West Nile Virus Infection in Occupational Settings-A Systematic Review

BACKGROUND

West Nile virus (WNV) is an emerging mosquito-borne neurotropic virus, belonging to the Flaviviridae family and the Orthoflavivirus genus. The effective control of WNV requires a targeted preventive strategy that also needs the identification of the higher-risk populations. Hence, this study focused on a systematic literature review of WNV-acquired infection in work-related settings and the assessment of the exposure risks among different occupational categories.

METHODS

A comprehensive search was conducted to identify studies until September 2023 in multiple databases such as PubMed/MEDLINE, SCOPUS and Web of Science, according to the PRISMA 2020 statement. Risk of bias of collected papers was assessed by the ROB tool of the National Toxicology Program's Office of Health Assessment and Translation handbook.

RESULTS

A total of 21 studies were included in the systematic review, out of which seventeen were observational studies and four were case reports. Workers identified as at higher risk for WNV infection were military workers, veterinarians, agricultural workers, farmers, and laboratory workers with contact with infected fluids or aerosols.

CONCLUSIONS

The identification of higher-risk workers could facilitate active surveillance by occupational physicians, which could improve our understanding of the epidemiology of WNV and, in addition, could help tailor appropriate preventive recommendations, reducing the overall burden of disease in high-risk areas.

Genetic characterization of parvoviruses identified in stray cats in Nigeria

Parvoviruses are a major cause of haemorrhagic gastroenteritis, leukopenia and high mortality in cats and dogs. In this study, the presence and genetic characteristics of parvoviruses circulating among cats in Nigeria are reported. Faecal samples of stray cats from live animal markets in southwestern (Oyo and Osun States) and north-central (Kwara State) Nigeria were screened for the presence of parvoviral DNA using a qPCR. Positive samples were further characterized using a qPCR based on minor groove binder probes. Overall, 85/102 (83.3 %) stray cats tested positive for feline panleukopenia virus (FPV) DNA and one cat was co-infected with canine parvovirus-2 type a. Sequence analysis of the complete capsid region of 15 Nigerian FPV strains revealed that they were up to 99.9 % similar to the American reference strain FPV-b at the nucleotide level, and three of them presented amino acid mutations in key capsid residues. This is the first report of identification and molecular characterization of FPV strains in cats in Nigeria. The high prevalence of the virus emphasizes the need for constant surveillance of the circulation of parvoviruses in Nigeria and underscores the need to deploy an effective vaccination strategy.

A Brief Focus on SARS-CoV-2 Genomic Evolution and Vaccines

Severe acute respiratory syndrome-coronavirus type 2 (SARS-CoV-2) emerged in a live animal market in the Hubei Province of Wuhan in China in late 2019 and was declared a pandemic by the World Health Organization (WHO) on 11 March 2020 [...].

Assessing Contact Time and Concentration of Thymus vulgaris Essential Oil on Antibacterial Efficacy In Vitro

The overuse and misuse of antibiotics can pose the risk of spreading mutant strains that show antimicrobial resistance (AMR), with negative impacts on the management of bacterial infections and economic implications for healthcare systems. The research and development of natural antibacterial agents could be a priority in the next years to improve a number of effective antibacterial molecules and to reduce the AMR phenomenon and its development. The present study identified the most effective concentration and contact time of Thymus vulgaris L. essential oil (TEO) to obtain bactericidal effects in vitro against different Gram-positive and Gram-negative bacterial strains. Six clinically isolated (wild types) bacterial strains, (Citrobacter freundii, Enterococcus feciorum, Proteus mirabilis, Acinetobacter cioffi, Pseudomonas putrefaciens and Klebsiella pneumoniae) and two ATCCs (Staphylococcus aureus and Streptococcus mutans) were tested after 1 min, 3 min and 5 min of contact with TEO. The preliminary results on S. aureus after 24 h of incubation revealed a TEO concentration of 9.28 mg/mL (w/v) that completely inhibited bacteria growth, keeping cell viability. The total suppression of bacterial growth at all tested contact times was observed for all tested bacterial strains, and the results were confirmed after 48 h of incubation. Bacterial growth suppression was confirmed even with the presence of organic components. These preliminary results showed the in vitro antimicrobial efficacy of TEO against different Gram-positive and Gram-negative bacterial strains. Future studies are necessary to confirm the reproducibility of these results even on other strains and to define the exact molecular mechanisms of EOs in order to consider TEO as a valid alternative to classic antibiotic therapies and subsequently to reduce the occurrence of AMR.

Antibacterial and Biofilm Production Inhibition Activity of Thymus vulgaris L. Essential Oil against Salmonella spp. Isolates from Reptiles

Salmonellosis is an infectious disease affecting both animals and humans. Antimicrobial resistant (AMR) and biofilm-producing Salmonella spp., frequently detected in reptiles (who can then act as asymptomatic carriers for warm-blooded animals), have developed resistance to biocides; this represents a warning for the emergence of biocide/antimicrobial cross-resistance. The aim of this study was to evaluate the efficacy of Thymus vulgaris L. essential oil (TEO) in inhibiting bacterial growth and biofilm production of Salmonella spp., which had been isolated from wild reptiles housed in a Zoo in Italy. The resistance profile against different classes of antibiotics showed that all the isolates were susceptible to the tested antibiotics, despite the presence of several AMR genes. All the isolates were also tested with aqueous solutions of TEO at different dilutions (5% to 0.039%). Interestingly, TEO proved effective both in inhibiting bacterial growth at low dilutions, with MIC and MBC values ranging between 0.078% and 0.312%, and in inhibiting biofilm production, with values ranging from 0.039% to 0.156%. TEO demonstrated effective bioactivity against the biofilm producer Salmonella spp., proving to be a valid disinfectant for the prevention of salmonellosis from reptiles, a possible source of infection for humans exposed to the reptiles' environment.

Old and Novel Enteric Parvoviruses of Dogs

Parvovirus infections have been well known for around 100 years in domestic carnivores. However, the use of molecular assays and metagenomic approaches for virus discovery and characterization has led to the detection of novel parvovirus species and/or variants in dogs. Although some evidence suggests that these emerging canine parvoviruses may act as primary causative agents or as synergistic pathogens in the diseases of domestic carnivores, several aspects regarding epidemiology and virus-host interaction remain to be elucidated.

A One Health Perspective on Canine Coronavirus: A Wolf in Sheep’s Clothing?

Canine coronavirus (CCoV) is a positive-strand RNA virus generally responsible for mild-to-severe gastroenteritis in dogs. In recent years, new CCoVs with acquired pathogenic characteristics have emerged, turning the spotlight on the evolutionary potential of CCoVs. To date, two genotypes are known, CCoV type I and CCoV type II, sharing up to 96% nucleotide identity in the genome but highly divergent in the spike gene. In 2009, the detection of a novel CCoV type II, which likely originated from a double recombination event with transmissible gastroenteritis virus (TGEV), led to the proposal of a new classification: CCoV type IIa, including classical CCoVs and CCoV type IIb, including TGEV-like CCoV. Recently, a virus strictly correlated to CCoV was isolated from children with pneumonia in Malaysia. The HuPn-2018 strain, classified as a novel canine–feline-like recombinant virus, is supposed to have jumped from dogs into people. A novel CoV of canine origin, HuCCoV_Z19Haiti, closely related to the Malaysian strain was also detected in a man with fever after travel to Haiti, suggesting that infection with Malaysian-like strains may occur. These data and the emergence of highly pathogenic CoVs in humans underscore the significant threat that CoV spillovers pose to humans and how we should mitigate this hazard.

Virucidal Activity of Lemon Essential Oil against Feline Calicivirus Used as Surrogate for Norovirus

Norovirus (NoV) is regarded as a common cause of acute gastrointestinal illness worldwide in all age groups, with substantial morbidity across health care and community settings. The lack of in vitro cell culture systems for human NoV has prompted the use of cultivatable caliciviruses (such as feline calicivirus, FCV, or murine NoV) as surrogates for in vitro evaluation of antivirals. Essential oils (EOs) may represent a valid tool to counteract viral infections, particularly as food preservatives. In the present study, the virucidal efficacy of lemon EO (LEO) against FCV was assessed in vitro. The gas chromatography hyphenated with mass spectrometry (GC/MS) technique was used to reveal the chemical composition of LEO. The following small molecules were detected as major components of LEO: limonene (53%), β-pinene (14.5%), γ-terpinene (5.9%), citral (3.8%), α-pinene (2.4%), and β-thujene (1.94%). LEO at 302.0 μg/mL, exceeding the maximum non cytotoxic limit, significantly decreased viral titre of 0.75 log₁₀ TCID50/50 μL after 8 h. Moreover, virucidal activity was tested using LEO at 3020.00 μg/mL, determining a reduction of viral titre as high as 1.25 log₁₀ TCID50/50 μL after 8 h of time contact. These results open up perspectives for the development of alternative prophylaxis approaches for the control of NoV infection.

SARS-CoV-2 antibodies in dogs and cats in a highly infected area of Brazil during the pandemic

SARS-CoV-2 was a worldwide threat during the COVID-19 pandemic, and the state of Mato Grosso had the second highest mortality rate in Brazil, with 427. 4 deaths/100,000 inhabitants. However, no large-scale study among dogs and cats in such highly infected areas of Brazil has so far been conducted. Accordingly, the present study reports on a serosurvey among dogs and cats in Cuiabá, capital of Mato Grosso from November 2020 to July 2021, where the human mortality rate was 605/100,000 at that time. Overall, 33/762 dogs (4.3%) and 4/182 cats (2.2%) were found to be seropositive for SARS-CoV-2 through ELISA, and 3/762 dogs (0.4%) and 3/182 cats (1.6%) were seropositive through the serum neutralization test. Cats presented higher seroprevalence with higher titers of neutralizing antibodies. Although N-protein based ELISA may be a good screening test, cross-reactivity with other canine coronaviruses may impair its diagnostic use among dogs.

SARS-CoV-2 and Animals: From a Mirror Image to a Storm Warning

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), emerged in Wuhan city (Hubei province, China) in December 2019, and the World Health Organization (WHO) declared an international public health emergency on 11 March 2020 [...].

Severe acute respiratory syndrome coronavirus 2 detection by real time polymerase chain reaction using pooling strategy of nasal samples

COVID-19 is a life-threatening multisistemic infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Infection control relies on timely identification and isolation of infected people who can alberg the virus for up to 14 days, providing important opportunities for undetected transmission. This note describes the application of rRT-PCR test for simpler, faster and less invasive monitoring of SARS-CoV-2 infection using pooling strategy of samples. Seventeen positive patients were provided with sterile dry swabs and asked to self-collected 2 nasal specimens (#NS1 and #NS2). The #NS1 was individually placed in a single tube and the #NS2 was placed in another tube together with 19 NSs collected from 19 negative patients. Both tubes were then tested with conventional molecular rRT-PCR and the strength of pooling nasal testing was compared with the molecular test performed on the single NS of each positive patient. The pooling strategy detected SARS-CoV-2 RNA to a similar extent to the single test, even when Ct value is on average high (Ct 37–38), confirming that test sensibility is not substantially affected even if the pool contains only one low viral load positive sample. Furthermore, the pooling strategy have benefits for SARS-CoV-2 routinary monitoring of groups in regions with a low SARS-CoV-2 prevalence.

Antimicrobial Activity of Essential Oils Evaluated In Vitro against Escherichia coli and Staphylococcus aureus

The spread of extended-spectrum β-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus has caused a reduction in antibiotic effectiveness and an increase in mortality rates. Essential oils (EOs), known for their therapeutic efficacy, can be configured as novel broad-spectrum biocides. Accordingly, the bacteriostatic–bactericidal activity of Citrus Lemon (LEO), Pinus Sylvestris (PEO), Foeniculum Vulgaris (FEO), Ocimum Basilicum (BEO), Melissa Officinalis (MEO), Thymus Vulgaris (TEO), and Zingiber Officinalis Rosc. (GEO), at concentrations ranging from 1.25 to 40% (v/v), were tested in vitro against different E. coli and S. aureus strains using minimal inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). The chemical compositions of the EOs were analyzed using GC/MS. The major components of all seven tested oils were limonene, α-pinene, anethole, estragole, citral, thymol, and zingiberene, respectively. We found that the bacteriostatic–bactericidal activity of the EOs was related to their chemotypes and concentrations, as well as the strain of the bacteria. A dose–effect correlation was found when testing GEO against S. aureus strains, whilst FEO was found to have no activity regardless of concentration. PEO, MEO, and BEO were found to have bactericidal effect with a MIC and MBC of 1.25% (v/v) against S. aureus strains, and LEO was found to have values of 1.25% (v/v) and 5% (v/v) against ATCC and clinical isolate, respectively. Interestingly, the antimicrobial activity of TEO was not related to oil concentration and the complete inhibition of growth across all E. coli and S. aureus was observed. Although preliminary, our data demonstrate the efficacy of EOs and pave the way for further investigations on their potential synergistic use with traditional drugs in the human and veterinary fields.

Detection and Genetic Characterization of Canine Adenoviruses, Circoviruses, and Novel Cycloviruses From Wild Carnivores in Italy

Wild carnivores are known to play a role in the epidemiology of several canine viruses, including canine adenoviruses types 1 (CAdV-1) and 2 (CAdV-2), canine circovirus (CanineCV) and canine distemper virus (CDV). In the present study, we report an epidemiological survey for these viruses in free ranging carnivores from Italy. A total of 262 wild carnivores, including red foxes (Vulpes vulpes), wolves (Canis lupus) and Eurasian badgers (Meles meles) were sampled. Viral nucleic acid was extracted and screened by real-time PCR assays (qPCR) for the presence of CAdVs and CanineCV DNA, as well as for CDV RNA. CAdV-1 DNA was detected only in red foxes (4/232, 1.7%) whilst the wolves (0/8, 0%) and Eurasian badgers (0/22, 0%) tested negative. CanineCV DNA was detected in 4 (18%) Eurasian badgers, 4 (50%) wolves and 0 (0%) red foxes. None of the animals tested positive for CDV or CAdV-2. By sequence and phylogenetic analyses, CAdV-1 and CanineCV sequences from wild carnivores were closely related to reference sequences from domestic dogs and wild carnivores. Surprisingly, two sequences from wolf intestines were identified as cycloviruses with one sequence (145.20-5432) displaying 68.6% nucleotide identity to a cyclovirus detected in a domestic cat, while the other (145.201329) was more closely related (79.4% nucleotide identity) to a cyclovirus sequence from bats. A continuous surveillance in wild carnivores should be carried out in order to monitor the circulation in wildlife of viruses pathogenic for domestic carnivores and endangered wild species.

Feline Coronavirus and Alpha-Herpesvirus Infections: Innate Immune Response and Immune Escape Mechanisms

Simple Summary

Feline coronavirus (FCoV) and feline herpesvirus-1 (FeHV-1) can induce infections that are difficult to prevent and to treat due to the involvement of host genetic factors and immune mechanisms. These two viruses areimportant examples of viral immune evasion of the host’s innate immune response. The innate immune system provides an early form of host protection from infectious diseases without pre-exposure and plays an essential role in determining the outcome of viral infections. The mechanisms that the innate immune system utilizes to counteract infections are based on therecognition of a relatively limited set of molecular structures that are either products of microbes (virus, bacteria, fungi, parasites) or expressed by injured or dead host cells. This review provides a brief overview of the main mechanisms achieved by host’s innate immunity, focusing primarily on the immune escape mechanisms developed and carried out by FCoV and FeHV-1 during infection.

Abstract

Over time, feline viruses have acquired elaborateopportunistic properties, making their infections particularly difficult to prevent and treat. Feline coronavirus (FCoV) and feline herpesvirus-1 (FeHV-1), due to the involvement of host genetic factors and immune mechanisms in the development of the disease and more severe forms, are important examples of immune evasion of the host’s innate immune response by feline viruses.It is widely accepted that the innate immune system, which providesan initial universal form of the mammalian host protection from infectious diseases without pre-exposure, plays an essential role in determining the outcome of viral infection.The main components of this immune systembranchare represented by the internal sensors of the host cells that are able to perceive the presence of viral component, including nucleic acids, to start and trigger the production of first type interferon and to activate the cytotoxicity by Natural Killercells, often exploited by viruses for immune evasion.In this brief review, we providea general overview of the principal tools of innate immunity, focusing on the immunologic escape implemented byFCoVand FeHV-1 duringinfection.

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.

The knotty biology of canine coronavirus: A worrying model of coronaviruses' danger

Severe clinical diseases associated to αCoronavirus (αCoV) infections were recently demonstrated for the first time in humans and a closely related but distinct canine CoV (CCoV) variant was identified in the nasopharyngeal swabs of children with pneumonia hospitalized in Malaysia, in 2017-2018. The complete genome sequence analysis demonstrated that the isolated strain, CCoV-HuPn-2018, was a novel canine-feline-like recombinant virus with a unique nucleoprotein. The occurrence of three human epidemics/pandemic caused by CoVs in the recent years and the detection of CCoV-HuPn-2018, raises questions about the ability of these viruses to overcome species barriers from their reservoirs jumping to humans. Interestingly, in this perspective, it is interesting to consider the report concerning new CCoV strains with a potential dual recombinant origin through partial S-gene exchange with porcine transmissible gastroenteritis virus (TGEV) identified in pups died with acute gastroenteritis in 2009. The significance of the ability of CCoVs to evolve is still unclear, but several questions arisen on the biology of these viruses, focusing important epidemiological outcomes in the field, in terms of both virus evolution and prophylaxis. The new CCoV-Hupn-2018 should lead researchers to pay more attention to the mechanisms of recombination among CoVs, rather than to the onset of variants as a result of mutations, suggesting a continuous monitoring of these viruses and in particular of SARS-CoV-2.

A simple pooling salivary test for SARS-CoV-2 diagnosis: A Columbus' egg?

Saliva is an appropriate specimen for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) diagnosis. The possibility of pooling samples of saliva, using non-invasive bibula strips for sampling, was explored employing Bovine coronavirus (BCoV) spiked saliva. In laboratory, up to 30 saliva-soaked strips were pooled in a single tube with 2 mL of medium. After quick adsorption with the medium and vortexing, the liquid was collected and tested with a quantitative molecular assay to quantify viral RNA genome copies. On testing of single and pooled strips, the difference between the median threshold cycles (Ct) value of test performed on the single positive saliva sample and the median Ct value obtained on the pool of 30 strips, was 3.21 cycles. Saliva pooling with bibula strips could allow monitoring of COVID-19 on a large scale, reducing costs for the health bodies in terms of medical material and skilled personnel. Finally, saliva sampling is noninvasive and less traumatic than nasopharyngeal swabs and can be self-collected.

Factors Affecting the Development of Bovine Respiratory Disease: A Cross-Sectional Study in Beef Steers Shipped From France to Italy

Bovine respiratory disease (BRD) is a complex, multifactorial syndrome and one of the major welfare and economical concerns for the cattle industry. This 1-year cross-sectional study was aimed at documenting the prevalence of BRD-related pathogens and clinical signs before and after a long journey and at identifying possible predisposition factors. Male Limousine beef steers (n = 169) traveling from France to Italy were health checked and sampled with Deep Nasopharyngeal Swabs (DNS) at loading (T0) and 4 days after arrival (T1). Real-time quantitative PCR was used to quantify the presence of bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), bovine alphaherpesvirus 1 (BoHV-1), bovine coronavirus (BCoV), bovine adenovirus (BAdV), bovine parainfluenza virus 3 (BPIV-3), Histophilus somni, Mannheimia haemolytica, Mycoplasma bovis, and Pasteurella multocida. Weather conditions at departure and arrival were recorded, and the travel conditions were taken from the travel documentation. At T0, even if no animals displayed clinical signs, some of them were already positive for one or more pathogens. At T1, the number of animals displaying clinical signs and positive for BCoV, BAdV, BRSV, H. somni, M. haemolytica, M. bovis, and P. multocida increased dramatically (p < 0.001). Transport also significantly increased co-infection passing from 16.0% at T0 to 82.8% at T1 (p < 0.001). An extra stop during the journey seemed to favor BRSV, M. haemolytica, and P. multocida (p < 0.05). Weather conditions, in particular sudden climate changes from departure to arrival and daily temperature variance, were found to be predisposing factors for many of the pathogens. The farm of arrival also played a role for BRSV, BAdV, and H. somni (p < 0.05). BCoV increased dramatically, but no associations were found confirming that it spreads easily during transport phases. Our findings increased our understanding of factors increasing the likelihood of BRD-related pathogens shedding and can be useful to minimize the incidence of BRD and to implement animal transport regulations.

Use of recombinant canine granulocyte-colony stimulating factor to increase leukocyte count in dogs naturally infected by canine parvovirus

Canine parvovirus (CPV) is one of the most important cause of mortality in young dogs and no specific treatment exists. Since prolonged leukopenia greatly increases the risk of death in infected pups, strategies to counteract this decline were investigated. The outcomes of CPV naturally infected pups treated with the recombinant canine granulocyte-colony stimulating factor (rcG-CSF), in combination with the routine therapy, were compared with similarly-managed infected pups not treated with rcG-CSF. A non-randomized prospective clinical trial was performed on 62 CPV infected pups with WBC counts <3000 cells/μL and two different groups were selected based on a non-randomized approach. Group A dogs (31/62) received 5 μg/Kg of rcG-CSF daily from the hospitalization day until WBC reached the reference range (3-5 days) and group B (31/62) received 1 ml of placebo injection. All dogs in group A recovered, while five dogs in group B died. The rcG-CSF treatment demonstrated a statistically significant effect on WBC counts (p < 0.0001) and, surprisingly, also on lymphocytes and monocytes counts (p < 0.0001). There was no significant effect of treatment on neutrophil count (p = 0.5502). Although lymphocytes and monocytes are not a specific target for rcG-CSF, our study highlights that rcG-CSF is able to improve haematological parameters compared to untreated dogs and a clear increase in their number was detected, as previously described for humans treated with the homologous molecule.

Small ruminant lentiviruses in goats in southern Italy: Serological evidence, risk factors and implementation of control programs

Small ruminant lentiviruses (SRLVs) can drastically affect milk production in goat flocks and only an early detection can control and prevent their spread. Since SRLVs are responsible for persistent infections, antibody screening is the most valuable tool to identify infected animals. ELISA is recommended as the election test both for its sensitivity and for its ability to detect low antibody titers, thus identifying infected animals earlier than agar gel immunodiffusion (AGID). In the present study, an investigation was conducted to assess the SRLV seroprevalence in goat flocks in southern Italy and a transversal comparative study was carried out through the analysis of the possible risk factors influencing SRLV spread. A total of 4800 sera from 1060 flocks were analyzed and overall seroprevalences of 18,64% and 51,69% at animal and herd levels, respectively, were observed. Both the region and the herd production systems were able to affect seroprevalence, differently from the herd size, probably because the mean number of goats per herd is low and the semi-intensive management is similar regardless of the dimensional class of each herd. In particular, meat producing herds showed the higher seroprevalence, as a result of the poor sanitation and low animal monitoring in comparison to milk producing herds, where animals are managed twice daily and the relationship between dams and kids is checked to guarantee an adequate quantitative/qualitative milk yield. In the absence of vaccines or effective treatments, health preventive management and seroepidemiological investigations are the only successful approach to restrict SRLV spread as observed in countries were official/voluntary control programs are carried out.

Detection and phylogenetic characterization of astroviruses in insectivorous bats from Central-Southern Italy

In recent years, bats have been found to harbour many viruses, raising several questions about their role as reservoirs and potential disseminators of zoonotic viruses. We investigated the presence of six virus families in bats in three regions of Central‐Southern Italy. Astroviruses were identified in seven of 13 bat species. Sequence analysis revealed marked genetic heterogeneity among the astroviruses identified, with nucleotide identity ranging between 60.26% and 87.62%. Astrovirus diversity was not associated with the bat species, the geographic areas or the bat colony, suggesting the circulation of several astrovirus strains in Italian ecosystems. Genetic diversification and interspecies transmission appear common in bat astroviruses and could provide, potentially, the bases for transmission to humans and other mammals. Yet overemphasizing this risk might have detrimental consequences for bat conservation and preservation of the important ecosystem services bats provide.

Critical role of the lipid rafts in caprine herpesvirus type 1 infection in vitro

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A dose-dependent fall of CpHV.1 yeld was observed after MβCD treatment of MDBK cells.

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Cholesterol is mainly required during virus entry rather than during post-entry stage.

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Alteration of the lipid composition of the viral envelope affected virus entry.

The fusion machinery for herpesvirus entry in the host cells involves the interactions of viral glycoproteins with cellular receptors, although additional viral and cellular domains are required. Extensive areas of the plasma membrane surface consist of lipid rafts organized into cholesterol-rich microdomains involved in signal transduction, protein sorting, membrane transport and in many processes of viruses infection. Because of the extraction of cholesterol leads to disorganization of lipid microdomains and to dissociation of proteins bound to the lipid rafts, we investigated the effect of cholesterol depletion by methyl-β-cyclodextrin (MβCD) on caprine herpesvirus 1 (CpHV.1) in three important phases of virus infection such as binding, entry and post-entry. MβCD treatment did not prejudice virus binding to cells, while a dose-dependent reduction of the virus yield was observed at the virus entry stage, and 30 mM MβCD reduced infectivity evidently. Treatment of MDBK after virus entry revealed a moderate inhibitory effect suggesting that cholesterol is mainly required during virus entry rather than during the post-entry stage. Alteration of the envelope lipid composition affected virus entry and a noticeable reduction in virus infectivity was detected in the presence of 15 mM MβCD. Considering that the recognition of a host cell receptor is a crucial step in the start-up phase of infection, these data are essential for the study of CpHV.1 pathogenesis. To date virus receptors for CpHV.1 have not yet been identified and further investigations are required to state that MβCD treatment affects the expression of the viral receptors.

Role of the lipid rafts in the life cycle of canine coronavirus

Coronaviruses are enveloped RNA viruses that have evolved complex relationships with their host cells, and modulate their lipid composition, lipid synthesis and signalling. Lipid rafts, enriched in sphingolipids, cholesterol and associated proteins, are special plasma membrane microdomains involved in several processes in viral infections. The extraction of cholesterol leads to disorganization of lipid microdomains and to dissociation of proteins bound to lipid rafts. Because cholesterol-rich microdomains appear to be a general feature of the entry mechanism of non-eneveloped viruses and of several coronaviruses, the purpose of this study was to analyse the contribution of lipids to the infectivity of canine coronavirus (CCoV). The CCoV life cycle is closely connected to plasma membrane cholesterol, from cell entry to viral particle production. The methyl-β-cyclodextrin (MβCD) was employed to remove cholesterol and to disrupt the lipid rafts. Cholesterol depletion from the cell membrane resulted in a dose-dependent reduction, but not abolishment, of virus infectivity, and at a concentration of 15 mM, the reduction in the infection rate was about 68 %. MβCD treatment was used to verify if cholesterol in the envelope was required for CCoV infection. This resulted in a dose-dependent inhibitory effect, and at a concentration of 9 mM MβCD, infectivity was reduced by about 73 %. Since viral entry would constitute a target for antiviral strategies, inhibitory molecules interacting with viral and/or cell membranes, or interfering with lipid metabolism, may have strong antiviral potential. It will be interesting in the future to analyse the membrane microdomains in the CCoV envelope.

A population prevalence study on influenza infection in dogs in Southern Italy

Despite several data on influenza infection in dogs, the first natural outbreak of canine influenza virus, closely related to H3N8 equine subtype, dates back to 2004 in Florida. Subsequent studies highlighted the role of dogs in adaptation of H5N1 to mammals and the susceptibility of dogs to different subtypes of influenza. A prevalence study was carried out on 562 sera collected from pet and kennel dogs in the south of Italy. A c-ELISA test was employed and c-ELISA-positive, c-ELISA-doubtful and random c-ELISA-negative samples were also tested in subtype- specific HI test using H3N8 and H3N2 strains. c-ELISA detected a positivity of 3.56%. HI performed with the H3N8 revealed 2 positive samples and when performed with the H3N2, HI revealed 47 positive samples. c-ELISA proved to be a sensitive and specific technique. HI is a specific method only when the test antigen is homologous to the circulating virus and, because non-specific-hemagglutination inhibitors may be present in dog sera, false positives can result. The study emphasizes that due to their close contact with humans dogs must be a target for testing. Furthermore because it remains to be determined how long antibodies to influenza virus persist in canine sera, the observed prevalence might be underestimated.

Serological and virological detection of canine herpesvirus-1 in adult dogs with and without reproductive disorders

Canine herpesvirus 1 (CaHV-1) is known to cause reproductive disorders in adult dogs and neonatal mortality in puppies. The seroprevalence of CaHV-1 has not been documented in Italy. Sera from 865 dogs were screened for CaHV-1 using a serum neutralization assay (SN). All CaHV-1 positive sera and 100 CaHV-1 negative sera were also tested using an in-house immunofluorescence (IF) test. Thirteen bitches with reproductive disorders and three bitches with no history of reproductive diseases were also examined clinically so that lesions associated with CaHV-1 and CaHV-1 DNA could be identified using PCR analysis of vaginal swabs. An overall seroprevalence of 14.6% was observed using SN, and 18.6% using IF. The correlation between SN and IF was moderate. The SN assay demonstrated a greater sensitivity than IF, with a few exceptions. None of the vaginal swabs tested positive for CaHV-1 DNA. The differences in the seropositivity rates between SN and IF were not statistically significant (P = 0.16). Using the SN test as the reference standard, the sensitivity and specificity of IF were 29% and 95%, respectively. These results suggest that CaHV-1 is common in canine populations and could pose a threat to neonatal survival and canine fertility in breeding kennels in Italy. Vaccination of breeding bitches should be recommended if there is a history of reproductive disorders.

Agreement between the cell culture titrations of canine minute virus determined by two susceptibility-testing methods

The correct diagnosis of canine minute virus is critical in dog breeding. In this study, the Bland Altman test was used to compare the performance of two susceptibility-testing methods, namely polymerase chain reaction (PCR) and indirect immunofluorescence assay (IFA). The agreement between IFA and PCR in monocytes revealed a mean difference of -1752.16 with 95% confidence and an interval ranging from -3229.80 to -274.53 (SD=2325.62). The agreement between IFA and PCR in Walter Reed canine cells (WRCC) revealed a mean difference of -2396.55 with 95% confidence and an interval ranging from -3774.63 to -1018.48 (SD=2168.93). The Bland Altman test confirmed the overall accuracy of PCR vs IFA and the plot showed that all points were not randomly arranged in the range of average ± 1.96 × SD of the differences.

Development of antibiotic resistance in Mycoplasma gallisepticum in vitro

The results of in vitro tests for induction of antibiotic resistance in some strains of Mycoplasma gallisepticum are reported. The number of passages required to induce resistance varied considerably between different antibiotics. In two groups of tests, with different strains of M. gallisepticum, resistance (>/= 1 mg/ml) to streptomycin appeared after two to three passages, to erythromycin and spiramycin after five to eight passages, to tylosin after nine to eleven and to enrofloxacin after eight to ten passages. With chlortetracycline the increase in resistance was very low (no more than ten times the starting minimal inhibitory concentration). Cross-sensitivity tests using strains with induced resistance to the different antibiotics demonstrated that those which were resistant to tylosin were also resistant to other macrolides ( > 1 mg/ml), whereas strains made resistant to erythromycin and spiramycin appeared only less sensitive (2 to 200 mug/ml) to tylosin in comparison with the original strains. Streptomycin, chlortetracycline and enrofloxacin induced very little or no cross-resistance.

Host range of Canine minute virus in cell culture

Canine minute virus (CnMV) is a member of the Bocavirus genus, together with Bovine parvovirus (BPV), which emerged as a new pathogen of dogs in 1967. The genus Bocavirus gained more recognition after the recent identification of Human bocavirus in pooled specimens from the respiratory tract of children. The cell culture host range of CnMV appears to be restricted to the Walter Reed canine cell (WRCC) line, although there is a report that indicates susceptibility of the Madin-Darby canine kidney (MDCK) cell line. In order to study the susceptibility of different cell lines to CnMV, the replication in cell cultures of canine, bovine, and human origin and the interaction of the virus with freshly isolated canine peripheral blood mononuclear cells were evaluated. The in vitro host range was unexpectedly wide. As shown by indirect fluorescent antibody and polymerase chain reaction assays, CnMV replicates efficiently in the A72 and MDCK canine cell lines. Bovine and human cell lines support the replication of CnMV less efficiently. In contrast, canine mononuclear blood cells are permissive to replication of CnMV in vitro. The present study revealed the ability of CnMV to replicate in continuous cell lines of different origin and, partially, in canine mononuclear cells.

Basic science track. Entry and release of canine coronavirus from polarized epithelial cells

Virus entry into and release from epithelial cells are polarized as a result of the distribution of the viral receptors. In order to establish the polarity of entry and release of CCoV from epithelial cells, the interactions of the virus with A72 and CrFK cells grown on permeable supports was evaluated, and the amount of infective virus in the apical and in the basolateral media was determined and compared. Infection of A72 cells after different times post seeding demonstrated that CCoV grow after infection from both apical and basolateral sides. In CrFK cells, CCoV was observed in both compartments only in the later phase of the infection. To establish the reciprocal binding of CCoV on plasma membrane, A72 cells on a permeable support were preincubated with a mAb specific for CCoV. Infection from the apical side was blocked by mAb applied to that side; in contrast, such treatment on the basolateral side had no effect on the infectious process. Similarly, the low levels of CCoV observed after basolateral exposure to virus was abolished following mAb treatment of that side. The identification of CCoV into the basolateral medium could play an important role in the viral pathogenesis.

Comparison of serologic techniques for the detection of antibodies against feline coronaviruses

The seroprevalence of feline coronavirus (FCoV) antibodies was studied in cats in southern Italy. One hundred twenty sera collected from cats belonging to catteries or community shelters and to households were tested for FCoV type I and II antibodies. The virus neutralization (VN) was performed and compared with indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA). Ninety-six sera tested positive for FCoV antibodies by VN and ELISA. Interestingly, ELISA revealed 2 more positive sera than did the VN test and 3 more positive sera than did the IFAT. All results were confirmed by Western blotting. ELISA proved to be more sensitive and detected a seroprevalence of about 82%. Considering the cross-reactivity of FCoV type I and type II, ELISA was able to detect antibodies against both serotypes, allowing the use of the assay as a reference test for sera screening. The high prevalence of antibodies observed indicates that FCoVs are common in southern Italian cat populations.

Action of disinfectants on canine coronavirus replication in vitro

Canine coronavirus (CCoV) is responsible for enteric disease in pups. Infected dogs generally have a rapid recovery, so the virus is highly contagious and the spread of infection is difficult to control. Chemical disinfectants have been widely used in human disease-control programmes to prevent viral infectious diseases from spreading, but to date, there are no studies in the literature on the sensitivity of CCoV to chemical biocides. The present study investigated the sensitivity of CCoV to disinfectants currently used for prophylaxis in kennel and dog breeding locations. The effects of three agents: alkyl-dimethyl-benzyl-ammonium chloride, benzalkonium chloride and didecyl-dimethyl-ammonium chloride, on the infectivity titre of CCoV in A72 cell lines, were studied at different concentrations. Although they may regard a small number of agents, the findings showed that the sensitivity of CCoV to disinfectants varies and the differences are dose correlated. In general, virus inactivation implies a permanent loss of infectivity which can be evaluated in suspensions and hand disinfection tests.

High-cell-passage canine coronavirus vaccine providing sterilising immunity

Objectives: To evaluate the ability of a high‐cell‐passage canine coronavirus vaccine to immunise dogs against challenge with a field isolate of the virus.

Methods: Three dogs that had previously tested seronegative and virus‐negative for canine coronavirus were inoculated twice, at 21‐day intervals, with the vaccine and kept under observation. Two seronegative and virus‐negative dogs served as unvaccinated controls. For safety tests, two additional dogs were inoculated oronasally with 10 times the vaccinal dose and no reactions were observed. Faecal samples were collected daily from the vaccinated dogs after the first and second inoculations. Both vaccinated and control dogs were challenged two weeks after the second vaccination with a field canine coronavirus strain. Blood samples were collected for serological tests before vaccination and at weekly intervals after vaccinations and challenge.

Results: Virus was not detected in faecal samples after the first or second vaccinations by virus isolation assays and PCR. Significantly, the vaccinated dogs did not have clinical signs after challenge and no virus shedding was observed. The two unvaccinated control dogs had moderate enteritis, and virus was detected in cell cultures starting from three days postchallenge (dog 1) and two days postchallenge (dog 2), and by PCR for 23 median days.

Clinical Significance: This study showed the efficacy of a high‐cell‐passage canine coronavirus vaccine in preventing infection of dogs by virulent virus and, specifically, its ability to induce sterilising immunity.

Serological prevalence of canine respiratory coronavirus in southern Italy and epidemiological relationship with canine enteric coronavirus

Canine respiratory coronavirus (CRCoV) has been detected in dogs suffering from respiratory disease and is thought to be involved in canine infectious respiratory disease (CIRD) complex. Canine enteric coronavirus (CECoV) is a widespread pathogen of dogs, responsible for mild to severe diarrhea in pups. The purpose of this study was to establish the seroprevalence of CRCoV in Italy and its relationship to CECoV type II seroprevalence. The age and year of sample collection from seropositive dogs was also assessed. Of adult domestic dogs, 23.3% had antibodies to CRCoV, compared with 86.1% with antibodies to CECoV. Amongst a population of kenneled pups, 4.0% had antibodies to CRCoV, and 97.0% had antibodies to CECoV.

Canine coronavirus inactivation with physical and chemical agents

Canine coronavirus (CCoV) is responsible for mild or moderate enteritis in puppies. The virus is highly contagious and avoiding contact with infected dogs and their excretions is the only way to ensure disease prevention. Since no studies have yet focused on the sensitivity of CCoV to chemical biocides the present investigation examined the efficiency of physical and chemical methods of viral inactivation. CCoV infectivity was stable at +56 degrees C for up to 30 min, but tended to decrease rapidly at +65 degrees C and +75 degrees C. Germicidal ultra-violet (UV-C) light exposure demonstrated no significant effects on virus inactivation for up to 3 days. CCoV was observed to be more stable at pH 6.0-6.5 while extreme acidic conditions inactivated the virus. Two tested aldehydes inactivated the virus but their action was temperature- and time-dependent. The methods for CCoV inactivation could be applied as animal models to study human coronavirus infection, reducing the risk of accidental exposure of researchers to pathogens during routine laboratory procedures.

Genetic evolution of canine coronavirus and recent advances in prophylaxis

Since the first identification of the virus in 1971, the disease caused by canine coronavirus (CCoV) has not been adequately investigated and the role that the virus plays in canine enteric illness has still not been well established. In the last decade, as a consequence of the relatively high mutation frequency of RNA positive stranded viruses, CCoV has evolved and a new genotype has been identified in the faeces of infected dogs. The several studies carried out by different researchers have focused upon the epidemiological relevance of these viruses and, considering the wide diffusion of CCoV infections among dog populations, the author underlines the need for further investigation on the biology of CCoV and on the pathogenetic role of their infections.

Canine coronavirus infection in Turkish dog population

Canine coronavirus (CCoV) is one of the most important viral agents affecting the gastrointestinal system of dogs. In this study virological and serological investigations were performed to demonstrate the existence and prevalence of CCoV infection in a Turkish dog population. A total of 269 animals were subjected to the study. Of 179 dogs tested for CCoV antibodies, 112 (62.5%) were found to be positive by serum neutralization test, while 133 (74.3%) were positive by ELISA. The highest prevalence (94.2%) was detected in kennel dogs. Detection of CCoV genome in faeces was performed in samples from 90 diarrhoeic puppies by reverse transcription-polymerase chain reaction. Fourteen (15.5%) faeces were positive for CCoV RNA, five of which were characterized as CCoV type I. The widespread CCoV infection in the Turkish dog population may be attributed as an important cause of viral diarrhoea in dogs.

Quantitation of canine coronavirus RNA in the faeces of dogs by TaqMan RT-PCR

A TaqMan^® fluorogenic reverse transcriptase-polymerase chain reaction (RT-PCR) assay was developed for the detection and quantitation of canine coronavirus (CCoV) RNA in the faeces of naturally or experimentally infected dogs. The CCoV fluorogenic RT-PCR assay, which targeted the ORF5 (M gene), was more sensitive than a conventional RT-PCR assay targeting the same gene, showing a detection limit of 10 copies of CCoV standard RNA, and was linear from 10 to 10⁸ copies, allowing quantitation of samples with a wide range of CCoV RNA loads. A total of 78 faecal samples of diarrhoeic dogs were tested simultaneously by conventional and fluorogenic RT-PCR: 29 were negative by both techniques, whereas 27 tested positive by conventional RT-PCR and 48 by the established CCoV fluorogenic assay. One sample, which was positive by conventional RT-PCR, gave no signal in the fluorogenic assay. In addition, by the fluorogenic assay CCoV shedding in the faecal samples of an experimentally infected dog was monitored for 28 days. The high sensitivity, simplicity and reproducibility of the CCoV fluorogenic RT-PCR assay, combined with its wide dynamic range and high throughput, make this method especially suitable for efficacy trials on CCoV vaccines.

Cloning and expression of two fragments of the S gene of canine coronavirus type I

Two fragments, S66 and S55, of the S glycoprotein of the newly identified canine coronavirus type I (CCoV type I), were expressed in a procariotic system. The purified recombinant proteins of 350 and 366 amino acids in length, respectively, were employed to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of CCoV type I antibodies in dog sera. Four canine sera-positive for CCoV type II, four sera-positive for CCoV type I and 10 negative control sera were examined. Only the sera-positive for CCoV type I strongly reacted with both the proteins, whereas the sera-positive for CCoV type II showed low reactivity in the ELISA test. As CCoV type I seems to be not cultivable in cell cultures, the recombinant fragments of the S protein represent a unique method to study, preliminarily, the immunological and the pathogenetic characteristics of this new virus.

A canine parvovirus mutant is spreading in Italy

By antigenic and genetic characterization of canine parvovirus type 2 (CPV-2) strains collected in 2001 and 2002 in Italy, it was possible to observe the spread of viruses with an unusual mutation, Glu-426, affecting a major antigenic epitope of CPV-2. Out of 67 strains analyzed, 49 (73.13%) were characterized as CPV-2a, 6 (8.95%) were characterized as CPV-2b, and 12 (17.91%) were characterized as the Glu-426 mutant.

Fecal immunoglobulin A antibodies in dogs infected or vaccinated with canine coronavirus

Fecal secretory immunoglobulin A (IgA) antibodies in dogs infected or vaccinated with canine coronavirus (CCV) were evaluated by an enzyme-linked immunosorbent assay. The study was carried out with 32 fecal samples collected just before inoculation and at 28 days postinoculation. Five groups were studied: naturally infected dogs, experimentally infected dogs, dogs inoculated with a modified live (ML) CCV vaccine by the intramuscular route, dogs inoculated with an ML CCV vaccine by the oronasal route, and dogs given an inactivated CCV vaccine. Both the naturally and the experimentally infected dogs developed high levels of fecal IgAs. Interestingly, dogs inoculated with the ML CCV vaccine by the oronasal route developed levels of fecal IgA that were higher than those observed in the dogs inoculated with the same CCV vaccine by the intramuscular route or those observed in dogs inoculated with the inactivated vaccine. A relationship between the level of fecal IgAs to CCV and the degree of protection against CCV infection was observed.

Two genotypes of canine coronavirus simultaneously detected in the fecal samples of dogs with diarrhea

Sixty-nine fecal samples from diarrheic puppies were examined by reverse transcription-PCR assays for the M and the S genes of canine coronaviruses (CCoVs). The isolates in 10 samples were recognized as CCoV type I, and the isolates in 6 samples were recognized as CCoV type II, while isolates of both genotypes were simultaneously detected in 53 samples.

Development of a western blotting assay to discriminate Brucella spp. and Yersinia enterocolitica O:9 infections in sheep

Outer membrane proteins (OMPs) of Rev-1 strain of Brucella melitensis were used in a Western blotting assay for the serological diagnosis of brucellosis in ovine sera. Fifty-four sheep sera were tested and divided into the following groups: Group A) n. 9 samples from one sheep that had been experimentally infected with Y. enterocolitica O:9; Group B) n. 10 samples collected from sheep infected with Brucella melitensis and 1 sample from a sheep vaccinated with the Rev 1 strain; Group C) n. 10 samples collected in "officially brucellosis-free" herds; Group D) n. 12 samples classified as "suspicious"; Group E) n. 12 samples classified as "positive". Antibodies were detected by routine tests performed for the diagnosis of brucellosis in serum samples of the sheep infected with Y. enterocolitica O:9 after the 2nd week post infection. In the WB assay, sera of group B recognised a 17 kDa protein, whereas sera of groups A, and D and 9 out of 12 of group E exhibited no reactivity to this protein. The results obtained encourage the use of the WB assay as a confirmatory test for the diagnosis of brucellosis.

Immunogenicity of an Inactivated Oil-Emulsion Canine Distemper Vaccine in African Wild Dogs

The immunogenicity of an inactivated oil-emulsion vaccine against canine distemper virus was evaluated in nine captive African wild dogs (Lycaon pictus). Antibody levels were determined by neutralization test in Vero cells. No significant local or systemic adverse reactions were observed in the animals. Virus neutralizing antibody levels >1:20 were detected, especially in animals that were vaccinated twice. The use of oil adjuvants is suggested as a good way to enhance the immune response to inactivated canine distemper vaccine.

Canine distemper and related diseases: report of a severe outbreak in a kennel

An outbreak of canine distemper in a kennel of German shepherds in the province of Bari is reported. Six 42-day-old pups developed typical signs of canine distemper (fever, conjunctivitis, respiratory distress and enteritis) and died within 7-10 days. Neurological symptoms were observed only in one pup. Four additional pups, which had shown no sign of illness, were separated and vaccinated, but two of these developed a severe, fatal nervous form 15 days later. Post-mortem examination, carried out on two pups which died without neurological signs, showed pneumonia and enteritis, more severe in one of the two examined pups. Smears from the brain and the conjunctiva of both dogs tested positive for canine distemper virus (CDV) by an immunofluorescent assay, confirmed by the identification of viral RNA using RT-PCR. Bordetella bronchiseptica and a canine adenovirus strain, characterized as canine adenovirus type 2 by a differential PCR assay, were isolated from the lungs of the pup showing the most pronounced lesions. Furthermore, canine coronavirus was detected by PCR in the intestinal content of this pup, suggesting a multifactorial aetiology of the outbreak.

Safety and efficacy of a modified-live canine coronavirus vaccine in dogs

The safety and the efficacy of a modified-live (ML) canine coronavirus (CCoV) vaccine strain 257/98-3c was evaluated in 14 dogs seronegative and virus negative for CCoV. For the safety test, four dogs were inoculated, two by intramuscular and two by oronasal route, with 10 times the vaccinal dose. During the observation period (28 days) all dogs did not display any local or systemic reaction. For the efficacy test, eight dogs were vaccinated by intramuscular (four dogs-group A) or by oronasal route (four dogs-group B). Two dogs were maintained as non-vaccinated controls. In the dogs of group A, vaccinal virus was not detected in faecal samples by virus isolation (VI) and by PCR assay, while in the dogs of group B, the virus was revealed for six median days only by PCR. Twenty-eight days later, the vaccinated and control dogs were challenged with a field CCoV strain. After the challenge, the vaccinated dogs did not display clinical signs and the dogs of group A shed virus for 5.5 median days, evaluated by VI, and for 10 median days evaluated by PCR. Virus shedding was not observed, both by VI and PCR assay, in the dogs of group B. The two control dogs displayed moderate clinical signs and the virus was detected by VI for 14.5 median days starting from day 3 post-challenge (dpc 3) and by PCR assay for 23 median days starting from dpc 1.