sick of = taken with. Greek. sunecho. See Luk_4:38.
a fever = fevers. Greek. puretos. Elsewhere Mat_8:15. Mar_1:31. Luk_4:38, Luk_4:39. Joh_4:52. Always in singular. But found in plural in medical works. Perhaps to convey the idea of severity which is expressed by "great" in Luk_4:38. or of their recurrence bloody flux. Greek. duaenteria. Hence Engl, dysentery. Only here