Effects of infection of the tick Ornithodoros moubata with African swine fever virus

The effects of infection with African swine fever virus (ASFV) on adult and nymphal Ornithodoros moubata Murray (Ixodoidea, Argasidae) ticks were examined. Three groups of ticks were used, an uninfected control group, one group infected with the VIC T90/1 isolate of ASFV and another group infected with the LIV 13/33 isolate of ASFV. Infection with ASFV did not affect the oviposition rates of infected ticks when compared with uninfected ticks. There was no difference between infected and uninfected ticks in progeny hatching rates and first nymphal stage feeding rates. Feeding rates of infected adult ticks were also unaffected. However, a significant increase in mortality rates was observed amongst the adult ticks that fed on an infective bloodmeal compared to ticks fed on an unifected bloodmeal.     

Assessing the utility of metabarcoding for diet analyses of the omnivorous wild pig (Sus scrofa)

Wild pigs (Sus scrofa) are an invasive species descended from both domestic swine and Eurasian wild boar that was introduced to North America during the early 1500s. Wild pigs have since become the most abundant free‐ranging exotic ungulate in the United States. Large and ever‐increasing populations of wild pigs negatively impact agriculture, sport hunting, and native ecosystems with costs estimated to exceed $1.5 billion/year within the United States. Wild pigs are recognized as generalist feeders, able to exploit a broad array of locally available food resources, yet their feeding behaviors remain poorly understood as partially digested material is often unidentifiable through traditional stomach content analyses. To overcome the limitation of stomach content analyses, we developed a DNA sequencing‐based protocol to describe the plant and animal diet composition of wild pigs. Additionally, we developed and evaluated blocking primers to reduce the amplification and sequencing of host DNA, thus providing greater returns of sequences from diet items. We demonstrate that the use of blocking primers produces significantly more sequencing reads per sample from diet items, which increases the robustness of ascertaining animal diet composition with molecular tools. Further, we show that the overall plant and animal diet composition is significantly different between the three areas sampled, demonstrating this approach is suitable for describing differences in diet composition among the locations.     

A Modified Heterotopic Swine Hind Limb Transplant Model for Translational Vascularized Composite Allotransplantation (VCA) Research

Vascularized Composite Allotransplantation (VCA) such as hand and face transplants represent a viable treatment option for complex musculoskeletal trauma and devastating tissue loss. Despite favorable and highly encouraging early and intermediate functional outcomes, rejection of the highly immunogenic skin component of a VCA and potential adverse effects of chronic multi-drug immunosuppression continue to hamper widespread clinical application of VCA. Therefore, research in this novel field needs to focus on translational studies related to unique immunologic features of VCA and to develop novel immunomodulatory strategies for immunomodulation and tolerance induction following VCA without the need for long term immunosuppression.This article describes a reliable and reproducible translational large animal model of VCA that is comprised of an osteomyocutaneous flap in a MHC-defined swine heterotopic hind limb allotransplantation. Briefly, a well-vascularized skin paddle is identified in the anteromedial thigh region using near infrared laser angiography. The underlying muscles, knee joint, distal femur, and proximal tibia are harvested on a femoral vascular pedicle. This allograft can be considered both a VCA and a vascularized bone marrow transplant with its unique immune privileged features. The graft is transplanted to a subcutaneous abdominal pocket in the recipient animal with a skin component exteriorized to the dorsolateral region for immune monitoring.Three surgical teams work simultaneously in a well-coordinated manner to reduce anesthesia and ischemia times, thereby improving efficiency of this model and reducing potential confounders in experimental protocols. This model serves as the groundwork for future therapeutic strategies aimed at reducing and potentially eliminating the need for chronic multi-drug immunosuppression in VCA.     

Investigations on the influence of duodenal histidine infusion on nitrogen and amino acid turnover of growing German holstein bulls

The effect of a continuous duodenal infusion of L‐histidine (His) (8 g/d) on the retention of nitrogen was investigated in two experiments (I, II), each of which was carried out using two young bulls. In Exps. I and II, the animals (150–250 kg BW) were fitted with a re‐entrant cannula in the proximal duodenum and were fed diets containing 125 g CP/kg DM and 11.5 MJ ME/kg DM. A third experiment (III) using two young bulls (140–200 kg BW) fitted with a simple T‐cannula was carried out infusing 6 g L‐His. The animals were fed a low protein diet (94 g CP/kg DM and 11 MJ ME/kg DM). The study was done to find out whether or not L‐His is the first limiting amino acid (AA) for growing ruminants.

N retention was 28 and 31, 38 and 38, 22 and 24 g/d without L‐His infusion and with L‐His infusion for Exps. I, II and III, respectively. Both in the experiments with a standard protein supply (I, II) and in the experiment with reduced protein supply (III), no significant differences were found between periods with and without infusion of L‐His. The utilisation of duodenal NAN varied between 39% and 50% and was also not significantly influenced by the duodenal infusion of L‐His. No significant effect was observed on the flow of AA into the duodenum. The faecal excretion of AA was also not significantly influenced by the infusion of L‐His. The utilisation of individual amino acids as calculated by the ratio of retained AA to intestinal apparently digested AA, did not differ significantly following the duodenal infusion of L‐His. As expected, the utilisation of His decreased. Of the different essential AA, L‐His was the most utilised (80%) followed by Arg (72%), Met (60%), Leu (45%) and Lys (44%), during periods without supplementation of L‐His.

It is concluded that the intestinal supply of L‐His from the basal diet was sufficient for the potential growth level of animals under these experimental conditions. In all AA present at the proximal duodenum, L‐His could have at first a limiting effect on the performance of growing young bulls with high body gain. Arg and Met, but not Lys, could be second or co‐limiting AA.     

Consequences of a low litter birth weight phenotype for postnatal lean growth performance and neonatal testicular morphology in the pig

The consequences of a low litter average birth weight phenotype for postnatal growth performance and carcass quality of all progeny, and testicular development in male offspring, were investigated. Using data from 25 sows with one, and 223 sows with two consecutive farrowing events, individual birth weight (BW) was measured and each litter between 9 and 16 total pigs born was classified as low (LBW), medium (MBW) or high (HBW) birth weight: low and high BW being defined as >1 standard deviation below or above, respectively, the population mean for each litter size. Litter average BW was repeatable within sows. At castration, testicular tissue was collected from 40 male pigs in LBW and HBW litters with individual BW close to their litter average BW and used for histomorphometric analysis. LBW piglets had a lower absolute number of germ cells, Sertoli cells and Leydig cells in their testes and a higher brain : testis weight ratio than HBW piglets. Overall, LBW litters had lower placental weight and higher brain : liver, brain : intestine and brain : Semitendinosus muscle weight ratios than MBW and HBW litters. In the nursery and grow–finish (GF) phase, pigs were kept in pens by BW classification (9 HBW, 17 MBW and 10 LBW pens) with 13 males and 13 females per pen. Average daily gain tended to be lower in LBW than HBW litters in lactation (P = 0.06) and throughout the nursery and GF phases (P < 0.01), resulting in an increasing difference in body weight between LBW, MBW and HBW litters (P < 0.05). Average daily feed intake was lower (P < 0.001) in LBW than HBW litters in the nursery and GF phases. Feed utilization efficiency (feed/gain) was similar for LBW and HBW litters in the nursery, but was lower (P < 0.001) in HBW than LBW litters in the GF phase. By design, slaughter weight was similar between BW classifications; however, LBW litters needed 9 more days to reach the same slaughter weight than HBW litters (P < 0.001). BW classification did not affect carcass composition traits. In conclusion, LBW litters showed benchmarks of intrauterine growth retardation, LBW had a negative impact on testicular development and germ and somatic cell populations, and was associated with decreased postnatal growth during all phases of production; however, no measurable effect on carcass composition traits was established.     

Co-inoculation of DNA and protein vaccines induces antigen-specific T cell suppression

Immunization can sometimes lead to antigen-specific immune suppression. In this study, we investigated this phenomenon by testing several combinations of DNA and protein vaccines directed against various viruses. We find that co-inoculation of mice with combined DNA and protein vaccines induces immune suppression if the two vaccines are "matched" by targeting the same antigen. Conversely, vaccine combinations never lead to immune suppression if they are derived from different viruses and, thus, mismatched antigenically. We have further identified CD4+CD25- T cells as the type of regulatory T cells induced by and are responsible for suppressing T cell activities in an antigen-specific manner in immunized animals. These regulatory T cells are phenotypically unique in their expression of Foxp3, IL-10, and IFN-gamma. Our study thus shows for the first time that co-administration of antigen-matched DNA and protein vaccines can generate this type of adaptive regulatory T cells.     

Unbiased analysis by high throughput sequencing of the viral diversity in fetal bovine serum and trypsin used in cell culture

Fetal bovine serum (FBS) and trypsin are reagents used in cell culture and have been the source of viral contamination of pharmaceutical products. We performed high throughput sequencing (HTS) of two pools of commercial batches of FBS and three commercial batches of trypsin. Taxonomies were assigned by comparing sequences of contigs and singletons to the entire NCBI nucleic acid and protein databases. The same major viral species were evidenced between batches of a given reagent but the proportion of viral reads among total reads varied markedly between samples (from 0.002% to 22.7%). In FBS, the sequences found were mainly from bovine viral diarrhea virus (BVDV) 1 to 3 and bovine parvovirus 3 (BPV3). The BVDV sequences derived from FBS showed only minor discrepancies with primers generally used for the screening of BVDV. Viral sequences in trypsin were mainly from porcine circovirus type 2. Other known viral sequences at lower read counts and potential new viral species (bovine parvovirus and bovine pegivirus) were evidenced. The load of some known and new viruses detected by HTS could be quantified by qPCR. Results of HTS provide a framework for evaluating the pertinence of control measures including the design of PCRs, bioassays and inactivation procedures.     

Seasonal changes in Sphagnum peatland testate amoeba communities along a hydrological gradient

Testate amoebae are an abundant and functionally important group of protists in peatlands, but little is known about the seasonal patterns of their communities. We investigated the relationships between testate amoeba diversity and community structure and water table depth and light conditions (shading vs. insolation) in a Sphagnum peatland in Northern Poland (Linje mire) in spring and summer 2010. We monitored the water table at five sites across the peatland and collected Sphagnum samples in lawn and hummock micro-sites around each piezometer, in spring (3 May) and mid-summer (6 August) 2010. Water table differed significantly between micro-sites and seasons (Kruskal–Wallis test, p = 0.001). The community structure of testate amoebae differed significantly between spring and summer in both hummock and lawn micro-sites. We recorded a small, but significant drop in Shannon diversity, between spring and summer (1.76 vs. 1.72). Strongest correlations were found between testate amoeba communities and water table lowering and light conditions. The relative abundance of mixotrophic species Hyalosphenia papilio, Archerella flavum and of Euglypha ciliata was higher in the summer.     

The medical and veterinary role of Ornithodoros erraticus complex ticks (Acari: Ixodida) on the Iberian Peninsula

Argasid ticks of the Ornithodoros erraticus complex are associated with traditional pig‐farming practices on the Iberian Peninsula and are also found elsewhere in North Africa, West Africa, and western Asia. The ticks associated with pig farming on the Iberian Peninsula are the only biological vectors of African swine fever virus (ASFV) known to occur in Europe, and their ecology makes them an extremely effective reservoir of both ASFV and the Borrelia species which cause tick‐borne relapsing fever (TBRF) in humans. The recent reappearance of ASFV in the European Union, coupled with evidence that Portuguese tick populations continue to harbor Borrelia despite a lack of confirmed human infections, suggest that these populations merit closer attention. In Portugal, a series of surveys over the last twenty‐five years indicates that the number of farm sites with tick infestations has declined and suggest that populations are sensitive to changes in farm management, particularly the use of modern pig housing. Various technologies have been suggested for the control of farm‐associated Ornithodoros ticks and related species but, in our opinion, farm management changes are still the most effective strategy for population control. Furthermore, we suggest that this species could probably be eradicated from Iberian pig farms.