Leukaemia:

• It is malignant state of leucopoietic disorder characterized by leucoproliferative changes in bone marrow along with appearance of abnormal premature leukocytes in peripheral circulation.
• It is typically known as “blood cancer”.
• It is recorded in dog, cat, pig, horse, cattle and sheep.
• Lymphoma is common in large animals.
• Bovine leukemia/ lymphosarcoma occurs as 4 distinct clinical case in cattle:
  • Juvenile multicentric lymphosarcoma: It occurs at birth or in early life. It is multicentric and commonly involves bone marrow and lymph nodes.
  • Thymic lymphosarcoma: It develops in cattle from 3 months to 2 years of age. It involves thymus, occasionally spreads to other lymph nodes and rarely infiltrates other organs.
  • Cutaneous lymphosarcoma: It occurs primarily in cattle of 1-3 years of age.
  • Adult multicentric lymphosarcoma: Bovine viral leukosis

Etiology:

• Genetic factor
• Viral causes is possible
• Chemical exposure
• Excessive exposure to radiation

Types of Leukaemia:

Based on clinical findings and immature cells, leukaemia can be classified into 2 types:

1. Acute leukaemia:

• It causes a high production of immature blood cells that cannot function properly.
• There are predominant blast cells in blood and bone marrow.
• It is typically accompanied by severe symptoms.

2. Chronic leukaemia:

• It progresses slowly and steadily overtime.
• Blood cells in chronic leukaemia are fully mature and can perform their normal function but not as well.

Based on total WBC count, leukaemia can be classified into 2 types:

1. Leukaemic leukaemia:

• In this type of leukaemia, count of WBC is more than 15000/c mm.
• There are plenty of premature leucocytes in blood.

2. Aleukaemic leukaemia:

• There are moderate to few numbers of premature cells in blood.

Based on point of origin, leukaemia can be classified as:

1. Myelogenous leukaemia:

• These leukaemia are originated from myeloid cells in bone marrow.
• It is less common in dog and cat.

2. Lymphocytic leukaemia:

• These leukaemia originates from lymphoid tissues and affects lymphoid organ or cells.
• It is more common in dog and cats.

Clinical Signs:

• Enlargement of superficial lymph nodes
• Weakness and depression
• Anorexia and vomiting
• Thirst and polyuria
• Dyspnoea and coughing
• Ocular and nasal discharge
• Unilateral or bilateral bulging of eyes
• Jaundice and ascites
• Anemia
• Tendency to bleed easily or nose bleeding
• Chronic leukaemia as progress slowly donot show any typical signs. They are picked up at routine veterinary examinations or during investigation for something completely unrelated.
• Fall of milk yield in cattle
• Abomasal ulceration and haemorrhage
• Enlarged thymus or thoracic lymph nodes
• Posterior paresis

Diagnosis:

• Based on clinical findings
• Blood examination; CBC, blood smear examination
• Bone marrow examination

Treatment:

• No specific treatment is available to this disease. Treatment principles for this disease is to expand life of animal and improve life quality of affected animals.
• Supportive care should be given such as fluid therapy to replenish fluid lost, administering antibiotics, supplementing animal’s body with blood components and feeding them well-balanced and healthy diet.
• Chemotherapy or immunotherapy or combination of both. Drugs like prednisolone, methotrexate, chlorambucicyclophosphamide has found to be effective. These medicine are usually given in oral form and in severe cases parenteral injection is given.
• Repeated blood transfusion is required.