No abstract

Serological surveys of the prevalence of antibodies against Toxoplasma gondii were carried out amongst swine and cattle in the Netherlands. Data were analysed according to the different categories of animals. The results show very low seroprevalences of Toxoplasma gondii in finishing pigs (1.8%) and in fattening calves (1.2%). In sows and dairy cattle, respectively, seroprevalences of 30.9% and 27.9% respectively, were found, demonstrating clearly the environmental infection pressure and illustrating the importance of housing and management in establishing low infection rates. Substantially different seroprevalences were found between dairy cattle sampled in the North and in the South of the Netherlands (13.1% and 42.6%, respectively). The infection rates in the samples from finishing pigs, fattening calves, and dairy cattle demonstrate that seroprevalences in individual farms or herds may differ considerably. Investigation of the factors involved can be useful in determining the causes of infection and for developing measures with regard to prevention. The very low seroprevalences in finishing pigs and fattening calves indicate, however, that the production of toxoplasma-free meat may be well within reach in modern husbandry. Since farm animals easily are infected, serological screening of individual farms or herds for the absence of T. gondii infection, as a part of the Integrated Quality Control programme, can be helpful in determining the quality of livestock production and in developing certain standards of hygiene for individual farms.

An enzyme-linked immunosorbent assay is described for the detection of serum antibodies to visceral larva migrans (Toxocariasis). Excretory-secretory antigens of the second-stage larvae of Toxocara canis were used as antigen to coat the polystyrene plates. With sera from patients high antibody titers were observed in both ocular and visceral disorders. Cross-reactions due to other parasitic infections could be excluded, including other migrating larval infections such as ascariasis, trichinellosis, strongyloidiasis, filariasis, and anisakiasis. In a small seroepidemiologic survey of healthy primary schoolchildren, a remarkably high percentage (7.1) reacted positively to this method. These children showed eosinophilia as compared to the seronegative group. The data were compared with those observed in other countries and the results prompt reconsideration of the significance of T. canis for public health.

No abstract

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.