Miljenko Bujanić

Molecular identification of the rumen flukes Paramphistomum leydeni and Paramphistomum cervi in a concurrent infection of the red deer Cervus elaphus.

Paramphistomosis, caused by paramphistomid flukes, is a gastrointestinal parasitic disease of domestic and wild ruminants. Originally thought to be limited to the tropics and subtropics, the disease has recently been reported in temperate regions. Here we describe the concurrent infection of a red deer doe (Cervus elaphus) with Paramphistomum leydeni and Paramphistomum cervi. This is the first report of P. leydeni in Croatia. Flukes were identified on the basis of morphological keys (tegumental papillae) and sequencing of the internal transcribed spacer region 2 in ribosomal DNA. Our results confirm that the absence of tegumental papillae allows P. cervi to be differentiated morphologically from other paramphistomid species in Europe based on incident light stereomicroscopy. Nevertheless the limitations of morphological identification and taxonomic issues suggest that previous findings on paramphistomid infection should be interpreted carefully. The possible worldwide distribution of these pathogens means that paramphistomosis may be more common and its economic impact greater than previously thought.

Evolution of MHC class II SLA-DRB1 locus in the Croatian wild boar (Sus scrofa) implies duplication and weak signals of positive selection

The wild boar is an ancestor of the domestic pig and an important game species with the widest geographical range of all ungulates. Although a large amount of data are available on major histocompatibility complex (MHC) variability in domestic pigs, only a few studies have been performed on wild boars. Due to their crucial role in appropriate immune responses and extreme polymorphism, MHC genes represent some of the best candidates for studying the processes of adaptive evolution. Here, we present the results on the variability and evolution of the entire MHC class II SLA-DRB1 locus exon 2 in 133 wild boars from Croatia. Using direct sequencing and cloning methods, we identified 20 SLA-DRB1 alleles, including eight new variants, with notable divergence. In some individuals, we documented functional locus duplication, and SLA-DRB1*04:10 was identified as the allele involved in the duplication. The expression of a duplicated locus was confirmed by cloning and sequencing cDNA-derived amplicons. Based on individual genotypes, we were able to assume that alleles SLA-DRB1*04:10 and SLA-DRB1*06:07 are linked as an allelic combination that co-evolves as a two-locus haplotype. Our investigation of evolutionary processes at the SLA-DRB1 locus confirmed the role of intralocus recombination in generating allelic variability, whereas tests of positive selection based on the dN/dS (non-synonymous/synonymous substitution rate ratio) test revealed atypically weak and ambiguous signals.

First identification of Echinococcus multilocularis in golden jackals in Croatia

Alveolar echinococcosis, caused by the tapeworm Echinococcus multilocularis, is one of the world’s most dangerous zoonosis and an emerging disease with growing incidence in humans. The disease has been reported in new areas and host species in the last two decades, and the primary hosts of the parasite — red fox, golden jackal and grey wolf — are expanding their distribution in Europe. Here we report the morphological and molecular identification of Echinococcus multilocularis tapeworms in one of 29 carcasses of adult golden jackals in Croatia, where the only previous report of the parasite was in red foxes in 2016. These results suggest that alveolar echinococcosis should be treated as an emerging disease in Croatia.