DISEASES
TRANSMITTED
ANIMALS TO HUMANS
Arkansas Academy of Family Physicians
June 21, 2014
Elton R. Cleveland D.V.M., M.D., FAAFP
CAQ Sports Med, CAQ Adolescent Med
Objectives
• A) Identify several human diseases
associated with animals.
• B) Understand some occupational risks
associated with animal exposure.
• C) Discuss an occasional reverse zoonosis
Disclosure
• Financial relationships – none with companies or
personnel that would have an impact on
presentation
• Financial relationships – married – enough said
• Other disclosures – wife says I am old and
crotchety –probably true
• I love animals.
Animals and Sport
Some People ?
Some People ?
• Source = San Francisco Newspaper
Pet Pearls
62% of U.S. households (72.9 million homes)
have pets
• 78.2 million dogs
• 86.4 million cats
• 16.2 million birds
• 13.0 million reptiles
Pet Pearls
• 164.6 million dogs and cats are domestic
pets in USA
• Relationship between pets and childhood
asthma is well documented
Pet Pearls
• Iguanas, ranked in the TOP TEN pets, are the
most popular reptile in the USA.
• Especially popular with teenage boys and young
men.
Increasing Incidence of MRSA in the
Community
• Rapid change over past decade
• Why?
Methicillin-Resistant Staphylococcus Aureus
(MRSA)
American Society of Microbiology: 2007 Toronto
• MRSA found in 100% of fomites in subways,
buses and trains
• MRSA survives up to two weeks on fomites
Methicillin-Resistant Staphylococcus Aureus
(MRSA)
• Airline tray tables – WORSE!
• Public restrooms –
only 6.3% positive
MRSA in Dogs and Cats
• Dogs and cats are the most common therapy
animals used in healthcare settings.
• Healthcare settings that utilize animal-assisted
therapy include long-term care facilities and
pediatric institutions.
MRSA in Dogs and Cats (continued)
• With the emerging
problem of communityacquired MRSA, we
decided to re-visit local
animal grooming clinics
to determine if dogs and
cats might be possible
carriers of MRSA.
MRSA in Dogs and Cats (continued)
• All pets studied were from a
local grooming clinic.
• They were deemed healthy
and had not received
antibiotics in the previous 30
days.
MRSA in Dogs and Cats (continued)
• Groomers,
veterinarian,
physician and
student were all
cultured.
• No personnel were
found to harbor
MRSA.
MRSA in Dogs and Cats (continued)
• All 42 animals were
colonized with
Staphylococcus
aureus.
• Seven (16%) of the
42 isolates obtained
were resistant to
methicillin.
Animal Study Results
Recovered from outer surface of cages:
• Staphylococcus (coagulase + and -)
• Bacillus
• E. coli
• Proteus spp.
• Serratia marcescens
• Other gram-negative microorganisms
Animal Study Results (continued)
Recovered from ALL water tanks in the animal cages:
• Pseudomonas aeruginosa
• Several animals were colonized with
multiple organisms
Post-operative MRSA Infection
• Two-year old, hernia repair patient with post-op
incision infection (MRSA)
• Dog at home cultured: MRSA-positive mouth
• Mother had multiple abscesses: MRSA-positive
abscesses
• Specimens for child, dog and
mother sent to Tulane!
Pearls of Pet Therapy Study
• Animals are usually culture-negative for
salmonella in home environments.
• Under travel stress (being placed into carriers,
transported, or exposed to unfamiliar
surroundings), they often become culturepositive for salmonella by the time they get to the
hospital.
Recommendations
• If dogs and cats are used in animal-assisted
therapy programs, they should be screened for
pathogens, including MRSA
• Use of dogs and cats in institutional facilities
should only be used after careful assessment of
risk/benefits to all patients, staff members and
visitors.
Animal Use Recommendations
• Handling of animals should only be allowed when
potential risks and benefits are carefully
considered.
• Handwashing should be strictly enforced after
handling animals and / or cages.
Some people love their animals
Animal Bites
• Most common cause of Zoonosis.
• There are 2 – 4.7 million animal bites yearly.
• 1 out of 2 people in the U.S. (In life time)
• 1.5 % require an Emergency Department visit
• 2% require hospitalization
Animal Bites
• 80% of animal bites come from dogs.
• 85% of dog bites is from a family owned dog or a
neighbor’s dog.
• Children are the most likely to get bitten. Boys
ages 5 – 9 have the highest incidents of dog bites.
• Less than 300 deaths were attributed to dog bites
between 1979 – 1996.
Animal Bites
• Little evidence for specific breed predilection but
75% of fatal attacks have been caused by Pit Bull
& Rottweiler breeds.
• Male- dogs 3:1, Female- cats 3:1
Animal Bites
• Pasturella Multocida has been implicated as
major pathogen.
• Infectious complications occur in approximately
20 – 50% of dog bites with a higher percentage
occurring from cat bites.
Animal Bites
• Treatment medication options: Penicillin,
Cefotaxime, Tetracycline, Bactrim, Ciprofloxacin
and Levofloxacin.
• P. Multocida is resistant to Vancomycin,
Erythromycin and Clindamycin.
Animal Bites
• Other organisms
• CDC – DF2 (“dysgonic fermenter Type 2”)
• Capnocytophaga Canimorsus
• Fastidious Growth
• 30% fatality rate with cases C. Septicaemia
Animal Bites
• CDC – NO1-(non – oxidizer) – similar to Acinetobacter
• Proteus, Klebsiella, Enterobacter, Staph, Strep,
Bacteroides, Clostridium, Erysipelas, Etc.
• Rabies
Interesting Case
Rabies – Myth & Movies
Myth
Werewolves, Vampires & Rabies
Movies
• Old Yeller
• Cujo
Rabies
• May be the oldest disease known to man ~ 2300
BC
• The word “rabies” has many origins.
• Ancient Sanskrit: “rabhas” = to do violence
• Greek: “lyssa” or “lytta” = frenzy or madness
• Latin: “rabere” = to rave or rage
Rabies
• USA: 2 or 3 cases per
year in humans
• Worldwide: >30,000
per year in humans.
Rabies
• Before 1960 cases involved
domestic animals.
• Currently, cases are now being
seen in skunks, raccoons, and
bats.
• Most human cases of Rabies are
due to bat exposure.
• New Carrier: Woodchuck
Rabies
• Kansas
• Vaccine
• In 2006, a horse stabled at Tennessee Walking
Horse National Celebration tested positive for
rabies.
• The CDC notified approximately 150,000 people who
attended the event of possible exposure to rabies.
US Rabies Reservoirs
Rabies - Speculation
• Carter Administration: Wanted to continue
“coonhunting” while living in Washington, D.C.
• Raccoons transported to Virginia forests.
• 1977: By Carter’s inaugural address, the first
case of rabies was reported in Virginia raccoons!
Rabies
• Treatment
• Wound Cleaning
• Rabies Immune Globulin (RIG)
• Rabies Vaccine
• Controversy
• USA/CDC = 5 doses vs. WHO = 3 to 4 doses.
Rabies
• RIG
• HDC 4 – 0, 3, 7, 14 or 28
Human Illnesses Associated with Animals
DISEASE (organism)
ANIMAL SOURCE
SOURCE
Aeromona sp.
Aquatic
Wound infection,
contaminated food
Cat-Scratch
(Bartonella henselae)
Cats
Scratches, bites, fleas
Brucellosis
(Brucella sp.)
Cattle, goats, sheep, Contact with birth
swine, dogs (occas.) products
Campylobacteriosis
(Campylobactes jejuni)
Poultry, dogs, cats,
ferrets, hamsters
Contaminated food,
direct contact, fecaloral
Brucellosis
• Undulant fever
• B. Melitensis > B. Suis > B. Abortus> B. Canis
• Unpasteurized milk
• Contact Birth products
Brucellosis
• Sx intermittent fever
• headache, chills, depression, profound weakness,
arthralgia myalgia, weight loss
• Orchitis/Epididymitis in men
• Spon. AB in pregnant women
Human Illnesses Associated with Animals
(continued)
DISEASE (organism)
ANIMAL SOURCE
SOURCE
Leptospirosis
(Leptospica sp.)
Dogs, rats,
livestock
Contact with urine
Lyme Disease
(Borrelia burgdorferi)
Wild rodents, birds
Tick bites
Salmonellosis
(Salmonella sp.)
Poultry, reptiles,
dogs, cats, turtles,
etc.
Contaminated food,
direct contact, personto-person
Diseases Associated with Bioterrorism
DISEASE (organism)
ANIMAL
SOURCE
SOURCE
Plague
(Yersinia pestis)
Rodents, rabbits,
cats, fleas
Contact with infected
animals
Tularemia
(Francisella tularensis)
Rodents, rabbits,
cats
Tick bites, infected
animals, claws / teeth
of cats
Male Xenopsylla cheopsis (oriental rat flea)
engorged with blood. This flea is the primary
vector of plague in most large plague epidemics
in Asia, Africa, and South America. Both male
and female fleas can transmit the infection.
Photo Credit: courtesy of the
Centers for Disease Control and Prevention
Diseases Associated with Bioterrorism
(continued)
Anthrax
• The name Anthrax comes from the Greek word
“anthrakas” which means “coal”, reflecting the
black rash associated with this infection.
• Encapsulated
• Resistant Spores
• 200 year old remains discovered in an archeological dig
• Resistant to microwave irradiation at 100◦C for 30
minutes
• Resistant to conventional pasteurization
Anthrax in Humans
• Cutaneous Anthrax: black necrotic “eschar”
• Inhalational Anthrax: flu like symptoms,
mediastinum wide, highly fatal.
• Gastrointestinal Anthrax: infection oral, → highly
fatal.
Anthrax in Humans
Outbreaks
• Russia – Sverdlovsk – April/May 1979
• Spores were released into the air surrounding a
biological weapons facility.
• Humans and cattle were infected.
Other Diseases Associated with Animals
FUNGAL INFECTIONS
SOURCE
Cryptococcosis
Birds
Ringworm
Cats, dogs, rabbits, rodents
Sporotrichosis
Cats
Other Diseases Associated with Animals
(continued)
The pork tapeworm, Taenia solium has a
scolex that features a double crown of 22
to 32 rostellar hooks and four simple,
round suckers. As with other cestodes, the
pork tapeworm fastens onto its host
(primarily muscles for this species) and
absorbs nutrients through its skin.
PARASITES
SOURCE
Dwarf Tapeworm
Hamsters, rodents
Cryptosporidiosis
Domestic animals
Cutaneous Larva Migrans
Dogs, cats
Dog Tapeworm
Dogs, cats
Giardiasis
Dogs, cats, beavers
Other Diseases Associated with Animals
(continued)
CHLAMYDIAL and
RICKETTSIAL
SOURCE
Ehlichiosis
Deer, dogs, horses
Psittacosis
Psittacine, domestic birds
Q Fever
Sheep, other livestock,
research labs
Dogs, wild rodents
Rocky Mountain
Spotted Fever
Ehrlichiosis
• Monocytotropic Ehrlichiosis in dogs = E. Canis
• Human Monocytotropic Ehrlichiosis in humans =
E. Chaffeensis
• Symptoms include: fever, malaise, chills, headache,
Arthralgia Myalgia, Anorexia, nausea, Leukopenia,
Thrombocytopenia and increase in liver enzymes.
Anaplasmosis in Cattle
• Anaplasma marginale
• 19 different tick vectors
• Blood transfusion
• Severity of illness increases with animals age.
• Calves more resistant
• Older cows are more susceptible
Anaplasmosis
• First recognized in the mid 1990’s
• Reportable by the CDC in 1999
• Bacterium Anaplasma Phagocytophilum
• CDC previously described as HGE – Human
Granulocytic Ehrlichiosis
Group A Streptococcus (GAS)
• It is debated whether or not dogs in an household
can serve as a source of infection for humans.
• Human beings are the primary reservoir for GAS,
not dogs, so when an animal in an household is
infected, is this an example of a reverse osmosis?
• (Crowder et al., 1978: Wilson et al., 1995) found
zero correlation between GAS in presence of dogs
in a household and human infection.
Group A Streptococcus (GAS) (Continued)
• (Mayer & VanOre, 1983, Copperman, 1982)
documented resolution of chronic GAS in
households after isolation of organism from, and
treatment of, dogs.
• There has only been one case reported of
Zoonosis GAS involving cats. (Roos et al., 1988)
Other Diseases Associated with Animals
(continued)
VIRAL
INFECTIONS
SOURCE
West Nile
Birds
Hantaviruses
Wild rodents
Rabies
Bats, cats, ferrets, dogs
The Culex mosquito, which bites from
dusk to dawn, is a vector of St. Louis
encephalitis and West Nile virus; it
becomes infected by feeding on birds
that carry these viruses. St. Louis
encephalitis and West Nile virus affect
mainly older adults.
Other Diseases Associated with Animals
(continued)
Avian
Influenza
A (H5N1)
Bird Flu Hits Trailer Park in Florida
NEWS
FLASH
Dateline: Orlando