Fig. 7.2. Granulopoietic reaction in infected rabbits exposed to an EMF.
A 200 gauss, 50 Hz EMF also altered the natural resistance to infection (19). Following EMF
exposure, mice were injected intraperitoneally with various concentrations of Listeria. The initial cell
concentration required to kill half the animals was about one-fifth of that which produced the same
killing effect in the controls. Additionally, the exposed animals exhibited more extensive bacterial
growth in the Iymph nodes, liver, and spleen, and the phagocytic activity of their blood cells was
decreased.
There are several reports of altered phagocytic capability in animals exposed to high-frequency
EMFs (21-24). When rats were exposed intermittently over a 6-month period to a pulsed EMF it was
reported that neutrophil phagocytic activity and blood-plasma bacteriocidal activity (determined using
agar cultures of E. coli) were both decreased (21). Similar results were seen following the exposure of
rats to 100 and 2250 v/m, at 14.88 MHz (22): at both field strengths, there was a marked increase in
phagocytic activity of the neutrophils during the first month's exposure followed by a prolonged period
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