Figure 1From: Canine infection with Dirofilaria immitis, Borrelia burgdorferi, Anaplasma spp., and Ehrlichia spp. in the United States, 2010–2012Evidence of antigen to Dirofilaria immitis in dogs by county, grouped according to percent positive tests. No results (<30) were received from counties shaded gray, precluding interpretation of the presence of antigen in dogs from these areas. Counties depicted in white had no dogs reported as positive (0%). Remaining counties were coded as follows: 0.1-2.0% (light pink), 2.1-4.0% (pink), 4.1-6.0% (red), and > 6.0% (dark red).Back to article page