ZOONOSES &

VECTOR-BORNE DISEASES

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

PHYSICAL EXAM ◦ 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

CBC/SERUM CHEMISTRIES◦ Elevated ALT. ALP, total bilirubin◦ CBC WNL

FeLV/FIV Test◦ Neg/Neg

Thoracic radiographs◦ pneumonia

Paired titers ELISA FECAL

◦ See next slide

PNEUMONIA IS MOST COMMON IN NEONATALLY OR TRANSPLACENTALLY INFECTED CATS

THESE OOCYTSARE DIFFICULT & RARETO FIND

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

Cats are the definitive host for Toxoplasma gondii, but several animal can serve as intermediate hosts

CATS ONLY SHED OOCYTSIN THE FECES FOR 1-2 WEEKSTHE OOCYTS BECOME INFECTIVEAFTER 1-5 DAYS

TACHYZOITES ARE THE RAPIDLYDIVIDING STAGE OF THIS PARASITETHAT INFECTS THE TISSUES

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

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

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 Cook all meat thoroughly DON’T PANIC

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.

PHYSICAL EXAM◦ 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

CBC/SERUM CHEMISTRIES◦ Anemia◦ Leukocytosis w/left shift◦ Thrombocytopenia◦ Increased liver enzymes (ALT, ALP)◦ Hypoproteinemia

SERUM TITERS – 4-fold increase between titers

TISSUE BIOPSY & FLUORESCENT STAINING

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 5-20HOURS BEFORE TRANSMITTING INFECTIOUS ORGANISM

TREATMENT◦ Doxycycline◦ Tetracycline◦ Antibiotics only reduce the number of

organisms, the animal must have a good immune system to eliminate them.

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

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.

PHYSICAL EXAM◦ Temp: 103.8, HR: 120, RR: 28◦ Mild epistaxis◦ Petechial hemorrhages◦ Edema of the extremities◦ Ticks found in the coat

CBC/SERUM CHEMISTRY◦ 25% have pancytopenia◦ Anemia◦ Thrombocytopenia◦ Hyperglobulinemia

Blood smear Observe morula in mononuclear cells

IFA

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

CANINE GRANULOCYTIC EHRLICHIOSIS caused by Ehrlichia ewingii or Ehrlichia equi

Clinical signs associated with Ehrlichia ewingii infection:◦ Fever◦ Lethargy◦ Lameness◦ Muscle stiffness◦ CBC: Thrombocytopenia◦ Blood smear: morulae found in neutrophils

◦ Transmitted by the Amblyomma americanum tick

CANINE GRANULOCYTIC EHRLICHIOSIS caused by Ehrlichia ewingii or Ehrlichia equi

Clinical signs of Ehrlichia equi infection:◦ Fever◦ Debilitating lethargy◦ Anorexia◦ CBC: thrombocytopenia◦ Serum chemistries: Increased ALP

◦ Transmitted by the Ixodes dammini tick

ANTIBIOTICS◦ Doxycycline◦ Tetracycline◦ +/- blood transfusions

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.

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

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.

Radiographs◦ Would be normal

ELISA TEST◦ Lyme Positive

SYNOVIAL FLUID ANALYSIS◦ Increased nucleated cells

• 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

• Other clinical signs:– Fever– Anorexia– Lymphadenopathy– Chronic flare-ups–Myocardial abnormalities– Nephritis, esp in Labs

ANTIBIOTICS◦ Doxycycline is the treatment of choice for

Borreliosis Treatment may not completely eliminate the

organism and some animals may remain permanently infected.

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

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.

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

The dogs should be examined and handled carefully. He should be quarantined until the results from the bat are known.

Rabies virus is spread through the saliva of an infected animal◦ Bite, open wound, or mucous membranes

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

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

CLINICAL SIGNS:◦ Behavioral changes◦ Difficulty swallowing◦ Voice changes◦ CNS signs (seizures, ataxia)◦ hypersalivation

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.