Prevalence of canid herpesvirus-1 infection in stillborn and dead neonatal puppies in Denmark

Whole-Genome Sequencing of Two Canine Herpesvirus 1 (CaHV-1) Isolates and Clinicopathological Outcomes of Infection in French Bulldog Puppies

Canine herpesvirus 1 (CaHV-1) infects dogs, causing neonatal death and ocular, neurological, respiratory, and reproductive problems in adults. Although CaHV-1 is widespread in canine populations, only four studies have focused on the CaHV-1 whole genome. In such context, two CaHV-1 strains from both the kidney and spleen of 20-day-old deceased French Bulldog puppies were recently isolated in Sardinia, Italy. The extracted viral DNA underwent whole-genome sequencing using the Illumina MiSeq platform. The Italian CaHV-1 genomes were nearly identical (>99%), shared the same tree branch, and clustered near the ELAL-1 (MW353125) and BTU-1 (KX828242) strains, enlarging the completely separated clade discussed by Lewin et al., in 2020. This study aims to provide new insights on the evolution of the CaHV-1, based on high-resolution whole-genome phylogenetic analysis, and on its clinicopathological characterization during a fatal outbreak in puppies.

Prevalence of Chlamydophila spp. and Canid herpesvirus-1 in Polish dogs

Background and Aim

Chlamydophila spp. affect Leydig and Sertoli cells by dysregulating spermatogenesis, inducing apoptosis and sperm DNA fragmentation, as well as benign prostate hyperplasia. Canid herpes virus 1 (CHV-1) infection in male dogs is manifested by lesions on the base of the penis and foreskin. There is a lack of information on the influence of these microorganisms on the quality of canine semen. Seroprevalence of Chlamydophila spp. (55%-61%) and CHV-1 (22%-81%) in Europe is high. The prevalence of Chlamydophila spp. and CHV-1 has been evaluated using polymerase chain reaction (PCR) only in Sweden and Croatia, respectively. No positive samples were detected in either case. The aim of this study was to evaluate the epidemiological situation in Polish male dogs (PMDs) to provide a solution to limit the spread of these microorganisms using assisted reproduction techniques or elimination from the reproduction of CHV-1 carriers. In addition, we assessed the semen quality of Chlamydophila spp. carriers and CHV-1 carriers.

Materials and Methods

Cotton swabs were collected from prepuce or semen from each dog (n = 130). Real-time PCR for Chlamydophila spp. and CHV-1, as well as semen analysis, was performed using the computer-assisted semen analysis system.

Results

To the best of our knowledge, this is the first report of Chlamydophila spp. infection in PMD confirmed by real-time PCR. All parameters, except progressive movement in Chlamydophila semen carriers, were normal.

Conclusion

The average velocity values for a dog with Chlamydia are detailed. No CHV-1 was detected. The results achieved should be verified on the basis of a larger number of studies. However, the high prevalence of these pathogens in the PMD population has not been established.

The ameliorative role of Aloe vera-loaded chitosan nanoparticles on Staphylococcus aureus induced acute lung injury: Targeting TLR/NF-κB signaling pathways

Background

Acute lung injury (ALI) is a severe condition distinguished by inflammation and impaired gas exchange in the lungs. Staphylococcus aureus, a common bacterium, can cause ALI through its virulence factors. Aloe vera is a medicinal plant that has been traditionally used to treat a variety of illnesses due to its anti-inflammatory properties. Chitosan nanoparticles are biocompatible and totally biodegradable materials that have shown potential in drug delivery systems.

Aim

To explore the antibacterial activity of Aloe vera-loaded chitosan nanoparticles (AV-CS-NPs) against S. aureus in vitro and in vivo with advanced techniques.

Methods

The antibacterial efficacy of AV-CS-NPs was evaluated through a broth microdilution assay. In addition, the impact of AV-CS-NPs on S. aureus-induced ALI in rats was examined by analyzing the expression of genes linked to inflammation, oxidative stress, and apoptosis. Furthermore, rat lung tissue was scanned histologically. The rats were divided into three groups: control, ALI, and treatment with AV-CS-NPs.

Results

The AV-CS-NPs that were prepared exhibited clustered semispherical and spherical forms, having an average particle size of approximately 60 nm. These nanoparticles displayed a diverse structure with an uneven distribution of particle sizes. The maximum entrapment efficiency of 95.5% ± 1.25% was achieved. The obtained findings revealed that The minimum inhibitory concentration and minimum bactericidal concentration values were determined to be 5 and 10 ug/ml, respectively, indicating the potent bactericidal effect of the NPs. Also, S. aureus infected rats explored upregulation in the mRNA expression of TLR2 and TLR4 compared to healthy control groups. AV-CS-NP treatment reverses the case where there was repression in mRNA expression of TLR2 and TLR4 compared to S. aureus-treated rats.

Conclusion

These NPs can serve as potential candidates for the development of alternative antimicrobial agents.

[Fatalities in a litter of French bulldogs puppies due canine herpesvirus 1]

This case report describes the occurrence of canine herpesvirus 1 in a litter of French bulldogs. In addition, the literature dealing with CHV-1 in puppies is summarized. Two puppies were presented due to dyspnea. During the night, one of them developed diarrhea as well as a highly disturbed general condition and was subsequently euthanized the following day. The second puppy was euthanized 6 hours later with a highly disturbed general condition. Necropsy revealed evidence of canine herpesvirus infection. This was confirmed by a virological examination. The presented case report shows that canine herpesvirus infection must also be considered as a cause of death in newborn puppies in Germany.

A retrospective cohort study of canid herpesvirus-1 seroprevalence and epidemiology in kennel dogs in Croatia

Canid alphaherpesvirus-1 (CaHV-1) is an endemic pathogen of dogs worldwide. CaHV-1 is often related to abortions, neonatal mortality, and the death of puppies. Since the first description of the virus in 1965, there has been no generally accepted method for diagnosing CaHV-1. Many authors used the virus neutralisation test (VNT) as a 'reference standard' due to its high specificity. Nasal, vaginal, preputial swabs and serum samples for this study were collected in the population of kennel dogs in Croatia. To determine the optimal VNT protocol, three modifications of the VNT were compared. These modifications were: VNT using native serum samples, VNT using thermally inactivated serum samples, and VNT using thermally inactivated serum samples with the addition of the complement. The correlation between the results of the VNT methods was significant (P < 0.001). Of all three modifications of VNT, the one using native serum samples was the one that increased VNT sensitivity. The overall seroprevalence of CaHV-1 was 32.02%. The PCR did not confirm the CaHV-1 presence in collected swabs. According to analysed anamnestic data, significant risk factors for CaHV-1 infection were: kennel size, attendance at the dog shows, hunt trials, kennel disinfection protocols, and mating. The oestrus cycle had no significant effect on seropositivity. The study results indicate that CaHV-1 spreads horizontally between dams living in kennels and in males during mating. Although there was no correlation between seropositivity and a history of reproductive disorders, significantly more stillborn puppies were recorded in seronegative dames (P < 0.01).

Characterization of intestinal microbiota in normal weight and overweight Border Collie and Labrador Retriever dogs

Obesity in dogs is an emerging issue that affects canine health and well-being. Its development is ascribed to several factors, including genetic predisposition and dietary management, and recent evidence suggests that intestinal microbiota may be involved as well. Previous works have shown obesity to be linked to significant changes in gut microbiota composition in humans and mice, but only limited information is available on the role played by canine gut microbiota. The aim of this exploratory study was to investigate whether composition of canine faecal microbiota may be influenced by overweight condition and breed. All the enrolled companion dogs were young adults, intact, healthy, and fed commercial extruded pet food; none had received antibiotics, probiotics or immunosuppressant drugs in the previous six months. Labrador Retriever (LR) and Border Collie (BC) were chosen as reference breeds and Body Condition Score (BCS) on a 9-point scale as reference method for evaluating body fat. The faecal microbial communities of 15 lean (BCS 4-5/9; 7 LRs and 8 BCs) and 14 overweight (BCS > 5/9; 8 LRs and 6 BCs) family dogs were analysed using 16S rRNA gene sequencing. Moreover, for each dog, the daily intake of energy (kcal/d) and dietary macronutrients (g/d) were calculated according to an accurate feeding history collection. Firmicutes and Bacteroidetes resulted the predominant phyla (51.5 ± 10.0% and 33.4 ± 8.5%, respectively) in all dogs. Bioinformatic and statistical analysis revealed that no bacterial taxon differed significantly based on body condition, except for genus Allisonella (p < 0.05); BC gut microbiota was richer (p < 0.05) in bacteria belonging to phyla Actinobacteria (family Coriobacteriaceae in particular) and Firmicutes (Allobaculum and Roseburia genera). No remarkable differences were recorded either for diversity indices (i.e., alpha diversity, p > 0.10) or for divergence within the sample set (i.e., beta diversity, p > 0.05). PERMANOVA tests performed on single factors demonstrated the tendency of dietary protein to influence the recruited dogs' microbiota beta-diversity at amplicon sequence variant level (p = 0.08). In conclusion, the faecal microbiota of dogs involved in this exploratory study showed no major variations based on body condition. However, our findings suggested that certain bacterial taxa previously acknowledged in obesity-related studies may be detected in dissimilar amounts depending on canine breed.

Metatranscriptomics Analysis Reveals Diverse Viral RNA in Cutaneous Papillomatous Lesions of Cattle

Bovine papillomavirus (BPV) is associated with bovine papillomatosis, a disease that forms benign warts in epithelial tissues, as well as malignant lesions. Previous studies have detected a co-infection between BPV and other viruses, making it likely that these co-infections could influence disease progression. Therefore, this study aimed to identify and annotate viral genes in cutaneous papillomatous lesions of cattle. Sequences were obtained from the GEO database, and an RNA-seq computational pipeline was used to analyze 3 libraries from bovine papillomatous lesions. In total, 25 viral families were identified, including Poxviridae, Retroviridae, and Herpesviridae. All libraries shared similarities in the viruses and genes found. The viral genes shared similarities with BPV genes, especially for functions as virion entry pathway, malignant progression by apoptosis suppression and immune system control. Therefore, this study presents relevant data extending the current knowledge regarding the viral microbiome in BPV lesions and how other viruses could affect this disease.

Disease Progression in Lake Trout (Salvelinus namaycush) Experimentally Infected With Epizootic Epitheliotropic Disease Virus (Salmonid Herpesvirus-3)

Epizootic epitheliotropic disease virus (salmonid herpesvirus-3; EEDV) is responsible for the death of millions of hatchery-raised lake trout (Salvelinus namaycush) in the Laurentian Great Lakes Basin. However, little is known about its biology, pathology, tropism, and host interactions. In this study, the presence and disease progression of EEDV were evaluated following exposure of naïve juvenile lake trout to EEDV via bath immersion under controlled laboratory conditions (n = 84 infected; n = 44 control). Individual tissues (n = 10 per fish), collected over 6 weeks, were analyzed for viral load by quantitative polymerase chain reaction, gross and histopathologic changes, and virus cellular targets using in situ hybridization. Skin, fin, and ocular tissues were the earliest viral targets and yielded the highest viral loads throughout the course of infection. Early gross lesions included exophthalmia, ocular hemorrhage, fin congestion, and hyperemia of visceral blood vessels. Advanced disease was characterized by multifocal to coalescing erosions and ulcerations of the skin, and congestion of visceral organs. Microscopically, there was cellular degeneration and necrosis in the epidermis and spleen, and lymphohistiocytic perivasculitis of the dermis, omentum, and the epicardium. EEDV DNA was first detected by in situ hybridization in epithelial cells of the epidermis, with subsequent labeling in the epithelial lining of primary and secondary gill lamellae. During advanced disease, EEDV was detected in endothelial and dendritic cells as well as blood monocytes. This study characterized EEDV tissue tropism and associated pathologic features, to guide research aimed at understanding EEDV disease ecology and improving strategies for disease control.

First molecular study of Canine herpesvirus-1 in reproductive specimens of adult dogs in southeast of Iran

Canine herpesvirus-1 (CHV-1) is recognized to be enzootic in the dog population with a widespread distribution. This pathogen leads to a lethal generalized illness in newborn puppies and is associated with reproductive disorders. CHV-1 should be considered as an important pathogen of neonatal death and infertility; so, it appears to pose a threat for breeding kennels. Although serologic data point to the circulation of CHV-1 among dogs of Iran are available, no definitive diagnosis has been conducted based on the molecular assay. So, this research was done to detect the prevalence of CHV-1 in dogs of Kerman. In this study, the presence of CHV-1 in vaginal specimens and biopsies of the uterus of dogs referring to the Veterinary Hospital of Shahid Bahonar University of Kerman was determined. Fifteen uterine samples and seven vaginal samples were included in group of the pregnant dogs. Moreover, thirteen uterine samples and twenty vaginal samples were related to the dogs displaying suspicious clinical signs such as reproductive disorders. Samples were collected and evaluated using real-time PCR. Viral DNA was detected in 21 samples from a total of 140 (15 %) collected samples which were related to 14 uterine samples (20 %) and 7 (10 %) vaginal specimens. The association of this virus with age, breed, housing, pregnancy and reproductive disorders was not significant. Five positive reproductive samples were belonged to the dogs with a history of reproductive disorders including pyometra, metritis, stillbirths, vaginitis and vaginal prolapse. This study is the first molecular detection of CHV-1 in reproductive samples of dogs in Iran. Considering the significant prevalence of this virus, it is necessary to carry out management measures in controlling and preventing this disease. Tracing CHV-1 requires further research on this virus in dogs of this region.

YARS2 Missense Variant in Belgian Shepherd Dogs with Cardiomyopathy and Juvenile Mortality

Dog puppy loss by the age of six to eight weeks after normal development is relatively uncommon. Necropsy findings in two spontaneously deceased Belgian Shepherd puppies indicated an abnormal accumulation of material in several organs. A third deceased puppy exhibited mild signs of an inflammation in the central nervous system and an enteritis. The puppies were closely related, raising the suspicion of a genetic cause. Pedigree analysis suggested a monogenic autosomal recessive inheritance. Combined linkage and homozygosity mapping assigned the most likely position of a potential genetic defect to 13 genome segments totaling 82 Mb. The genome of an affected puppy was sequenced and compared to 645 control genomes. Three private protein changing variants were found in the linked and homozygous regions. Targeted genotyping in 96 Belgian Shepherd dogs excluded two of these variants. The remaining variant, YARS2:1054G>A or p.Glu352Lys, was perfectly associated with the phenotype in a cohort of 474 Belgian Shepherd dogs. YARS2 encodes the mitochondrial tyrosyl-tRNA synthetase 2 and the predicted amino acid change replaces a negatively charged and evolutionary conserved glutamate at the surface of the tRNA binding domain of YARS2 with a positively charged lysine. Human patients with loss-of-function variants in YARS2 suffer from myopathy, lactic acidosis, and sideroblastic anemia 2, a disease with clinical similarities to the phenotype of the studied dogs. The carrier frequency was 27.2% in the tested Belgian Shepherd dogs. Our data suggest YARS2:1054G>A as the candidate causative variant for the observed juvenile mortality.

Bovine respiratory syncytial virus in experimentally exposed and rechallenged calves; viral shedding related to clinical signs and the potential for transmission

Background

Bovine respiratory syncytial virus (BRSV) is an important respiratory pathogen worldwide, detrimentally affecting the economy and animal welfare. To prevent and control BRSV infection, further knowledge on virus shedding and transmission potential in individual animals is required. This study aimed to detect viral RNA and infective virions during BRSV infection to evaluate duration of the transmission period and correlation with clinical signs of disease. The outcome of BRSV re-exposure on calves, their housing environment and effect of introduction of sentinel calves was also investigated.

A live animal experiment including 10 calves was conducted over 61 days. Initially, two calves were inoculated with a non-passaged BRSV field isolate. Two days later, six naïve calves (EG: Exposed group) were introduced for commingling and four weeks later, another two naïve calves (SG: Sentinel group) were introduced. Seven weeks after commingling, EG animals were re-inoculated. Clinical examination was performed daily. Nasal swabs were collected regularly and analysed for viral RNA by RT-ddPCR, while virus isolation was performed in cell culture. BRSV serology was performed with ELISA.

Results

All the EG calves seroconverted and showed clinical signs of respiratory disease. Viral RNA was detected from days 1–27 after exposure, while the infective virus was isolated on day 6 and 13. On day 19, all animals were seropositive and virus could not be isolated. Total clinical score for respiratory signs corresponded well with the shedding of viral RNA. The SG animals, introduced 27 days after exposure, remained negative for BRSV RNA and stayed seronegative throughout the study. Inoculation of the EG calves seven weeks after primary infection did not lead to new shedding of viral RNA or clinical signs of disease.

Conclusion

Viral RNA was detected in nasal swabs from the calves up to four weeks after exposure. The detection and amount of viral RNA corresponded well with the degree of respiratory signs. The calves were shedding infective virions for a considerable shorter period, and naïve calves introduced after four weeks were not infected. Infected calves were protected from reinfection for at least seven weeks. This knowledge is useful to prevent spread of BRSV.

Development of a nanoparticle-assisted PCR assay for detection of bovine respiratory syncytial virus

Background

Bovine respiratory syncytial virus (BRSV) is a common pathogen causing respiratory disease in cattle and a significant contributor to the bovine respiratory disease (BRD) complex. BRSV is widely distributed around the world, causing severe economic losses. This study we established a new molecular detection method of BRSV pathogen NanoPCR attributed to the combination of nano-particles in traditional PCR (Polymerase chain reaction) technology.

Results

In this study, the BRSV NanoPCR assay was developed, and its specificity and sensitivity were investigated. The results showed that no cross-reactivity was observed for the NanoPCR assay for related viruses, including the infectious bovine rhinotracheitis virus (IBRV), bovine viral diarrhea virus (BVDV), and bovine parainfluenza virus type 3 (BPIV3), and the assay was more sensitive than the conventional PCR assay, with a detection limit of 1.43 × 10² copies recombinant plasmids per reaction, compared with 1.43 × 10³ copies for conventional PCR analysis. Moreover, thirty-nine clinical bovine samples collected from two provinces in North-Eastern China, 46.15% were determined BRSV positive by our NanoPCR assay, compared with 23.07% for conventional PCR.

Conclusions

This is the first report to demonstrate the application of a NanoPCR assay for the detection of BRSV. The sensitive and specific NanoPCR assay developed in this study can be applied widely in clinical diagnosis and field surveillance of BRSV infection.

Long-term shedding of Canine alphaherpesvirus 1 in naturally infected newborn pups

The long-term shedding of Canine alphaherpesvirus 1 (CaHV-1) by neonatal pups with natural infection is reported. The pups belonged to a litter of 11 pointers of a breeding kennel in southern Italy, 9 of which developed a fatal form of systemic infection, as resulted by the detection of CaHV-1 in internal organs (kidney, liver, lung and brain) of one of this dogs and in the vaginal swab of their mother. The two remaining animals displayed a milder form of disease, with one pup showing ocular involvement, and underwent a progressive recovery. These pups were monitored from 11 to 36  days of age, showing a long-term shedding of the virus through the nasal and ocular secretions and the faeces. CaHV-1 shedding, as assessed by means of a specific and sensitive real-time PCR assay, occurred mainly through the nasal secretions, although the pup displaying ocular disease shed the virus at high titres and for a long period even in the ocular secretions.

New Paradigms for the Study of Ocular Alphaherpesvirus Infections: Insights into the Use of Non-Traditional Host Model Systems

Ocular herpesviruses, most notably human alphaherpesvirus 1 (HSV-1), canid alphaherpesvirus 1 (CHV-1) and felid alphaherpesvirus 1 (FHV-1), infect and cause severe disease that may lead to blindness. CHV-1 and FHV-1 have a pathogenesis and induce clinical disease in their hosts that is similar to HSV-1 ocular infections in humans, suggesting that infection of dogs and cats with CHV-1 and FHV-1, respectively, can be used as a comparative natural host model of herpesvirus-induced ocular disease. In this review, we discuss both strengths and limitations of the various available model systems to study ocular herpesvirus infection, with a focus on the use of these non-traditional virus-natural host models. Recent work has demonstrated the robustness and reproducibility of experimental ocular herpesvirus infections in dogs and cats, and, therefore, these non-traditional models can provide additional insights into the pathogenesis of ocular herpesvirus infections.

Viral molecular and pathological investigations of Canid herpesvirus 1 infection associated respiratory disease and acute death in dogs

Canid herpesvirus 1 (CaHV-1) is a member of the canine infectious respiratory disease complex (CIRDC). The outcome of CaHV-1 infection can be occasionally fatal. So far, no information on CaHV-1 circulation in Thailand has been reported resulting in a lack of preventive strategies. In this study, nasal (NS) and oropharyngeal (OS) swabs were collected from 100 live dogs with respiratory distress. Among them, 23 pleural effusions were aspirated. A panel of CIRDC-associated viruses was screened by (RT)-PCR, including CaHV-1, CIV, CPIV, CDV, CRCoV and CAdV-2, for all collected samples. The CaHV-1 was detected in 32 dogs. Additionally, CaHV-1 was consistently detected in six pleural effusions. Most CaHV-1 infected dogs were over 5 years of age (43.8%) and expressed a mild nasal discharge. Pathological results of four three-month-old puppies, naturally moribund from respiratory disease, revealed a severe multifocal necrotic-hemorrhagic disease in several organs without pathognomonic inclusion bodies. They were only found to be CaHV-1 positive by PCR. Phylogenetic analysis demonstrated concordant results of CaHV-1 circulation in Thailand. Although mostly found as a co-infection with other CIRDC viruses (68.8%) it also occurred alone. Therefore, rapid ante-mortem diagnosis might facilitate the investigation of unclassical CaHV-1 infection, which is fatal in neonates and causes illness in annually core-vaccinated adults.

Immunology of bovine respiratory syncytial virus infection of cattle

Bovine respiratory syncytial virus (BRSV) is a respiratory pathogen of cattle that causes severe disease in calves alone and as one of several viruses and bacteria that cause bovine respiratory disease complex. Like human RSV this virus modulates the immune response to avoid stimulation of a vibrant CD8+ T cytotoxic cell response and instead promotes a Th2 response. The Th2 skew sometimes results in the production of IgE antibodies and depresses production of the Th1 cytokine interferon γ. Innate immune cells have a pivotal role in guiding the adaptive response to BRSV, with selective secretion of cytokines by pulmonary dendritic cells. Here we review some of the pertinent observations on immune responses to BRSV infection and vaccination and illustrate how experimental infection models have been used to elucidate the immunopathogenesis of BRSV infection. Recent experiments using intranasal vaccination and/or immune modulation with DNA based adjuvants show promise for effective vaccination by the stimulation of Th1 T cell responses.

Human and bovine respiratory syncytial virus vaccine research and development

Human (HRSV) and bovine (BRSV) respiratory syncytial viruses (RSV) are two closely related viruses, which are the most important causative agents of respiratory tract infections of young children and calves, respectively. BRSV vaccines have been available for nearly 2 decades. They probably have reduced the prevalence of RSV infection but their efficacy needs improvement. In contrast, despite decades of research, there is no currently licensed vaccine for the prevention of HRSV disease. Development of a HRSV vaccine for infants has been hindered by the lack of a relevant animal model that develops disease, the need to immunize immunologically immature young infants, the difficulty for live vaccines to find the right balance between attenuation and immunogenicity, and the risk of vaccine-associated disease. During the past 15 years, intensive research into a HRSV vaccine has yielded vaccine candidates, which have been evaluated in animal models and, for some of them, in clinical trials in humans. Recent formulations have focused on subunit vaccines with specific CD4+ Th-1 immune response-activating adjuvants and on genetically engineered live attenuated vaccines. It is likely that different HRSV vaccines and/or combinations of vaccines used sequentially will be needed for the various populations at risk. This review discusses the recent advances in RSV vaccine development.

Age-dependent differences in cytokine and antibody responses after experimental RSV infection in a bovine model

Respiratory syncytial virus (RSV) causes severe respiratory disease in both infants and calves. As in humans, bovine RSV (BRSV) infections are most severe in the first 6 months of life. In this study, experimental infection with BRSV was performed in calves aged 1-5, 9-16 or 32-37 weeks. Compared to younger animals, older calves showed significantly less fever and lower TNFalpha levels and less virus-specific IFNgamma release. In addition, blood from older animals had more mononuclear cells, more B cells and stronger BRSV-specific IgA and neutralising antibody responses to infection. A strong "inflammatory" but weak humoral antiviral response in very young animals suggests that enhanced inflammation contributes to disease during RSV infection during the early postnatal period.