by David Rethorst, DVM, Veterinary Diagnostic Lab
Historically, anaplasmosis in Kansas has been diagnosed in the counties east of and including the I-35 corridor. The 2013 Disease Trend Map from the Kansas State Veterinary Diagnostic Laboratory (KSVDL) shows that anaplasmosis was diagnosed in 37 of the 51 counties in this area and only 8 of the 54 counties west of the I-35 corridor.
In 2015, the KSVDL map revealed that cattle infected with anaplasmosis were diagnosed in 45 of the 51 eastern counties and 24 of 54 counties west of the I-35 corridor. Three of the fifteen counties west of the I-35 corridor, yet east of and including the 281 corridor, had positive cases of anaplasmosis in 2013.
Yet in 2015, cattle infected with anaplasmosis were diagnosed in 13 of the 15 counties. Are there more cases of anaplasmosis creeping west in Kansas or are our improved diagnostic tools and our awareness of the disease helping us do a better job of finding this problem in our cows? Or is it a little bit of both? With cows being routinely hauled into and out of disease endemic areas on an annual basis for summer grazing and reports of strains of Anaplasma marginale that are resistant to chlortetracycline, one can see why the prevalence is increasing in Kansas.