Serum antibodies and DNA indicate a high prevalence of equine papillomavirus 2 (EcPV2) among horses in Switzerland

BACKGROUND: The DNA of equine papillomavirus type 2 (EcPV2) is consistently found in equine papillomas and squamous cell carcinomas, indicating a causal association of EcPV2 in the pathogenesis of these tumours; however, little is known about the prevalence of this virus. HYPOTHESIS/OBJECTIVES: The aim of this study was to determine the geno- and seroprevalence of EcPV2 in clinically healthy horses in Switzerland. ANIMALS: Fifty horses presented to the equine department of the university clinic, displaying no skin or mucous membrane lesions or severe signs of other diseases, were sampled. METHODS: Cytobrush samples from the penis or vulva and serum samples were collected. To determine the genoprevalence of EcPV2, DNA was extracted from cytobrush samples and tested for viral DNA with a PCR assay amplifying a 338 bp fragment of the E7/E1 region of the viral genome. Seroprevalence was tested using an enzyme-linked immunosorbent assay aimed to detect antibodies against the major capsid protein (L1) of EcPV2. RESULTS: In five of 50 horses (10%), EcPV2-specific DNA was amplified but no antibodies could be detected, whereas in 14 of 50 horses (28%), antibodies against EcPV2 but no DNA were demonstrated. Both antibodies and viral DNA were detected in four of 50 horses (8%). Neither antibodies nor viral DNA were found in 27 of 50 horses (54%). CONCLUSIONS AND CLINICAL IMPORTANCE: The seroprevalence suggests that EcPV2 is prevalent in the Swiss equine population, while the genoprevalence indicates that currently ongoing infections are less common. The discrepancy between geno- and seroprevalence probably indicates different stages of infection in the tested cohort

Post-harvest N 2 O and CO 2 emissions related to plant residue incorporation of oilseed rape and barley straw depend on soil NO 3 - content

The sustainable production of bioenergy from crops like oilseed rape, barley, and maize presents a significant option to mitigate climate change by reducing fossil CO2 emissions. Greenhouse gas emissions (specifically N2O) during the energy crop production need to be quantified precisely for reliable life cycle analysis of bioenergy cropping systems. Energy crops (specifically oilseed rape) have a very high N demand, which results in a higher N-fertilizer application and thus higher risk of N2 O emissions not only during the vegetation period but also after crop harvest due to i) incorporation of N rich plant residue to soil and/or ii) residual N. An incubation experiment was conducted under conditions favoring denitrification (80% water-holding capacity), to study the drivers of N2O emissions specifically during the post-harvest period. Here we compared two different plant residues varying in C/N ratio (oilseed rape (RST) and barley straw (BST)) with or without N supply and measured CO2, and N2O emissions. Stable isotope labeling (15N) was used to quantify soil- and residue-born N2O. Incorporation of both plant residues alone induced significant increases in CO2 emissions compared to control soil without straw addition (p < .05). However, the increase in CO2 emissions was less pronounced when straw was incorporated in conjunction with mineral N. There was a clear increase in cumulative N2O emissions (p < .05) when soil amended with BST or RST (6- and 9-fold) was compared to control, however, the increase of cumulative N2O emissions was drastic when mineral N was added (15- and 23-fold). No significant differences in N2O emission were observed when comparing residue types (p > .05). Stable isotope labeling of barley straw clearly showed that the share of residue-born N2O was very low (1.35 or 0.4%) in the overall N2O fluxes in BST and BST+N. The present study suggests that N fertilization in autumn should be avoided to minimize N2O fluxes regardless of type of straw