Dr. Murai Éva szerk.: Parasitologia Hungarica 21. (Budapest, 1988)
DISCUSSION Surveys on the prevalence of gastrointestinal nematodes of cattle and on the composition of the helminthi population have been conducted in numerous countries. The number of helminth species found varies depending on the type of study (Table 1). Mixed infection with Trichostrongylidae and members of other families is common. Our results and data of surveys conducted in the Federal Republic of Germany, Austria and Switzerland (Table 6) show that in Hungary also Ostertagia ostertagi, a nematode parasite of the abomasum, is predominant both in prevalence and intensity. Cooperia spp. (C. oncophora and C. punctata) , Trichostron gylus axei , Haemonchus contortus , and Grosspiculagia podjapolskyi, a helminth belonging to one of the subgenera of the genus Ostertagia and previously unidentified in Hungary, are also common. On the basis of prevalence and worm numbers, the other helminth species are less important in the age group studied. As regards the intensity of infection, the worm counts found indicate a very mild infection as compared to data from abroad. The cattle slaughtered and examined showed no clinical signs indicative of gastrointestinal helminthosis, therefore the infection can. be considered subclinical. Most of the 58 cattle examined were cows in the age range of 3 to 14 years. In younger, more susceptible cattle kept on pasture the intensity of infection is presumably higher. Numerous surveys conducted abroad showed that the digestive tract of cows can be colonized by a substantial helminth population. BORGSTEEDE and BURG (1982) examined abomasa from 200 cows and found an average total worm count of 3 011. Others (BARTH, BERNARD and LAMINA, 1981a, 1981b; BECK LUND, 1962) reported substantially higher average worm counts (6 836). Sometimes extremely high individual worm counts (15 260-447 212) may occur (BARTH, BERNARD and LAMINA, 1981a, 1981b; BECKLUND, 1962; BORGSTEEDE and BURG, 1982; GUTIERRES, TODD and CROWLEY, 1979). The results of helminthological analysis performed on 58 slaughter cattle directed our attention towards enzyme digestion studies. These studies have revealed that O. ostertagi is the most prevalent helminth parasite of cattle in Hungary. Previous to this study, no investigations had been made in Hungary to detect larvae inhabiting the wall of the abomasum by the enzyme digestion method, a new procedure that had not been used in Hungary earlier. So we took the first steps towards collecting data that would expand our knowledge of bovine trichostrongylidosis. In our experience the method is suitable for this purpose. The cost of digesting an abomasum is 15 to 30 Fts. As only abomasa were examined during this survey, the prevalence of 51% cannot be considered very low, considering that no data were available on the origin and managemental conditions of cattle slaughtered at the Budapest Abattoir (that is, we did not know when and how long the animals were kept on pasture or in the barn). Expprience obtained during the present study suggests that in the future wider surveys should be conducted to clarify the epidemiology of ostertagiosis in Hungary. Good examples of such surveys can be found in publications of Dutch (BORGSTEEDE and BURG, 1982), Swiss (ECKERT and BURGER, 1979) and West German (BARTH, BERNARD and LAMINA, 1981a, 1981b) authors. Results of the coprological examinations confirmed necropsy findings in that gastrointestinal helminthosis is highly prevalent in the Hungarian cattle population. The proportion of infected animals is particularly high among the younger cattle. In these animals EPG counts were also higher, indicating their higher susceptibility and greater contribution to environmental and pasture contamination. From the egg counts it seems probable that even in the more severely infected herds there is only a mild, subclinical gastrointestinal helminthosis. This assumption was confirmed by farm veterinarians reporting the absence of clinical signs indicative of gastrointestinal hel-
