The aim of this study was to evaluate the activity of kidney phagocytes after immunization of fish with inactivated bacteria of Aeromonas hydrophila and to determine the location and permanence of the bacterial antigen in the lymphoid organs, the kidney and the spleen, of carps immunized intraperitoneally (group I) and by immersion (group II) at 12°C. We examined the absorption of bacteria by kidney leucocytes (PK%), the killing capacity of phagocytes (IB) and chemiluminescent activity (CL). Evaluations were performed 12 h, as well as 3, 7, 14 and 28 days after immunization. At all these time points, the values of the parameters examined were higher in fish immunized intraperitoneally than in those immunized by immersion. The absorption of bacterial cells by kidney phagocytes was particularly high after 14 days after immunization in fish group I whereas their killing and chemiluminescent activity was particularly high in 7 days after immunization in group I. Immunohistochemical examination revealed an extensive distribution and large amounts of the antigen in the interstitial part and melanomacrophage centers of the kidneys and spleen after the intraperitoneal administration of the antigen, By contrast, small amounts of the antigen were found in these organs after it had been administered by immersion.
We analysed 251 early spring and winter storage honey samples, individually collected from the apiaries of 9 districts of Małopolska province in South Poland and revealed that 51 of these specimens were contaminated with different levels of P. larvae larvae spores Among these samples 8.8% were classified as a category I contamination and 11.5% as a category II - reperesenting 22 (43.1%) and 29 (56.9%) of the total positives, respectively. We conclude from these analyses that: (1) - the total number of new outbreaks of AFB in Poland are most likely to be higher than previously reported, (2) - the quantitative examination of samples of winter stored or early spring honeys for the presence of P. larvae .larvae spores can improve the detection rate of AFB outbreaks, (3) - the high percentage of apiaries that were found to be free of P. larvae larvae (80%) may facilitate the implementation of an AFB eradication programme on a large scale in Poland.