Pliny Natural History, Vol. VI (Loeb Latin-English)

...confused if I translate opisthotonus as "opisthotonic tetanus" and any of the breathing complaints as "asthma."

It is curious that Pliny makes so few references to the common cold. Gravedo (head cold), according to Jan's Index, occurs 4 times, and destillatio (catarrh) 17 times. Of these, some (e.g., XX. 122) refer to catarrh, not of the throat and nose, but of the stomach. It may be that in ancient times, catarrhs were less troublesome than today, if not absolutely, at least in comparison with other minor ailments.

The medical historian feels more confident when discussing the meaning of febris (fever). This is sometimes just a symptom—high temperature—that accompanies many serious illnesses. It can also denote, not a mere symptom, but a disease, and then it is almost always malaria that is meant. As has been said, the common infectious fevers of modern times cannot be identified with any described by the ancient medical writers, but malaria can be diagnosed with ease and certainty owing to its periodicity, its habitat, its seasonal epidemics, and its effect upon the spleen.

Quartana febris (quartan ague), with attacks after intervals of two days;
tertiana febris (tertian ague), with attacks every other day;
cottidiana febris (quotidian ague), with attacks every day.

There were also, besides these intermittent fevers, remittent or sub-continuous forms, which were much more serious. Pliny does not mention the original: "καῦσος" (kausos, or burning fever) and original: "ἡμιτριταῖος" (hemitritaios, or semi-tertian fever) which Hippocrates and Galen deal with.