Histopathological and histoenzymatic studies on experimental Taenia saginata cysticercosis

In young Taenia saginata cysticerci the reactions for alkaline phosphatase (AlPh), acid phosphatase (AcPh), ATP-ases, succinic dehydrogenase (SDH) and lacto dehydrogenase (LDH) were mild. The reactions were concentrated in the walls of spiral canals (AlPh, SDH) and in the outer layer of the bladder (AlPh). The reactions were more intensive in older cysticerci. In these, the reaction of AlPh marked a network of blood vessels winding around the larva. In dying cysticerci the reactions for oxidative enzymes (SDH, LDH) were weaker but the activity of the hydrolytic enzymes (AlPh, AcPh) was increased. These findings suggest that histoenzymatic reactions may be helpful in determining the viability and the age of cysticerci. T. saginata cysticerci in sheep and goats provoked an early and intensive cellular reaction. The histopathological appearance of the cysticerci as they were destroyed in the abnormal hosts was similar to that of cysticerci localized in abnormal tissue of the natural host (e.g., lung of calves). Treatment with mebendazole caused an intensive infiltrative reaction against dying cysticerci and a degenerative process in the surrounding muscle tissue. The treatment with praziquantel provoked a weak infiltration around dead cysticerci and did not affect the muscle tissue. In both cases the remnants of T. saginata cysticerci disappeared very slowly.     

Changes of eel exploitation in Polish lakes

The paper discusses briefly eel exploitation and traditional methods of catching eel. Attention is drawn to changes taking place in eel exploitation in Polish lakes, and to their causes. Most effective methods of eel catching are reviewed. It is pointed out that utilization of active fishing gear, mainly seine nets and electric aggregates, creates significant possibilities of increasing eel catches. Eel yields up to 40 kg/ha are not unusual with this type of gear. Furthermore, active fishing gear is more effective and can be used also in lakes in which it is difficult to apply traditional eel traps. The latter fact is of special significance in view of the increasing number of lakes stocked with eel, and improvement of eel stocking effectiveness.