WORM POPULATION CHARACTERISTICS AND PATHOLOGICAL-CHANGES IN LAMBS AFTER A SINGLE OR TRICKLE INFECTION WITH TELADORSAGIA-CIRCUMCINCTA

Citation
L. Gruner et al., WORM POPULATION CHARACTERISTICS AND PATHOLOGICAL-CHANGES IN LAMBS AFTER A SINGLE OR TRICKLE INFECTION WITH TELADORSAGIA-CIRCUMCINCTA, International journal for parasitology, 24(3), 1994, pp. 347-356
Citations number
40
Categorie Soggetti
Parasitiology
ISSN journal
00207519
Volume
24
Issue
3
Year of publication
1994
Pages
347 - 356
Database
ISI
SICI code
0020-7519(1994)24:3<347:WPCAPI>2.0.ZU;2-9
Abstract
The regulation of the worm population and of its pathological effects was studied after a single or trickle infection with T. circumcincta. One hundred and twenty lambs, 60 Romanov and 60 Merinos d'Arles, 3 mon ths old, were distributed in four balanced groups: non-infected (G0), infected with 7000 L3 per animal once and slaughtered after 4 weeks (G 14) or 8 weeks (G18), and infected 8 times and slaughtered after 8 wee ks (G88). Parasitological, histological, haematological parameters and weight pins were recorded on each animal. Female and artificially nur sed lambs had lower worm burdens and egg counts (epg) than males and n aturally suckled lambs. No difference in parasitological parameters wa s seen between the two breeds, but Merinos lambs infected once, had a higher increase in pepsinogen concentrations than Romanov lambs. In th e infected animals, a significant proliferation of mast and eosinophil cells was observed in the abomasum wall. Serum pepsinogen concentrati ons were significantly higher 3 weeks p.i. and the weight gain was dep ressed during the first month p.i. The worm population was more numero us and younger in group G 14 compared with G18 in which 24% of the wor ms had been expelled during the second month p.i. The female worms in G 18 were longer and had more eggs in utero and higher egg output. Aft er the trickle infection (G88) the take was reduced, female worms were longer with more eggs in vagina (pars ejectrix) and there was a highe r variability in the number of eggs (compared with G18 data). The peps inogen rise was smaller but no specific effect was seen on histologica l and haematological parameters. Repeatability values around 0.5 were estimated between 4 consecutive days of egg counts. However the correl ations between epg 1 and 2 months p.i. or between pepsinogen concentra tion and parasitological parameters were not significant.