Theileria

Theileria parva Life Cycle Diagram - Dennis Jacobs & Mark Fox RVC

File:Lymph node smear East Coast Fever.jpg

Lymph node smear of a cow with East Coast Fever - Drs. Elizabeth Howerth and Bruce LeRoy, Department of Pathology, UGA College of Veterinary Medicine

File:H and E stain brain East Coast Fever.jpg

H and E stain of brain and meningal vessels of a cow with East Coast Fever - Drs. Elizabeth Howerth and Bruce LeRoy, Department of Pathology, UGA College of Veterinary Medicine

Theileria cervi (deer) - Drs. Elizabeth Howerth and Bruce LeRoy, Department of Pathology, UGA College of Veterinary Medicine

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• Main species of veterinary importance is Theileria parva
  • Causes East Coast Fever
    • Severe, proliferative lymphatic disease of cattle
    • Central and Eastern Africa
    • Transmitted by Rhipicephalus appendiculatus
    • Trans-stadial transmission

• Other Theileria species cause production losses in cattle and sheep in the Middle East, Mediterranean and in Northern Africa

Life Cycle

• Incubation phase lasts 1 week

• Lymphoblast proliferation
  • Local lymph node first infected then spreads through body
  • Occurs in week two

• Lymphoid depletion
  • Lymphocytes killed
  • Decreases lymphopoiesis
  • Occurs in week 3

• Total incubation period takes about 18 days

Diagnosis

• Clinical signs
  • Pyrexia
  • Enlarged local lymph node
    • Usually parotid lymph node as Rhipicephalus appendiculatus feeds in the ear
  • Loss of condition

• Examine Giemsa stained smears of:
  • Local lymph node aspirated for schizonts
  • Blood smears for piroplasms in red blood cells

• Post-mortem
  • Pulmonary oedema
  • Gut mucosal haemorrhages
  • Lymph node and splenic cellular atrophy

Control

• Integrated control of both the tick vector and disease
  • Vaccination and Ectoparasiticides

• Current vaccination is live unattentuated
  • Contains frozen stabilate of ground up tick gut containing infective sporozoites
  • Long lasting oxytetracycline administered at the same time to slow down schizogony giving the immune response time to develop

Theileria equi (formerly Babesia equi) and Babesia caballi cause babesiosis in horses

Theileriosis - Cattle

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