From: Key factors influencing canine heartworm, Dirofilaria immitis, in the United States
1 | Vector presence (+) |
2 | HDU (calculated from weather with a 14°C threshold) (±) |
3 | Lagged weather (7 months to 24 months prior to diagnosis) |
 |   a. Precipitation, temperature, and or relative humidity (±) |
 |   b. Moisture Index (Precipitation and Evaporation) (±) |
4 | Presence of coyote and feral dog populations – categorical data (+) |
5 | Human population density (+) |
6 | Land cover (Dominant type or Percentage classification) (±) |
7 | Cropland (Dominant type or Percentage classification) (±) |
8 | Social economic status (±) |
 |   a. Household income (-) |
 |   b. Education (-) |
 |   c. Foreclosure rates (+) |
9 | Irrigation (±) |