Table 1.

The extent of favorability of meteorological conditions for autochthonous transmission of malaria.

Index of Favorability of Thermal Conditions (Kf)	Transmission	Epidemiological Outcomes when an Imported Case Appears
<0.5	No transmission	Occurrence of secondary (introduced) cases is impossible.
0.5–1	Unfavorable (shortened) season, a sporadic transmission	Occurrence of a few introduced cases is possible; however, these would not produce a new generation of tertiary cases.
≥1	Favorable season, an established transmission	In addition to a few introduced cases at the beginning of the season, a second generation of tertiary cases may appear (indigenous cases), thus producing an epidemic.