Diseases Flashcards
What is another name for the Bufo Toad?
Colorado River Toad.
How does the bufo toad produce toxins?
Glands in the skin, largest of which are by the eyes. White, creamy, thick toxin.
What are the toxic principles in bufo toads?
bufagenins and bufotoxins
What is the MOA of bufagenins?
Digitalis-like:
What is the MOA of bufotoxins?
Local anesthetic-like: block sodium channels
Signs of bufo toad toxicity?
Mild: frothy salivation, head shaking, pawing at mouth from local irritation, vomiting or retching
Severe: Convulsions, arrhythmias (various types), dyspnea, death
Treatment for Bufo toad toxicity?
Mild: lavage mouth (toxin can aerosolize so remove animal from area after ravaging)
Severe: treat arrhythmias as standard (atropine for brady, lidocaine for tachy), benzodiazepines for seizures, oxygen support as needed
Full name of Valley Fever
Coccidioides immitis or posadasii
What species are significantly affected by Valley Fever?
All can be affected, only dogs show significant infections usually
When most prone to getting Valley Fever?
Rainy period then a long drought.
How often does dissemination of Valley Fever occur?
20% of the time
If a cat gets Valley Fever what are the signs?
Skin lesions +/- weight loss, fever, inappetence
How often do cats get disseminated disease?
50% but they don’t get it that often to begin with.
Nodules of valley fever have what histological apperance?
Pyogranulomatous and epithelial/giant cells
Diagnosis of valley fever
Enlarged thoracic lymph nodes
Pyogranulomatous nodules with spherules
Confirmative: spherules in tissue
Can also use AGID assays for titers
In tissue what does coccidioides look like?
Spherules
Treatment of valley fever
Fluconazole x 6-12 mo
Amphotericin B best but too toxic
What form is valley fever in in the soil?
Mycelium
Describe the type of fungus coccidioides is
Dimorphic, saprophytic
Describe the lifecycle of valley fever
Mycelium in soil –> inhaled by canine
Gets to hilar lymph nodes within 10 days of exoposure
Spherules in lungs –> releases endospores
Endospores most vulnerable to phagocytosis
Forms more spherules
Dissemination usually 4 months from exposure (faster in immunosuppressed animals)
Most common symptom of Valley Fever
Cough (dry if LN, wet if alveolar)
Ehrlichia canis is transmitted by what type of tick?
Rhipicephalus (brown dog tick)
Ehrlichia is what type of organism?
Obligate intracellular bacteria
What type of cell does ehrlichia infect?
Monocytes
Ehrlichiosis can be caused by which two species?
E. canis and E. chaffennsis
Is ehrlicha zoonotic?
Not from dogs, but occasionally humans can be infected with the pathogen.
Ehrliche chaffennsis is transmitted by which tick?
Amblyomma (lone star tick, white-tailed deer tick)
Most common signs of ehrlichiosis in the dog?
Fever
Reticuloendothelial hyperplasia (generalized lymphadenomegaly and splenomegaly)
Thrombocytopenia (+/- petechia depending on severity)
Stiff gait / limb edema
Anorexia
Coughing
Ehrlichiosis is most common at what times of the year?
Warmer months
What breeds are most prone to developing chronic ehrlichiosis infections?
German Shepherds
What additional symptoms occur in cases of chronic ehrlichiosis?
Glomerulonephritis --> renal failure Weight loss Hyperglobulinemia (polyclonal) Anterior uveitis Interstitial pneumonia Meningitis
Diagnosis of ehrlichiosis?
CBC to look for thrombocytopenia
IFA titers or ELISA tests (both may be cross reactive or be indicative of previous infection)
Intracytoplasmic inclusion body (low sensitivity)
Response to treatment (return to normothermic in 24-48 hours)
Treatment of ehrlichiosis?
Doxycycline (due to good intracellular penetration and consistent sensitivity of ehrlichia)
Treat empirically before test results
Could also try tetracycline
Supportive care
Prevention of ehrlichiosis?
Tick prevention
Use only seronegative dogs for blood transfusions
Prophylactic use of low dose tetracycline in very endemic, high dog population kennels.
Do all Gila monster bites contain venom
No
What are the most serious signs of Gila monster bites?
Hypotension, pain, anaphylaxis, arrhythmias
Treatment for Gila monster bites
Supportive (pain meds, abx, fluids)
What family of snakes is the rattlesnake in?
Crotalidae
What does rattlesnake venom do?
Hemotoxic
Necrotizing
Anticoagulant
Where is the worst place to get bit by a snake?
Thorax or abdomen
When does antivenin work the best?
If administered <6 hours after a bite
But still has positive effects later
What antibiotics should be used for rattlesnake bites?
Broad spectrum (gen ampicillin or cephalosporins) for tissue necrosis
What is the main sign of black widow envenomation?
Muscle cramping and fasciculation.
Venom is a neurotoxin that depletes neurotransmitters at synaptic junctions
Treatment of black widow spider envenomation?
Antivenin is super expensive so only very severe cases Calcium gluconate Opioids Muscle relaxants \+/- diazepam
