Summary:The antibody isotype response to Trichinella spiralis excretory/secretory (ES) products of muscle larva was examined using sera from patients with confirmed trichinellosis. Using Western blots we identify components of the ES antigen that are recognized by IgM and IgG antibodies. A 45 kDa component was strongly recognized by different antibody classes and subclasses. We observed a 45 kDa-specific lgG4 response that was detected exclusively using sera of patients with trichinellosis and not of patients with echinococcosis, filariasis, cysticercosis, ascariasis, strongyloidiasis or toxocariasis. These results are relevant for the diagnosis of human trichinellosis.KEYWORDS : human trichinellosis, ES antigen, 45 kDa, lgG4.M onitoring programs for detection of trichinellosis in slaughterhouse animals have dramatically decreased the incidence of human trichinellosis. However, in many parts of the world, including Europe, it continues to occur. Recent outbreaks of trichinellosis have been reported from Germany, France, Spain and Italy (Ancelle et al, 1998;Rodriguez et al., 1999); (Pozio 1998).In our laboratory the immunodiagnosis of trichinellosis is performed by using an enzyme-linked immunosorbent assay (ELISA) in which the excretory/secretory (ES) products of Trichinella spiralis muscle larvae are used as antigen (van Knapen et al., 1982 MATERIALS AND METHODST he excretory/secretory (ES) antigen was prepared using viable muscle larva of T. spiralis as previously described by Gamble (1985). The 45 kDa antigenic component was purified from freshly obtained muscle larva using two-step affinity chromatography as described by Homan et al. (1992) SERUM SAMPLES Serum samples from trichinellosis patients recently received at our laboratory and from an outbreak of trichinellosis that took place in Slupsk, Poland in 1991 were used in this study. The patients here studied were all at an early stage of trichinellosis. All serum samples used tested positive for IgM and/or IgG by means of ELISA using T. spiralis ES antigen. Infection was confirmed for several patients from the outbreak in Poland and for the other patients used in this study by identification of Trichinella larva in muscle biopsy.The source for T. spiralis infection for the outbreak was undercooked pork. Sera from our laboratory from echinococcosis, filariasis, cysticercosis, ascariasis, strongyloidiasis or toxocariasis patients were also included. WESTERN BLOTTING PROCEDUREThe ES antigen or the 45 kDa protein was solubilized under reducing conditions and electrephorized on Parasite, 2001, 8, S168-S171 ANTIGENS S168.

A serological survey on toxoplasmosis was carried out amongst horses, sheep, cattle, pigs and poultry in the Netherlands. Sera were obtained from slaughter animals and the results were compared with those of previous studies of this kind in the Netherlands. In horses and cattle the percentage of seropositive animals remained the same in the past 20 years. In sheep and particularly in pigs, however, a remarkable decline of seropositive animals was found. This is probably due to the age of the animals examined and a change in present day methods of farming. In poultry it was shown that only free scratching hens were seropositive in up to 30 per cent of the animals tested, whereas broilers and battery animals were seronegative. Since as yet no individual control measures in the slaughterhouse exist with regard to toxoplasmosis it is recommended to carry out periodic epizootiological surveys amongst farm animals to be able to follow trends of the infection.

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