MHC, parasites and antler development in red deer : no support for the Hamilton & Zuk hypothesis

The Hamilton-Zuk hypothesis proposes that the genetic benefits of preferences for elaborated secondary sexual traits have their origins in the arms race between hosts and parasites, which maintains genetic variance in parasite resistance. Infection, in turn, can be reflected in the expression of costly sexual ornaments. However, the link between immune genes, infection, and the expression of secondary sexual traits has rarely been investigated. Here, we explored whether the presence and identity of functional variants (supertypes) of the highly polymorphic major histocompatibility complex (MHC), which is responsible for the recognition of parasites, predict the load of lung and gut parasites and antler development in the red deer (Cervus elaphus). While we found MHC supertypes to be associated with infection by a number of parasite species, including debilitating lung nematodes, we did not find support for the Hamilton-Zuk hypothesis. On the contrary, we found that lung nematode load was positively associated with antler development. We also found that the supertypes that were associated with resistance to certain parasites at the same time cause susceptibility to others. Such tradeoffs may undermine the potential genetic benefits of mate choice for resistant partners

Effect of seasonal diet composition changes on the characteristics of the gastrointestinal tract contents of the Eurasian beaver (Castor fiber).

The goal of the study was to compare chemical and physical parameters of the content of various gastrointestinal (GI) tract segments of adult beavers and to relate the obtained results to seasonal changes in the composition of natural diet. The study was conducted on 36 adult beavers originated from the natural environment that were captured in winter, summer and autumn. The obtained results demonstrated that pH, redox potential (Eh), dry matter (DM), short-chain fatty acids (SCFA) and distribution of food particles varied along the beaver GI tract during the year. The lowest value of pH was observed in stomach whereas the highest in the small intestine and cecum. The reverse pattern of changes was found for the value of redox potential. The research indicated that anaerobic conditions were predominant in the cecum and so contributed to development of microbial population. Also, the increase in the SCFA contents in the cecum and colon indicated that beavers belong both to hindgut fermenters as well as to the mixed moderate type animals. In summary, the obtained results indicated that seasonal changes in the diet composition affected physical and chemical parameters as well as microbial activity of the GI tract of beaver

Onchocerca jakutensis Filariasis in Humans

We identified Onchocerca jakutensis as the causative agent of an unusual human filariasis in a patient with lupus erythematosus. To our knowledge, this is the first case of human infection with O. jakutensis and the first human case of zoonotic onchocercosis involving >1 worm

Distribution of large lungworms (Nematoda: Dictyocaulidae) in free-roaming populations of red deer Cervus elaphus (L.) with the description of Dictyocaulus skrjabini n. sp.

Lungworms of the genus Dictyocaulus are causative agents of parasitic bronchitis in domestic and wild ungulates. This study investigates the distribution, morphology and genetic diversity of D. cervi and a new lungworm species, Dictyocaulus skrjabini n. sp. infecting red deer Cervus elaphus, fallow deer Dama dama and moose Alces alces in Poland and Sweden. The study was conducted on 167 red deer from Poland and on the DNA of lungworms derived from 7 fallow deer, 4 red deer and 2 moose collected in Sweden. The prevalence of D. cervi and D. skrjabini n. sp. in dissected red deer in Poland was 31.1% and 7.2%, respectively. Moreover, D. skrjabini n. sp. was confirmed molecularly in 7 isolates of fallow deer lungworms and 1 isolate of red deer lungworms from Sweden. Dictyocaulus skrjabini n. sp. was established based on combination of their distinct molecular and morphological features; these included the length of cephalic vesicle, buccal capsule (BC), buccal capsule wall (BCW), distance from anterior extremity to the nerve ring, the width of head, oesophagus, cephalic vesicle, BC and BCW, as well as the dimensions of reproductive organs of male and female. Additionally, molecular analyses revealed 0.9% nucleotide sequence divergence for 1,605 bp SSU rDNA, and 16.5–17.3% nucleotide sequence divergence for 642 bp mitochondrial cytB between D. skrjabini n. sp. and D. cervi, respectively, and 18.7–19% between D. skrjabini n. sp. and D. eckerti, which translates into 18.2–18.7% amino acid sequence divergence between D. skrjabini n. sp. and both lungworms

Tissue nematods of the superfamily Filarioidea occurring in ruminants in Poland

In the years 1985-1988 in the Białowieża Forest and in the woods in the vicinity of Olsztyn, 130 deer, 136 roe-deer, 52 bisons and 40 cattle were subject to parasitological section. Seven species of tissue nematods of the superfamily Filarioidea were detected. Onchocerca jakutensis, O. garmsi and Cutifilaria wenki in deer, Dipetalonema rugosicauda in roe-deer, and Onchocerca lienalis and O. gutturosa in bison and cattle are first records of these species in Poland. The bison is a new host for O. lienalis and O. gutturosa, the roe-deer - for O. flexuosa