Table 1.

Factors purported to influence Ehrlichia seroprevalence in domestic dogs. For further discussion, including the source of each factor, see [18, 20]

	Factor	Data period	Scale	Notation	Numerical scale of data
Climate factors	Annual temperature	1895–2015	Climate Division	X s,1 (t)	Continuous
	Annual precipitation	1895–2015	Climate Division	X s,2 (t)
	Annual relative humidity	2006–2015	Climate Division	X s,3 (t)
Geographical factors	Elevation	2012	County	X s,4 (t)	Continuous
	Percentage forest coverage	2012	County	X s,5 (t)
	Percentage surface water coverage	2010	County	X s,6 (t)
Societal factors	Population density	2011–2014	County	X s,7 (t)	Continuous
	Median household income	1997–2014	County	X s,8 (t)