. 2020 Jan 31;3(1):e1920261. doi: 10.1001/jamanetworkopen.2019.20261

Table. Human EEE Cases and 12-Month SPI From July of Each Year in Massachusetts.

Calendar Year	Regional SPI^a						Human EEE Cases, No.
Calendar Year	Western	Connecticut River	Central	Northeast	Southeast	Cape and Islands	Human EEE Cases, No.
1999^b	−0.75	−1.31	−1.26	−0.87	−0.32	−1.69	0
2000	1.56	2.07	0.89	1.20	1.24	−0.19	1
2001^b	−0.32	−0.20	−0.41	0.37	0.67	−1.18	1
2002^b	−1.27	−1.41	−1.55	−0.98	−0.96	−1.44	0
2003	0.34	0.27	0.52	0.95	1.66	1.10	0
2004	1.22	1.54	−0.003	0.58	0.04	−0.81	4
2005	0.64	0.79	1.37	1.29	0.94	0.60	4
2006	1.68	2.11	2.91	3.28	3.28	1.15	5
2007^b	0.48	0.81	0.76	0.92	0.56	0.15	0
2008	1.42	1.58	0.72	0.85	0.06	−0.22	1
2009	1.94	1.52	1.68	2.11	2.34	1.19	0
2010	−0.02	−0.58	0.42	1.57	2.32	1.28	1
2011	0.71	1.16	0.27	0.56	0.13	0.86	1
2012	1.49	1.39	1.36	1.28	0.63	0.79	7
2013	0.61	0.96	0.55	0.76	0.79	1.46	1
2014	1.17	0.61	−0.22	−0.46	−0.22	−0.87	0
2015^b	−0.30	0.02	−0.25	0.35	−0.09	−0.18	0
2016^b	−0.18	−0.92	−1.51	−1.44	−0.62	0.00	0
2017^b	0.25	−0.13	0.30	0.94	0.30	0.07	0
2018	0.86	0.42	0.50	0.15	0.08	1.55	0
2019^c	2.36	2.30	2.37	2.25	2.54	1.81	12

Abbreviations: EEE, Eastern equine encephalitis; SPI, Standard Precipitation Index.

^{^a}

The SPI is calculated for a given location based on the long-term precipitation record for the same time period. A positive SPI indicates greater than the median precipitation and a negative SPI, less than the median precipitation.

^{^b}

For all 6 regions, the SPI was lower than 1.0.

^{^c}

Data collection ended December 1, 2019.