Perhaps the most difficult thing to come to terms with is the scale of death. Influenza, for example, is an affliction which you no doubt have come across. However, you have never encountered anything like Elizabe­than flu. It arrives in December 1557 and lasts for eighteen months. In the ten-month period August 1558 to May 1559 the annual death rate almost trebles to 7.2 percent (normally it is 2.5 percent). More than 150,000 people die from it—5 percent of the population. This is proportionally much worse than the great influenza pandemic of 1918–19 (0.53 percent mortality). Another familiar disease is malaria, which Elizabethans refer to as ague or fever. You might associate this with more tropical countries of the modern world but in marshy areas in sixteenth-century England, such as the Lincolnshire and Cambridgeshire Fens, the Norfolk Broads, and Romney Marsh in Kent, it kills thousands.

–The Time Traveler's Guide to Elizabethan England,
Ian Mortimer

What is the central idea of this passage?

Large numbers of Elizabethans died from illness and disease.
Elizabethans easily recovered from the spread of influenza.
Elizabethan influenza was much like the influenza of today.
Malaria was one disease that Elizabethans faced.