Meda (9) found a Iymphocyte decrease and a neutrophil and eosinophil increase in rats after a single 6-hour exposure to 100 kv/m, 50 Hz. A similar blood picture was found in mice after 500- and 1000-hour exposures to 100 kv/m (9). A significant increase in WBC was found in rabbits that had been exposed to 50 kv/m, 50 Hz, for 3 months (14). As has been the case with almost all biological indicators, the time course of the changes in blood parameters following EMF exposure was not the same in each test animal (11). Guinea pigs were exposed to 3GHz, 10 min/day, for 30 days (11), and both the irradiated and the sham-exposed animals were sampled before and after each daily exposure bout.
The sham-exposed group revealed no significant changes, but animals exposed to 25 or 50 µW/cm2 exhibited EMF-induced alterations with time dependencies that differed with each animal. For a given exposure duration, the WBC was above the normal level in some animals, and below it in others; as a result, the average values varied little during the study. At 500 µW/cm2, however, even on the average there was a pronounced leukopenia and Iymphocytosis.