A 3-YEAR EVALUATION OF ABOMASAL HELMINTHS OF PIZ-ALBRIS IBEX COLONY

The abomasal helminth fauna of 60 female alpine ibex (Capra i. ibex), culled monthly from June 1988 to May 1991 from Pit Albris colony (Gris ons, Switzerland), was monitored. To enlarge sample size, we added pre viously published data from another 66 females from the same study are a. 15 helminth species were found, with Teladorsagia circumcincta and Marshallagia marshalli the most representative. These species are also discussed in relation to those in the literature for other wild and d omestic ruminants sharing ibex habitat. Mean monthly total burden and monthly burdens for the two helminth species were fitted by a polynomi al smoothing model and a well defined seasonal dynamic was revealed, w ith higher values in summer and lower in autumn-winter. Multiple regre ssion stepwise analysis was performed to detect the effects of weight, age of the animals and some meteorological variables on abomasal burd en. In the summer, rainfall, mean minimum and mean maximum temperature significantly influenced the observed abomasal burden (r(2) = 0.49). There were no significant differences between the parasite burdens obs erved during the three summers. However, the 1991 winter burdens were significantly higher than 1990's. This difference, referable to more s evere climatic conditions, is also discussed in relation to a concommi tant significant weight decrease in the animals sampled. Finally, the importance of continuous parasite monitoring through successive years to obtain sufficient data for management programs is stressed.