Journal of Veterinary Research最新文献

Introduction: The circulation of influenza D virus (IDV) has been confirmed in Europe, North America, Asia and Africa through seroprevalence and molecular studies, as well as by virus isolation. Its broad host range raises concerns about zoonotic potential, with cattle recognised as the natural reservoir. This study finds the seroprevalence of IDV in cattle, associates animal-level variables such as age, sex and origin and assesses the frequency of IDV exposure in small ruminants and horses in Poland.

Material and methods: A total of 1,029 serum samples were analysed, comprising 755 from cattle, 224 from small ruminants and 50 from horses. To assess the serological response, haemagglutination inhibition tests were performed, and samples classified as positive were subsequently tested with a virus neutralisation test.

Results: The findings suggest possible circulation of IDV among cattle in Poland and give an estimated seroprevalence of 45.2%. Seroprevalence was related to age, with older cattle being more likely to test IDV seropositive. Regional differences were also observed, with the highest seroprevalence found in the Wielkopolskie voivodeship, an area known for its intensive cattle farming and one of the largest bovine populations in Poland, exceeding one million animals. No confirmation of IDV occurrence was obtained in any of the 274 sheep, goats, or horses.

Conclusion: To the best of our knowledge, this is the first evidence of IDV circulation in the country, highlighting the need for further research to better understand the virus' transmission pathways.

Introduction: Yolkin is an egg yolk-derived protein with well-established immunoregulatory activities. In this study its potential restorative properties in cyclophosphamide (CP)-immunocompromised mice were evaluated.

Material and methods: Mice were treated with a sublethal dose of CP, followed by an access to yolkin contained in drinking water. The mice were immunised with oxazolone (OXA) for contact sensitivity (CS) and with ovalbumin (OVA) for the antibody specific response after 15 or 26 days of treatment with yolkin, respectively. The lymphoid organs were isolated for determination of immune cell numbers and their phenotypes.

Results: A significant suppression of CS following CP treatment and a restoration of this response by yolkin were found. However, no effects of CP and yolkin on the antibody response were registered. In the case of CS a significant loss of T cell numbers in splenocytes was noted. The restoration of CS correlated with reversal of CD3+, CD4+ and CD8+ T cell loss to 88%, 89% and 76.6% of the values observed in the control mice. A significant depletion of the B cells, and all bone marrow cells after CP treatment, was completely restored after 26 day treatment with yolkin.

Conclusion: The presented results add new information to the already described immunoregulatory properties of the protein and indicate a potential of oral yolkin in restoration of cellular immune response in immunocompromised individuals.

Introduction: Bartonella spp. are gram-negative, facultative intracellular bacteria with zoonotic potential. These microorganisms are emerging vector-borne pathogens distributed worldwide and infecting humans, domestic mammals and wildlife. This study investigated the possibility of culturing Bartonella henselae in a tick cell line derived from Ixodes ricinus.

Material and methods: The Ixodes ricinus embryonic cell line (IRE/CTVM19) and the Houston-1 strain of B. henselae were used for culture studies. Replication of B. henselae was quantified with the use of a SYBR Green real-time PCR and transcribed complementary DNA (cDNA) in samples collected separately from the supernatant and monolayer of culture from 1 to 9 days post-infection (d.p.i.). Identification of B. henselae was based on the detection of a fragment of the ribC gene encoding riboflavin synthase. Quantification was performed indirectly by determining the threshold cycle.

Results: Microscopic observations confirmed that infection with B. henselae did not show any visible negative effect on tick cells. The quantity of B. henselae cDNA from the monolayer remained low, and a slight increase was observed at 4, 8 and 9 d.p.i. Significantly, the highest amount of B. henselae was observed at 2 d.p.i. in samples isolated from the supernatant.

Conclusion: The maintenance of live B. henselae in an I. ricinus-derived cell line was confirmed. The low level of multiplication in the tick cell line suggested a limited role of I. ricinus as a reservoir of B. henselae. The IRE/CTVM19 tick cell line is suitable for culture of B. henselae, and this model may be useful in further studies.

Introduction: Giardia duodenalis (syn. G. intestinalis and G. lamblia) is a protozoan intestinal parasite that infects various vertebrates. Genetic analyses of G. duodenalis have identified eight genetic assemblages (groups), designated A-H. This study aimed to determine the prevalence of G. duodenalis in household dogs and cats in Poland, analyse isolates by assemblage and relate assemblage results to zoonotic potential.

Material and methods: From January to February 2024, 1,937 faecal samples from dogs and 1,077 samples from cats were examined microscopically for G. duodenalis cysts using the zinc flotation method. Positive samples were retained for further molecular tests. Genetic analysis was performed on the basis of the β-giardin locus which is 511 base pairs long. The obtained sequences were compared with reference sequences in the GenBank database.

Results: Giardia duodenalis cysts were detected in 11.3% (219/1,937) of dogs and 7.06% (76/1,077) of cats using the zinc flotation method. Assemblages B, C, D and F were identified in 11, 77, 126 and 5 dogs, respectively. All isolates from cats were identified as assemblage F.

Conclusion: The high rate of infection in pets increases the risk of transmission of zoonotic Giardia genetic assemblages to humans.

Introduction: The Shewanella genus is widely distributed in aquatic environments and occurs in different niches with a wide range of temperatures and salinities. It includes a novel species, S. oncorhynchi, described as recently as 2022, causing lens atrophy, inappetence and growth retardation in rainbow trout (Oncorhynchus mykiss, Walbaum 1792). Shewanella oncorhynchi also occurs in common carp (Cyprinus carpio L.), but its potential pathogenicity in this species is unclear.

Material and methods: In this study, the pathogenicity of three well-characterised S. oncorhynchi strains was assessed in vivo in experimental infection of common carp and in vitro by estimation of their cytotoxicity to an epithelioma papulosum cyprini cell line. The strains' characterisation involved whole-genome sequencing to identify possible virulence genes.

Results: Our study proved the pathogenicity of S. oncorhynchi to common carp and the bacterium's cytotoxicity to epithelioma papulosum cyprini cells. Swollen abdomens, lens opacity, areas of discoloration and skin lesions were recorded in infected common carp. However, the ability to cause disease symptoms and mortality depended on the strain.

Conclusion: The study showed the potential roles of the quorum-sensing system, type IV pili, fimbriae, stress survival, iron metabolism and secretion system genes in the virulence of S. oncorhynchi. Of these, the vscC2, vscN2, vscR2, vscS2 and vscU2 type III secretion system genes potentially and probably enhance the bacterium's ability to cause lesions in common carp.

Introduction: The aim of the research was to determine the levels of dioxins and polychlorinated biphenyls (PCBs) in muscle samples of free-living and farmed cervids and to estimate the health risk to consumers of food originating from these animals.

Material and methods: The research material was collected from red deer (Cervus elaphus L.) (n = 22), roe deer (Capreolus capreolus L.) (n = 6) and fallow deer (Dama dama) (n = 6). The isotope dilution technique, supported by high resolution gas chromatography coupled with high resolution mass spectrometry was used.

Results: The average concentration of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and dioxin-like PCBs in the muscles of free-living cervids was 4.77 ± 2.92 pg World Health Organization toxic equivalency quotients (WHO-TEQ)/g fat, and in the muscles of farmed cervids was 1.85 ± 1.21 pg WHO-TEQ/g fat. Of the tested samples taken from free-living animals, approximately 13% did not meet the requirements of EC Regulation No. 2023/915 EU as they exceeded the maximum limit for congeners.

Conclusion: Both frequent and occasional consumption of meat obtained from free-living and farmed cervids do not pose a threat to human health, because estimated intake of the analysed congeners is very low from these sources. However, very frequent consumption of highly contaminated free-ranging wild game muscles can pose a health risk (in this pattern, an adult consumes dioxins at 133% of the tolerable weekly intake (TWI) and a child at 202% of the TWI).

Introduction: In recent years, probiotics have been increasingly used in companion animals. However, there are few studies on their effect on canine vaginal flora. The objective of this study was to evaluate the effect of orally administrated multi-strain lactic-acid probiotic bacteria on the vaginal flora of healthy bitches.

Material and methods: A total of 38 Labrador retriever bitches were given one sachet of multi-strain probiotic with food once a day for nine weeks. Samples for microbiological examination were taken twice (on day 0 and day 63) from the cranial vagina and cultured for aerobic and anaerobic bacteria.

Results: Bacterial growth was found in 84.2% of the samples on day 0 and in 94.7% of the samples on day 63. Mixed cultures were found in 63.1% of bitches with positive bacterial tests on day 0 and in 73.6% on day 63, and contained a mean 1.8 bacterial strains. An increase in the prevalence of E. coli, Gram-negative rods other than E. coli, Staphylococcus spp. and Streptococcus spp./ Enterococcus spp. was noted after nine weeks (P < 0.05). After the oral administration of the lactic-acid probiotic bacteria, potentially pathogenic Clostridium perfringens, Canicola haemoglobinophilus and Pseudomonas aeruginosa were not isolated. The prevalence of Streptococci other than Streptococcus canis was significantly higher after the administration of the probiotic (26.3% vs 5.3%, P < 0.05), and Enterococcus spp. were isolated in the samples of 28.9% of bitches. There was no increase in the prevalence of Lactobacillus spp.

Conclusion: The results indicate a beneficial effect of oral lactic-acid probiotic bacteria on the composition of vaginal flora in bitches; however, further research is needed.

Introduction: Contagious equine metritis (CEM) is a cosmopolitan infectious, venereal disease of equids caused by the bacterium Taylorella equigenitalis. Its frequently asymptomatic course leads to its prevalence sometimes being underestimated, and knowledge of the spread of infections with its causative agent is insufficient. The aim of this study is to summarise and present data on the incidence of T. equigenitalis infections in horses in Poland.

Material and methods: In the years 2018-2023, routine laboratory tests of horses for CEM were carried out. Between 52 and 99 horses were examined annually. Swabs from the external parts of the urogenital system of mares and stallions were investigated. The supplied swabs were inoculated onto microbiological media and then DNA was isolated from each swab for PCR.

Results: In 2018 and 2020, no horses infected with T. equigenitalis were found by any method. In other years, from 1 to 3 (1.01-4.41%) infected horses were found. All positive horses were stallions and came from stables located in central Poland.

Conclusion: The detection of infected horses in relatively small groups of tested animals indicates an urgent need to introduce monitoring to estimate the spread of T. equigenitalis infections throughout the country. This may facilitate a more precise assessment of the prevalence of T. equigenitalis infections in Poland and, consequently, their more effective containment.

Introduction: Staphylococci commonly colonise the skin and mucous membranes of humans and animals, the close contact between which may promote interspecies transmission of these microorganisms and determinants of drug resistance.

Material and methods: Material collected from animals (n = 274) and humans (n = 261) between 2019 and 2023 was studied. Samples were swabbed from six anatomical sites of each pet: the external ear canal, conjunctival sacs, nares, oral cavity, groin skin and anus. Swabs were taken from four places of each human: the vestibule of the nasal cavity, the throat near the tonsils, and the skin behind the auricle and in the elbow bend. The pets' owners and the human participants completed a questionnaire about the study subject and the subject's living environment to elucidate risk factors associated with staphylococci colonisation.

Results: The prevalence of Staphylococcus aureus was 12.42% in cats and 8.85% in dogs, while S. pseudintermedius was isolated from 5.59% of cats and 58.41% of dogs. Of the people, 38.7% were carriers of S. aureus and 2.68% carriers of S. pseudintermedius. A total of 202 S. aureus strains and 165 S. pseudintermedius strains were analysed. Drug resistance was tested in disc diffusion and resistance genes were detected by PCR. The most frequent resistance of S.aureus was to ampicillin (62.4%), penicillin (61.4%) and erythromycin (29.2%), while S. pseudintermedius was mostly resistant to penicillin (71.5%), ampicillin (63.6%) and clindamycin and erythromycin (41.2% in both cases). Methicillin resistance was found in 4.5% of S. aureus and 12.1% of S. pseudintermedius isolates. The most common S. aureus resistance genes were blaZ (79.7%), tet[M] (53.1%) and ermA (29.7%) and the S. pseudintermedius pattern was of blaZ (84.2%), tet[M] (53.3%) and ermB (38.2%). Regarding risk factors, animals from non-commercial sources had 11-fold higher methicillin resistance than those from commercial breeders, dogs had 50-fold lower risk than humans, and recent antibiotic treatment also increased resistance.

Conclusion: Monitoring the epidemiology of strains and knowing the prevalence of resistant isolates can shape preventive programmes in both veterinary and human medicine, inform appropriate therapeutic decisions and combat the phenomenon of drug resistance.

Introduction: The study determined the effects of different forms of phosphorus deficiency on white blood cell parameters in cows during the periparturient period and on the cows' immune status.

Material and methods: Thirty-two Holstein-Friesian cows aged 3-6 years were divided into four equal groups (I - control group, II - cows with atypical hypophosphataemia, III - cows with post-parturient haemoglobinuria and clinical hypophosphataemia and IV - cows with periparturient recumbency and clinical hypophosphatemia). The experiment used antibodies against CD4⁺ and CD8⁺ T cells (TCD4⁺ and TCD8⁺), CD21⁺ B cells (BCD21⁺) and major histocompatibility complex class II (MHC II). Immunophenotyping was performed by flow cytometry. The morphological examination determined the white and red blood cell and platelet counts, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. Microscopy of manual smears was performed to ascertain the percentage of leukocytes which was each of the granulocyte, segmented granulocyte and lymphocyte subpopulations.

Results: The TCD4⁺ lymphocyte subpopulation was larger in diseased cows and the largest in group IV animals. The TCD8⁺ lymphocyte subpopulation was smaller in hypophosphataemic Holstein-Friesians, and the smallest in group II. The CD4 : CD8 lymphocyte ratio in all diseased animals was higher than that in the control group, peaking in group II. Expression of MHC II protein was higher in affected than in healthy animals. The BCD21⁺ lymphocyte subpopulation was larger in diseased animals.

Conclusion: Long-term (even minor) phosphorus deficiency in an atypical form affects bovine cellular immunity (CD4 :CD8 ratio). In formerly affected cows, infectious diseases are more likely, even after their inorganic phosphorus level has been restored. Despite the less marked symptoms in animals with atypical hypophosphataemia, such animals have increased susceptibility to infectious agents and greater disturbance in their immune parameters.