41.   At Oxford he intends to study mathematical biology, which tries to create models to explain and predict the way diseases spread or populations grow.

42.   A new disease spreads widely in part because of careless public health, Heymann says.

43.   All borders were put on heightened alert, and Veneman issued statements saying that the disease would not spread here.

44.   Agricultural societies dependent on one crop were more prone to bad health caused by crop failures or diseases spread by pests that thrive in grain stores and sedentary populations.

45.   But because most developing nations cannot afford the drugs, the disease is spreading in the Third World.

46.   But disease may spread before anyone realizes a child is sick.

47.   But if the body is weak, the disease spreads.

48.   But many trees are grown on large plantations and can be wiped out quickly if a disease spreads.

49.   By the time she learned she had ovarian cancer, the disease had spread to her internal organs and filled a lung with fluid.

50.   Could the disease be spreading from cows to people?