Table 1.

Sets of predictors in different models.

Models	Incidence	Squared incidence	Climatic variables	Monthly effect
1	√	.	.	.
2	√	√	.	.
3	√	.	√	.
4	√	.	.	√
5	√	√	√	.
6	√	√	.	√
7	√	.	√	√
8	√	√	√	√