VT121 Pansystemic PowerPoint

VT121 Pansystemic Diseases

Terminology

  • Pansystemic: A disease that affects all body systems.
  • FeLV: Feline Leukemia Virus.
  • FIV: Feline Immunodeficiency Virus.
  • FIP: Feline Infectious Peritonitis.
  • Panleukopenia: A decrease of all types of white blood cells (WBCs) in blood.
  • Retrovirus: An RNA virus that inserts a DNA copy of its genome into the host cell in order to replicate.
  • Parvovirus: A small, species-specific virus capable of self-replication.
  • Erythropoietin: A hormone produced by the kidneys that stimulates red blood cell (RBC) production in the bone marrow.

Pansystemic Diseases Covered in This Lesson

  • Feline Leukemia Virus (FeLV)
  • Feline Immunodeficiency Virus (FIV)
  • Feline Infectious Peritonitis (FIP)
  • Feline Panleukopenia
  • Toxoplasmosis
  • Canine Distemper Virus (CDV)
  • Canine Parvovirus (CPV)
  • Rickettsial infections
  • Rabies

Feline Leukemia Virus (FeLV)

  • Overview:
    • FeLV is a retrovirus that destroys white blood cells and the immune system.
    • It is unstable in the environment and spreads both vertically (from queen to kitten) and horizontally (from cat to cat).
    • Transmission occurs through body fluids such as grooming, bite wounds, feces, etc.
    • FeLV tends to be most severe in young animals; older cats develop a natural resistance.

Possible Outcomes of Infection

  • Rapid-onset death—common in neonates and very young cats.
  • Development of bone marrow suppression, leading to death related to anemia or secondary infections.
  • Virus-induced lymphoma.
  • Nothing—some cats clear the virus completely, while others remain positive but never succumb to the disease.

Clinical Signs

  • Signs are variable based on which organs are affected.
  • Chronic debilitating diseases should be tested for FeLV.
  • Common clinical signs include:
    • Weight loss
    • Fever
    • Chronic infections
    • Gastrointestinal signs

Diagnosis

  • Point-of-care testing (ELISA/SNAP/Witness).
  • Cats may be transiently affected and can clear the virus.
  • Real-time PCR tests at a diagnostic lab.
  • Complete Blood Count (CBC) showing bone marrow suppression (anemia/leukopenia).
  • Biopsy with histopathology for lymphoma diagnosis.

Treatment

  • Chemotherapy for lymphoma.
  • Management of bone marrow suppression may require:
    • Blood transfusions.
    • Erythropoietin.
    • Granulocyte-stimulating factor.
    • Antibiotics for secondary infections.
    • +/- Antiviral and immunomodulatory medications.
    • Nursing care.

Preventing Transmission/Infection

  • Vaccination is especially important for young, breeding, and high-risk outdoor cats.
  • Keep naive cats and positive cats indoors and housed apart from other cats.

Feline Immunodeficiency Virus (FIV)

  • Overview:
    • FIV is a retrovirus, also referred to as Feline Acquired ImmunoDeficiency Syndrome (AIDS).
    • Predominantly affects adult outdoor male cats.

Transmission

  • The virus is shed in saliva and transmitted through bite wounds.
  • Queens can transmit the virus to her kittens both during pregnancy and through milk.
  • Transmission can also occur via blood transfusions.

Possible Outcomes of Infection

  • Impairs the immune system by destroying T-cells, leading to severe illness from simple infections, +/- death.
  • Development of bone marrow suppression and death related to anemia.
  • Some infected animals may live completely normal, healthy lives.

Diagnosis

  • Point-of-care testing (ELISA/SNAP/Witness).
  • Maternal antibodies may result in transient positive test results.
  • Real-time PCR tests.
  • CBC showing signs of bone marrow suppression.

Managing the Disease

  • There is no cure for FIV.
  • If bone marrow suppression occurs, treatments may include:
    • Blood transfusions.
    • Erythropoietin to stimulate RBC production.
    • Granulocyte-stimulating factor for neutrophil production.
    • Antibiotics for secondary infections.
    • Antiviral and immunomodulatory medications may be employed.

Preventing Transmission/Infection

  • Keep FIV positive and healthy cats indoors.
  • Recommended spaying/neutering to prevent wandering and fighting.
  • The vaccine is no longer available due to limited protection and increased risk of sarcomas.

Feline Infectious Peritonitis (FIP)

  • Overview:
    • FIP is the mutated form of the feline coronavirus (FECV or FCoV).
    • FCoV is common, with 90% of all cats testing positive.
    • Mutation leads to the virus leaving the intestinal tract and infiltrating the body; only a small percentage of cats with FCoV develop FIP.
    • An animal with FIP does NOT transmit it; the virus must mutate within an individual cat.

Possible Outcomes of Infection

  • Wet Form:
    • Severe vasculitis, leading to effusion (fluid accumulation) in the abdominal or thoracic cavities.
  • Dry Form:
    • Granulomas and inflammation in tissues (e.g., eyes, central nervous system).
  • Nothing—some cats may have dormant FIP infections.

Diagnosis

  • Difficult to diagnose due to the absence of a simple test.
  • New tests under development at Colorado State University include:
    • Fluid analysis (if fluid is present).
    • PCR on effusion.
    • Bloodwork abnormalities such as elevated total protein due to globulin elevation.
    • Histopathology and lymph node biopsies; tissues show vasculitis with pyogranulomatous lesions.

Treatment

  • Currently, there is no cure. Most animals showing clinical signs typically die despite therapy.
  • New antiviral drugs like Mutian from China are promising but not yet approved in the US.

Prevention

  • Due to widespread FCoV, it’s nearly impossible to prevent infection.
  • Breeding only negative cats is recommended.
  • Current intranasal FIP vaccine is not recommended due to clinical ineffectiveness; ongoing research for new vaccines is needed.

Feline Panleukopenia

  • Overview:
    • Caused by the feline parvovirus.
    • High morbidity and mortality rates in infected cats; kittens are most susceptible.
    • Attacks rapidly dividing cells found in the bone marrow and gastrointestinal tract.

Transmission

  • Spread through feces, urine, and blood, with high environmental persistence.
  • Fomite spread is common.

Possible Outcomes of Infection

  • Sudden death in kittens.
  • Clinical signs include:
    • Vomiting, diarrhea, fever, lethargy, anemia.
    • Leukopenia and thrombocytopenia.
    • Possible shock or recovery (more likely in adults).
    • Nothing in well-vaccinated adult cats.

Diagnosis

  • Point-of-care testing (canine parvovirus SNAP/Witness test).
  • Clinical signs observation.
  • Bloodwork shows panleukopenia, thrombocytopenia, and sometimes mild anemia.

Treatment

  • Supportive care including:
    • Crystalloid and colloid fluids.
    • Broad-spectrum antibiotics against secondary infections.
    • Anti-nausea medication.
    • Pain control and strict hygiene to prevent exposure.
    • Isolation from other cats.

Prevention

  • Vaccination for kittens, breeding queens, and adult cats.
  • Isolation of infected animals and practicing good hygiene/disinfection in multi-cat settings.

Toxoplasmosis

  • Overview:
    • A protozoal disease affecting cats of all ages.

Transmission

  • Cats are the definitive hosts and the only animal that sheds oocysts.
  • Cats contract the disease by eating raw meat, ingesting infected prey, or maternal transmission between queens and their kittens.

Possible Outcomes of Infection

  • Silent infection (no clinical signs) is most common.
  • Death in neonatal kittens due to utero exposure.
  • Disease can affect multiple organ systems with varying clinical signs depending on the affected systems.
  • Dormant infections can recur due to stress, cancer, viral infections, or immunosuppressive drugs without re-shedding organisms.

Diagnosis

  • Fecal test: for identifying oocysts in stool samples.
  • Antibody titers in serum, CSF, or aqueous humor.
  • Cytology demonstrating tachyzoites or bradyzoites in affected fluids or tissue samples.

Treatment

  • Antibiotics: Clindamycin, Trimethoprim Sulfonamide, or Azithromycin.
  • Supportive care:
    • Fluid support with electrolyte balance.
    • Seizure control if necessary.
    • Anti-inflammatory therapy for uveitis.
    • Pain control for myositis or pancreatitis.
    • Liver support supplements and draining of effusions.
    • Oxygen therapy for respiratory involvement and heart failure treatment if present.

Prevention of Feline Infections

  • Prevent cats from hunting and control rodent populations.
  • Avoid feeding raw foods to cats.

Preventing Human Infections

  • Excellent daily litter box hygiene.
  • Hand washing and thorough washing of vegetables.
  • Cooking foods thoroughly and avoiding unpasteurized milk.
  • Maintain excellent kitchen hygiene and wear gloves while gardening.

Canine Distemper Virus (CDV)

  • Overview:
    • A deadly disease affecting many carnivorous animals.

Transmission

  • Spread through bodily fluids (urine, feces, vomit) and respiratory secretions via inspiration or oral ingestion.
  • Fomite transmission is common.

Possible Outcomes of Infection

  • Predisposed in puppies.
  • Severe infections include:
    • Epithelial and neurologic involvement.
    • Clinical signs: vomiting, diarrhea, pneumonia, dermatologic changes, neurologic changes, and potential death or recovery with persistent signs.
  • Prognosis is poor with severe neurologic signs; mild infections more likely in animals with some immunity prior to exposure.

Diagnosis

  • Based on clinical signs and WBC inclusions.
  • PCR test or immunofluorescent antibody testing.
  • IgM and IgG titers can be difficult to interpret if previously vaccinated and are best done in pairs several weeks apart.

Treatment

  • Primarily supportive care:
    • Correcting fluid and electrolyte imbalances.
    • Appropriate nutrition.
    • Antibiotics for secondary infections.
    • Acknowledge that some patients may not survive regardless of aggressive treatment.

Prevention

  • Vaccination at appropriate age and intervals.
  • Maintain excellent hygiene to prevent fomite transmission.
  • Isolate affected dogs and avoid overcrowding/stressful environments.

Canine Parvovirus (CPV)

  • Overview:
    • A highly contagious and deadly virus affecting dogs.

Transmission

  • Fecal-oral spread through diarrhea, vomit, contaminated environments, or fomites.
  • The virus can persist in the environment for years, making it highly contagious.

Possible Outcomes of Infection

  • Most likely to die are young, poorly vaccinated puppies.
  • Symptoms may include:
    • Anorexia, vomiting, diarrhea, destruction of intestinal lining, and bone marrow suppression with leukopenia and anemia.
    • Outcomes range from death or recovery, and moderate clinical illness depending on severity.

Diagnosis

  • Point-of-care ELISA test (SNAP/Witness).
  • PCR tests may be utilized if CPV is suspected despite negative ELISA test results.
  • CBC showing signs of bone marrow suppression.

Treatment

  • IV fluids (crystalloids +/- colloids) for dehydration and electrolyte balance.
  • Broad-spectrum antibiotics for secondary infections.
  • Administer anti-nausea medications and prokinetics.
  • Provide nutrition, possibly via NG tube if unable to eat.
  • Nursing care and isolation of infected puppies are critical.

Prevention

  • Vaccination at appropriate age and intervals.
  • Keep puppies in safe environments until fully vaccinated.
  • Effective disinfection with products like dilute bleach or potassium peroxymonosulfate is essential.

Rickettsial Diseases

  • Overview:
    • Bacterial infections transmitted through ticks, prevalence varies geographically.
    • Travel history may be relevant in diagnosis and treatment planning.

Transmission

  • Rocky Mountain Spotted Fever (RMSF): spread by Dermacentor ticks.
  • Ehrlichiosis: spread by Rhipicephalus sanguineus and Dermacentor variabilis.
  • Anaplasmosis: spread by Ixodes ticks.
  • Lyme Disease: also spread by Ixodes ticks where Borrelia burgdorferi is the causative agent.

Possible Outcomes of Infection

  • Infection can be subclinical or clinical with significant damage:
    • RMSF and Ehrlichiosis cause vasculitis and bleeding.
    • Common symptoms include rash, fever, polyarthritis, lymphadenitis, and nephritis.
    • All major organs can be adversely affected, and patients may experience chronic infections without immunity post-infection.

Diagnosis

  • Based on clinical signs with a history of tick exposure or geographical location.
  • Identification of morulae in white cells on buffy coat smear evaluation.
  • Point-of-care SNAP testing for antibodies.
  • Titer testing and PCR testing for confirmation.
  • Chemistry and CBC results can vary based on affected organs.

Treatment

  • Immediate tick removal is crucial.
  • Tetracyclines, particularly doxycycline, are the most commonly used antibiotics.
  • Anti-inflammatories (NSAIDs or steroids, but never both simultaneously) and supportive care are also provided as needed.

Prevention

  • Keep pets away from tick-infested areas and promptly remove any ticks.
  • Consistent use of flea and tick prevention products such as:
    • Simparica, Bravecto, Nexgard (all oral).
    • Frontline Plus, Advantix (topical).
    • Seresto and Preventic (collars).

Rabies

  • Overview:
    • Rabies is a highly contagious and lethal virus that can infect any mammal, including humans.

Transmission

  • Infection occurs through contact with the saliva or central nervous system (CNS) tissues from infected animals.
  • The virus affects wildlife such as skunks, raccoons, foxes, bats, and domestic/agricultural animals including dogs, cats, ferrets, and farm animals like horses and cows.

Possible Outcomes of Infection

  • Humans vaccinated prior to the onset of clinical signs typically remain unharmed; however, rabies is usually fatal once clinical signs are observed.
  • Clinical disease can manifest as unusual behavior (aggression or depression) and paralysis.

Diagnosis

  • Submit the brain to a qualified laboratory for examination.
  • Refrigerate the samples and submit the entire body or head for harvest.
  • Diagnostic labs perform direct fluorescent antibody tests on multiple areas of brain tissue to confirm rabies.

Human Treatment

  • Treatment consists of post-exposure prophylaxis (PEP) which includes:
    • Immediate washing of the exposure site for 15 minutes.
    • Rinsing mouth or flushing eyes if exposure involves mucous membranes.
    • Infusion of rabies antibodies and administering a series of rabies vaccinations depending on the patient's vaccination status.

Animal Treatment

  • No effective treatment for animals once rabies is suspected.
  • Suspected wildlife, agricultural animals, or unvaccinated pets should be euthanized and submitted for testing.
  • Booster vaccines are recommended for vaccinated pets that encounter known or suspected rabid animals.

Prevention

  • Regular vaccination of domestic species.
  • Vaccination efforts for vector wildlife.
  • Wildlife vector control and vaccination for individuals who handle wildlife or domestic species frequently.
    • Flavored rabies vaccines are air-dropped for wildlife in endemic areas.

Quarantine

  • Quarantine protocols vary by county; general guidelines include:
    • 10-day quarantine for pets that bite humans.
    • 45-day quarantine for vaccinated animals exposed to potentially rabid animals.
    • 6-month quarantine for unvaccinated pets that encounter rabid animals, potentially leading to euthanasia depending on circumstances.