Bacterial Zoonotic diseases of pets

SUBMITTED TO:
Dr. Ali Raza

 Those diseases and infections which are naturally
transmitted between vertebrate animals and man.
(Shakespeare, 2009)

 Zoonotic diseases are the diseases being common to,
shared by or transmitted between human beings and other
vertebrate animals.
(Bjerkås, 2008)

Zoonoses Continue…

 A comprehensive literature review identifies 1415 species of
infectious organism known to be pathogenic to humans.
 This include 217 viruses and prions, 538 bacteria and
rickettsia, 307 fungi, 66 protozoa and 287 helminthes.
 Out of these, 868 (61%) are zoonotic, that is, they can be
transmitted between humans and animals, and 175 pathogenic
species are associated with diseases considered to be 'emerging'.
Out of the emerging pathogens, 132 (75%) are zoonotic.

(Taylor et al., 2001)

Emerging Zoonoses

 A zoonosis that is newly recognized or newly evolved, or that has occurred previously but
shows an increase in incidence or expansion in geographical, host or vector range". Emerging
zoonotic diseases have potentially serious human health and economic impacts and their current
upwards trends are likely to continue.

(WHO, 2004)

The causative organisms responsible for
zoonoses are very diverse and
representative of a wide range of
pathogens, or parasites.

 The range of symptoms and effects that this extensive range of causative organisms produce
in both their animal hosts and humans is just as diverse, from the asymptomatic, through the
slightly inconvenient, to some associated cases with fatalities in excess of 50% of infected
individuals.

(Shakespeare, 2009)

Routes of Transmission

 A potential zoonosis may not necessarily cause detectable
symptomatic disease in the animal host, nor is transmission to
humans certain from every exposure to the pathogen. As with any
other infection, the size of inoculum necessary to initiate progress
to clinical disease varies from causative organism to causative
organism, and also depends on the route of transmission.
 The mode of transmission varies from zoonosis to zoonosis, and
can also vary for the same causative organism from host species
to host species. Transmission from animal to human can be not
only by direct, but also by indirect contact. Indirect spread by
physical contact with a previously infected object or surface is
known as fomite spread.

(Shakespeare, 2009)

Routes of Transmission Continue…

The disease presentation and the clinical course
associated with a particular pathogen may also vary
depending on the route and mode of infection.

(Shakespeare, 2009)

Risk Groups

 Most healthy adults with a competent immune
system are unlikely to acquire a zoonotic
infection even if an inoculum of potentially
infective magnitude is present.
 This does not indicate that infection does not
occur in this group only that it is less likely
than in the groups shown in Table, who are
identified by the WHO as primarily „at risk‟.

(Shakespeare, 2009)

Animal Bites

 Diseases mainly transferred by saliva through bites and
scratches. Many bite wounds caused by dogs or cats
develop into infections.
 Cat bites are usually associated with a higher risk of
wound infection than dog bites.
 Potential pathogen bacteria can be cultivated from about
90 % of bite wounds caused by a cat or a dog, and in
most cases more than one agent is diagnosed.

J. Grøndalen, B. Sævik, H. Sørum, 2008, EJCAP

Animal Bites Continued…

 The most common isolates include species of
Pasteurella, Streptococcus, Staphylococcus, Neisseria
and Moraxella.
 Pasteurella multocida is also part of the normal flora in
most vertebrates, including the dog and cat. Pasterurella
infections are especially seen after cat bites.
 Clinical signs may include cellulitis, lymphangitis and
lymphadenopaty, in some cases in combination with
arthritis

Cat Scratch Disease

 Casautive Agent:
 Bartonella henselae
 hemotropic gram – negative
 Most humans that develop “cat scratch disease” are children
or young adults.
 It is estimated to affect 22,000 people in the United States
every year
 the disease is considered to be the most common cause of
chronic lymphadenopathy in this age group.
 Cats with chronic bacteremia are contagious through saliva.
J. Scott Weese and Martha B. Fulford, 2011, Companion Animal Zoonoses

Cat Scratch Disease Continued…

 The most common clinical symptoms in humans are
 non-pruritic swelling on the inoculation site
 Lymphadenopathy
 In some cases fever and general malaise occur
 In rare cases, acute encephalopathy, liver- and spleen abscesses and
pneumopathies may develop
 Dogs are believed also to develop and transfer disease caused by
Bartonella spp.



 Diagnosis:
1. Culture of B. henselae from blood or infected tissues
 Culture can be difficult, and B. henselae will not be recovered using
routine blood culture methods because of the fastidious, slow growing
nature of the organism. Ten to fi fty - six days may be required before
visible colonies are identified.

2. Detection of Bartonella spp. DNA by PCR is standard for
diagnosis.



 Prevention:
a. The main preventive measures are proper training and handling of cats to avoid bites,
scratches, licks and flea control.
b. Any bites or scratches should be promptly and carefully cleaned.
c. Extra care should be taken in households with immunocompromised individuals.
d. Animals that are negative could be exposed any time thereafter, so a negative result
cannot be taken as indication of an absence of the risk of B. henselae exposure.
e. Screening of feline blood donors for B. henselae has been recommended because of the
ability to transmit infection through contaminated blood.



 Treatment:
 Patients with mild or moderate CSD, only conservative symptomatic treatment is
recommended
1) Administration of antipyretics and analgesics as needed
2) Occasionally, lymph node aspiration is indicated for pain relief in patients
3) Use of antibiotics is controversial and not indicated for typical CSD in
immunocompetent patients

Stephen J Nervi, New Jersey Medical School

Anthrax

 Causative Agent:
 B. anthracis
 Gram-positive
 encapsulated, spore-forming bacterium
 Exist in both vegetative and spore forms
 Vegetative cells have a characteristic polypeptide
capsule that is visible with methylene blue or Giemsa
stains.
 Spores are dormant forms that are highly resistant to
environmental effects and disinfectants.
 When culture form ‘medusa-head colonies’


Anthrax Continued…

 4 forms of acute disease in humans:
 Cutaneous (most frequent and least dangerous)
 Gastrointestinal (rare)
 Inhalational (rare and extremely dangerous)
 Intravenous – injection drug users


 Clinical presentation:
o Infection almost always originates from oral exposure
o Fever
o Anorexia
o Inflammation of regional lymph nodes of the head, neck, and
mediastinum
o Severe lymph node enlargement can cause asphyxiation
o Toxemia and shock are more common causes of death
o Hemorrhagic gastroenteritis can develop, particularly in
younger animals



 Diagnosis:
 A history of potential exposure greatly facilitates diagnosis, both in terms of making the correct diagnosis and safety
of the diagnostician.
 Aspirates of blood, lymph nodes, other affected tissues, or pharyngeal swabs can be collected for cytological
examination and culture.
 Methylene blue or Giemsa stains should be used on aspirates to look for the characteristic encapsulated organism.
 Culture is the definitive diagnostic test but should only be attempted by facilities with proper containment.
 Animals that have died of anthrax typically display little or no rigor mortis and often have dark blood oozing from
various orifices.
 ELISA
 PCR



 Prevention:
 The risk of anthrax exposure from companion animals, either in households or in veterinary
clinics, is very low in most areas.
 Reducing roaming of dogs and cats should greatly reduce the risk of anthrax exposure and
infection.
 In veterinary clinics, care should be taken to reduce the risk of environmental contamination or
personnel exposure.
 Necropsy should not be performed because it will permit the formation of highly resistant B.
anthracis spores


Salmonellosis

 Human salmonellosis is most commonly associated with
foodborne infection, but transmission of Salmonella from
pets can occur.
 The risk is greatest with reptiles.
 Salmonellae are gram negative enteric bacteria that are
normally found in a wide range of
mammals, reptiles, amphibians, birds, and insects.
 Transmission of Salmonella from dogs and cats to people
can occur in households, shelters, and veterinary clinics.


Salmonellosis Continued…

 In dogs, salmonellosis can range from mild self limited diarrhea to severe hemorrhagic
gastroenteritis and septicemia
 Fever
 Vomiting
 Abdominal pain
 Dehydration
 Diarrhea may be mucoid, watery, or hemorrhagic
 Animals recovering from infection may shed bacteria up till six weeks post infection.



Turtles are asymptomatic carriers of salmonella. It
has been reported that reptiles can have a carrier
frequency of more than 90%. All reptiles must be
considered potential carriers.



 Diagnosis:  Treatment:
 Isolation of Salmonella from feces is the  Replacement of fluids
standard for the diagnosis
 Anti-diarrheals
 Isolation of the bacterium from blood or
other sterile body sites is diagnostic for  Antibiotics
invasive infections.
 PCR


Brucellosis

 Causative Agent:
 Brucella spp.
 non spore forming
 gram negative coccobacilli
 The most clinically relevant Brucellae are Brucella abortus
(primarily from cattle), Brucella melitensis (primarily from goats
and sheep), and Brucella suis (swine). B. canis is associated with
dogs and is a zoonotic pathogen, but is the least common cause
of human brucellosis.
 The risk of infection is low in people that do not have contact
with breeding dogs, but is relatively high in people who handle
breeding dogs and who are exposed to reproductive tissues and
fluids from infected dogs.

Brucellosis Continued…

 Subclinical infections are common
 Late - term abortion is common
 Decreased fertility with early embryonic death, stillbirths, and birth of
weak puppies can also occur
 Lymphadenopathy may be present
 Male dogs can develop
 Orchitis
 Epididymitis
 Testicular enlargement in acute infection & atrophy with chronic disease
 Mortality is low but morbidity can be high



 Clinical presentation: (Humans)
 Undulent fever  Granulomatous hepatitis
 It usually starts as  Gastroenteritis
 Acute febrile illness  Hepatosplenomegaly
 Headache  Endocarditis
 Weakness
 Myalgia
 Back pain



 Diagnosis:
 Isolation of B. canis is the gold standard for diagnosis
 Blood culture is most often successful in the first 8 weeks after infection
 Rapid slide agglutination test (RSAT)
 Agar gel immunodiffusion (AGID)
 Indirect fluorescent antibody (IFA)
 ELISA
 Urine culture



 Prevention & Treatment:
 Isolation of Infected animals
 The use of gloves and protective outerwear when handling the dog or
potential infected fluids, or having contact with a contaminated
environment.
 Positive dogs should not be bred and should be neutered.
 Infected dogs should not have any direct or indirect contact with
uninfected dogs.
 Stable plurilamellar vesicles (SPLVs) entrapping aminoglycosides are used.
 Antibiotics

Journal of Infectious Diseases, 1985 Sep;152(3):529-35

Campylobacteriosis

 Campylobacter spp.
 Diarrheic disease is most common
 C. upsaliensis is the most common species found
in dogs
 C. upsaliensis , C. helveticus , and C. jejuni are
found in cats
 Shedding ranged from 44 days to more than 6
months.


Campylobacteriosis Continued…

 Most infected animals have no signs of disease.
 Diarrhea is the predominant clinical sign.
 Anorexia
 Vomiting
 Abdominal pain
 Dehydration


Campylobacteriosis Continued…

 Diagnosis:
 Diagnosis of Campylobacteriosis is
challenging, largely because of the high
prevalence of colonization in healthy animals.
 Fecal culture is currently the standard for
diagnosis, although interpretation can be difficult
because of the presence of Campylobacter in a
large percentage of healthy animals.
 PCR


Escherichia coli

 E. coli is a gram negative
 The main zoonotic disease concern involves verotoxigenic E.
coli (VTEC), particularly E. coli O157:H7
 These strains produce verotoxins (also known as Shiga toxins)
 The organism can be commonly found in the intestinal tracts
of healthy cattle, sheep, goats, pets and wild birds
 The main source of human infections is contaminated food.
 The overall risk of E. coli O157 from pets is quite low.


Escherichia coli Continued…

 Mild self limited diarrhea to bloody diarrhea
 Hemorrhagic colitis
 Hemolytic uremic syndrome


Leptospirosis

 Leptospira spp.
 Long, thin, spiral shaped
 gram negative bacteria


Leptospirosis Continued…

 Subclinical infections appear to be the most  Severe weakness
common form.  Depression
 Clinical disease is rarely reported in cats, even  icterus
when leptospiremia and histological renal and
hepatic damage are present.
 Fever
 Vomiting
 Abdominal pain
 Diarrhea



 Diagnosis:
 Microscopic agglutination test (MAT)
 ELISA
 Macroscopic slide agglutination test (MSAT)
 indirect hemagglutination assay (IHA)
 PCR



 Prevention:
 Reducing exposure of animals Wet areas with drainage from potentially infected cattle, deer, or
wildlife are of higher risk, particularly with slow moving, warm, and alkaline water.
 Vaccination
 Isolation of infected animals
 Prophylactic treatment of exposed persons



 Treatment:
 High doses of antibiotics. Antibiotic treatment (doxycycline, Vibramycin, Oracea, Adoxa,
Atridox, penicillin)
 Fluid replacement
 Antipyretic
 Antiemetic

William C. Shiel Jr., MD, FACP, FACR on 12/20/2010

Q-Fever

 Coxiella burnetii
 Obligate intracellular gram – negative bacterium
 Cats are the most important reservoir in urban areas
 Numerous outbreaks of Q-fever have been reported from contact
with periparturient cats.
 Close contact with periparturient cats is not required for
transmission, and simply being in the same house or room may be
adequate.
 Dog - associated Q fever is uncommonly reported and is likely very
rare, but can occur.


Q-Fever Continued…

 In Humans:
 infections in companion animals are
typically subclinical.  Flu like illness

 Fever, anorexia, and lethargy can develop in  Fever
cats after experimental infection.  headache,
 Splenomegaly in dogs reported.  Sweats
 Abortion, stillbirth, and birth of weak  Cough
puppies and kittens can occur
 Concurrent pneumonia or hepatitis is
common.


Q-Fever Continued…

 Prevention:
 The greatest risk of pet associated Q fever comes from periparturient animals, particularly
cats, so efforts should be focused on that group.
 Immunocompromised individuals and pregnant women should avoid contact with periparturient
and newborn animals.
 Good hygiene practices should be used when handling dogs.
 Household pets should not have direct contact with periparturient ruminants.
 An inactivated whole cell unlicensed vaccine is effective in for protection against exposure, but
severe local reactions to this vaccine may be seen in those who already possess immunity.
Therefore, an intradermal skin test is recommended to detect pre-sensitized or immune
individuals.


Yersiniosis

 Yersinia enterocolitica is a bacterium that can replicate at refrigerator
temperatures and exists as a number of different subgroups called
serotypes.
 Serotype 3 and 9 cause most of the disease in humans and are zoonotic
agents that are common in dogs, cats and pigs.
 Transmission to humans occurs through contact with a household pet that
is shedding the bacterium in their faeces, by similar direct contact with
pigs or by consumption of undercooked pork.
 Several other Yersinia spp. are zoonotic agents including Yersinia
pseudotuberculosis, which causes gastrointestinal disease in humans and
systemic granulomatous disease in cats.

Psittacosis

 Psittacosis is a disease caused by a bacterium
Chlamydophila psittaci
 It is transmitted to humans from birds.
 161 cases were diagnosed in Australia in 2005,
of which 34 cases originated in Victoria.
 This disease is usually contracted by inhalation
of dust containing faecal matter from infected
birds.
 Clinical signs are most severe in
immunosuppressed individuals.


 Disease is typically nonspecific and difficult to
differentiate clinically from various other
illnesses.
 Lethargy
 Anorexia
 Ruffled feathers
 Mucopurulent nasal & ocular discharge
 Diarrhea
 Excretion of green to yellow green urates


 Chronic conjunctivitis,
 Enteritis
 Air sacculitis
 Pneumonitis
 Hepatosplenomegaly
 Pericarditis,
 Nasal adenitis
 Peritonitis
 Sudden death.


Psittacosis Continued…

 Birds carrying this disease range from being clinically normal, to
very ill. All ill birds should be handled carefully, and never allow
any bird to place their head near your mouth.
 Good personal hygiene, such as washing hands with soap after
handling your bird and dampening down the floor of your bird's
cage before cleaning to prevent aerosolisation of dusty faecal
matter, will help prevent transmission of this disease to humans.


Tuberculosis

 M. tuberculosis, M. avium, Mycobacterium
battey, “M. genavense”
 Aerobic
 Non spore forming
 Slow growing organism (in vitro & in vivo)


Tuberculosis Continued…

 Clinical presentation:  In Humans:
 Fever  Fever
 Weight loss  Weight loss
 Anorexia  Chills
 Nonproductive cough  Productive cough
 Gastrointestinal TB is more common in cats  Night Sweats
 Vomiting  Extrapulmonary manifestations include
 Weight loss  Meningitis
 Anorexia,  Lymphadenitis
 Anemia  Septic arthritis
 Diarrhea  Osteomyelitis



 Diagnosis:
 Isolation of M. tuberculosis is the gold standard
 Molecular testing of tissues and exudates can provide a rapid
and specific diagnosis of M. tuberculosis .
 Tuberculin testing is inconsistent and unreliable in dogs and
cats.
 PCR can be performed on tissues or fluid samples.



 Prevention:
 In households with infected pets, contact with the
infected site should be avoided as much as possible.
 Hand hygiene should be performed after contact.


Summary

 Companion animals live in close contact with the human population
 The risk of transmitting zoonotic diseases to humans is significant if the animal itself
has been infected.
 Increased travel activity increases the possibility of transfer of infection between
animal populations, and increased risk for contact with new infectious agents.
 An increasing number of people suffer from immunodeficiencies.
 Environmental- and climatic conditions cause a change in distribution of vectors in
need of special climatic conditions to establish.

NVJ, 11/2004.

Summary Continued…

 Exotic species are also to an increasing extent introduced as
family pets, which may contribute to a wider panorama of
infections. However, the traditional zoonotic diseases are still
the most important.
 Vaccination, proper hygiene measurements and knowledge on
preventive measures restrict the risk of transmittance of
infections from companion animals.
 The most significant risk of companion animals in Norway are
mostly related to dog and cat bites or other physical injuries.

NVJ, 11/2004.

 European Academies Science Advisory Council (EASAC).
Combating the Threat of Zoonotic Infections. London: Royal
Society, 2008.
 Taylor et al. 2001 Risk factors for human disease emergence
Philosophical Transactions of the Royal Society B
356(1411):983-9.
 Stevenson, WJ. & Hughes, KL. (1988) Synopsis of Zoonoses in
Australia, 2nd edition, Canberra: Australian Government
Publishing Service.
 WHO/FAO/OIE joint consultation on emerging zoonotic
diseases, Geneva, 3-5 May 2004.

Bacterial Zoonotic diseases of pets

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