bacterial zoonotic diseases of pets

Zoonotic Diseases of Companion Animals (Bacterial Origin)

Zoonotic Diseases of Companion Animals (Bacterial Origin)Submitted to:

Dr. Ali Raza

ZoonosisThose 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.(Bjerks, 2008)

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Zoonoses ContinueA 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 ZoonosesA 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)

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

BSE, bovine spongiform encephalopathy; vCJD, variant CreutzfeldtJakob disease.5

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)

Causative Pathogens Continued

Routes of TransmissionA 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)

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)Routes of Transmission Continue

Risk GroupsMost 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)

Diseases of Bacterial Origin

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Animal BitesDiseases 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. Grndalen, B. Svik, H. Srum, 2008, EJCAP

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

Animal Bites Continued

Cat Scratch DiseaseCasautive Agent:Bartonella henselaehemotropic gram negativeMost humans that develop cat scratch disease are children or young adults.It is estimated to affect 22,000 people in the United States every yearthe 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 ContinuedThe most common clinical symptoms in humans arenon-pruritic swelling on the inoculation siteLymphadenopathyIn some cases fever and general malaise occurIn rare cases, acute encephalopathy, liver- and spleen abscesses and pneumopathies may developDogs are believed also to develop and transfer disease caused by Bartonella spp.


Diagnosis:Culture of B. henselae from blood or infected tissuesCulture 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.Detection of Bartonella spp. DNA by PCR is standard for diagnosis.

J. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesCat Scratch Disease Continued

Prevention:The main preventive measures are proper training and handling of cats to avoid bites, scratches, licks and flea control.Any bites or scratches should be promptly and carefully cleaned.Extra care should be taken in households with immunocompromised individuals.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.Screening of feline blood donors for B. henselae has been recommended because of the ability to transmit infection through contaminated blood.J. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesCat Scratch Disease Continued

Treatment:Patients with mild or moderate CSD, only conservative symptomatic treatment is recommended Administration of antipyretics and analgesics as neededOccasionally, lymph node aspiration is indicated for pain relief in patientsUse of antibiotics is controversial and not indicated for typical CSD in immunocompetent patientsStephen J Nervi, New Jersey Medical SchoolCat Scratch Disease Continued

AnthraxCausative Agent:B. anthracisGram-positiveencapsulated, spore-forming bacteriumExist in both vegetative and spore formsVegetative 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


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

Anthrax Continued

Anthrax Continued

Clinical presentation:Infection almost always originates from oral exposureFeverAnorexiaInflammation of regional lymph nodes of the head, neck, and mediastinumSevere lymph node enlargement can cause asphyxiationToxemia and shock are more common causes of deathHemorrhagic gastroenteritis can develop, particularly in younger animals

J. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesAnthrax Continued

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.ELISAPCR


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


SalmonellosisHuman 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.


Clinical presentation:In dogs, salmonellosis can range from mild self limited diarrhea to severe hemorrhagic gastroenteritis and septicemiaFeverVomitingAbdominal painDehydrationDiarrhea may be mucoid, watery, or hemorrhagicAnimals recovering from infection may shed bacteria up till six weeks post infection.J. Grndalen, B. Svik, H. Srum, 2008, EJCAPSalmonellosis Continued

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.J. Grndalen, B. Svik, H. Srum, 2008, EJCAPSalmonellosis Continued

Diagnosis:Isolation of Salmonella from feces is the standard for the diagnosisIsolation of the bacterium from blood or other sterile body sites is diagnostic for invasive infections.PCRJ. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesTreatment:Replacement of fluidsAnti-diarrhealsAntibiotics

Salmonellosis Continued

Causative Agent:Brucella spp.non spore forminggram negative coccobacilliThe 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


Clinical presentation:Subclinical infections are commonLate - term abortion is common Decreased fertility with early embryonic death, stillbirths, and birth of weak puppies can also occurLymphadenopathy may be presentMale dogs can developOrchitisEpididymitisTesticular enlargement in acute infection & atrophy with chronic diseaseMortality is low but morbidity can be highJ. Grndalen, B. Svik, H. Srum, 2008, EJCAP

Brucellosis Continued

Clinical presentation: (Humans)Undulent feverIt usually starts as Acute febrile illnessHeadacheWeaknessMyalgiaBack painBrucellosis ContinuedGranulomatous hepatitisGastroenteritisHepatosplenomegalyEndocarditisJ. Scott Weese and Martha B. Fulford, 2011, Companion Animal Zoonoses

Diagnosis:Isolation of B. canis is the gold standard for diagnosisBlood culture is most often successful in the first 8 weeks after infectionRapid slide agglutination test (RSAT)Agar gel immunodiffusion (AGID)Indirect fluorescent antibody (IFA)ELISAUrine cultureJ. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesBrucellosis Continued

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Prevention & Treatment:Isolation of Infected animalsThe 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

Brucellosis Continued

CampylobacteriosisCampylobacter spp.Diarrheic disease is most commonC. upsaliensis is the most common species found in dogsC. upsaliensis , C. helveticus , and C. jejuni are found in catsShedding ranged from 44 days to more than 6 months.J. Scott Weese and Martha B. Fulford, 2011, Companion Animal Zoonoses

Clinical presentation:Most infected animals have no signs of disease.Diarrhea is the predominant clinical sign.AnorexiaVomitingAbdominal painDehydrationJ. Grndalen, B. Svik, H. Srum, 2008, EJCAP

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.PCRJ. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesCampylobacteriosis Continued

Escherichia coliE. coli is a gram negativeThe main zoonotic disease concern involves verotoxigenic E. coli (VTEC), particularly E. coli O157:H7These 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 birdsThe main source of human infections is contaminated food.The overall risk of E. coli O157 from pets is quite low.


Clinical presentation:Mild self limited diarrhea to bloody diarrheaHemorrhagic colitisHemolytic uremic syndrome

J. Grndalen, B. Svik, H. Srum, 2008, EJCAP

Escherichia coli Continued

LeptospirosisLeptospira spp.Long, thin, spiral shapedgram negative bacteria


Clinical presentation:Subclinical infections appear to be the most common form.Clinical disease is rarely reported in cats, even when leptospiremia and histological renal and hepatic damage are present.FeverVomitingAbdominal painDiarrhea

Severe weaknessDepressionicterus

J. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesLeptospirosis Continued

Diagnosis:Microscopic agglutination test (MAT)ELISAMacroscopic slide agglutination test (MSAT)indirect hemagglutination assay (IHA)PCRJ. Scott Weese and Martha B. Fulford, 2011, Companion Animal Zoonoses

Leptospirosis Continued

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.VaccinationIsolation of infected animalsProphylactic treatment of exposed personsJ. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesLeptospirosis Continued

Treatment:High doses of antibiotics. Antibiotic treatment (doxycycline, Vibramycin, Oracea, Adoxa, Atridox, penicillin)Fluid replacementAntipyreticAntiemeticWilliam C. Shiel Jr., MD, FACP, FACR on 12/20/2010Leptospirosis Continued

Q-FeverCoxiella burnetiiObligate intracellular gram negative bacteriumCats are the most important reservoir in urban areasNumerous 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.


Periparturient: the phenomenon of increase in number of nematode eggs produced by mother in the period 4 to 8 weeks after parturition.43

Clinical presentation:infections in companion animals are typically subclinical.Fever, anorexia, and lethargy can develop in cats after experimental infection.Splenomegaly in dogs reported.Abortion, stillbirth, and birth of weak puppies and kittens can occurIn Humans:Flu like illnessFeverheadache,SweatsCoughConcurrent pneumonia or hepatitis is common.J. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesQ-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.J. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesQ-Fever Continued

YersiniosisYersinia 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.

PsittacosisPsittacosis 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.

J. Grndalen, B. Svik, H. Srum, 2008, EJCAP

Disease is typically nonspecific and difficult to differentiate clinically from various other illnesses.LethargyAnorexiaRuffled feathersMucopurulent nasal & ocular dischargeDiarrheaExcretion of green to yellow green urates


Chronic conjunctivitis,EnteritisAir sacculitisPneumonitisHepatosplenomegaly Pericarditis,Nasal adenitisPeritonitis Sudden death.


http://goldcoastbirdvet.weebly.com/avian-chlamydia-in-birds-psittacosis-in-us.html49

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.

J. Grndalen, B. Svik, H. Srum, 2008, EJCAPPsittacosis Continued

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TuberculosisM. tuberculosis, M. avium, Mycobacterium battey, M. genavenseAerobicNon spore formingSlow growing organism (in vitro & in vivo)


Tuberculosis ContinuedClinical presentation:FeverWeight lossAnorexiaNonproductive coughGastrointestinal TB is more common in catsVomitingWeight lossAnorexia,AnemiaDiarrheaJ. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesIn Humans:FeverWeight lossChillsProductive coughNight SweatsExtrapulmonary manifestations include MeningitisLymphadenitisSeptic arthritis Osteomyelitis

Diagnosis:Isolation of M. tuberculosis is the gold standardMolecular 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.J. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesTuberculosis Continued

Tuberculin (Mantoux) Skin Testhttp://www.lung.ca/tb/tbtoday/tbdiagnosis/skin_test.html53

Tuberculosis Continued

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.

J. Scott Weese and Martha B. Fulford, 2011, Companion Animal ZoonosesTuberculosis Continued

SummaryCompanion animals live in close contact with the human populationThe 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.

NVJ, Norwegian Veterinary Journal, 11/2004.56

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.Summary Continued

NVJ, Norwegian Veterinary Journal, 11/2004.57

ReferencesEuropean 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.

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