Transcript INFECTIOUS DISEASES

ZOONOSES
&
VECTOR-BORNE DISEASES
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SIGNALMENT: ~6mth old neutered, male DSH
PRESENTING COMPLAINT: depression, feels
“hot”, looks yellow, painful abdomen, and
difficulty breathing. Cat began to act strange
over the last week. Poor appetite, soft stool
Hx: indoor/outdoor cat, fully vaccinated, but
not against FeLV and FIV, microchipped, often
brings “gifts of mice” home
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PHYSICAL EXAM
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Temp: 104.1, HR:220, RR:40, shallow
Depression
Labored breathing
Icteric mm, CRT: difficult to assess, >2sec
Painful on abdominal palpation
OS: signs of inflammation/uveitis
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CBC/SERUM CHEMISTRIES
◦ Elevated ALT. ALP, total bilirubin
◦ CBC WNL
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FeLV/FIV Test
◦ Neg/Neg
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Thoracic radiographs
◦ pneumonia
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Paired titers
ELISA
FECAL
◦ See next slide
PNEUMONIA IS MOST COMMON IN NEONATALLY
OR TRANSPLACENTALLY INFECTED CATS
THESE OOCYTS
ARE DIFFICULT & RARE
TO FIND
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TRANSMISSION:
◦ EATING CONTAMINATED MEAT
 Ingestion of uncooked or undercooked meat is most
likely the main route of infection in both cats and
humans.
◦ Fecal – oral route
◦ Transplacental route
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Cats are the definitive host for Toxoplasma
gondii, but several animal can serve as
intermediate hosts
CATS ONLY SHED OOCYTS
IN THE FECES FOR 1-2 WEEKS
THE OOCYTS BECOME INFECTIVE
AFTER 1-5 DAYS
TACHYZOITES ARE THE RAPIDLY
DIVIDING STAGE OF THIS PARASITE
THAT INFECTS THE TISSUES
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Clindamycin or Trimethoprim Sulfa for 2-3
weeks (may require 4 weeks treatment)
Prognosis is poor for young patients with
hepatic or respiratory involvement, but good
for the older cat with minimal or no signs of
disease
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Exposure to Toxoplasma is common – 30%60% of adult humans are seropositive
Humans who are immunosuppressed should
avoid contact with infected cats
◦ Have someone else clean the litter box
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Avoid getting a new cat during pregnancy
Have antibody titers checked before getting
pregnant
◦ Infection during the 1st or 2nd trimester can lead to
birth defects
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Cook all meat thoroughly
DON’T PANIC
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SIGNALMENT: 2yr old hound mix, intact male
PRESENTING COMPLAINT: dog is reluctant to
move, has a stiff gait and seems painful,
possibly ataxic, lethargic for the last week.
Hx: dog goes hunting with the owner about
once month for the last 3 months. Dog is
current on HW and flea preventive.
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PHYSICAL EXAM
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Temp: 103.5, HR: 116, RR:24
Mild mucopurulent ocular discharge
Mm:pale pk, CRT: 2sec
Animal is somewhat painful and ataxic
Technician finds several ticks on the head and neck
region
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CBC/SERUM CHEMISTRIES
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Anemia
Leukocytosis w/left shift
Thrombocytopenia
Increased liver enzymes (ALT, ALP)
Hypoproteinemia
SERUM TITERS – 4-fold increase between
titers
TISSUE BIOPSY & FLUORESCENT STAINING
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DIAGNOSIS: TICK-BORNE DISEASE
◦ ROCKY MOUNTAIN SPOTTED FEVER – caused by
Rickettsia rickettsii, a gram- obligate intracellular
bacterial organism.
◦ This organism is carried in the saliva of the tick
◦ Clinical signs occur secondary to vasculitis of small
blood vessels throughout the body. Other clinical
signs include: edema, hemorrhage, seizures,
coughing, vomiting, diarrhea, and more…
TICKS MUST BE ATTACHED TO HOST FOR 5-20
HOURS BEFORE TRANSMITTING INFECTIOUS ORGANISM
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TREATMENT
◦ Doxycycline
◦ Tetracycline
◦ Antibiotics only reduce the number of organisms,
the animal must have a good immune system to
eliminate them.
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Blood from infectious patients and from the
tick can be infectious
Client should watch for signs of myalgia,
headache, fever, or abdominal pain
Keep pets out of heavily infested tick areas
and remove ticks quickly. Add tick prevention
to the pet’s health regimen.
Incubation period is ~7days
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SIGNALMENT: 2yr old mixed breed, castrated
male
PRESENTING COMPLAINT: lethargy, labored
breathing, swollen neck, and swollen rt rear leg
for about a week that seemed to resolve. About 6
weeks later developed bleeding from the nose,
dyspnea, weakness, and “red spots” on the skin
Hx: outdoor dog, vaccinations current, on HW
and flea preventive.
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PHYSICAL EXAM
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Temp: 103.8, HR: 120, RR: 28
Mild epistaxis
Petechial hemorrhages
Edema of the extremities
Ticks found in the coat
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CBC/SERUM CHEMISTRY
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25% have pancytopenia
Anemia
Thrombocytopenia
Hyperglobulinemia
Blood smear
 Observe morula in
mononuclear cells
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IFA
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DIAGNOSIS: TICK-BORNE DISEASE
◦ CANINE MONOCYTIC EHRLICHIOSIS, caused by
Ehrlichia canis transmitted by the tick Rhipicephalus
sanguineus
◦ After infection, E. canis causes acute, subclinical,
and chronic stages of the disease
◦ ACUTE: lasts 2-4 weeks
 Organisms multiplies in mononuclear cells
 Mononuclear cells carry the organism to other organs
including the lungs, kidneys, and meninges.
 Vasculitis develops
◦ SUBCLINICAL PHASE
 Few clinical signs if any
◦ CHRONIC PHASE
 Bone marrow suppression
 Bleeding tendencies
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CANINE GRANULOCYTIC EHRLICHIOSIS caused by
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Clinical signs associated with Ehrlichia ewingii
infection:
Ehrlichia ewingii or Ehrlichia equi
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Fever
Lethargy
Lameness
Muscle stiffness
CBC: Thrombocytopenia
Blood smear: morulae found in neutrophils
◦ Transmitted by the Amblyomma americanum tick
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CANINE GRANULOCYTIC EHRLICHIOSIS caused
by Ehrlichia ewingii or Ehrlichia equi
Clinical signs of Ehrlichia equi infection:
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Fever
Debilitating lethargy
Anorexia
CBC: thrombocytopenia
Serum chemistries: Increased ALP
◦ Transmitted by the Ixodes dammini tick
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ANTIBIOTICS
◦ Doxycycline
◦ Tetracycline
◦ +/- blood transfusions
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CLIENT INFO:
◦ Ticks can be a threat to pets and humans
 Owners should avoid exposure to the blood of the tick
◦ The prognosis is good – Improvement often seen
within 48 hours
◦ Check pets frequently for ticks and remove them
when found.
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SIGNALMENT: 3yr old castrated male, English
Setter
Hx: Moved from the northeast about 3 weeks
ago. Prior to moving, owner pulled off a few
ticks . Some of the areas have a red rash. In
the last few days, the dogs is showing some
lameness in the rear legs
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PHYSICAL EXAM
◦ Temp:103.5, HR: 100, RR: 24
◦ Lethargic
◦ Swollen lymph nodes
◦ Wt. bearing lameness on the rt. Rear limb
that seems to come and go.
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Radiographs
◦ Would be normal
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ELISA TEST
◦ Lyme Positive
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SYNOVIAL FLUID ANALYSIS
◦ Increased nucleated cells
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LYME DISEASE is caused by the spirochete
Borrelia Burgodorferi, passed by an Ixodes
tick
– The tick must be attached to the host for more than
48 hours
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Other clinical signs:
– Fever
– Anorexia
– Lymphadenopathy
– Chronic flare-ups
– Myocardial abnormalities
– Nephritis, esp in Labs
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ANTIBIOTICS
◦ Doxycycline is the treatment of choice for
Borreliosis
 Treatment may not completely eliminate the
organism and some animals may remain
permanently infected.
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CLIENT INFO
◦ Vaccination is effective, unless dog has already
been exposed.
◦ Animal infection should alert owners to the
possibility of human infection from ticks in the
area.
◦ Use a tick preventive regularly
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SIGNALMENT: 4 yr old, neutered male mixed
breed.
HISTORY: owner saw dog playing with
remains of a dead bat out in the back yard
yesterday. The owner brings the dead bat into
the clinic in a box and wants to know what to
do.
◦ The dog is current on all vaccinations including
rabies. He is on HW and flea prevention.
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The bat should be sent to a laboratory for
analysis and rabies testing
◦ This requires a sample of brain tissue that has NOT
been frozen.
◦ There is no antemortem test available
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The dogs should be examined and handled
carefully. He should be quarantined until the
results from the bat are known.
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Rabies virus is spread through the saliva of an
infected animal
◦ Bite, open wound, or mucous membranes
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It travels up the nerve endings at the site of
infection until it reaches the brain where it
multiplies. It then enters the salivary glands
where it can be transmitted through saliva.
◦ This may take 3-8 weeks
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RABIES IS CHARACTERIZED BY 3 STAGES:
◦ PRODROMAL STAGE – people are greatest risk during
this phase. It is associated with behavior changes
◦ EXCITATIVE/FURIOUS STAGE- Infected animals may
attack inanimate objects or appear hyperreactive. Some
animals may appear “dumb”
◦ PARALYTIC STAGE - characterized by ascending
paralysis of the hind limbs which may progress to
respiratory paralysis and death.
◦ Death will occur between 2 and 10 days from the onset
of clinical signs
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CLINICAL SIGNS:
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Behavioral changes
Difficulty swallowing
Voice changes
CNS signs (seizures, ataxia)
hypersalivation
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CLIENT INFO:
◦ Never handle wild animals that appear tame or
friendly
 Leave wild life in the wild
◦ Wear glove when examining a pet’s oral cavity,
esp if rabies is suspected
◦ Promote vaccination against rabies
◦ If your pet bites someone, it must be quarantined
for 10 days to observe for signs of clinical rabies
◦ Vaccinated animals exposed to a rabid animal
should be revaccinated and observed for 90 days.