Malaria increased in strength as the population diminished.
The climate is hot and malaria is prevalent.
The mortality from malaria in 1902 was higher than for any other part of Italy-1037 persons, or 154 per 100,000 (Basilicata, 141; Apulia, 104; Calabria, 77; Sicily, 76; province of Rome, 27).
It is subject, however, to extreme and rapid variations in temperature, to alternations of dry and humid winds (the latter, called catias, being irritating and oppressive), to chilling night mists brought up from the coast by the westerly winds, and to other influences productive of malaria, catarrh, fevers, bilious disorders and rheumatism.
Sir Patrick Manson has suggested that the problem of stamping out malaria may be assisted by the discovery of some at present unknown factors.