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Table 1 Factors purported to influence heartworm prevalence

From: Forecasting United States heartworm Dirofilaria immitis prevalence in dogs

  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)
Geographic 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)
Mosquito species Aedes aegypti 2008 County X s,9(t) X s,k  = 1 if present, and X s,k  = 0 otherwise
Aedes albopictus 2012 County X s,10(t)
Aedes canadensis 2004 County X s,11(t)
Aedes sierrensis 2004 County X s,12(t)
Aedes trivittatus 2004 County X s,13(t)
Anopheles punctipennis 2004 County X s,14(t)
Anopheles quadrimaculatus 2004 County X s,15(t)
Culex quinquefasciatus 2004 County X s,16(t)
  1. For further discussion, including the source of each factor, see [16]