Upper Respiratory Tract Disease in a Dog Infected by a Highly Pathogenic Avian A/H5N1 Virus.

In summer 2023, during an outbreak of highly pathogenic avian influenza (HPAI) in cats in Poland, a 16-year-old dog was presented to the veterinary clinic with persistent, debilitating, dry cough, submandibular lymphadenomegaly, mild serous nasal discharge, and left apical heart murmur. A preliminary diagnosis of kennel cough was made and the treatment with amoxicillin/clavulanic acid and dexamethasone was initiated. Due to the lack of improvement within 2 days, a blood check-up, thoracic radiography and ultrasonography, and echocardiography were performed. Moreover, a rapid test for orthomyxovirus type A antigen in a throat swab was carried out and proved positive. The result was verified using RT-qPCR, which yielded a positive result for A/H5N1 influenza virus and negative results for A/H1N1, A/H3N2, type B influenza, and SARS-CoV-2. This case indicates that HPAI should be considered as a differential diagnosis not only in cats, but also in dogs with upper respiratory tract disease, particularly in regions experiencing A/H5N1 avian influenza outbreaks.

A Fatal A/H5N1 Avian Influenza Virus Infection in a Cat in Poland.

A European Shorthair male cat, neutered, approximately 6 years of age, was presented to the veterinary clinic due to apathy and anorexia. The cat lived mostly outdoors and was fed raw chicken meat. After 3 days of diagnostic procedures and symptomatic treatment, respiratory distress and neurological signs developed and progressed into epileptic seizures, followed by respiratory and cardiac arrest within the next 3 days. Post-mortem examination revealed necrotic lesions in the liver, lungs, and intestines. Notably, the brain displayed perivascular infiltration of lymphocytes and histiocytes. Few foci of neuronal necrosis in the brain were also confirmed. Microscopic examination of the remaining internal organs was unremarkable. The A/H5N1 virus infection was confirmed using a one-step real-time reverse transcription polymerase chain reaction (RT-qPCR). The disease caused severe neurological and respiratory signs, evidence of consolidations and the presence of numerous B lines, which were detected on lung ultrasound examination; the postmortem findings and detection of A/H5N1 viral RNA in multiple tissues indicated a generalized A/H5N1 virus infection. Moreover, a multidrug-resistant strain of Enterococcus faecium was isolated in pure culture from several internal organs. The source of infection could be exposure to infected birds or their excrements, as well as contaminated raw poultry meat but, in this case, the source of infection could not be identified.

Is Vitamin D3 a Worthy Supplement Protecting against Secondary Infections in Dogs with Atopic Dermatitis?

Canine atopic dermatitis (CAD) is a common, chronic, inflammatory skin disease in dogs worldwide. This disease often predisposes for secondary organisms overgrowth and skin infections with pathogens, such as Staphylococcus pseudintermedius and Malassezia pachydermatis. Unfortunately, the causes of this disease in both humans and animals are not fully understood; therefore, the only possible option is a lifelong, symptomatic treatment. The management of CAD is mainly based on limiting contact with allergens and antipruritic therapy, most often with glucocorticoids and antihistamines. A serious problem in this situation is the fact, that long-term administration of glucocorticoids leads to side effects like polyuria, alopecia, increased susceptibility to infection, muscle atrophy, and many others. For this reason, great emphasis is placed on the development of replacement and supportive therapies. It is a well-documented fact that reduced concentrations of serum vitamin D3 contribute to the severity of atopic dermatitis symptoms in humans. Moreover, unlike the most commonly used therapeutic methods, of which the main goal is to ameliorate inflammation and pruritus, namely the symptoms of AD, vitamin D3 supplementation affects some underlying factors of this disease. Therefore, in this review, we summarize the current state of knowledge regarding the role of vitamin D3 in CAD, its protective effect against secondary bacterial and fungal infections, and the potential of its supplementation in dogs.

Equid Alphaherpesvirus 1 (EHV-1) Influences Morphology and Function of Neuronal Mitochondria In Vitro.

Mitochondria are key cellular organelles responsible for many essential functions, including ATP production, ion homeostasis and apoptosis induction. Recent studies indicate their significant role during viral infection. In the present study, we examined the effects of equine herpesvirus type 1 (EHV-1) infection on the morphology and mitochondrial function in primary murine neurons in vitro. We used three EHV-1 strains: two non-neuropathogenic (Jan-E and Rac-H) and one neuropathogenic (EHV-1 26). The organization of the mitochondrial network during EHV-1 infection was assessed by immunofluorescence. To access mitochondrial function, we analyzed reactive oxygen species (ROS) production, mitophagy, mitochondrial inner-membrane potential, mitochondrial mass, and mitochondrial genes' expression. Changes in mitochondria morphology during infection suggested importance of their perinuclear localization for EHV-1 replication. Despite these changes, mitochondrial functions were preserved. For all tested EHV-1 strains, the similarities in the increased fold expression were detected only for COX18, Sod2, and Tspo. For non-neuropathogenic strains (Jan-E and Rac-H), we detected mainly changes in the expression of genes related to mitochondrial morphology and transport. The results indicate that mitochondria play an important role during EHV-1 replication in cultured neurons and undergo specific morphological and functional modifications.

Challenges of the Immunotherapy: Perspectives and Limitations of the Immune Checkpoint Inhibitor Treatment.

Immunotherapy is a quickly developing type of treatment and the future of therapy in oncology. This paper is a review of recent findings in the field of immunotherapy with an emphasis on immune checkpoint inhibitors. The challenges that immunotherapy might face in near future, such as primary and acquired resistance and the irAEs, are described in this article, as well as the perspectives such as identification of environmental modifiers of immunity and development of anti-cancer vaccines and combined therapies. There are multiple factors that may be responsible for immunoresistance, such as genomic factors, factors related to the immune system cells or to the cancer microenvironment, factors emerging from the host cells, as well as other factors such as advanced age, biological sex, diet, many hormones, existing comorbidities, and the gut microbiome.

Pigeons as Carriers of Clinically Relevant Multidrug-Resistant Pathogens-A Clinical Case Report and Literature Review.

Pigeons are widespread bird species in urban regions (Columba livia forma urbana) and may carry pathogens with zoonotic potential. In recent years, more and more data indicate that these zoonotic pathogens are multidrug resistant. Our results confirmed that global trend. Three different multidrug-resistant pathogens were isolated from an oral cavity of a racing pigeon with lesions typical for pigeon pox virus infection. Staphylococcus aureus was recognized as methicillin resistant, thus resistant to all beta-lactams. Additionally, it was also resistant to many other classes of antibiotics, namely: aminoglycosides, tetracyclines, phenicols, lincosamides, and macrolides. Escherichia coli showed resistance to all antimicrobials tested, and it was classified as intermediate to amikacin. Moreover, Candida albicans resistant to clotrimazole, natamycin, flucytosine, and amphotericin and intermediate to ketoconazole, nystatin, and econazole was also isolated. This raises the question how pigeons acquire such highly resistant strains. Therefore, more data are needed concerning the resistance to antibiotics in strains from domestic and wild pigeons in Poland. Until the problem is fully understood, it will be challenging to implement adequate planning of any control measures and check their effectiveness.

Coronaviruses - a new old menace.

The current pandemic caused by novel coronavirus SARS-CoV-2 pandemic has been described as a global health emergency. The outbreak of this virus has raised a number of questions: what exactly is SARS-CoV-2? How transmissible the novel coronavirus is? How severely affected are patients infected with SARS-CoV-2? What are the risk factors for COVID-19? What are the differences between this novel coronavirus and other coronaviruses? To answer these questions, a comparative study of three pathogenic coronaviruses that primarily invade the human respiratory system and may cause death, namely, severe acute respiratory syndrome (SARS-CoV-1), Middle East respiratory syndrome (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Middle East respiratory syndrome coronavirus (MERS-CoV). This review describes the source of origin, transmission, and pathogenicity of these viruses. Prevention of SARS-CoV-2 spreading entails home isolation of suspected cases and those with mild illnesses and strict infection control measures at hospitals that include contact and droplet precautions. The novel coronavirus spreads faster than its two predecessors - the SARS-CoV-1 and MERS-CoV - but has lower fatality rate. The global impact of this new pandemic is still uncertain, but it is a challenge to healthcare systems around the world.

Human herpesvirus type 1 and type 2 disrupt mitochondrial dynamics in human keratinocytes.

Mitochondrial movement and distribution throughout the cytoplasm is crucial for maintaining cell homeostasis. Mitochondria are dynamic organelles but can be functionally disrupted during infection. Here, we show that the ubiquitous human pathogens HHV-1 and HHV-2 induce changes in the mitochondrial morphology and distribution in the early and late phases of productive infection in human keratinocytes (HaCaT cells). We observed a decrease in the mitochondrial potential at 2 h postinfection and a decrease in cell vitality at 24 h postinfection. Moreover, we found that mitochondria migrated to the perinuclear area, where HHV-1 and HHV-2 antigens were also observed, mainly in the early stages of infection. Positive results of real-time PCR showed a high level of HHV-1 and HHV-2 DNA in HaCaT cells and culture medium. Our data demonstrate that HHV-1 and HHV-2 cause mitochondrial dysfunction in human keratinocytes.

Deletion of psbQ' gene in Cyanidioschyzon merolae reveals the function of extrinsic PsbQ' in PSII.

KEY MESSAGE: We have successfully produced single-cell colonies of C. merolae mutants, lacking the PsbQ' subunit in its PSII complex by application of DTA-aided mutant selection. We have investigated the physiological changes in PSII function and structure and proposed a tentative explanation of the function of PsbQ' subunit in the PSII complex. We have improved the selectivity of the Cyanidioschyzon merolae nuclear transformation method by the introduction of diphtheria toxin genes into the transformation vector as an auxiliary selectable marker. The revised method allowed us to obtained single-cell colonies of C. merolae, lacking the gene of the PsbQ' extrinsic protein. The efficiency of gene replacement was extraordinarily high, allowing for a complete deletion of the gene of interest, without undesirable illegitimate integration events. We have confirmed the absence of PsbQ' protein at genetic and protein level. We have characterized the physiology of mutant cells and isolated PSII protein complex and concluded that PsbQ' is involved in nuclear regulation of PSII activity, by influencing several parameters of PSII function. Among these: oxygen evolving activity, partial dissociation of PsbV, regulation of dimerization, downsizing of phycobilisomes rods and regulation of zeaxanthin abundance. The adaptation of cellular physiology appeared to favorite upregulation of PSII and concurrent downregulation of PSI, resulting in an imbalance of energy distribution, decrease of photosynthesis and inhibition of cell proliferation.

Chloramphenicol acetyltransferase-a new selectable marker in stable nuclear transformation of the red alga Cyanidioschyzon merolae.

In this study, we have shown the applicability of chloramphenicol acetyltransferase as a new and convenient selectable marker for stable nuclear transformation as well as potential chloroplast transformation of Cyanidioschyzon merolae-a new model organism, which offers unique opportunities for studding the mitochondrial and plastid physiology as well as various evolutionary, structural, and functional features of the photosynthetic apparatus.

Transformation of the Cyanidioschyzon merolae chloroplast genome: prospects for understanding chloroplast function in extreme environments.

KEY MESSAGE: We have successfully transformed an exthemophilic red alga with the chloramphenicol acetyltransferase gene, rendering this organism insensitive to its toxicity. Our work paves the way to further work with this new modelorganism. Here we report the first successful attempt to achieve a stable, under selectable pressure, chloroplast transformation in Cyanidioschizon merolae-an extremophilic red alga of increasing importance as a new model organism. The following protocol takes advantage of a double homologous recombination phenomenon in the chloroplast, allowing to introduce an exogenous, selectable gene. For that purpose, we decided to use chloramphenicol acetyltransferase (CAT), as chloroplasts are particularly vulnerable to chloramphenicol lethal effects (Zienkiewicz et al. in Protoplasma, 2015, doi: 10.1007/s00709-015-0936-9 ). We adjusted two methods of DNA delivery: the PEG-mediated delivery and the biolistic bombardment based delivery, either of these methods work sufficiently with noticeable preference to the former. Application of a codon-optimized sequence of the cat gene and a single colony selection yielded C. merolae strains, capable of resisting up to 400 µg/mL of chloramphenicol. Our method opens new possibilities in production of site-directed mutants, recombinant proteins and exogenous protein overexpression in C. merolae-a new model organism.

The generation of CD8+ T-cell population specific for vaccinia virus epitope involved in the antiviral protection against ectromelia virus challenge.

Eradication of smallpox has led to cessation of vaccination programs. This has rendered the human population increasingly susceptible not only to variola virus infection but also to infections with other representatives of Poxviridae family that cause zoonotic variola-like diseases. Thus, new approaches for designing improved vaccine against smallpox are required. Discovering that orthopoxviruses, e.g. variola virus, vaccinia virus, ectromelia virus, share common immunodominant antigen, may result in the development of such a vaccine. In our study, the generation of antigen-specific CD8(+) T cells in mice during the acute and memory phase of the immune response was induced using the vaccinia virus immunodominant TSYKFESV epitope and CpG oligodeoxynucleotides as adjuvants. The role of the generated TSYKFESV-specific CD8(+) T cells was evaluated in mice during ectromelia virus infection using systemic and mucosal model. Moreover, the involvement of dendritic cells subsets in the adaptive immune response stimulation was assessed. Our results indicate that the TSYKFESV epitope/TLR9 agonist approach, delivered systemically or mucosally, generated strong CD8(+) T-cell response when measured 10 days after immunization. Furthermore, the TSYKFESV-specific cell population remained functionally active 2 months post-immunization, and gave cross-protection in virally challenged mice, even though the numbers of detectable antigen-specific T cells decreased.

[Herpesviruses survival strategies--latency and apoptosis]. / Strategie przetrwania herpeswirusów--latencja i apoptoza.

Apoptosis is a process of programmed cell death in response to various stimuli, including virus infection. Herpesviruses have evolved the ability to interfere with apoptosis by its inhibition or activation in host cells. They can interfere with the extrinsic and intrinsic pathways of apoptosis. A special feature of herpesviruses is establishing a latent infection, during which expression of virus genes is strongly restricted and production of infectious virus particles is not observed. HSV-1 establishes latency in neurons, CMV in bone marrow progenitor cells and monocytes, EBV and HHV-8 in B cells. Studies show that latent infections also depend on prevention of the death of the infected cells. Control of apoptosis machinery by viruses may be critical for their reproduction and provision of the adequate yield of progeny virions. The present article summarizes the current knowledge about the latent viral infection and mechanisms of apoptosis modulation by selected viruses from the Herpesviridae family.

Role of cytoskeletal motor proteins in viral infection.

Cytoskeleton, composed of actin filaments, microtubules and intermediate filaments, regulates many processes in the cell, e.g. intracellular transport. Actin and microtubules are polarized structures, along which bidirectional transport of motor proteins occurs: myosins along actin and the dynein/dynactin complex and kinesins along microtubules. Viruses interact with the cytoskeleton and motor proteins at different stages during their replication cycle. When entering and egressing the cell, viruses must penetrate the cortical layer of microfilaments, which usually takes place with the contribution of myosin. In the cytoplasm, retrograde transport involving dynein is used to move viruses to the microtubule organizing center. After replication, kinesins participate in anterograde transport of newly produced virions to the peripheral region, close to the plasma membrane. Some families of viruses have developed alternate routes of intracellular transport. The aim of this study is to describe the interactions between virus and cytoskeletal motor proteins and to determine their role in viral infection according to the current literature data.