I believe that the prisons were tested for antibodies, not the PCR. The antibodies will naturally have some cross reactivity with other species. So there is not a lot to do about that — however the actual dx of active disease (hospital) will utilize PCR which grow the specific genetics and we have mapped CoVID 19 — which means that it is specific to this disease.
I am assuming that the prisons engaged in antibody testing, however I could be wrong and I stand to be corrected.
+1.