Bovine coronavirus in naturally and experimentally exposed calves; viral shedding and the potential for transmission

Development and application of one-step multiplex Real-Time PCR for detection of three main pathogens associated with bovine neonatal diarrhea

Introduction

Neonatal calf diarrhea (NCD) is one of the most common diseases in calves, causing huge economic and productivity losses to the bovine industry worldwide. The main pathogens include bovine rotavirus (BRV), bovine coronavirus (BCoV), and Enterotoxigenic Escherichia coli (ETEC) K99. Since multiple infectious agents can be involved in calf diarrhea, detecting each causative agent by traditional methods is laborious and expensive.

Methods

In this study, we developed a one-step multiplex Real-Time PCR assay to simultaneously detect BRV, BCoV, and E. coli K99+. The assay performance on field samples was evaluated on 1100 rectal swabs of diseased cattle with diarrhea symptoms and compared with the conventional gel-based RT-PCR assay detect BRV, BCoV, and E. coli K99+.

Results

The established assay could specifically detect the target pathogens without cross-reactivity with other pathogens. A single real-time PCR can detect ~1 copy/µL for each pathogen, and multiplex real-time PCR has a detection limit of 10 copies/µL. Reproducibility as measured by standard deviation and coefficient of variation were desirable. The triple real-time PCR method established in this study was compared with gel-based PT-PCR. Both methods are reasonably consistent, while the real-time PCR assay was more sensitive and could rapidly distinguish these three pathogens in one tube. Analysis of surveillance data showed that BRV and BCoV are major enteric viral pathogens accounting for calves' diarrhea in China.

Discussion

The established assay has excellent specificity and sensitivity and was suitable for clinical application. The robustness and high-throughput performance of the developed assay make it a powerful tool in diagnostic applications and calf diarrhea research. ​.

The Role of Mycoplasma bovirhinis in the Development of Singular and Concomitant Respiratory Infections in Dairy Calves from Southern Brazil

The role of Mycoplasma bovirhinis in the development of pulmonary disease in cattle is controversial and was never evaluated in cattle from Latin America. This study investigated the respiratory infection dynamics associated with M. bovirhinis in suckling calves from 15 dairy cattle herds in Southern Brazil. Nasal swabs were obtained from asymptomatic (n = 102) and calves with clinical manifestations (n = 103) of bovine respiratory disease (BRD) and used in molecular assays to identify the specific genes of viral and bacterial disease pathogens of BRD. Only M. bovirhinis, bovine coronavirus (BCoV), ovine gammaherpesvirus 2 (OvGHV2), Histophilus somni, Pasteurella multocida, and Mannheimia haemolytica were detected. M. bovirhinis was the most frequently diagnosed pathogen in diseased (57.8%; 59/102) and asymptomatic (55.3%; 57/103) calves at all farms. BCoV-related infections were diagnosed in diseased (52%; 53/102) and asymptomatic (51.4%; 53/103) calves and occurred in 93.3% (14/15) of all farms. Similarly, infectious due to OvGHV2 occurred in diseased (37.2%; 38/102) and asymptomatic (27.2%; /28/103) calves and were diagnosed in 80% (12/15) of all farms investigated. Significant statistical differences were not identified when the two groups of calves were compared at most farms, except for infections due to OvGHV2 that affected five calves at one farm. These results demonstrated that the respiratory infection dynamics of M. bovirhinis identified in Southern Brazil are similar to those observed worldwide, suggesting that there is not enough sufficient collected data to consider M. bovirhinis as a pathogen of respiratory infections in cattle. Additionally, the possible roles of BCoV and OvGHV2 in the development of BRD are discussed.

Gene expression profile of HCT-8 cells following single or co-infections with Cryptosporidium parvum and bovine coronavirus

Among the causative agents of neonatal diarrhoea in calves, two of the most prevalent are bovine coronavirus (BCoV) and the intracellular parasite Cryptosporidium parvum. Although several studies indicate that co-infections are associated with greater symptom severity, the host-pathogen interplay remains unresolved. Here, our main objective was to investigate the modulation of the transcriptome of HCT-8 cells during single and co-infections with BCoV and C. parvum. For this, HCT-8 cells were inoculated with (1) BCoV alone, (2) C. parvum alone, (3) BCoV and C. parvum simultaneously. After 24 and 72 h, cells were harvested and analyzed using high-throughput RNA sequencing. Following differential expression analysis, over 6000 differentially expressed genes (DEGs) were identified in virus-infected and co-exposed cells at 72 hpi, whereas only 52 DEGs were found in C. parvum-infected cells at the same time point. Pathway (KEGG) and gene ontology (GO) analysis showed that DEGs in the virus-infected and co-exposed cells were mostly associated with immune pathways (such as NF-κB, TNF-α or, IL-17), apoptosis and regulation of transcription, with a more limited effect exerted by C. parvum. Although the modulation observed in the co-infection was apparently dominated by the virus, over 800 DEGs were uniquely expressed in co-exposed cells at 72 hpi. Our findings provide insights on possible biomarkers associated with co-infection, which could be further explored using in vivo models.

Expanding the range of the respiratory infectome in Australian feedlot cattle with and without respiratory disease using metatranscriptomics

BACKGROUND

Bovine respiratory disease (BRD) is one of the most common diseases in intensively managed cattle, often resulting in high morbidity and mortality. Although several pathogens have been isolated and extensively studied, the complete infectome of the respiratory complex consists of a more extensive range unrecognised species. Here, we used total RNA sequencing (i.e., metatranscriptomics) of nasal and nasopharyngeal swabs collected from animals with and without BRD from two cattle feedlots in Australia.

RESULTS

A high abundance of bovine nidovirus, influenza D, bovine rhinitis A and bovine coronavirus was found in the samples. Additionally, we obtained the complete or near-complete genome of bovine rhinitis B, enterovirus E1, bovine viral diarrhea virus (sub-genotypes 1a and 1c) and bovine respiratory syncytial virus, and partial sequences of other viruses. A new species of paramyxovirus was also identified. Overall, the most abundant RNA virus, was the bovine nidovirus. Characterisation of bacterial species from the transcriptome revealed a high abundance and diversity of Mollicutes in BRD cases and unaffected control animals. Of the non-Mollicutes species, Histophilus somni was detected, whereas there was a low abundance of Mannheimia haemolytica.

CONCLUSION

This study highlights the use of untargeted sequencing approaches to study the unrecognised range of microorganisms present in healthy or diseased animals and the need to study previously uncultured viral species that may have an important role in cattle respiratory disease. Video Abstract.

Prevalence of bovine coronavirus in cattle in China: A systematic review and meta-analysis

Bovine coronavirus (BCoV) is one of the important pathogens that cause calf diarrhea (CD), winter dysentery (WD), and the bovine respiratory disease complex (BRDC), and spreads worldwide. An infection of BCoV in cattle can lead to death of young animals, stunted growth, reduced milk production, and milk quality, thus bringing serious economic losses to the bovine industry. Therefore, it is necessary to prevent and control the spread of BCoV. Here, a systematic review and meta-analysis was conducted to assess the prevalence of BCoV in cattle in China before 2022. A total of 57 articles regarding the prevalence of BCoV in cattle in China were collected from five databases (PubMed, ScienceDirect, CNKI, VIP, and Wan Fang). Based on the inclusion criteria, a total of 15,838 samples were included, and 6,136 were positive cases. The overall prevalence of BCoV was 30.8%, with the highest prevalence rate (60.5%) identified in South China and the lowest prevalence (15.6%) identified in Central China. We also analyzed other subgroup information, included sampling years, sample sources, detection methods, breeding methods, age, type of cattle, presence of diarrhea, and geographic and climatic factors. The results indicated that BCoV was widely prevalent in China. Among all subgroups, the sample sources, detection methods, breeding methods, and presence or absence of diarrheal might be potential risk factors responsible for BCoV prevalence. It is recommended to strengthen the detection of BCoV in cattle, in order to effectively control the spread of BCoV.

Bovine Enteroids as an In Vitro Model for Infection with Bovine Coronavirus

Bovine coronavirus (BCoV) is one of the major viral pathogens of cattle, responsible for economic losses and causing a substantial impact on animal welfare. Several in vitro 2D models have been used to investigate BCoV infection and its pathogenesis. However, 3D enteroids are likely to be a better model with which to investigate host–pathogen interactions. This study established bovine enteroids as an in vitro replication system for BCoV, and we compared the expression of selected genes during the BCoV infection of the enteroids with the expression previously described in HCT-8 cells. The enteroids were successfully established from bovine ileum and permissive to BCoV, as shown by a seven-fold increase in viral RNA after 72 h. Immunostaining of differentiation markers showed a mixed population of differentiated cells. Gene expression ratios at 72 h showed that pro-inflammatory responses such as IL-8 and IL-1A remained unchanged in response to BCoV infection. Expression of other immune genes, including CXCL-3, MMP13, and TNF-α, was significantly downregulated. This study shows that the bovine enteroids had a differentiated cell population and were permissive to BCoV. Further studies are necessary for a comparative analysis to determine whether enteroids are suitable in vitro models to study host responses during BCoV infection.

Coronaviruses: Troubling Crown of the Animal Kingdom

The existence of coronaviruses has been known for many years. These viruses cause significant disease that primarily seems to affect agricultural species. Human coronavirus disease due to the 2002 outbreak of Severe Acute Respiratory Syndrome and the 2012 outbreak of Middle East Respiratory Syndrome made headlines; however, these outbreaks were controlled, and public concern quickly faded. This complacency ended in late 2019 when alarms were raised about a mysterious virus responsible for numerous illnesses and deaths in China. As we now know, this novel disease called Coronavirus Disease 2019 (COVID-19) was caused by Severe acute respiratory syndrome-related-coronavirus-2 (SARS-CoV-2) and rapidly became a worldwide pandemic. Luckily, decades of research into animal coronaviruses hastened our understanding of the genetics, structure, transmission, and pathogenesis of these viruses. Coronaviruses infect a wide range of wild and domestic animals, with significant economic impact in several agricultural species. Their large genome, low dependency on host cellular proteins, and frequent recombination allow coronaviruses to successfully cross species barriers and adapt to different hosts including humans. The study of the animal diseases provides an understanding of the virus biology and pathogenesis and has assisted in the rapid development of the SARS-CoV-2 vaccines. Here, we briefly review the classification, origin, etiology, transmission mechanisms, pathogenesis, clinical signs, diagnosis, treatment, and prevention strategies, including available vaccines, for coronaviruses that affect domestic, farm, laboratory, and wild animal species. We also briefly describe the coronaviruses that affect humans. Expanding our knowledge of this complex group of viruses will better prepare us to design strategies to prevent and/or minimize the impact of future coronavirus outbreaks.

Bovine Coronavirus Co-infection and Molecular Characterization in Dairy Calves With or Without Clinical Respiratory Disease

Bovine respiratory disease (BRD) is considered a major cause of morbidity and mortality in young calves and is caused by a range of infectious agents, including viruses and bacteria. This study aimed to determine the frequency of viral and bacterial pathogens detected in calves with BRD from high-production dairy cattle herds and to perform the molecular characterization of N and S1 genes in identified bovine coronavirus (BCoV) strains. Nasal swabs were collected from 166 heifer calves, namely, 85 symptomatic and 81 asymptomatic calves aged between 5 and 90 days, from 10 dairy cattle herds. Nasal swabs were evaluated using molecular techniques for the identification of viruses (BCoV, bovine alphaherpesvirus 1, bovine viral diarrhea virus, bovine parainfluenza virus 3, and bovine respiratory syncytial virus) and bacteria (Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, and Mycoplasma bovis). In addition, five and two BCoV-positive samples were submitted to N and S1 gene amplification and nucleotide sequencing, respectively. The frequency of diagnosis of BCoV was higher (56%, 93/166) than the frequency of P. multocida (39.8%, 66/166) and M. haemolytica (33.1%, 55/166). The three microorganisms were identified in the calves of symptomatic and asymptomatic heifer calve groups. All other pathogens included in the analyses were negative. In the phylogenetic analysis of the S1 gene, the Brazilian strains formed a new branch, suggesting a new genotype, called # 15; from the N gene, the strains identified here belonged to cluster II. This study describes high rates of BCoV, P. multocida, and M. haemolytica in heifer calves from high-production dairy cattle herds with BRD. Additionally, the molecular characterization provides evidence that the circulating BCoV strains are ancestrally different from the prototype vaccine strains and even different BCoV strains previously described in Brazil.

Bovine Coronavirus Infects the Respiratory Tract of Cattle Challenged Intranasally

Bovine Coronavirus (BCoV) is a member of a family of viruses associated with both enteric and respiratory diseases in a wide range of hosts. BCoV has been well-established as a causative agent of diarrhea in cattle, however, its role as a respiratory pathogen is controversial. In this study, fifteen calves were challenged intranasally with virulent BCoV in order to observe the clinical manifestation of the BCoV infection for up to 8 days after initial challenge, looking specifically for indication of symptoms, pathology, and presence of viral infection in the respiratory tract, as compared to six unchallenged control calves. Throughout the study, clinical signs of disease were recorded and nasal swabs were collected daily. Additionally, bronchoalveolar lavage (BAL) was performed at 4 days Post-challenge, and blood and tissue samples were collected from calves at 4, 6, or 8 days Post-challenge to be tested for the presence of BCoV and disease pathology. The data collected support that this BCoV challenge resulted in respiratory infections as evidenced by the isolation of BCoV in BAL fluids and positive qPCR, immunohistochemistry (IHC), and histopathologic lesions in the upper and lower respiratory tissues. This study can thus be added to a growing body of data supporting that BCoV is a respiratory pathogen and contributor to respiratory disease in cattle.

Environmental Effects on Viable Virus Transport and Resuspension in Ventilation Airflow

To understand how SARS-CoV-2 spreads indoors, in this study bovine coronavirus was aerosolized as simulant into a plexiglass chamber with coupons of metal, wood and plastic surfaces. After aerosolization, chamber and coupon surfaces were swiped to quantify the virus concentrations using quantitative polymerase chain reaction (qPCR). Bio-layer interferometry showed stronger virus association on plastic and metal surfaces, however, higher dissociation from wood in 80% relative humidity. Virus aerosols were collected with the 100 L/min wetted wall cyclone and the 50 L/min MD8 air sampler and quantitated by qPCR. To monitor the effect of the ventilation on the virus movement, PRD1 bacteriophages as virus simulants were disseminated in a ¾ scale air-conditioned hospital test room with twelve PM2.5 samplers at 15 L/min. Higher virus concentrations were detected above the patient’s head and near the foot of the bed with the air inlet on the ceiling above, exhaust bottom left on the wall. Based on room layout, air measurements and bioaerosol collections computational flow models were created to visualize the movement of the virus in the room airflow. The addition of air curtain at the door minimized virus concentration while having the inlet and exhaust on the ceiling decreased overall aerosol concentration. Controlled laboratory experiments were conducted in a plexiglass chamber to gain more insight into the fundamental behavior of aerosolized SARS-CoV-2 and understand its fate and transport in the ambient environment of the hospital room.

Human Challenge Studies with Coronaviruses Old and New

Coronavirus infections have been known to cause disease in animals since as early as the 1920s. However, only seven coronaviruses capable of causing human disease have been identified thus far. These Human Coronaviruses (HCoVs) include the causes of the common cold, but more recent coronaviruses that have emerged (i.e. SARS-CoV, MERS-CoV and SARS-CoV-2) are associated with much greater morbidity and mortality. HCoVs have been relatively under-studied compared to other common respiratory infections, as historically they have presented with mild symptoms. This has led to a relatively limited understanding of their animal reservoirs, transmission and determinants of immune protection. To address this, human infection challenge studies with HCoVs have been performed that enable a detailed clinical and immunological analysis of the host response at specific time points under controlled conditions with standardised viral inocula. Until recently, all such human challenge studies were conducted with common cold HCoVs, with the study of SARS-CoV and MERS-CoV unacceptable due to their greater pathogenicity. However, with the emergence of SARS-CoV-2 and the COVID-19 pandemic during which severe outcomes in young healthy adults have been rare, human challenge studies with SARS-CoV-2 are now being developed. Two SARS-CoV-2 human challenge studies in the UK studying individuals with and without pre-existing immunity are underway. As well as providing a platform for testing of antivirals and vaccines, such studies will be critical for understanding the factors associated with susceptibility to SARS-CoV-2 infection and thus developing improved strategies to tackle the current as well as future HCoV pandemics. Here, we summarise the major questions about protection and pathogenesis in HCoV infection that human infection challenge studies have attempted to answer historically, as well as the knowledge gaps that aim to be addressed with contemporary models.

Literature Review: Coinfection in Young Ruminant Livestock-Cryptosporidium spp. and Its Companions

The protozoan Cryptosporidium parvum is one of the major causative pathogens of diarrhoea in young ruminants; therefore, it causes economic losses and impairs animal welfare. Besides C. parvum, there are many other non-infectious and infectious factors, such as rotavirus, Escherichia coli, and Giardia duodenalis, which may lead to diarrhoeic disease in young livestock. Often, more than one infectious agent is detected in affected animals. Little is known about the interactions bet-ween simultaneously occurring pathogens and their potential effects on the course of disease. In this review, a brief overview about pathogens associated with diarrhoea in young ruminants is presented. Furthermore, information about coinfections involving Cryptosporidium is provided.

One Health: EAACI Position Paper on coronaviruses at the human-animal interface, with a specific focus on comparative and zoonotic aspects of SARS-CoV-2

The latest outbreak of a coronavirus disease in 2019 (COVID‐19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), evolved into a worldwide pandemic with massive effects on health, quality of life, and economy. Given the short period of time since the outbreak, there are several knowledge gaps on the comparative and zoonotic aspects of this new virus. Within the One Health concept, the current EAACI position paper dwells into the current knowledge on SARS‐CoV‐2’s receptors, symptoms, transmission routes for human and animals living in close vicinity to each other, usefulness of animal models to study this disease and management options to avoid intra‐ and interspecies transmission. Similar pandemics might appear unexpectedly and more frequently in the near future due to climate change, consumption of exotic foods and drinks, globe‐trotter travel possibilities, the growing world population, the decreasing production space, declining room for wildlife and free‐ranging animals, and the changed lifestyle including living very close to animals. Therefore, both the society and the health authorities need to be aware and well prepared for similar future situations, and research needs to focus on prevention and fast development of treatment options (medications, vaccines).

Natural Bovine Coronavirus Infection in a Calf Persistently Infected with Bovine Viral Diarrhea Virus: Viral Shedding, Immunological Features and S Gene Variations

Simple Summary

The evolution of a bovine coronavirus (BCoV) natural infection in a calf persistently infected with bovine viral diarrhea virus (BVDV) was described. The infected calf developed intermittent nasal discharge, diarrhea and hyperthermia. The total number of leukocytes/mL and the absolute differential number of neutrophils and lymphocytes resulted within the normal range, but the monocytes increased at T28 (time 28 post-infection) and the CD8⁺ subpopulation increased at T7 and between T28 and T35. BCoV shedding in nasal discharges and feces was detected up to three weeks post infection (p.i.) and high antibody titers persisted for up to 8 weeks p.i. Virus shedding increased until T14, contrary to what was observed in a previous study where BCoV was detected with a lower load in the co-infected (BCoV/BVDV) calves than in the calves infected with BCoV only. We can suppose that BVDV may have exacerbated the long viral excretion, as well as favoring the onset of mutations in the genome of BCoV. An extensive study was performed to verify if the selective pressure in the S gene could be a natural mode of variation of BCoV.

Abstract

The evolution of a bovine coronavirus (BCoV) natural infection in a calf persistently infected with bovine viral diarrhea virus (BVDV) was described. The infected calf developed intermittent nasal discharge, diarrhea and hyperthermia. The total number of leukocytes/mL and the absolute differential number of neutrophils and lymphocytes resulted within the normal range, but monocytes increased at T28 (time 28 post-infection). Flow-cytometry analysis evidenced that the CD8⁺ subpopulation increased at T7 and between T28 and T35. BCoV shedding in nasal discharges and feces was detected up to three weeks post infection and high antibody titers persisted up to T56. The RNA BCoV load increased until T14, contrary to what was observed in a previous study where the fecal excretion of BCoV was significantly lower in the co-infected (BCoV/BVDV) calves than in the calves infected with BCoV only. We can suppose that BVDV may have modulated the BCoV infection exacerbating the long viral excretion, as well as favoring the onset of mutations in the genome of BCoV detected in fecal samples at T21. An extensive study was performed to verify if the selective pressure in the S gene could be a natural mode of variation of BCoV, providing data for the identification of new epidemic strains, genotypes or recombinant betacoronaviruses.

Interactions between Cryptosporidium parvum and bovine corona virus during sequential and simultaneous infection of HCT-8 cells

Neonatal diarrhoea in calves is one of the major health problems in the cattle industry. Although co-infections are often associated with greater severity of disease, there is limited information on any impact on the pathogens themselves. Herein, we studied Cryptosporidium parvum and bovine coronavirus (BCoV) in human HCT-8 cells, inoculated either sequentially or simultaneously, to investigate any influence from the co-infections. Quantitative results from (RT)-qPCR showed that prior inoculation with either of the two pathogens had no influence on the other. However, the results from simultaneous co-inoculation showed that entry of viral particles was higher when C. parvum sporozoites were present, although elevated virus copy numbers were no longer evident after 24 h. The attachment of BCoV to the sporozoites was probably due to specific binding, as investigations with bovine norovirus or equine herpes virus-1 showed no attachment between sporozoites and these viruses. Flow cytometry results at 72 h post inoculation revealed that C. parvum and BCoV infected 1-11% and 10-20% of the HCT-8 cells, respectively, with only 0.04% of individual cells showing double infections. The results from confocal microscopy corroborated those results, showing an increase in foci of infection from 24-72 h post inoculation for both pathogens, but with few double infected cells.

Seasonal and Age-Associated Pathogen Distribution in Newborn Calves with Diarrhea Admitted to ICU

Calf mortality constitutes a substantial loss for agriculture economy-based countries and is also a significant herd problem in developed countries. However, the occurrence and frequency of responsible gastro-intestinal (GI) pathogens in severe newborn diarrhea is still not well known. We aimed to determine the seasonal and age-associated pathogen distribution of severe diarrhea in newborn calves admitted to the intensive care unit (ICU) of Erciyes University animal hospital over a year. Fecal samples were collected during the ICU admissions, and specimens were subjected to a diarrheal pathogen screening panel that included bovine coronavirus (BCoV), Cryptosporidium spp., ETEC K99+, and bovine rotavirus, using RT-PCR and conventional PCR methods. Further isolation experiments were performed with permissive cell cultures and bacterial enrichment methods to identify the clinical importance of infectious pathogen shedding in the ICU. Among the hospitalized calves aged less than 45 days old, the majority of calves originated from small farms (85.9%). The pathogen that most frequently occurred was Cryptosporidium spp. (61.5%) followed by rotavirus (56.4%). The frequency of animal admission to ICU and GI pathogen identification was higher during the winter season (44.9%) when compared to other seasons. Most calves included in the study were 1-6 days old (44.9%). Lastly, co-infection with rotavirus and Cryptosporidium spp. occurred more frequently than other dual or multi-infection events. This study was the first to define severe diarrhea-causing GI pathogens from ICU admitted newborn calves in Turkey.

SARS-CoV-2 Viral Shedding and Transmission Dynamics: Implications of WHO COVID-19 Discharge Guidelines

The evolving nature of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has necessitated periodic revisions of COVID-19 patient treatment and discharge guidelines. Since the identification of the first COVID-19 cases in November 2019, the World Health Organization (WHO) has played a crucial role in tackling the country-level pandemic preparedness and patient management protocols. Among others, the WHO provided a guideline on the clinical management of COVID-19 patients according to which patients can be released from isolation centers on the 10th day following clinical symptom manifestation, with a minimum of 72 additional hours following the resolution of symptoms. However, emerging direct evidence indicating the possibility of viral shedding 14 days after the onset of symptoms called for evaluation of the current WHO discharge recommendations. In this review article, we carried out comprehensive literature analysis of viral shedding with specific focus on the duration of viral shedding and infectivity in asymptomatic and symptomatic (mild, moderate, and severe forms) COVID-19 patients. Our literature search indicates that even though, there are specific instances where the current protocols may not be applicable ( such as in immune-compromised patients there is no strong evidence to contradict the current WHO discharge criteria.

Porcine Hemagglutinating Encephalomyelitis Virus Infection In Vivo and Ex Vivo

Porcine hemagglutinating encephalomyelitis virus (PHEV) is a betacoronavirus that causes vomiting and wasting disease and/or encephalomyelitis in suckling pigs. This study characterized PHEV infection, pathogenesis, and immune response in cesarean-derived, colostrum-deprived (CDCD) neonatal pigs. Infected animals developed mild respiratory, enteric, and neurological clinical signs between 2 to 13 days postoronasal inoculation (dpi). PHEV did not produce viremia, but virus shedding was detected in nasal secretions (1 to 10 dpi) and feces (2 to 7 dpi) by reverse transcriptase quantitative PCR (RT-qPCR). Viral RNA was detected in all tissues except liver, but the detection rate and RT-qPCR threshold cycle (C_T) values decreased over time. The highest concentration of virus was detected in inoculated piglets necropsied at 5 dpi in turbinate and trachea, followed by tonsils, lungs, tracheobronchial lymph nodes, and stomach. The most representative microscopic lesions were gastritis lymphoplasmacytic, moderate, multifocal, with perivasculitis, and neuritis with ganglia degeneration. A moderate inflammatory response, characterized by increased levels of interferon alpha (IFN-α) in plasma (5 dpi) and infiltration of T lymphocytes and macrophages were also observed. Increased plasma levels of interleukin-8 (IL-8) were detected at 10 and 15 dpi, coinciding with the progressive resolution of the infection. Moreover, a robust antibody response was detected by 10 dpi. An ex vivo air-liquid CDCD-derived porcine respiratory cells culture (ALI-PRECs) system showed virus replication in ALI-PRECs and cytopathic changes and disruption of ciliated columnar epithelia, thereby confirming the tracheal epithelia as a primary site of infection for PHEV.

IMPORTANCE Among the ∼46 virus species in the family Coronaviridae, many of which are important pathogens of humans and 6 of which are commonly found in pigs, porcine hemagglutinating encephalomyelitis remains one of the least researched. The present study provided a comprehensive characterization of the PHEV infection process and immune responses using CDCD neonatal pigs. Moreover, we used an ex vivo ALI-PRECs system resembling the epithelial lining of the tracheobronchial region of the porcine respiratory tract to demonstrate that the upper respiratory tract is a primary site of PHEV infection. This study provides a platform for further multidisciplinary studies of coronavirus infections.

Airborne Coronaviruses: Observations from Veterinary Experience

The virus responsible for the pandemic that has affected 152 countries worldwide is a new strain of coronavirus (CoV), which belongs to a family of viruses widespread in many animal species, including birds, and mammals including humans. Indeed, CoVs are known in veterinary medicine affecting several species, and causing respiratory and/or enteric, systemic diseases and reproductive disease in poultry. Animal diseases caused by CoV may be considered from the following different perspectives: livestock and poultry CoVs cause mainly "population disease"; while in companion animals they are a source of mainly "individual/single subject disease". Therefore, respiratory CoV diseases in high-density, large populations of livestock or poultry may be a suitable example for the current SARS-CoV-2/COVID-19 pandemic. In this review we describe some strategies applied in veterinary medicine to control CoV and discuss if they may help to develop practical and useful strategies to control the SARS-CoV-2/COVID-19 pandemic.

Bovine Coronavirus and the Associated Diseases

Coronaviruses (CoVs) possess the largest and most complex RNA genome (up to 32 kb) that encodes for 16 non-structural proteins regulating RNA synthesis and modification. Coronaviruses are known to infect a wide range of mammalian and avian species causing remarkably diverse disease syndromes. Variable tissue tropism and the ability to easily cross interspecies barriers are the well-known characteristics of certain CoVs. The 21st century epidemics of severe acute respiratory CoV (SARS-CoV), Middle East respiratory CoV and the ongoing SARS-CoV-2 pandemic further highlight these characteristics and emphasize the relevance of CoVs to the global public health. Bovine CoVs (BCoVs) are betacoronaviruses associated with neonatal calf diarrhea, and with winter dysentery and shipping fever in older cattle. Of interest, no distinct genetic or antigenic markers have been identified in BCoVs associated with these distinct clinical syndromes. In contrast, like other CoVs, BCoVs exist as quasispecies. Besides cattle, BCoVs and bovine-like CoVs were identified in various domestic and wild ruminant species (water buffalo, sheep, goat, dromedary camel, llama, alpaca, deer, wild cattle, antelopes, giraffes, and wild goats), dogs and humans. Surprisingly, bovine-like CoVs also cannot be reliably distinguished from BCoVs using comparative genomics. Additionally, there are historical examples of zoonotic transmission of BCoVs. This article will discuss BCoV pathogenesis, epidemiology, interspecies transmission, immune responses, vaccines, and diagnostics.

Bovine Coronavirus Immune Milk Against COVID-19

After a year of evolution of the SARS-CoV-2 epidemic, there is still no specific effective treatment for the disease. Although the majority of infected people experience mild disease, some patients develop a serious disease, especially when other pathologies concur. For this reason, it would be very convenient to find pharmacological and immunological mechanisms that help control SARS-CoV-2 infection. Since the COVID-19 and BCoV viruses are very close phylogenetically, different studies demonstrate the existence of cross-immunity as they retain shared epitopes in their structure. As a possible control measure against COVID-19, we propose the use of cow’s milk immune to BCoV. Thus, the antigenic recognition of some highly conserved structures of viral proteins, particularly M and S2, by anti-BCoV antibodies present in milk would cause a total or partial inactivation of SARS-COV-2 (acting as a particular vaccine) and be addressed more easily by GALT’s highly specialized antigen-presenting cells, thus helping the specific immune response.

Bovine respiratory coronavirus enhances bacterial adherence by upregulating expression of cellular receptors on bovine respiratory epithelial cells

Bovine coronavirus (BCoV) is one of the agents causing bovine respiratory disease complex (BRDC), with single infection tending to be mild to moderate; the probability of developing pneumonia in BRDC may be affected by viral and bacterial combinations. Previously, we reported that bovine respiratory syncytial virus (BRSV) infection enhances adherence of Pasteurella multocida (PM) to cells derived from the bovine lower respiratory tract but that BRSV infection in cells derived from the upper respiratory tract reduces PM adherence. In this study, we sought to clarify whether the modulation of bacterial adherence to cells derived from the bovine upper and lower respiratory tract is shared by other BRDC-related viruses by infecting bovine epithelial cells from the trachea, bronchus and lung with BCoV and/or PM. The results showed that cells derived from both the upper and lower respiratory tract were susceptible to BCoV infection. Furthermore, all cells infected with BCoV exhibited increased PM adherence via upregulation of two major bacterial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and platelet-activating factor receptor (PAF-R), suggesting that compared with BRSV infection, BCoV infection differentially modulates bacterial adherence. In summary, we identified distinct interaction between bovine respiratory viruses and bacterial infections.

Interspecies transmission of coronaviruses and immunization: An Indian perspective

The milder form of infection and higher rates of recovery witnessed among COVID-19 patients in India is indicative of the potential intervention of other “unconventional” biological mechanisms. The recently established similarity between beta-coronavirus strains in animals and humans led us to hypothesize that previous contact with infected dogs or cattle could shield humans from the circulating SARS-CoV-2 virus. We further believe that our hypothesis, if confirmed by further studies, could be used as a potential vaccine strategy.

Could Naturally Occurring Coronaviral Diseases in Animals Serve as Models for COVID-19? A Review Focusing on the Bovine Model

The current pandemic of COVID-19 has highlighted the importance of basic studies on coronaviruses (CoVs) in general, and severe acute respiratory syndrome CoV type 2 (SARS-CoV-2) in particular. CoVs have for long been studied in veterinary medicine, due to their impact on animal health and welfare, production, and economy. Several animal models using coronaviral disease in the natural host have been suggested. In this review, different animal models are discussed, with the main focus on bovine CoV (BCoV). BCoV is endemic in the cattle population worldwide and has been known and studied for several decades. SARS-CoV-2 and BCoV are both betacoronaviruses, where BCoV is highly similar to human coronavirus (HCoV) OC43, encompassing the same virus species (Betacoronavirus 1). BCoV causes respiratory and gastrointestinal disease in young and adult cattle. This review summarizes the current knowledge of the similarities and dissimilarities between BCoV and SARS-CoV-2, as well as discussing the usage of BCoV as a model for human CoVs, including SARS-CoV-2.

Integrative Network Analysis of Predicted miRNA-Targets Regulating Expression of Immune Response Genes in Bovine Coronavirus Infection

Bovine coronavirus (BCoV) infection that causes disease outbreaks among farm animals, resulting in significant economic losses particularly in the cattle industry, has the potential to become zoonotic. miRNAs, which are short non-coding segments of RNA that inhibits the expression of their target genes, have been identified as potential biomarkers and drug targets, though this potential in BCoV remains largely unknown. We hypothesize that certain miRNAs could simultaneously target multiple genes, are significantly conserved across many species, thereby demonstrating the potential to serve as diagnostic or therapeutic tools for bovine coronavirus infection. To this end, we utilized different existing and publicly available computational tools to conduct system analysis predicting important miRNAs that could affect BCoV pathogenesis. Eleven genes including CEBPD, IRF1, TLR9, SRC, and RHOA, significantly indicated in immune-related pathways, were identified to be associated with BCoV, and implicated in other coronaviruses. Of the 70 miRNAs predicted to target the identified genes, four concomitant miRNAs (bta-miR-11975, bta-miR-11976, bta-miR-22-3p, and bta-miR-2325c) were found. Examining the gene interaction network suggests IL-6, IRF1, and TP53 as key drivers. Phylogenetic analysis revealed that miR-22 was completely conserved across all 14 species it was searched against, suggesting a shared and important functional role. Functional annotation and associated pathways of target genes, such as positive regulation of cytokine production, IL-6 signaling pathway, and regulation of leukocyte differentiation, indicate the miRNAs are major participants in multiple aspects of both innate and adaptive immune response. Examination of variants evinced a potentially deleterious SNP in bta-miR-22-3p and an advantageous SNP in bta-miR-2325c. Conclusively, this study provides new insight into miRNAs regulating genes responding to BCoV infection, with bta-miR-22-3p particularly indicated as a potential drug target or diagnostic marker for bovine coronavirus.

Bovine respiratory disease in beef calves supported long transport stress: An epidemiological study and strategies for control and prevention

BRD is associated with infectious agents, but management and transport-stress are trigger factors. Metaphylactic administration of antimicrobial reduces colonization of respiratory tract by pathogens, but the development of antibiotic-resistance raises public health concerns leading to propose new control strategies. The study analyzed nasopharyngeal swabs of 231 imported cattle, 10% of 49 trucks, transported from France to southern Italy and, through Real-time PCR identified the prevalence of the involved pathogens speculating on strategies to reduce the impact of BRD. The samples were tested by Real-time PCR, for the detection of bovine coronavirus (BCoV), bovine respiratory syncytial virus (BRSV), bovine parainfluenza virus (BPiV), bovine adenovirus (BAdV), Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis. Yates-corrected chi squared, or Fisher's exact test were used to compare both animal-health status and positivity/negativity to pathogens, and the relationship between presence/absence of clinical signs and Real-time PCR-positivity. H. somni and BCoV were the most frequently identified pathogens. In BRD-diagnosed cattle, BAdV was detected in 13.8% (19/138), BRSV in 14.5% (20/138) and BPiV in 4.3% (6/138). Healthy cattle were mostly positive for H. somni (89.2%, 83/93). A statistically significant association was observed between clinical signs and positivity to M. haemolytica (p value = 0.016). Although mass-medication and vaccination are used for BRD control, it still remains a primary health problem. Our results highlight that the nasopharyngeal microbiota could be affected by transport and that strategies to enhance calf immunity for reducing BRD-risk development would be more effective if applied at farm of origin prior to loading.

Molecular-based cross-species evaluation of bovine coronavirus infection in cattle, sheep and goats in Ghana

Background

Apart from the huge worldwide economic losses often occasioned by bovine coronavirus (BCoV) to the livestock industry, particularly with respect to cattle rearing, continuous surveillance of the virus in cattle and small ruminants is essential in monitoring variations in the virus that could enhance host switching. In this study, we collected rectal swabs from a total of 1,498 cattle, sheep and goats. BCoV detection was based on reverse transcriptase polymerase chain reaction. Sanger sequencing of the partial RNA-dependent RNA polymerase (RdRp) region for postive samples were done and nucleotide sequences were compared with homologous sequences from the GenBank.

Results

The study reports a BCoV prevalence of 0.3%, consisting of 4 positive cases; 3 goats and 1 cattle. Less than 10% of all the animals sampled showed clinical signs such as diarrhea and respiratory distress except for high temperature which occurred in > 1000 of the animals. However, none of the 4 BCoV positive animals manifested any clinical signs of the infection at the time of sample collection. Bayesian majority-rule cladogram comparing partial and full length BCoV RdRp genes obtained in the study to data from the GenBank revealed that the sequences obtained from this study formed one large monophyletic group with those from different species and countries. The goat sequences were similar to each other and clustered within the same clade. No major variations were thus observed between our isolates and those from elsewhere.

Conclusions

Given that Ghana predominantly practices the extensive and semi-intensive systems of animal rearing, our study highlights the potential for spillover of BCoV to small ruminants in settings with mixed husbandry and limited separation between species.

Dissecting Transcription Factor-Target Interaction in Bovine Coronavirus Infection

Coronaviruses are RNA viruses that cause significant disease within many species, including cattle. Bovine coronavirus (BCoV) infects cattle and wild ruminants, both as a respiratory and enteric pathogen, and possesses a significant economic threat to the cattle industry. Transcription factors are proteins that activate or inhibit transcription through DNA binding and have become new targets for disease therapies. This study utilized in silico tools to identify potential transcription factors that can serve as biomarkers for regulation of BCoV pathogenesis in cattle, both for testing and treatment. A total of 11 genes were identified as significantly expressed during BCoV infection through literature searches and functional analyses. Eleven transcription factors were predicted to target those genes (AREB6, YY1, LMO2, C-Rel, NKX2-5, E47, RORAlpha1, HLF, E4BP4, ARNT, CREB). Function, network, and phylogenetic analyses established the significance of many transcription factors within the immune response. This study establishes new information on the transcription factors and genes related to host-pathogen interactome in BCoV infection, particularly transcription factors YY1, AREB6, LMO2, and NKX2, which appear to have strong potential as diagnostic markers, and YY1 as a potential target for drug therapies.

Comparative Pathogenesis of Bovine and Porcine Respiratory Coronaviruses in the Animal Host Species and SARS-CoV-2 in Humans

Discovery of bats with severe acute respiratory syndrome (SARS)-related coronaviruses (CoVs) raised the specter of potential future outbreaks of zoonotic SARS-CoV-like disease in humans, which largely went unheeded. Nevertheless, the novel SARS-CoV-2 of bat ancestral origin emerged to infect humans in Wuhan, China, in late 2019 and then became a global pandemic. Less than 5 months after its emergence, millions of people worldwide have been infected asymptomatically or symptomatically and at least 360,000 have died. Coronavirus disease 2019 (COVID-19) in severely affected patients includes atypical pneumonia characterized by a dry cough, persistent fever, and progressive dyspnea and hypoxia, sometimes accompanied by diarrhea and often followed by multiple organ failure, especially of the respiratory and cardiovascular systems. In this minireview, we focus on two endemic respiratory CoV infections of livestock: bovine coronavirus (BCoV) and porcine respiratory coronavirus (PRCV). Both animal respiratory CoVs share some common features with SARS-CoV and SARS-CoV-2. BCoV has a broad host range including wild ruminants and a zoonotic potential. BCoV also has a dual tropism for the respiratory and gastrointestinal tracts. These aspects, their interspecies transmission, and certain factors that impact disease severity in cattle parallel related facets of SARS-CoV or SARS-CoV-2 in humans. PRCV has a tissue tropism for the upper and lower respiratory tracts and a cellular tropism for type 1 and 2 pneumocytes in lung but is generally a mild infection unless complicated by other exacerbating factors, such as bacterial or viral coinfections and immunosuppression (corticosteroids).

Coronaviruses in cattle

Bovine coronaviruses are spread all over the world. They cause two types of clinical manifestations in cattle either an enteric, calf diarrhoea and winter dysentery in adult cattle, or respiratory in all age groups of cattle. The role of coronaviruses in respiratory infections is still a hot topic of discussion since they have been isolated from sick as well as healthy animals and replication of disease is rarely successful. Bovine coronavirus infection is characterised by high morbidity but low mortality. The laboratory diagnosis is typically based on serological or molecular methods. There is no registered drug for the treatment of virus infections in cattle and we are limited to supportive therapy and preventative measures. The prevention of infection is based on vaccination, biosecurity, management and hygiene. This paper will cover epidemiology, taxonomy, pathogenesis, clinical signs, diagnosis, therapy, economic impact and prevention of coronavirus infections in cattle.

Bovine coronavirus in neonatal calf diarrhoea in Iran

Partial gene sequencing for the bovine coronavirus at the World Genebank is available for many countries, which are distributed unevenly in five continents, but so far, no sequencing of strains has been recorded in Iran. One hundred ninety‐four stool samples from calves with diarrhoea less than one‐month old were collected from five different geographical regions of country in order to detect coronavirus and characterize it if coronavirus was found. Samples were screened for the presence of BCoV by using a commercially available ELISA kit. Furthermore, RT‐PCR was carried out on positive samples for confirmation of the presence of N and S specific genes. Sequencing and phylogenetic analysis was carried out following RT‐PCR tests. 7.2% of samples, were positive for BCoV and all stool samples from the South‐West, Northeast and West regions of Iran were negative. The results showed that all the strains of coronavirus identified in Iran were completely in independent clusters and that they did not stand in the same cluster as any of the strains identified in other parts of the world. The strains from Iran were quite different from strains in other parts of the world but from the point of similarity these viruses showed some similarities to the European strains, such as those found in France, Croatia, Denmark and Sweden.

Using Biosecurity Measures to Combat Respiratory Disease in Cattle: The Norwegian Control Program for Bovine Respiratory Syncytial Virus and Bovine Coronavirus

Bovine respiratory disease (BRD) cause important health problems in all cattle husbandry systems. It contributes substantially to the use of antimicrobial substances and compromises animal welfare and the sustainability of the cattle industry. The existing preventive measures of BRD focus at the individual animal or herd level and include vaccination, mass treatment with antimicrobials and improvement of the animal's environment and general health status. Despite progress in our understanding of disease mechanism and technological development, the current preventive measures are not sufficiently effective. Thus, there is a need for alternative, sustainable strategies to combat the disease. Some of the primary infectious agents in the BRD complex are viruses that are easily transmitted between herds such as bovine respiratory syncytial virus (BRSV) and bovine coronavirus (BCoV). This conceptual analysis presents arguments for combatting BRD through improved external biosecurity in the cattle herds. As an example of a population-based approach to the control of BRD, the Norwegian BRSV/BCoV control-program is presented. The program is voluntary and launched by the national cattle industry. The core principle is classification of herds based on antibody testing and subsequent prevention of virus-introduction through improved biosecurity measures. Measures include external herd biosecurity barriers and regulations in the organization of animal trade to reduce direct and indirect transmission of virus. Improved biosecurity in a large proportion of herds will lead to a considerable effect at the population level. Positive herds are believed to gain freedom by time if new introduction is avoided. Vaccination is not used as part of the program. Dissemination of information to producers and veterinarians is essential. We believe that reducing the incidence of BRD in cattle is essential and will lead to reduced antimicrobial usage while at the same time improving animal health, welfare and production. Alternative approaches to the traditional control measures are needed.

Prevalence of Pathogens Related to Bovine Respiratory Disease Before and After Transportation in Beef Steers: Preliminary Results

Simple Summary

Bovine respiratory disease (BRD) affects the lower respiratory tract of cattle, causing high mortality. The syndrome has a multifactorial etiology and transport seems to favor pathogen proliferation. This study investigated the prevalence of different pathogens involved in BRD, in the nasal microbiota of beef steers collected before and after a long-distance journey. A total of 56 Limousine animals were included, travelling in three different shipments, on the same route from France to southern Italy in a semitrailer, on three different days from February to April. Prior to shipment (T0) and four days after arrival (T1), two deep nasopharyngeal swabs (DNS)/steer were collected and tested by bimolecular analysis. Neither bovine viral diarrhea virus (BVDV) nor bovine herpesvirus type 1 (BoHV-1) were detected. A higher prevalence of Histophilus somni was observed in the DNS collected during the third shipment in comparison with those registered during the first and the second one, probably due to a higher prevalence at departure. Conversely, the prevalence of bovine coronavirus, bovine respiratory syncytial virus, Mannheimia haemolytica, Mycoplasma bovis and Pasteurella multocida was higher on arrival in comparison with departure, confirming data reported in the literature. Overall, there were nasal microbiota changes in beef steers, with an increase in the prevalence of pathogens associated with BRD after travelling.

Abstract

Bovine respiratory disease (BRD) is a serious health and economic problem in the beef industry, which is often associated with transportation and caused by different pathogens. The prevalence of bovine herpesvirus type 1 (BoHV-1), bovine adenovirus (BAdV), bovine viral diarrhea virus (BVDV), bovine coronavirus (BCoV), bovine respiratory syncytial virus (BRSV), bovine parainfluenza virus (BPiV), Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, Mycoplasma bovis, in the nasal microbiota of beef steers before and after the same long-distance journey from France to southern Italy was documented. Fifty-six Limousine animals of three different shipments, travelling on three different days from February to April, were included. Prior to shipment (T0) and four days after arrival (T1), two DNS/animal were collected and tested by Real Time quantitative PCR (qPCR). Univariate logistic regression was carried out, considering time and day as fixed factors and the outcome of qPCR for each pathogen as a dependent categorical dichotomous variable (positive/negative, 1/0). The fact that the number of H. somni positive animals were found to be higher in the third shipment than the first and second one, indicating that this pathogen was already present before loading, is relevant. The prevalence of BCoV, BRSV, M. haemolytica, M. bovis, P. multocida was higher at T1 than T0, suggesting that other factors, such as stress and the epidemiological status of the arrival farm, played a role. The tested animals were not treated before and after transport, and our results are in agreement with the current literature, supporting the hypothesis that the prevalence of pathogens related to BRD would increase after travelling, with an increased risk of pathogens shedding.

Sero-prevalence, cross-species infection and serological determinants of prevalence of Bovine Coronavirus in Cattle, Sheep and Goats in Ghana

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Bovine coronavirus has considerable seroprevalence in cattle across Ghana.

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Sheep and goats are kept without strict separation from cattle and show seropositivity against bovine coronavirus.

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Bovine coronavirus seroprevalence is positively correlated with large farm size.

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Highest bovine coronavirus seroprevalence was found in Ghana´s Northern Province with prevailing arid climate.

Cattle, goats and sheep are dominant livestock species in sub-Saharan Africa, with sometimes limited information on the prevalence of major infectious diseases. Restrictions due to notifiable epizootics complicate the exchange of samples in surveillance studies and suggest that laboratory capacities should be established domestically. Bovine Coronavirus (BCoV) causes mainly enteric disease in cattle. Spillover to small ruminants is possible. Here we established BCoV serology based on a recombinant immunofluorescence assay for cattle, goats and sheep, and studied the seroprevalence of BCoV in these species in four different locations in the Greater Accra, Volta, Upper East, and Northern provinces of Ghana. The whole sampling and testing was organized and conducted by a veterinary school in Kumasi, Ashanti Region of Ghana. Among sampled sheep (n = 102), goats (n = 66), and cattle (n = 1495), the seroprevalence rates were 25.8 %, 43.1 % and 55.8 %. For cattle, seroprevalence was significantly higher on larger farms (82.2 % vs 17.8 %, comparing farms with >50 or <50 animals; p = 0.027). Highest prevalence was seen in the Northern province with dry climate, but no significant trend following the north-south gradient of sampling sites was detected. Our study identifies a considerable seroprevalence for BCoV in Ghana and provides further support for the spillover of BCoV to small ruminants in settings with mixed husbandry and limited separation between species.

Protective effect of intranasal peste des petits ruminants virus and bacterin vaccinations: Clinical, hematological, serological, and serum oxidative stress changes in challenged goats

Background and Aim:

The current vaccination for peste des petits ruminants virus (PPRV) is stalled by myriad challenges and continuous endemicity of pneumonia due to fulminant bacterial complication in goats. The present study evaluated the protective effect of intranasal PPRV linage 1 and bacterine vaccinations.

Materials and Methods:

Twelve West African Dwarf (WAD) goats aged 6 months were randomly grouped and vaccinated within 2 weeks using a combination of PPRV lineage 1 vaccine (Nig/75), and bacterin from Mannheimia haemolytica (Mh) or Pasteurella multocida intranasally. The goats were observed for 3 weeks post-vaccination before comingled with a known infected WAD goat with apparent clinical signs of peste des petits ruminants and further observed clinically for 5 weeks post-infection (PI). Blood samples were taken for hematology while sera were assayed for antioxidants (glutathione peroxidase, glutathione transferase, and superoxide dismutase) activities and pro-oxidants (malondialdehyde content, reduced glutathione, hydrogen peroxide generation_, and myeloperoxidase) using spectrophotometric methods. Data were subjected to parametric statistics at α=0.05 using GraphPad Prism version 21.

Results:

Clinically, there were pyrexia, oculonasal discharge, diarrhea, anemia, leukopenia, and increased pro-oxidants in the unvaccinated goats, while moderate neutrophilia and leukocytosis were observed in PPRV and bacterin vaccinated goats. Two unvaccinated goats were weak and euthanized at 13 and 28 days PI. The goats vaccinated with PPRV and Mh showed better response clinically and biochemically.

Conclusion:

The mucosal vaccination of goats with PPRV vaccine and bacterine will protect against exposure and culminate in the development of protective mucosal, humoral, and cell-mediated immune responses. This vaccination strategy will provide framework needed in the prevention and control of endemic caprine pneumonia in Nigeria.

Management factors associated with bovine respiratory disease in preweaned calves on California dairies: The BRD 100 study

The objective of this cross-sectional study was to determine how management practices on California dairies may be associated with bovine respiratory disease (BRD) in preweaned calves. A convenience sample of 100 dairies throughout California, providing a study population of 4,636 calves, were visited between May 2014 and April 2016. During each farm visit, in-person interviews with the herd manager or calf caretaker were conducted to collect information about herd demographics, maternity pen, colostrum and calf management, herd vaccinations, and dust abatement. A random sample of preweaned calves was identified and evaluated for the presence of BRD using a standardized tool. A survey-adjusted generalized linear mixed model with a logit link function was fitted with calf as the unit of analysis and dairy as the random effect. Mean study herd size (±SE) was 1,718 (±189.9) cows. Survey-adjusted estimates of breed types in the sample were 81.6% (±0.6) Holstein, 13.1% (±0.4) Jersey, and 5.3% (±0.5) crossbred or other purebred breeds, and calf sex proportions were 73.8% (±1.0) female and 26.2% (±1.0) male. Overall survey-adjusted BRD prevalence in the study herds was 6.91% (±0.69). Housing factors positively associated with BRD were metal hutches compared with wood hutches [odds ratio (OR) = 11.19; 95% confidence interval (CI) = 2.80–44.78], calf-to-calf contact in calves >75 d of age (OR = 9.95, 95% CI = 1.50–65.86), feeding Holstein calves <2.84 L of milk or replacer per day (OR = 7.16, 95% CI = 1.23–41.68), and lagoon water used for flushing manure under hutches compared with no flush (OR = 12.06, 95% CI = 1.93–75.47). Providing extra shade over hutches (OR = 0.08; 95% CI = 0.02–0.37), feeding calves at least 90% saleable milk (OR = 0.27, 95% CI = 0.13–0.54) or pasteurized milk (OR = 0.10; 95% CI = 0.03–0.36), and feeding >5.68 L of milk or replacer per day to Jersey calves (OR = 0.04; 95% CI = 0.01–0.28) were negatively associated with BRD. Our study identified management practices on California dairies with variability and that may contribute to differences in BRD prevalence, which will be incorporated into a risk-assessment tool to control and prevent BRD in preweaned dairy calves.

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.

What is the evidence that bovine coronavirus is a biologically significant respiratory pathogen in cattle?

Coronaviruses, including bovine coronavirus (BCoV), are etiologically associated with enteric and respiratory disease across a wide range of mammalian and avian species. The role of BCoV in calfhood diarrhea is well-established, but its role in the bovine respiratory disease complex (BRDC) has been controversial. This review re-examines the evidence that BCoV is a significant pathogen in the BRDC.

Coagulant residues' influence on virus enumeration as shown in a study on virus removal using aluminium, zirconium and chitosan

Research on microorganism reduction by physicochemical water treatment is often carried out under the assumption that the microbiological enumeration techniques are not affected by the presence of coagulants. Data presented here indicate that bacteriophage enumeration by plaque assay and RT-qPCR (reverse transcription quantitative polymerase chain reaction) can be affected by these water treatment chemicals. Treatment of water samples with an alkaline protein-rich solution prior to plaque assay and optimization of RNA extraction for RT-qPCR were implemented to minimize the interference. The improved procedures were used in order to investigate reduction of three viral pathogens and the MS2 model virus in the presence of three coagulants. A conventional aluminium coagulant was compared to alternative agents (zirconium and chitosan) in a coagulation-filtration system. The highest virus reduction, i.e., 99.9-99.99%, was provided by chitosan, while aluminium and zirconium reduced virus by 99.9% in colour-rich water and by 90% in water with less colour, implying an effect of coagulant type and raw water quality on virus reduction. Although charge characteristics of viruses were associated with virus reduction, the results reveal that the MS2 phage is a suitable model for aggregation and retention of the selected pathogens.

Temporary carriage of bovine coronavirus and bovine respiratory syncytial virus by fomites and human nasal mucosa after exposure to infected calves

BACKGROUND

In order to prevent spread of the endemic pathogens bovine coronavirus (BCoV) and bovine respiratory syncytial virus (BRSV) between herds, knowledge of indirect transmission by personnel and fomites is fundamental. The aims of the study were to determine the duration of viral RNA carriage and the infectivity of viral particles on fomites and human nasal mucosa after exposure to BCoV and BRSV. During two animal infection experiments, swabs were collected from personnel (nasal mucosa) and their clothes, boots and equipment after contact with calves shedding either virus. Viral RNA was quantified by RT-qPCR or droplet digital RT-PCR (RT-ddPCR), and selected samples with high levels of viral RNA were tested by cell culture for infectivity.

RESULTS

For BCoV, 46% (n = 80) of the swabs from human nasal mucosa collected 30 min after exposure were positive by RT-qPCR. After two, four and six hours, 15%, 5% and 0% of the swabs were positive, respectively. Infective virions were not detected in mucosal swabs (n = 2). A high viral RNA load was detected on 97% (n = 44) of the fomites 24 h after exposure, and infective virions were detected in two of three swabs. For BRSV, 35% (n = 26) of the human nasal mucosa swabs collected 30 min after exposure, were positive by RT-ddPCR, but none were positive for infective virions. Of the fomites, 89% (n = 38) were positive for BRSV RNA 24 h after exposure, but all were negative for infective viruses.

CONCLUSIONS

The results indicate that human nasal mucosa can carry both BCoV and BRSV RNA after exposure to virus shedding calves, but the carriage seems short-lived and the transmission potential is likely limited. High viral loads on contaminates fomites 24 h after exposure to infected animals, and detection of infective BCoV, indicate that contaminated fomites represent a significant risk for indirect transmission between herds.

Single primer isothermal amplification (SPIA) combined with next generation sequencing provides complete bovine coronavirus genome coverage and higher sequence depth compared to sequence-independent single primer amplification (SISPA)

Coronaviruses are of major importance for both animal and human health. With the emergence of novel coronaviruses such as SARS and MERS, the need for fast genome characterisation is ever so important. Further, in order to understand the influence of quasispecies of these viruses in relation to biology, techniques for deep-sequence and full-length viral genome analysis are needed. In the present study, we compared the efficiency of two sequence-independent approaches [sequence-independent single primer amplification (SISPA) and single primer isothermal amplification (SPIA, represented by the Ovation kit)] coupled with high-throughput sequencing to generate the full-length genome of bovine coronavirus (BCoV) from a nasal swab. Both methods achieved high genome coverage (100% for SPIA and 99% for SISPA), however, there was a clear difference in the percentage of reads that mapped to BCoV. While approximately 45% of the Ovation reads mapped to BCoV (sequence depth of 169–284 944), only 0.07% of the SISPA reads (sequence depth of 0–249) mapped to the reference genome. Although BCoV was the focus of the study we also identified a bovine rhinitis B virus (BRBV) in the data sets. The trend for this virus was similar to that observed for BCoV regarding Ovation vs. SISPA, but with fewer sequences mapping to BRBV due to a lower amount of this virus. In summary, the SPIA approach used in this study produced coverage of the entire BCoV (high copy number) and BRBV (low copy number) and a high sequence/genome depth compared to SISPA. Although this is a limited study, the results indicate that the Ovation method could be a preferred approach for full genome sequencing if a low copy number of viral RNA is expected and if high sequence depth is desired.

Passive immunity to control Bovine coronavirus diarrhea in a dairy herd in Argentina

Bovine coronavirus (BCoV) is a viral enteric pathogen associated with calf diarrhea worldwide being, in Argentina, mostly detected in dairy husbandry systems. The aim of the present work was to study if maternal IgG1 antibodies (Abs) to BCoV acquired by colostrum intake modulate the development of BCoV infection in calves reared in a dairy farm in Argentina. Thirty Holstein calves were monitored during their first 60 days of age. Animals were classified into two groups depending on their initial BCoV IgG1 Ab titers. The “failure of passive transfer” (FPT) group had significantly lower IgG1 Abs to BCoV than the “acceptable passive transfer” (APT) group of calves (log10 1.98 vs. 3.38 respectively) (p < 0.0001). These differences were also observed when the total protein levels in both groups were compared (p = 0.0081). Moreover, 71% (5/7) of calves from the FPT group showed IgG1 seroconversion to BCoV compared to 29.4% (5/17) of animals from the APT group. Regarding viral circulation, BCoV was detected in 10% (3/30) of all calves and BCoV IgG1 Ab seroconversion was detected in 42% of the total animals showing that almost half of the calves were infected with BCoV. In conclusion, calves with high titers of specific BCoV IgG1 (≥1024) were mostly protected against viral infection, while animals with low titers of IgG1 (<1024) were mostly infected with BCoV. IgG1 Abs from colostrum origin are critical for prevention of BCoV infection.

Genome Sequence of a Bovine Rhinitis B Virus Identified in Cattle in Sweden

A bovine rhinitis B virus, identified in a calf from Sweden, was genetically characterized. The complete polyprotein was recovered, and phylogenetic analysis showed that this virus has the highest similarity to a bovine rhinitis B virus previously identified in Mexico.

Evolving views on bovine respiratory disease: An appraisal of selected key pathogens - Part 1

Bovine respiratory disease (BRD) is one of the most commonly diagnosed causes of morbidity and mortality in cattle and interactions of factors associated with the animal, the pathogen and the environment are central to its pathogenesis. Emerging knowledge of a role for pathogens traditionally assumed to be minor players in the pathogenesis of BRD reflects an increasingly complex situation that will necessitate regular reappraisal of BRD pathogenesis and control. This review appraises the role of selected key pathogens implicated in BRD pathogenesis to assess how our understanding of their role has evolved in recent years.