Dr. Murai Éva szerk.: Parasitologia Hungarica 25. (Budapest, 1992)

In harmony with the above facts, the objective of our study was to survey the prevalence of nematode infections in the given zoo population of bison, llama and Hungarian Grey cattle, and then to study the efficacy and mode of action of a nematocidal preparation successfully used in domestic ruminants. Review of common nematode species of bison and llamas According to data of the literature (Wade et al. 1979, Boever 1986, Tessaro 1989, Drozdz et al. 1989), members of the genera Trichostrongylus, Cooperia, Ostertagia and Haemonchus are the most prevalent in bison and llamas (see Table 1). Tessaro (1989) reviewed those infectious, parasitic and noninfectious diseases of North American bison populations which may occur in cattle and other ruminant species as well. He established that cross-infection between the bison and other artiodactylous mammals was possible, and indicated Babesia bigemina and Ostertagia ostertagi infection as the primary causes of deaths. He attributed poor growth and the different clinical signs observed to nematodes parasitizing the gastrointestinal tract. Table 1 Commonest nematodes parasitic in the gastrointestinal tract of artiodactylids (on the basis of data reported by W. J. Boever (1986) Parasite genus Location of adult worm Clinical signs produced Haemonchus abomasum oedema, haemorrhage, anaemia Ascarops stomach occasionally diarrhoea Physocephalus stomach occasionally diarrhoea Hyostrongylus stomach occasionally diarrhoea Ostertagia abomasum oedema, haemorrhage, anaemia Trichostrongylus abomasum oedema, haemorrhage, anaemia Cooperia small intestine diarrhoea, lack of appetite, emaciation Strongyloides small intestine diarrhoea, weakening Oesophagostomum small intestine, diarrhoea, weakening large intestine diarrhoea, weakening Researchers of the University of Colorado (Cheney and Allen 1989) studied helminth infections, more closely the prevalence of nematodes, in North American llamas. They developed several treatment methods against nematode species. By faecal examination, they demonstrated the following genera of Trichostrongylidae: Haemonchus, Cooperia, Bunostomum, Trichostrongylus, Ostertagia, Oesophagostomum. In faceal samples from South American llamas, Cheney and Allen (1989) detected the genera Spiculopteragia, Lamenema, Graphinema and Camelostrongylus. They established that the clinical signs produced by nematodes in llamas are similar to those reported for cattle and sheep. In addition to the common signs (diarrhoea, anaemia, exsiccation, emaciation), breaking of the staples and a reduction in their length and diameter were observed in the same way as in the case of sheep.