Seroprevalence and Risk Factors for Bovine Coronavirus Infection among Dairy Cattle and Water Buffalo in Campania Region, Southern Italy

Cattle exposure to bubaline herpesvirus (BuHV-1) in Southern Italy: A hidden threat for IBR eradication?

There is sufficient evidence that both bovine herpesvirus (BoHV-1) and bubaline herpesvirus (BuHV-1) can overcome the species barrier represented by their respective hosts, cattle and buffalo. Although several studies have focused on the impact of BoHV-1 on buffalo, little is known about the impact of BuHV-1 on cattle. In this work, we evaluated the seroprevalence of BuHV-1 in the cattle population in an area where intensive buffalo farming is highly developed (Campania region, Italy). BuHV-1 seroprevalence of cattle sampled in this study was estimated to be 21.4% using a specific commercial ELISA for the detection of antibodies against glycoprotein E of the virus. Risk factor assessment by univariate analysis revealed a correlation between housing type and higher prevalence. Similarly, cattle housed with buffalo and adult animals had a higher likelihood of being seropositive. BoHV-1 vaccination did not prove to be a protective factor against BuHV-1 exposure. The role of age, grazing, and co-living with buffalo in influencing BuHV-1 exposure was also confirmed by multivariate analysis. All BuHV-1 positive animals were also tested with cross-serum neutralization aimed at evaluating the specific antibody titers against BoHV-1 and BuHV-1. We, therefore, assessed the potential cross-reaction between BoHV-1 and BuHV-1, the co-infection rate, and the agreement of the assays used. This study described the presence of BuHV-1 in the cattle population of the Campania region (Italy) and indicated the requirement to take BuHV-1 into consideration for any measures and control and/or eradication plans to be applied against BoHV-1.

Detection of Coxiella antibodies in ruminants using a SucB recombinant antigen

The detection of Coxiella burnetii in ruminants remains challenging despite the use of new technology and the accumulation of novel knowledge. Serology tools, the primary methods of infection surveillance in veterinary medicine, have limitations. We used recombinant antigen production to develop an ELISA based on the SucB protein, one of the major immunodominant antigens described in humans and laboratory animals. We produced the antigen successfully in an Escherichia coli heterologous system, confirmed by sequencing and mass spectrometry, and seen as a band of ~50 kDa in SDS-PAGE and on western blot analysis. We compared the performance of the recombinant ELISA with a commercial ELISA. We observed agreement of 83.5% and a substantial Cohen κ value of 0.67 in our pilot study.

First evidence of schmallenberg virus infection in southern Italy

BACKGROUND

Schmallenberg virus (SBV) is a vector-borne pathogen that mainly affects ruminants. Schmallenberg disease has never been described in southern Italy, although this geographic area displays climatic features suitable for Culicoides biting midges, which transmit the pathogen. An observational study was carried out in the Campania region in 2020 to evaluate the seroprevalence in cattle and water buffalo as well as to identify the risk factors involved in the distribution of SBV.

RESULTS

Relatively high seroprevalences of 38.2% (cattle) and 43% (water buffalo) were found by using a commercial SBV ELISA, which is comparable to the prevalence obtained in other countries under post-epidemic conditions. A virus neutralization assay performed on positive samples showed high titers in a large percentage of animals which is assumed to indicate recent exposure. Bivariate analysis of several variables revealed some environmental factors associated with higher seroprevalence, such as mean annual temperature, distance from the coast, and altitude. Multivariate logistic regression confirmed the statistical association only for mean annual temperature, that was found to be the main factor responsible for the distribution of the virus in southern Italy. In addition, molecular diagnosis attempts were performed on serum samples and resulted in the detection of SBV RNA in two herds and six animals.

CONCLUSIONS

In this work we have demonstrated the circulation of SBV in southern Italy using both molecular and serological assays. This study emphasized the essential role of monitoring in preventing the re-emergence of vector-borne diseases in ruminants.