Rickettsial Diseases

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Rickettsial Diseases

• 4-H Veterinary Science
• Extension Veterinary Medicine
• Texas AgriLife Extension Service
• College of Veterinary Medicine and Biomedical
  Sciences
• Texas AM System
• http//aevm.tamu.edu

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Objectives

• Discuss arthropod transmission of rickettsiae
• Describe a rickettsial disease of cattle
• Decribe a rickettsial disease of swine
• Describe a rickettsial disease of horses
• Describe two rickettsial diseases of dogs

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Review

• Infectious diseases
• Bacterial diseases
• Viral diseases
• Fungal diseases
• Parasitic diseases
• Rickettsial diseases

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• Infectious -

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Rickettsiae

• Definition
• A genus of small, rod-shaped, round to
  pleomorphic microorganisms in the order
  Rickettsiales. They are true bacteria,
  gram-negative, and cultivable only in living
  tissues. Transmitted by lice and ticks, they
  cause disease in humans and domestic animals but
  are also found in the cytoplasm of tissue cells
  of lice, fleas, ticks and mites, which may act as
  reservoirs and vectors

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• Symptoms
• Fever
• Anemia
• Edema
• Icterus (jaundice)
• Hemorrhages of mucous membranes
• Enlarged spleen
• Death

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• Acute
• Young animals
• Summer during vector season
• Chronic
• Older animals
• Stressful events

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• Transmission
• Biological
• Examples
• Ticks
• Sucking lice
• Live inside arthropods for months
• Mechanical
• Examples
• Biting flies
• Instruments
• Blood transfusions
• Live short time outside of host

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Types
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• Anaplasmosis (Gall sickness)
• Affects ruminants
• Transmission
• Mechanical
• Horseflies
• Deerflies
• Instruments
• Ticks
• Non-contagious
• Treatable
• Prevention
• Vaccinate
• Biosecurity

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• Eperythrozoonosis (Epe)
• Affects swine
• Transmission
• Mechanical and biological
• Sucking lice
• Instruments
• Prevention is best treatment

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• Ehrilichiosis (Tick fever)
• Affects
• Dogs
• Transmission
• Brown dog tick
• Instruments
• Blood transfusion

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• Rocky mountain spotted fever
• Affects
• Dogs
• Transmission
• American god tick
• Instruments
• Blood transfusion

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• Ehrlichiosis
• Affects
• Horses
• Transmission
• Unknown

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Diagnosis

• Blood smears
• Anaplasma
• Eperythrozoon
• Ehrlichia rickettsial
• Serological
• Rocky mountains spotted fever