ABSTRACT
The conditioned infections due to opportunistic organisms, can be controlled by biological immunostimulators. The POLI-IF (Newcastle virus plus endotoxin of E. coli and Freund's incomplete adjuvant) rapidly induces the aspecific immunity. Given twice with 7-10 days interval in between, on occasion of a programmed stress (weaning, transport, crowding) it proved its efficacy in artificially suckled calves and in weaning piglets. The field trials, carried out on 2,782 treated calves in comparison with 2,909 untreated controls and on 4,387 piglets in comparison with 4,461 untreated controls, revealed statistically significant differences for P less than 0.005 among the groups of treated and control animals. The immunostimulator reduced the incidence of the disease, dead and discarded animals, as well as it shortened the mean duration of the disease in single heads. Though the way the POLI-IF acts is not perfectly known so far, yet it increases the serum bactericidal activity and the circulating leukocytes, while it induces high levels of IFN. In our opinion the activity of the POLI-IF is bound to 3 factors at least: activation of the complementary fractions, mobilization of the immunocompetent cells, induction of IFN.
