how many bactira virus or parsite are mintined in this lecture :
Zoonotic disease
DR: INTISAR ALNAGI
Objectives
• List common organisms transmitted from animal
to human
• Define different types of hosts, vectors and
disease transmission with examples for each
• Give examples of common diseases caused by
zoonosis
• List common methods of microbiology lab. Tests
used in diagnosis of zoonotic diseases.
• Explain how to prevent and control such
infections.
• Zoonoses are human diseases caused by
organisms that are acquired from animals.
bacterial.
viral.
fungal.
parasite.
• Bacteria :
gram-negative rods that have significant animal
reservoirs:
Brucella species.
Francisella tularensis.
Yersinia pestis.
Pasteurella multocida.
• Rabies Leishmania Tularemia
• Toxoplasmosis Cryptosporidiosis West Nile Virus
• Lyme Disease Brucellosis Q-fever
• BSE “Mad Cow ” Anthrax Rocky Mtn. Spotted Fever
• Tapeworms Erlichiosis Encephalitis viruses
• Roundworms Listeriosis Chagas disease
• Hookworms Salmonella Ringworm
• E.coli
• Bird Flu
• Giardia
• Plague Leptospirosis Histoplasmosis Campylobacter



• Host :is larger organism which harbour
smaller organisms and provides the
nourishmentExamples include animals playing
host to parasitic worms .
1. Definitive (primary) host
2. Intermediate (secondry) host
3. paratenic host
4. Reservoir host
Type of host
I. Definitive host: an organism in which the
parasite reaches the adult stage and
reproduces sexually, if possible.
II. Intermediate host: an organism that harbors
the sexually immature parasite and is required
by the parasite to undergo development and
complete its life cycle. EX: (larval form ).
III. Paratenic or transport host – an organism that
harbors the sexually immature parasite but is not
necessary for the parasite's development cycle to
progress, which they can accumulate in high numbers.
IV. Reservoir host: an organism that harbors
a pathogen but suffers no ill effects. However, it serves
as a source of infection to other species that are
susceptible, with important implications
for disease control.

Transmission of zoonotic disease
• Direct contact: Coming into contact with the
saliva, blood, urine, mucous, feces, or other
body fluids of an infected animal.
• Indirect contact: Coming into contact with
areas where animals live, or objects or
surfaces that have been contaminated with
germs.
• Vector-borne: Being bitten by a tick, or an
insect like a mosquito or a flea.
• Foodborne: Eating or drinking something
unsafe (such as unpasteurized milk,
undercooked meat or eggs, or raw fruits and
vegetables that are contaminated with feces
from an infected animal).

FRANCISELLA
• Disease Francisella
tularensis causes tularemia.
• Important Properties:
• F. tularensis is a small,
pleomorphic gram-negative
rod.
• It has a single serologic
type.
• There are two biotypes, A
and B
• The bacteria are transmitted among
animals by vectors such as ticks, mites,
and lice, especially the ticks that feed on
the blood of wild rabbits.
• Humans are accidental hosts who
acquire the infection by bitten the vector
or by having skin contact with the animal
.
• Rarely, the organism is ingested in
infected meat, causing gastrointestinal
tularemia, or is inhaled, causing
pneumonia.
• There is no person-to-person spread.
• The organism enters through the skin, forming
an ulcer at the site in most cases……….. then
localizes to the cells of the reticuloendothelial
system, and granulomas are formed.
• Caseation necrosis and abscesses can also
occur.
• Symptoms are caused primarily by endotoxin.
No exotoxins have been identified

Clinical Findings
• sudden onset of an influenza like syndrome
…or….
• prolonged onset of a low-grade fever and
adenopathy.
• Approximately 75% of cases are the
“ulceroglandular” type, in which the site of entry
ulcerates and the regional lymph nodes are
swollen and painful.
• Other, less frequent forms of tularemia include
glandular, oculoglandular, typhoidal,
gastrointestinal, and pulmonary.
• Disease usually confers lifelong immunity

Laboratory Diagnosis
• culture the organism in the laboratory are rarely
undertaken, because there is a high risk to laboratory
workers of infection by inhalation, and the special
cysteine-containing medium required for growth is not
usually available.
• The most frequently used diagnostic method is the
agglutination test with acute- and convalescent-phase
serum samples.
• Fluorescent-antibody staining of infected tissue can be
used if available.
Prevention
• involves avoiding both
being bitten by ticks and
handling wild animals.
• There is a live, attenuated
bacterial vaccine that is
given only to persons,
whose occupation brings
them into close contact
with wild animals, still
experimental.
PASTEURELLA
• Disease Pasteurella
multocida causes wound
infections associated with
cat and dog bites.
• Important Properties P.
multocida :
short, encapsulated gramnegative rod that exhibits
bipolar staining.
Pathogenesis
part of the normal flora in the mouths of many
animals, particularly domestic cats and dogs,
and is transmitted by biting.
Pathogenesis is not well understood, except
that the capsule is a virulence factor and
endotoxin is present in the cell wall.
No exotoxins are made
Clinical Findings
• A rapidly spreading cellulitis at the site of an
animal bite is indicative of P. multocida infection.
• The incubation period usually less than 24 hours.
Osteomyelitis .
Laboratory Diagnosis The diagnosis is made by
finding the organism in a culture of a sample from
the wound site.
Prevention People who have been bitten by a cat
should be given ampicillin to prevent P. multocida
infection.
Rickettsiae
• Rickettsiae are obligate intracellular bacteria
because they are unable to produce sufficient
energy to replicate extracellularly, Therefore,
must be grown in cell culture, embryonated
eggs, or experimental animals.
• poorly stained with Gram stain.
• Rickettsiae rickettsii
• Rickettsia prowazekii
• Coxiella burneti

C. burnetii has a sporelike stage that is highly
resistant to drying.
C. burnetii exists in two phases that differ in
their antigenicity and their virulence:
phase I organisms are isolated from the patient,
are virulent, and synthesize certain surface
antigens.
phase II organisms are produced by repeated
passage in culture, are nonvirulent, and have
lost the ability to synthesize certain surface
antigens.
Transmission
• rickettsiae are transmitted to humans by the
bite of the arthropod.
• The rickettsiae circulate widely in the
bloodstream (bacteremia), infecting primarily
the endothelium of the blood vessel walls.
• The exception to arthropod transmission is C.
burnetii, the cause of Q fever, which is
transmitted by aerosol and inhaled into the
lungs.
• Virtually all rickettsial diseases are zoonoses
with the prominent exception of epidemic
typhus, which occurs only in humans because
the causative organism, R. prowazekii, is
transmitted by the human body louse.
Pathogenesis
• The typical lesion caused by the rickettsiae is a
vasculitis, particularly in the endothelial lining of
the vessel wall where the organism is found.
Causing edema and hemorrhage due to increased
capillary permeability.
• The basis for pathogenesis by these organisms
is unclear.
There is some evidence that endotoxin is involved
(fever and petechiae). Still not confirmed
No exotoxins or cytolytic enzymes have been
found.

Rocky Mountain Spotted Fever
• acute onset of nonspecific symptoms (e.g., fever,
severe headache, myalgias, and prostration).
• The typical rash, which appears 2 to 6 days later,
begins with macules that frequently progress to
petechiae . The rash usually appears first on the
hands and feet and then moves inward to the
trunk.
• delirium and coma can occur.
• DIC, edema, and circulatory collapse in severe
cases.
• There is no person-to-person
transmission. Most cases occur
in children during spring and
early summer, when the ticks
are active.
• The diagnosis must be made
clinically and therapy started
promptly, because the
laboratory diagnosis is delayed
until a rise in antibody titer can
be observed, it is fatal if
untreated.

Q Fever
• The agent is C. burnetii
• the main organ involved in Q fever is the lungs
(Pneumonia ).
• It begins suddenly with fever, severe
headache, cough, and other influenzalike
symptoms.
• Hepatitis ……. combination of pneumonia and
hepatitis should suggest Q fever.
• A rash is rare.

Transmission and prevention
• not transmitted to humans by the bite of an
arthropod.
• The important reservoirs for human infection are
cattle, sheep, and goats where found in high
concentrations in the urine, feces, placental
tissue, and amniotic fluid of the animals.
• It is transmitted to humans by inhalation of
aerosols of these materials.
• Cow’s milk is usually responsible for subclinical
infections rather than disease in humans.
• Pasteurization of milk kills the organism.
Typhus
• There are several forms of typhus:
• louse-borne epidemic typhus caused by R.
prowazekii.
• flea-borne endemic typhus (murine
typhus)caused by Rickettsia typhi.
• chigger-borne scrub typhus caused by R.
tsutsugamushi.
• Typhus begins with the sudden onset of chills,
fever, headache, and other influenzalike
symptoms approximately 1 to 3 weeks after the
louse bite occurs.
• Between the fifth and ninth days after the onset
of symptoms, a maculopapular rash begins on the
trunk and spreads peripherally.
The rash becomes petechial and spreads over the
entire body but spares the face, palms, and soles.
Signs of severe meningoencephalitis, including
delirium and coma, begin with the rash and
continue into the second and third weeks.
In untreated cases, death occurs from peripheral
vascular collapse or from bacterial pneumonia.
Laboratory Diagnosis
• Diagnosis mainly serological. the indirect
immunofluorescence and (ELISA).
• Although rickettsiae can be grown in cell
culture or embryonated eggs, this is a
hazardous procedure that is not available in
the standard clinical laboratory.
Prevention
1. reduce exposure to the arthropod vector by
wearing protective clothing and using insect
repellent.
2. Frequent examination of the skin for ticks is
important in preventing Rocky Mountain
spotted fever; the tick must be attached for
several hours to transmit the disease.
3. There is no vaccine against Rocky Mountain
spotted fever. Prophylactic antibiotics are not
recommended in the asymptomatic person
bitten by a tick.
4. Persons at high risk of contracting Q fever,
such as veterinarians, shepherds, abattoir
workers, and laboratory personnel exposed to C.
burnetii, should receive the vaccine that consists
of the killed organism
Reference
• Levinson, Warren. Review of medical
microbiology and immunology. 13rd ed. The
McGraw-Hill Companies, 2014.

how many of them are fully explained