ABSTRACT Background: Towards preparation for a possible influenza pandemic, investigation of the molecular characteristics of the circulating avian H5N1 influenza virus strains is of crucial importance. These H5N1 viruses continue to spread, to infect animals and humans and to evolve and diversify providing so an ever-looming pandemic threat.Aim: To identify genetic structure and molecular biological characteristics of BiH's isolates of H5N1 HPAI as well as to assess the level of pathogenicity, phylogenetic origin and host- specificity of the isolates.Material and Methods: SPF embryonated chicken eggs were used for virus isolation. Viral RNA extracted using QIAamp viral RNA kit and manufacturer’s protocol (QIAGEN®) was used for PCR amplification. cDNA synthesis and PCR amplification of the coding region, using gene specific primer sets (primer sequences available on request), were carried out for all eight viral RNA segments separately. The Prism Big Dye Terminator v1.1 cycle sequencing kit (Applied Biosystems) was used and products were analyzed on an automatic ABI PRISM 3130 genetic analyzer (Applied Biosystems). Nucleotide sequences were analyzed using Bioedit software (v. 7.0.9.0) with an engine based on the ClustalW 1.4 algorithm. MEGA software (v. 4,0), using the neighbor joining tree inference analysis with the Tamura-Nei γ-model, was used to estimate phylogenies and calculate bootstrap values from the nucleotide sequences.Results: Full-length nucleotide sequences of the A/Cygnus olor/BIH/1/2006 (H5N1) strain were deposited in EMBL Nucleotide Sequence Database under accession nos. FN186008 to FN186014 and FM20943. The pathogenicity and host specificity of this strain, as polygenic traits, are determined in silico by the structure of its proteins, especially surface glycoproteins, HA and NA. Multibasic amino acid stretch PQGERRRKKR/GLF, marker of strains highly pathogenic to poultry, was present at the HA cleavage site of BiH strain. The RBS was typical for avian influenza viruses and contained Gln and Gly at positions 238 and 240 (H5 numbering) that is,226 and 228 according to H3 numbering with seven potential glycosylated sites but with increased binding to alpha2-6 sialoglycans thanks to substitutions, as follows, 110N, 171N, 171N, 172A, 205R and 251P. NA structure assigned this strain to the Z genotype, characterized also by the deletion of the five amino acid residues of the NS1 protein (positions 80-84). Amino acid residues, typical for the avian influenza viruses, were revealed in 40 out of 43 positions of M1, M2, NP, PA, PB2 and HA, determining the host range specificity. Phylogenetic analysis of the HA gene revealed that BiH isolates belonged to genetic clade 2.2., and presence of aspartic acid at the position of 403 of HA locate BiH isolates in 2.2.2. sub-clade.Conclusions: The BiH’s isolates were determined as HPAI virus with genes sequences closely related to A/Cygnus olor/Astrakhan/Ast05-2-10/2005 (H5N1). Three residues (M2 - 28V and 78K, NP - 33I), typical of human influenza viruses, were found, indicating a certain degree of intercurrent evolutionary adaptive changes in BiH isolates. Sequence comparison of HA and NA segments with relevant sequences in GenBank revealed that the BiH isolates and the ones from the southern Russia (Astrakhan region) group together phylogenetically, forming a monophyleticcluster in both genes indicating that these isolates have evolved from the same origin. Sequence derived phenotype markers of NA protein (E99, V129, D131, R136, H255 and Y256) as well as of M2 protein (26L, 27V, 30A, S31 and G34) showed that the isolates have an oseltamivir and amantadine sensitive genotype. 

Leishmania infantum causes potentially life-threatening disease in humans. To determine the extent of the animal reservoir for this pathogen in Bosnia and Herzegovina, we tested dogs and cats. We found that a large proportion of dogs were exposed to or infected with L. infantum, indicating endemicity in dogs and zoonotic risk for humans.

A century of debates on the taxonomy of members of the Metastrongyloidea Molin, 1861 led to many reclassifications. Considering the inconstant genus assignation and lack of genetic data, the main aim of this study was to support the validity of the genus Perostrongylus Schlegel, 1934, previously considered a synonym of Aelurostrongylus Cameron, 1927, based on new molecular phylogenetic data and to understand its evolutionary relationships with other metastrongyloid nematodes. Specimens of lungworm collected from European badgers in Germany, Romania and Bosnia and Herzegovina were morphologically and molecularly (rDNA, cox1) characterized. From a phylogenetic standpoint, Perostrongylus is grouped with high support together with the genera Filaroides van Beneden, 1858 and Parafilaroides Dougherty, 1946 and includes probably two species: Perostrongylus falciformis (Schlegel, 1933), a parasite of Meles meles in Europe and P. pridhami (Anderson, 1962), a parasite of Neovison vison in North America. Perostrongylus and Aelurostrongylus are assigned to different clades. Aelurostrongylus becomes a monotypic genus, with the only species Aelurostrongylus abstrusus (Railliet, 1898). In addition, we provide morphological and morphometric data for the first-stage (L1), second-stage (L2), and third-stage (L3) larvae of P. falciformis and describe their development in experimentally infected Cornu aspersum snails. The pathological and histopathological lesions in lungs of infected European badgers are also described. This is the first record of P. falciformis in Romania. Molecular phylogenetic and morphological data support the validity of the genus Perostrongylus, most probably with two species, P. falciformis in European badgers and P. pridhami in minks in North America. The two genera clearly belong to two different clades: Perostrongylus is grouped together with the genera Filaroides and Parafilaroides (both in the family Filaroididae Schulz, 1951), whereas Aelurostrongylus belongs to a clade with no sister groups.

BackgroundHepatozoon silvestris is an emerging apicomplexan parasite discovered in European wild cats from Bosnia and Herzegovina and blood samples of a domestic cat from Southern Italy in 2017. It has also been identified in Ixodes ricinus collected from a domestic cat in Wales, UK, in 2018. The clinical relevance, pathogenesis and epidemiology of this novel Hepatozoon species are not yet understood. Thus, the objective of this paper was to report and describe the first fatal case of an H. silvestris infection in a domestic cat.ResultsThe cat, which originated from Switzerland, died shortly after presenting clinical signs of lethargy, weakness and anorexia. At necropsy, no specific lesions were observed. Histopathology of the heart revealed a severe lympho-plasmacytic and histiocytic myocarditis. Mature and developing protozoal meronts morphologically compatible with Hepatozoon species were observed associated with the myocardial inflammation. No other lesions were present in any other organ evaluated, and the cat tested negative for retroviral and other immunosuppressive infectious agents. Polymerase chain reaction from the myocardium resulted in a specific amplicon of the Hepatozoon 18S rRNA gene. Sequencing and BLAST analysis revealed 100% sequence identity with H. silvestris.ConclusionsThe severity of the infection with fatal outcome in an otherwise healthy animal suggests a high virulence of H. silvestris for domestic cats. The presence of this emerging parasite in a domestic cat in Switzerland with no travel history provides further evidence for a geographical distribution throughout Europe.

Hepatozoon silvestris is an emerging apicomplexan parasite discovered in European wild cats from Bosnia and Herzegovina and blood samples of a domestic cat from Southern Italy in 2017. It has also been identified in Ixodes ricinus collected from a domestic cat in Wales, UK, in 2018. The clinical relevance, pathogenesis and epidemiology of this novel Hepatozoon species are not yet understood. Thus, the objective of this paper was to report and describe the first fatal case of an H. silvestris infection in a domestic cat. The cat, which originated from Switzerland, died shortly after presenting clinical signs of lethargy, weakness and anorexia. At necropsy, no specific lesions were observed. Histopathology of the heart revealed a severe lympho-plasmacytic and histiocytic myocarditis. Mature and developing protozoal meronts morphologically compatible with Hepatozoon species were observed associated with the myocardial inflammation. No other lesions were present in any other organ evaluated, and the cat tested negative for retroviral and other immunosuppressive infectious agents. Polymerase chain reaction from the myocardium resulted in a specific amplicon of the Hepatozoon 18S rRNA gene. Sequencing and BLAST analysis revealed 100% sequence identity with H. silvestris. The severity of the infection with fatal outcome in an otherwise healthy animal suggests a high virulence of H. silvestris for domestic cats. The presence of this emerging parasite in a domestic cat in Switzerland with no travel history provides further evidence for a geographical distribution throughout Europe.

SUMMARY Based on morphological and genetic characteristics, we describe a new species of Hepatozoon in the European wild cat (Felis silvestris silvestris), herein named Hepatozoon silvestris sp. nov. The study also provides the first data on the occurrence of H. felis in this wild felid. Hepatozoon meronts were observed in multiple cross-sections of different organs of four (44%) cats. Additionally, extracellular forms, resembling mature gamonts of Hepatozoon, were found in the spleen and myocardium of two cats. Furthermore, tissues of six animals (67%) were positive by PCR. Hepatozoon felis was identified infecting one cat (11%), whereas the 18S rRNA sequences of the remaining five cats (56%) were identical, but distinct from the sequences of H. felis. Phylogenetic analyses revealed that those sequences form a highly supported clade distant from other Hepatozoon spp. Future studies should include domestic cats from the areas where the wild cats positive for H. silvestris sp. nov. were found, in order to investigate their potential role to serve as intermediate hosts of this newly described species. Identification of its definitive host(s) and experimental transmission studies are required for elucidating the full life cycle of this parasite and the possible alternative routes of its transmission.