhaling dried secretions from

infected birds • Incubation 3 days - 3 weeks• Fever, chills anorexia, cough

Anthrax

• Bacillus anthracis, spore forming gram positive rod• World wide – ruminants, horses• Reportable disease• Animal symptoms- acute onset, sudden death,

hemorrhage • Spores remain in soil for decades

Anthrax• Human – Most cases occupational via contact with

animal hides, hair, wool, infected animals• Cutaneous form (most common): 2-5 day

incubation; small painful sores; Tx w/ Abx: penicillin, doxycycline, ciprofloxacin x 10d

• Inhalant form: often fatal even with treatment

Center for Food Security and Public Health Iowa State University 2005

Anthrax in People

• Three forms of the disease– Skin (direct, vector)– Intestinal (oral)– Inhalation (aerosol)

• Most skin lesions go away on their own

• People at risk:– Handle infected hides,

wool, and furs

Coccidioides immitis• Valley Fever• Saprozoonose• Fungus that lasts in contaminated dirt for long

time – when stirred up, dogs & humans infected from contaminated dust

Viral Encephalomyelitides

• Arboviral Encephalitides• WEE, EEE, VEE, West Nile Virus• Transmitted by mosquito (Culex tarsalis mostly)• Two presentations in humans 1. Flu: Fever, headache, then feel well 2. Neurological: Cervical stiffness, vomiting,

disorientation, coma, convulsions

Arboviruses

• Treatment – supportive care, prevention of secondary infections, good nursing care

• Protection – clothing, insect repellant, limit outside activities at dawn/dusk

• Horses, birds, rodents and humans are susceptible

Rabies• Rhabdoviridae family, genus Lyssavirus• Infectious viral disease• All mammals susceptible• Carried in saliva, transmitted through bites• Can excrete virus in saliva days prior to developing

clinical signs• Most human cases come from wild animals• Incubation 10 days to 1 year (average 30 to 50 days)

Rabies• Reservior: skunks, bats, raccoons, foxes• Other risky animals: feral cats, feral/wild dogs• Forms of rabies seen: – Prodromal (early): anxiuos, personality change– Furious– Paralytic (dumb)

• Neurologic signs: Mental depression, malaise, restlessness, fever, excessive salivation, painful spasms of throat, thirsty but can’t drink, hydrophobia. Death usually occurs 3 to 11 days from onset of symptoms. Treatment, symptomatic

Map of terrestrial rabies reservoirs in the United States during 2009. Raccoon rabies virus variant is present in the eastern United States, Skunk rabies in the Central United States and California, Fox rabies in Texas, Arizona, and Alaska, and Mongoose rabies in Puerto Rico.

Rabies Law

• Report all bites of humans to local health dept• Biting dogs, cats, ferrets: Quarantine / Isolate for ten days

after bite.– If clinical signs develop, euthanize & submit brain for testing– If no clinical signs, unlikely to be a risk

• Bitten dogs, cats, ferrets, livestock, potentially exposed to rabies– If currently Vx: Isolate for 30 days– If NOT current (not Vx or overdue): Isolate for 6 months

• VACCINATE within 48 hours of potential exposure

Rabies Law

• Wild, or rabies suspect domestic animal, euthanize and submit brain for testing.

• Prevention: leash laws, vaccination, control of wild animal population.

• Pre-exposure vaccine for at-risk workers• Post-exposure injections if exposed or bitten

Rabies Vaccination• All dogs in California: Vx @ 16 weeks (4 months), boost in 1

year then boost every 3 years with an approved rabies vaccine (Rabies Compendium, CDPH.ca.gov) by DVM or under DIRECT SUPERVISION of a DVM– O then required to license dog with county animal control

• Wolves / Wolf hybrids: Cannot be licensed, considered wild animals if bite or if bitten/exposed even if Vx; No Vx approved for use in wolves

• Some counties require cat Vx; recommend all cats be Vx regardless of law (1y – PureVax, lower risk of VAS; 3y – many, may be more practical for feral cats.

• Recommend equine Vx annually.

Center for Food Security and Public Health Iowa State University 2005

Rabies in Cattle

• Virus• 100 cases/year• Signs of illness

– Unexplained paralysis– Anorexia– Nervous, irritable,

hyperexcitable, unsteady – May be aggressive– Abnormal bellowing– Death within 7-10 days

Center for Food Security and Public Health Iowa State University 2005

Rabies in People

• Direct contact– Bite of infected animal or through broken skin

• Symptoms– Fever, headache– Itching at bite site– Confusion, abnormal behavior– Difficulty swallowing

• Death within 2-10 of signs• Vaccination BEFORE signs develop is

highly effective

Rabies survival?

• VERY RARE if exhibiting clinical signs

Rabies SurvivorWillow Creek girl becomes one of the few who’ve ever lived through the deadly virus(MAY 26, 2011)•http://www.northcoastjournal.com/news/2011/05/26/rabies-survivor/

Dermatomycosis(Ringworm)

• Patchy alopecia, scaly lesions – mostly face, paws• Common in kittens (6-88% prevalence)• Incubation: 1-3 weeks• Transmitted through direct contact, or through

grooming instruments. • Spores are viable for months• Clean environment, Shave affected to minimize

shedding, Treat with topical and/or oral antifungals, baths

Center for Food Security and Public Health Iowa State University 2005

Ringworm in Cattle

• Fungus, also called dermatophyte• Usually only grow in hair, nails and

outer layer of the skin• Signs of illness

– Areas of hair loss, scaling, crusts– “Ringworm” lesion– May or may not be itchy– Small area to whole body involvement

Center for Food Security and Public Health Iowa State University 2005

Ringworm in People

• Direct contact• Fomite• Symptoms

– Take 1-2 weeks to appear

– Itchy– “Ringworm” lesion

Mites• Sarcoptes (sarcoptic mange)– Burrowing mite– From prolonged contact with

infested pet– INTENSE PRURITIS

• Cheyletiella (walking dandruff) – Non-burrowing mite– Highly contagious, esp. in pups

2-8 weeks old

AscariasisVisceral, Ocular Larval Migrans

• Dogs: Toxocara canis• World wide – warm areas/poor sanitation• Parasite is not infectious until 2-3 weeks after

excretion human risk is from soil/sand that animals have defecated in (including raw, uncooked vegetables) eggs then incubate weeks to months Eggs hatch in intestines and spread to lymphatic system.

• Can involve CNS, eyes, liver, lungs and heart. Fever, cough, rash, recurrent pneumonia, eye lesions.

Raccoon Roundworms

Baylisascaris infection is caused by a roundworm found in raccoons. This roundworm can infect people as well as a variety of other animals, including dogs. Human infections are rare, but can be severe if the parasites invade the eye (ocular larva migrans), organs (visceral larva migrans) or the brain (neural larva migrans).Image: Left: Embryonated B. procyonis egg, showing the developing larva inside. Right: Larva of B. procyonis hatching from an egg. Center: Raccoons are hosts for the roundworms that can cause Baylisascaris infection. Credit: 

DPDx, U.S. Fish & Wildlife Service   

HookwormCutaneous larval migrans

• Ancylostoma, Uncinaria• Larva burrows into infected human’s skin (humans

are incidental hosts)• Found in warm, moist climates with poor sanitation

(tropical, subtropical, SW U.S.)• Produces intense itching• Causes anemia - threadlike trail of inflammation• Generally self-limiting: clears in 4-8 weeks, up to 1

year following exposure

TapewormsCystic Hydatid Dz

• Echinoccus granulosus, E. multilocularis (foxes, dogs)

• Common in Mexico, rare in U.S.• Human can be infected by ingesting eggs.• Penetrates intestinal wall and enters liver• Slow growing, asymptomatic for decades,

finally produces pain –> surgical removal

Toxoplasmosis• Toxoplasma gondii, protozoa• Cats are carriers – many cats seropositive• Passed by handling raw meat (esp lamb, pork)• Infected cats pass cysts in stool – shed millions of

oocysts daily for 1-3 weeks when infected…must mature in environment to become infectious…SO…pick up feces & dispose of daily, wash hands

• Can be transmitted to fetus – abortion in early pregnancy, birth defects or still births in later pregnancy

Cryptosporidia

• Cryptosporidium parvum• Protozoa • infective immediately upon excretion and

found in animals worldwide with peak illness occurring in the spring and late autumn/early winter.

• WASH YOUR HANDS!

Center for Food Security and Public Health Iowa State University 2006

Cryptosporidiosis in Cattle

• Protozoan: Cryptosporidium parvum

• Spring, late fall/early winter

• Scours in calves– < 3 weeks old

• Can be infected without signs of illness

• Estimated up to 50% of dairy calves shed “crypto”

Center for Food Security and Public Health Iowa State University 2005

Cryptosporidiosis in People

• Ingestion (oral)• Inhalation (aerosol)• Symptoms

– Profuse, watery diarrhea

– Abdominal pain– Usually self-limiting– Severe in people with

weak immune system

Giardia

• A flagellated protozoan parasite, Giardia duodenalis• Exists in two forms, the trophozoite and the cyst. • Has the ability to infect dogs, cats, mice, ground

squirrels, chinchilla, swine, guinea pigs and humans.

Giardia• Signs of infection is chronic or intermittent foul-

smelling diarrhea. (greasy and mucoid).• Difficult to diagnose because of sporadic

passage of cysts in feces. • Giardia ELISA test better way to dx than fecal– Note that ELISA may remain positive following

clearance of organism• Metronidazole is the drug of choice in treating

human infections.• Canine: fenbendazole + metronidazole

Giardia

• Transmission is through oral/fecal route.• Found in lakes, streams and ponds. Hikers,

and campers should use water filtration systems for both themselves and their animals

Center for Food Security and Public Health Iowa State University 2005

Giardiasis in Cattle• Protozoan: Giardia intestinalis • Adult cattle

– Usually do not show signs of illness– Source of infection for calves

• Calves– Scours >4 weeks old– Can become chronic

and lose weight

Center for Food Security and Public Health Iowa State University 2005

Giardiasis in People

• Ingestion (oral)• Symptoms

– May not be sick– Others may have

diarrhea, intestinal gas, stomach cramps, nausea

– Usually self-limiting in a few months

Campylobacteriosis• Campylobacter jejuni• Contracted by contact with contaminated food

and infected animals. Outbreaks of Campylobacter are usually associated with unpasteurized milk or contaminated water. Animals can also be infected, and some people have acquired their infection from contact with the stool of an ill dog

or cat. • Gastroenteritis – intermittent relapses• Self-limiting• Potential cause of Guillian barre syndrome

Salmonellosis

• Salmonella sp., gram negative rod• Common host – turtles, reptiles• Many contaminated food recalls recently as well• Passed through oral – fecal route• Fever, diarrhea• Age, resistance and type of bacteria influence

course of disease• Reportable

Center for Food Security and Public Health Iowa State University 2005

Salmonellosis in People

• Ingestion (oral)• Direct contact• Symptoms

– 12 - 72 hours after infection– Nausea, vomiting, diarrhea– Cramping, abdominal pain– Headache, fever, chills

• Severe in children, elderly and those with a weak immune system