Cranial Helminth Parasites in Species of Mustelidae: I. Frequency and Damage in Fresh Mustelids from Sweden

Abstract

Fresh skulls of 55 Mustela nivalis L., 172 M. erminea L., 35 M. putorius L., 126 M. vison Schreber, 97 Martes martes (L.), 30 Meles meles (L.) and 5 Lutra lutra (L.) were investigated for parasitic helminths. Skrjabingylus nasicola (Leuckart 1842) Petrov 1927 occurred in all Mustela spp. and S. petrowi Bageanov (in Petrov 1941) in M. martes. The trematode Troglotrema acutum (Leuckart 1842) Odhner 1914 was not found. Host specificity was found to a certain extent in the species of Skrjabingylus. Frequencies of invasion were: M. nivalis 53 %, M. erminea 53 %, M. putorius 89%, M. vison 45 %, M. martes 62 %. Intensities of invasion in the form of frequency of larva-distributing host specimens as calculated on the total skull material and the mean number of nematodes (in brackets) in invaded host specimens were: M. nivalis 34% (4.7), M. erminea 39% (9.7), M. putorius 80% (16.4), M. vison 13% (2.2), M. martes 39 % (5.9). The frequency of invaded host specimens was significantly different between M. putorius and all other host species and the frequency of parasite-distributing specimens clearly significantly differed in all Mustela species except between M. nivalis and M. erminea. Invasion was never found in host specimens with milk teeth. S. nasicola is able to persist for at least 3 years in captive M. nivalis. Skull lesions were found in all host species. The percentage damaged of invaded skulls were in M. nivalis 89 %, M. erminea 80 %, M. putorius 12 %, M. vison 32 %, M. martes 11 %. There was some relation between the size of the skull and the frequency of damage. The damage arose most rapidly and were both proportionately and absolutely most extensive in M. nivalis and M. erminea. The smallest proportion of lesions in comparison with the frequency and intensity of invasion was found in M. putorius.