Chicken pox is a contagious, vaccine-preventable infection by the varicella zoster virus. It causes an itchy, red, lumpy rash and is common in children.
Pleural effusion is a lung disease in which fluid accumulates in the pleura, two ballon-like linings which surround and separate the lungs from the heart.
Acute lymphoblastic leukaemia is the most common childhood cancer. It affects stem cells in bone marrow (lymphoblasts) which mature into blood vessels.