Is it farther or further?
xenodiagnosis xen·o·di·ag·no·sis (zěn'ə-dī'əg-nō'sĭs, zē'nə-)
n. pl. xen·o·di·ag·no·ses (-sēz)
Diagnosis of an infectious disease at an early stage by exposing a presumably infected individual or tissue to a clean, laboratory-bred mosquito, tick, or other vector and, following a suitable incubation period, examining the vector for the presence of the infective microorganism.