An approach to lifting self-isolation for health care workers with prolonged shedding of SARS-CoV-2 RNA

PURPOSE

According to the European Public Health Authority guidance for ending isolation in the context of COVID-19, a convalescent healthcare worker (HCW) can end their isolation at home and resume work upon clinical improvement and two negative RT-PCR tests from respiratory specimens obtained at 24-h intervals at least 8 days after the onset of symptoms. However, convalescent HCWs may shed SARS-CoV-2 viral RNA for prolonged periods.

METHODS

40 healthy HCWs off work because of ongoing positive RT-PCR results in combined nasopharyngeal (NP) and oropharyngeal (OP) swabs following SARS-CoV-2 infection were invited to participate in this study. These HCWs had been in self-isolation because of a PCR-confirmed SARS-CoV-2 infection. NP and OP swabs as well as a blood sample were collected from each participant. RT-PCR and virus isolation was performed with each swab sample and serum neutralization test as well as two different ELISA tests were performed on all serum samples.

RESULTS

No viable virions could be detected in any of 29 nasopharyngeal and 29 oropharyngeal swabs taken from 15 long-time carriers. We found SARSCoV- 2 RNA in 14/29 nasopharyngeal and 10/29 oropharyngeal swabs obtained from screening 15 HCWs with previous COVID-19 up to 55 days after symptom onset. Six (40%) of the 15 initially positive HCWs converted to negative and later reverted to positive again according to their medical records. All but one HCW, a healthy volunteer banned from work, showed the presence of neutralizing antibodies in concomitantly taken blood samples. Late threshold cycle (Ct) values in RT-PCR [mean 37.4; median 37.3; range 30.8-41.7] and the lack of virus growth in cell culture indicate that despite the positive PCR results no infectivity remained.

CONCLUSION

We recommend lifting isolation if the RT-PCR Ct-value of a naso- or oropharyngeal swab sample is over 30. Positive results obtained from genes targeted with Ct-values > 30 correspond to non-viable/noninfectious particles that are still detected by RT-PCR. In case of Ct-values lower than 30, a blood sample from the patient should be tested for the presence of neutralizing antibodies. If positive, non-infectiousness can also be assumed.

PRRSV-Eradikation in einem geschlossenen Herdbuchzuchtbetrieb ohne Unterbrechung der Produktion mit Einsatz einer Lebendvirus-(MLV-)Vakzine und Schließung der Herde

Gegenstand und Ziel: Bisher beschriebene PRRSV-Eradikationskonzepte brachten in vielen Fällen Erfolg, doch waren sie mit hohen Kosten und Produktionsausfällen verbunden. Ziel dieser Arbeit war die Erstellung eines Eradikationskonzeptes für einen geschlossenen Zuchtbetrieb mit arbeitsteiligem Produktionssystem an zwei Standorten ohne Unterbrechung der Produktion. Material und Methode: Die wesentlichen Elemente waren die zweimalige Vakzination aller Tiere (160 Zuchtsauen und 1180 Jungsauen) und die anschließende Vakzination aller im weiteren Verlauf geborenen Ferkel mit einer MLV-Vakzine (Porcilis® PRRS, Intervet), die Stabilisierung der Zuchtherde in einer Schließungsphase von 120 Tagen, das konsequente Absetzen aller Ferkel mit 21 Tagen, die Planung und Modifizierung der Tierbewegungen innerhalb des Betriebes sowie die Dokumentation der PRRSV-Eradikation durch intensive Diagnostik. Ergebnisse: Die Produktion PRRSV-Antikörper-(Ak-)negativer Jungsauen aus einer PRRSV-positiven Population und die Integration der PRRSV-Ak-negativen Zuchttiere in die PRRSV-positive Herde ohne Provokation eines neuen Infektionsausbruches (Koexistenz von PRRSV-positiven und -negativen Tieren) konnte über einen Zeitraum von zumindest 10 Monaten dokumentiert werden. Schlussfolgerung und klinische Relevanz: Durch gezielte Managementmaßnahmen und Verwendung einer MLV-Vakzine (Porcilis® PRRS, Intervet) ließ sich eine PRRSV-Eradikation erreichen. Allerdings bedarf die Anwendung einer MLV-Vakzine bei Ferkeln intensiver labordiagnostischer Untersuchungen, da neutralisierende maternale Antikörper den Impferfolg mindern können.

[Correlation between antibodies against porcine reproductive and respiratory syndrome virus and pathological-anatomical organ findings in slaughter pigs at farm level]

OBJECTIVE

The porcine reproductive and respiratory syndrome (PRRS) worldwide causes important economic losses in pig production. Its causative agent, the PRRS virus (PRRSV), is one of the most frequently detected infectious agents in relation to respiratory diseases in pigs in Austria. We investigated the correlation between the PRRSV status of pig farms, determined by detection of PRRSV antibodies in the serum of slaughter pigs, and the prevalence of pathological-anatomical lung lesions in slaughter pigs of the respective farms.

MATERIAL AND METHODS

Between December 1, 2011 and April 16, 2012, a total of 1056 serum samples of slaughter pigs from 66 pig farms were collected at an Austrian abattoir. The presence of PRRSV antibodies was tested by enzyme-linked immunosorbent assay in each sample and the PRRSV status of the respective farms was determined. No PRRSV vaccination was performed on any of the farms. In addition, the pathological-anatomical lung lesions of all slaughter pigs of the 66 farms that were slaughtered between September 1, 2011 and December 11, 2012 were recorded by authorized veterinarians at the abattoir. The prevalence of lung lesions and pleuritis in PRRSV-positive and unsuspected farms was compared and statistically interpreted.

RESULTS

Slaughter pigs of PRRSV positive farms had a significantly higher prevalence of severe lung lesions and pleuritis visceralis and parietalis than slaughter pigs of PRRSV unsuspected farms. Pigs of combined farms (nursery and fattening unit at the same location) displayed a tendency for more moderate and severe lung lesions than pigs of exclusive fattening farms.

CONCLUSIONS AND CLINICAL RELEVANCE

In the present study, the PRRSV status of pig farms displayed a significant influence on the prevalence of lung lesions in the slaughter pigs. Findings untypical for PRRS, including pleuritis, were also found significantly more often on those farms. This leads to the conclusion that other primary and/or secondary infections are involved, which can be exacerbated by the immunosuppressive effect of the PRRSV. There was a tendency for combined farms to be more severely affected than fattening farms.

[Serological detection of emerging viral infections in wild boars from different hunting regions of Southern Germany]

OBJECTIVE

Wild boars represent a possible virus reservoir for notifiable diseases of farm animals, including Aujeszky's disease (AD) and classical swine fever (CSF). Monitoring of the epidemiological situation in the wild boar population is especially relevant in countries that are officially free from these diseases. Apart from OIE-notifiable diseases, other viral agents that are widely distributed and play a significant role in farm animals, such as the porcine reproductive and respiratory syndrome virus (PRRSV), porcine circovirus type2 (PCV-2), and swine influenza virus (SIV), are sporadically detected in wild boars. Thus, the wild boar population is a potential source for maintenance of these infections in farm animals. The aim of this study was therefore to test for antibodies to the indicated emerging viral infections in wild boars in several hunting regions of Southern Germany.

MATERIAL AND METHODS

Blood serum of 94 shot wild boars from 19 hunting regions in Bavaria, Rhineland-Palatinate and Baden-Württemberg were collected. Antibodies to AD virus (ADV), CSF virus (CSFV), PRRSV, SIV (H1N1) (all by IDEXX ELISA) and PCV-2 (IgM and IgG by Ingenasa ELISA) in blood serum were determined.

RESULTS

Antibodies to ADV were detected in four animals (4.2%), to PRRSV in one animal (1.2%), to SIV (H1N1) in two animals (2.1%) and to PCV-2 (IgG) in 15 animals (16.0%) of which three animals also had antibodies to PCV-2 (IgM) (3.2%). CSFV antibodies were not detected in the examined wild boars.

CONCLUSIONS AND CLINICAL RELEVANCE

Compared to other studies in several European and American states, the seroprevalence to the tested emerging diseases was low in this study. Nevertheless, the wild boar population may still be a virus reservoir and therefore a source of infection for domestic pigs. This is especially important in the case of notifiable diseases, like AD and CSF. Therefore, a continuous monitoring of those diseases in the wild boar population would be advisable.

Serologische Erfassung von viralen Infektionskrank heiten in der Wildschweinpopulation verschiedener Jagdgebiete Süddeutschlands

Gegenstand und Ziel: Wildschweine gelten als mögliches Virusreservoir für anzeigepflichtige Tierseuchen wie Aujeszky‘sche Krankheit (AD) und Europäische Schweinepest (ESP). Die Überwachung der epidemiologischen Situation in der Wildschweinpopulation ist daher von großer Bedeutung für die Tierseuchenprophylaxe bei Nutztieren. Aber auch in Hausschweinebeständen weit verbreitete virale Erreger wie das Virus des Porcine Reproductive and Respiratory Syndrome (PRRSV), das porzine Circovirus Typ 2 (PCV-2) und das Schweineinfluenzavirus (SIV) können bei Wildschweinen immer wieder nachgewiesen werden. Ziel der Untersuchung war festzustellen, ob bei Wildschweinen in einzelnen Jagdrevieren Süddeutschlands Antikörper gegen die genannten Infektionskrankheiten vorkommen. Material und Methoden: Bei 94 Serum proben von erlegten Wildschweinen aus Bayern, Rheinland-Pfalz und Baden-Württemberg wurden mittels ELISA Antikörper gegen das ESP-Virus (ESPV), das AD-Virus (ADV), PRRSV, SIV (H1N1) und PCV-2 bestimmt. Ergebnisse: Antikörper gegen ADV wurden bei vier Tieren (4,2%) gefunden, gegen PRRSV bei einem Tier (1,2%), gegen SIV (H1N1) bei zwei Tieren (2,1%) und gegen PCV-2 (IgG) bei 15 Tieren (16,0%), wobei drei dieser 15 Wildschweine (3,2%) zusätzlich IgM-Antikörper gegen PCV-2 aufwiesen. Antikörper gegen ESPV ließen sich nicht nachweisen. Schlussfolgerung und klinische Relevanz: Die Seroprävalenz gegen die untersuchten Viruserkrankungen war bei den Wildschweinen in dieser Studie im Vergleich zu europäischen und amerikanischen Untersuchungen relativ gering. Nachweise sind dennoch möglich und die Rolle der Wildschweinpopulation als Virusreservoir sowie die Notwendigkeit eines umfassenden Wildschweinmonitorings werden dadurch bestätigt.

Exhaust expulsion of the porcine reproductive and respiratory syndrome virus (PRRSV) through ultrasound machines

Objective: Three experiments (EXP) were conducted to investigate if air contaminated with PRRS virus (Ingelvac PRRS MLV vaccine containing the North American strain) can be sucked into ultrasound machines and then expelled back into an infected (EXP-1) or a clean environment (EXP-3) through the action of ventilation fans, and if covering the machines prevents exhaust expulsion of the virus (EXP-2). Materials and methods: The experimental apparatus basically comprised of a plastic chamber, an ultrasound unit HS 1201, a device that allowed for virus aerosolization and a pipe system that allowed the air to return into the chamber (EXP-1) or to be expelled into the atmosphere (EXP-3), or was blocked by using a rubber membrane (EXP-2). In EXP-1, different virus concentrations were tested (i. e. 104, 105 and 106 TCID50, each concentration in three replicates and two runs). In EXP-2, the highest concentration, i. e. 106 TCID50 was used (three replicates and two runs). EXP-3 immediately followed EXP-2 without introduction of new virus (two runs). Virus exhaust expulsion was monitored by swabbing the pipe system with the swabs being subjected to RT-nPCR and culture. Results: In EXP-1, 106 TCID50 PRRSV, but none of the other concentrations, gave constantly virus-positive results by RT-nPCR. In EXP-2, covering completely prevented virus exhaust expulsion. In EXP-3, two out of eight swabs were positive by RT-nPCR. Cell culture of positive swabs was negative. Conclusion: The study suggests exhaust expulsion of PRRSV through ultrasound machines equipped with a ventilator fan into an infected and a clean environment, but failed to demonstrate infectivity of the expelled virus. Preventing exhaust air expulsion by complete covering prevents the expulsion of the virus.

Minipigs and potbellied pigs as pets in the veterinary practice--a retrospective study

Minipigs have become popular pets in recent years. Therefore, an increasing number of veterinarians are being challenged by specific problems of these animals. This retrospective study gives an overview on the diagnoses and therapeutic interventions of the patients submitted to the clinic for swine at the University of Veterinary Medicine Vienna during the last 6 years (n=48). Most frequently, colic symptoms of the gastro-intestinal tract (n=12) and orthopaedic locomotion disorders (n=10), mainly due to accidents or long claws, could be observed, followed by urogenital tract and skin disorders (n=4 each). Therapeutic interventions are discussed with regard to medical aspects as well as statutory provisions.

Fibroepithelial hamartoma in a domestic pig

This case report is the first description of a fibroepithelial hamartoma in a pig. The dysplasia, which covered half of the face of the newborn piglet, did not increase in relative size until the animal was euthanatized at 6 months of age. Histologic examination revealed a moderate orthokeratotic hyperkeratosis with variable degrees of epithelial proliferation. The main body of the dysplasia consisted of collagenous fibers. In addition, some proliferating small blood vessels as well as focally gathered dilated apocrine glands were evident. Given morphologic and clinical features, the diagnosis of a hamartoma seemed to be justified.

Immunophenotypic characterization of peripheral blast cells in a leukemic miniature pig

The health status of a 4-year-old female, dd-haplotype miniature pig deteriorated rapidly, so the animal finally had to be euthanized because of poor clinical condition. Necropsy revealed a massive leukocytic infiltration in the parenchymatous organs of the abdominal cavity. On hematologic cell counting, severe leukocytosis (69.3 x 10(9) cells/liter) and high-grade basophilia (6.9 x 10(9) cells/liter) were evident. Cytologic examination, as well as analysis of expression of leukocyte differentiation antigens by means of flow cytometry, classified blasts, which accounted for about 22% of leukocytes, as biphenotypic cells co-expressing the myeloid marker SWC3 (CD172a) and the lymphoid markers CD5 and CD25. Hematologic features resembled those seen in humans with chronic myeloid leukemia at blast phase.

Characterization of the Cytokine Pattern of Porcine Bone Marrow-Derived Cells Treated with 1alpha,25(OH)2D3

The biologically active form of vitamine D(3) [1alpha,25(OH)(2)D(3)] has recently been described not only to influence bone metabolism but also to exert immunomodulating activities, which may have an impact on bone formation/resorption as well. In this study, we analysed the effects of 1alpha,25(OH)(2)D(3) on the cytokine pattern of porcine bone marrow-derived cells from piglets aged 1-3 weeks. After culture for 1 week, the number of osteoclasts was determined, with tartrate-resistant acid phosphatase (TRAP)-positive, multinucleated cells being considered osteoclasts. Cultured bone marrow cell-derived mRNA was subjected to semiquantitative RT-PCR specific for a panel of porcine cytokines (IL-1alpha, IL-6, IL-8, IL-10, and TNF-alpha). In addition, an immunofluorescence analysis using anti-porcine mAbs specific for IL-1beta, IL-2, IL-4, IL-6, IL-12, TNF-alpha, and IFN-gamma was performed. In order to prove the existence of a porcine homologue of the receptor activator of NF-kappaB ligand (RANKL) bone marrow cell- as well as porcine white blood cell-derived mRNA was investigated by RT-PCR using primer pairs specific for murine RANKL. Cell culture supernatant was analysed for soluble RANKL by means of an ELISA designed for quantification of human RANKL. By means of RT-PCR, expression of IL-1alpha, IL-6, IL-8, IL-10 and TNF-alpha mRNA could be found in cells cultured with and without 1alpha,25(OH)(2)D(3). Immunofluorescence analysis revealed that IL-1, IL-6, and TNF-alpha were produced by both stromal cells and osteoclasts. Besides its known osteoclastogenic effects, 1alpha,25(OH)(2)D(3) tended to downregulate the respective cytokines, but significantly upregulated RANKL expression. The homology between the porcine RANKL-specific sequence and the corresponding human RANKL sequence was 79%. The data found support the idea that porcine bone marrow cell cultures may provide a suitable alternative to murine systems in human osteological research.

Porcine dermatitis and nephropathy syndrome (PDNS) is associated with a systemic cytokine expression profile indicative of proinflammation and a Th1 bias

Porcine dermatitis and nephropathy syndrome (PDNS) is broadly discussed as a porcine circovirus type 2 (PCV2)-associated disease, although PCV2, in contrast to postweaning multisystemic wasting syndrome (PMWS), has to date not been proven to be the aetiologic agent. In order to better understand the complex immunopathology of PDNS, the systemic cytokine expression profiles of (i) five pigs suffering from PDNS, (ii) five animals suffering from naturally acquired PMWS and (iii) five controls were investigated at mRNA and protein levels by means of multiplex real-time RT-PCR and flow cytometric intracellular cytokine detection, respectively. IL-1alpha, IL-6 and IFN-gamma mRNA expressions were found to be elevated in PDNS pigs. At the protein level, an increased capacity of peripheral blood mononuclear cells to produce IL-2, IL-4, IL-6, IL-12, TNF-alpha and IFN-gamma was evident. Hematological investigations revealed a hypochromic anemia while basophils and monocytes were relatively and neutrophils absolutely increased in PDNS pigs. PCV2 antibody levels did not differ significantly between PDNS and PMWS affected animals. Taken results together, the cytokine profile of the PDNS affected animals together with hematological data pointed towards a proinflammatory condition supporting a Th1 bias. Cytokine data of PMWS affected animals exhibited only minor non-significant differences when compared to controls, only IL-10 was significantly decreased at the mRNA level.

Analysis of theFusarium toxins Deoxynivalenol and Zearalenone in Austrian feeds of the crop years 2002 and 2003

164 feed samples were collected in Lower Austria, Upper Austria, Styria and Carynthia in the crop years 2002 and 2003 and were analysed by means of the RIDASCREEN(®) ELISA-assay for theFusarium toxins Deoxynivalenol (DON) and Zearalenone (ZON). The collected samples consisted of swine feeds, cereals and silages. DON concentrations were found up to the range of mg/kg (ppm), in contrast ZON results remained significantly lower.

Systemic cytokine profile in feeder pigs suffering from natural postweaning multisystemic wasting syndrome (PMWS) as determined by semiquantitative RT–PCR and flow cytometric intracellular cytokine detection

Postweaning multisystemic wasting syndrome (PMWS) is an economically important disease in pigs caused by porcine circovirus type 2 (PCV2). Development of this disease is presumably associated with an impairment of the immune system. We, therefore, investigated the systemic expression of relevant cytokines (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p40, TNF-alpha, IFN-gamma) and IL-2Ralpha at mRNA (semiquantitative RT-PCR) and at protein level (flow cytometric intracellular cytokine detection after short-time stimulation of peripheral blood mononuclear cells) in 10 feeder pigs aged 14 weeks suffering from natural PMWS and in 10 clinically healthy pen-mates. Hematological examination revealed a significant (p < 0.001) relative lymphopenia in the diseased animals when compared to reference pigs. IL-1alpha and IL-10 mRNA levels were notably increased in the affected pigs, whereas IL-2 and IL-2Ralpha (CD25) mRNA levels tended to be down-regulated. IL-8, TNF-alpha and IFN-gamma mRNA expressions appeared to be slightly increased. Intracellular cytokine levels as measured by flow cytometry revealed an increase of IL-1beta, IL-2, and IL-6, whereas IL-12 and TNF-alpha expressions were not affected. IFN-gamma was slightly decreased in the diseased animals. In conclusion, despite the assumption, that the cellular immune response to PMWS as a virus-induced disease should be characterized by either a Th1 driven cytokine profile or a cytokine profile indicative of T cell immunosuppression, our results did not support that hypothesis. Nevertheless, data from intracellular cytokine detection suggest an even increased percentage of the remaining lymphocytes capable to produce IL-2 upon in vitro stimulation, which is in contrast to the slightly diminished IL-2 mRNA levels reflecting the in vivo situation at least at the mRNA level.

Clinical and pathological features of the Porcine Ulcerative Dermatitis Syndrome (PUDS)

The nomenclature of ulcerative dermatitis as used in literature is somehow confusing because on the one hand this skin disorder is associated with bacterial growth and on the other hand it is a synonym for a chronic sporadic disease of adult sows with unknown aetiology. Thus, we propose the terminus 'Porcine Ulcerative Dermatitis Syndrome (PUDS)' for the latter to distinguish between these two disease complexes. This syndrome could be identified by clinical and pathological examinations in six sows, that were submitted to the clinic. Epidermal ulcers could be found nearly all over the body, but teats were always spared. Haematological examination showed a slight anaemia but physiological leucocyte counts. However, lymphopenia (x = 44.8%), granulocytosis (x = 42.0%) and an increased number of monocytes (x = 13.1%) could be found. Histologically, a lymphoplasmacytic and granulohistiocytic infiltration in the corium was most prominent. In some cases, a moderate leucocytoclastic vasculitis and perivasculitis could be seen at the dermo-epidermal border. Additionally, a multifocal interstitial nephritis with lymphoplasmacytic infiltration was a prominent feature in all animals. Participation of an immune complex associated disorder can be assumed when regarding histological findings as skin lesions in combination with glomerulonephritis are a common feature of such diseases. Also, IgG levels were elevated two- to fourfold in all affected sows when compared with healthy control pigs. This supports the hypothesis that not only T cells, as shown previously, but also the humoral branch of the immune system is involved in the aetiology of PUDS.

Hypothyroid Goitre in a Ram: Chemical Analysis gives Indirect Evidence for a Structurally Altered Type of Ovine Thyroglobulin

The thyroglobulin of a ram of the East Friesian milk sheep breed suffering from goitre was investigated by physico- and immunochemical methods. The respective ram was the only animal amongst the other sheep of the flock, that exhibited severe goitre, additionally showing depressed behaviour. Results of the thyroid-stimulating hormone response test were indicative of hypothyroidism. The dysfunction of the thyroid gland could be treated by additional iodine supplementation quite successfully, although all sheep had been given iodinated cattle salt throughout the course of the history. Without reducing conditions sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of isolated thyroglobulin molecules of the ram and control sheep did not reveal different band patterns, but under reducing conditions different band patterns were evident for the respective animals: the ram's thyroglobulin displayed two main bands, those of healthy reference sheep only one. Both bands reacted equally with anti-thyroglobulin antibodies, even with those produced by immunizing rabbits with single bands. The reduced single thyroglobulin band of healthy sheep corresponded to a truncated form of that molecule, whereas the additional main band of the ram was a more resistant, intact thyroglobulin subunit, as was shown by mass spectrometry. In conclusion, results of physico- and immunochemical investigations gave evidence of a modification of thyroglobulin with suspected different iodine binding properties in the ram. The latter finding may have clinical relevance in similar cases in other species, as it is an example of the impact that a minor change in a protein molecule may have on a complete metabolic pathway. Additionally, it could be shown, that in the ovine species the generally found single main band of thyroglobulin after reduction is a truncated form and not an intact subunit. This truncation seems to be induced in vitro by the reductive sample pretreatment prior to SDS-PAGE.

Genotyping of Clostridium perfringens Isolated from Domestic and Exotic Ruminants and Swine

Clostridium perfringens types A, B, C, D and E are known to cause severe enteritis/enterotoxaemia and diseases (especially caused by type A) belonging to the gas oedema complex in many species. Samples from the small intestine as well as faeces of domestic and exotic animals suffering from enterotoxaemic signs or having died within days after first occurance of toxaemia were submitted for typing C. perfringens toxovars by multiplex PCR. The following species have been investigated: domestic sheep (Ovis ammon; n = 10), domestic goat (Capra aegagrus hircus; n = 26), Japanese serow (Capricornis sumatraensis; n = 4), lechwe waterbuck (Hydrotragus leche; n = 1), blackbuck (Antilope cervicapra; n = 1), European reindeer (Rangifer tarandus tarandus; n = 4), domestic swine (Sus scrofa; n = 52), and collared peccary (Tayassu albirostris; n = 1). Interestingly, the predominant C. perfringens toxovar in domestic sheep was type A. This toxovar could also be diagnosed in all reindeer, in three Japanese serows, one lechwe waterbuck and most pigs (n = 47), the majority of those being at suckling age. Type D was the most prevalent toxovar (n = 18) in domestic goats, but also types A and E could be identified as pathogens in this species. Type C could only be found in domestic swine (n = 5) and in one case of clostridiosis in a Japanese serow. Two cases of enterotoxaemia in goats, one case in reindeer, and a single case in blackbuck and collared peccary were caused by C. perfringens type E. Genotyping of C. perfringens is recommended before starting vaccination programmes as it could be shown, that the importance of specific toxovars has been underestimated in specific species and/or age groups.

Nucleolar proteins and ultrastructure in bovine in vivo developed, in vitro produced, and parthenogenetic cleavage-stage embryos

In the present study, ribosomal RNA (rRNA) gene activation, monitored through nucleolus development, was studied by autoradiography following (3)H-uridine incubation, transmission electron microscopy, and immunofluorescence confocal laser scanning microscopy of key nucleolar proteins involved in rRNA transcription (topoisomerase I, upstream binding factor, and RNA polymerase I) and processing (fibrillarin, nucleolin, and nucleophosmin) in in vivo developed, in vitro produced, and parthenogenetic bovine embryos. In general, in vivo developed embryos displayed formation of fibrillo-granular nucleoli during the 4th post-fertilization cell cycle. During the previous stages of development, nucleolus precursor bodies (NPBs) were observed. However, on some occasions the initial steps of nucleolus formation were observed already at the 2- and 4-cell stage in cases where such embryos were collected from superovulated animals together with later embryonic stages presenting nucleolar development and autoradiographic labeling. The in vitro produced embryos displayed very synchronous formation of fibrillo-granular nucleoli and autoradiographic labeling during the 4th cell cycle. In vivo developed and in vitro produced embryos displayed allocation of nucleolar proteins to fibrillar and granular compartments of the developing nucleoli during the 4th cell cycle. The parthenogenetic embryos typically displayed formation of fibrillo- granular nucleoli during the 5th cell cycle and autoradiographic labeling was not observed until the morula stage. Moreover, the 1-, 2-, and 4-cell parthenogenetic embryos practically lacked NPBs. On the other hand, parthenogenetic embryos displayed allocation of nucleoar proteins to nuclear entities during the 4th cell cycle. In conclusion, both in vivo developed and in vitro produced bovine embryos displayed activation of transcription and nucleolar development during the 4th cell cycle. However, in vivo developed embryos flushed together with later developmental stages displayed premature activation of these processes. Parthenogenetic bovine embryos, on the other hand, displayed a delayed activation.

[Selection for disease and epidemic resistance in domestic ruminants and swine by indicator traits, marker and causal genes--a review. Part 2: Special immunogenetics of sheep and goats with particular regard for endoparasitoses, scrapie, foot rot and maedi-visna virus infection]

The introduction of the first part deals with immunogenetic investigations on the field of life-stock. The main chapter is outlined as a tabular overview of current opportunities of the application of indicator traits as well as marker and causal genes in breeding for disease resistance in cattle, sheep, goats and swine. In the discussion of the second part, emphasis was laied on diseases of small ruminants in central and western Europe with special respect of endoparasitoses, scrapie, foot-rot and maedi-visna virus infection. Indicator traits are discussed with respect of their advantages and disadvantages. The rigorous selection on specific traits is connected with an increase of the number of homozygotes. In contrary, pathogens do undergo mutations, thus escaping the host's immune system. Out of this point of view it is advisable, to set on selection very cautiously. The role of technologies of modern immunogenetics is pointed out in respect of constructing disease resistant animals.

[Selection for disease resistance in domestic ruminants and swine by indicator traits as well as marker and causal genes--a review. Part 1: Short introduction to immunogenetics of MHC and non-MHC genes and special immunogenetics of cattle and swine]

The introduction deals with immunogenetic investigations on the field of life-stock. The main chapter is outlined as a tabular overview of current opportunities of the application of indicator traits as well as marker and causal genes in breeding for disease resistance in cattle, sheep, goats and swine. In the discussion of the second part, emphasis was layed on diseases of small ruminants in central and western Europe. Indicator traits are discussed with respect of their advantages and disadvantages. The rigorous selection of specific traits is connected with an increase of the number of homozygotes. In contrary, pathogens do undergo mutations, thus escaping the host's immune system. Out of this point of view it is advisable, to set on selection very cautiously. The role of technologies of modern immunogenetics is pointed out in respect of constructing disease resistant animals.

PrP genotyping of Austrian sheep breeds

Scrapie, an ovine and caprine transmissible spongiforme encephalopathy, is widely spread among sheep populations in many European countries. As it is known that susceptibility to scrapie is determined genetically, breeding programmes aiming at providing scrapie-resistant flocks have been established. Selection is based on the prion protein (PrP) genotype, which is used to classify animals into risk groups of susceptibility (R1-R5) according to the amino acids encoded by codons at positions 136, 154 and 171, respectively. At position 136 (136V-->136A) alanine and at position 154 (154H-->154R) as well as 171 (171Q-->171R) arginine are the favoured amino acids. Whereas PrP genotyping data are available for many of the European sheep breeds, comparable data for local Austrian sheep breeds are missing. The most known among these are Tyrolean mountain sheep, forest sheep. Tyrolean stone sheep and Carynthian sheep. The genotypes of 112 sheep from these four local breeds were determined. In terms of PrP genetics, Austrian breeds belong to the group of non-valine-breeds, with the exception of the Carynthian sheep, that exhibited a frequency of 136V of 4.2%. The most frequent allele was ARQ with 64.6-71.2% (depending on the breed), followed by ARR (14.8-25.8%). In contrast to the above-mentioned findings, scrapie has never been diagnosed in any of the Austrian sheep breeds. Native Austrian sheep breeds exhibit a very robust constitution, a pronounced adaptation to harsh climates and good reproduction parameters as well as a marked mother instinct. Therefore, these breeds are often used in crossbreeding programmes. Beside the above-mentioned characteristics, our results indicate that the investigated breeds may be effectively used in crossing-out breeding programmes for eliminating valine at position 136 of PrP.

[Isoimmune haemolytic icterus in neonatal calves as a consequence of vaccination against piroplasmosis]

The article refers about several cases of isoimmunohaemolytic icterus in neonatal calves from different farms, whose dams had all been vaccinated against piroplasmosis. Clinical signs of immunomediated icterus neonatorum gravis, results of blood chemistry (with special regard to liver-specific parameters in the neonatal calf and results of haematology) as well as gross pathology and pathohistology are to be discussed. It is summarized, that the most relevant indicators for a hepatopathy in the newborn calf are total-bilirubin and the glutamate-dehydrogenase. Today, the production of piroplasmosis-vaccines out of blood of splenectomized animals is referred to as the only practicable method of harvesting sufficient amounts of vaccine-antigen.

Activation of mouse oocytes requires multiple sperm factors but not sperm PLCgamma1

A sperm cytosolic factor is responsible for oocyte activation at fertilization in mammals. The molecular identity of this factor is not yet known, although a sperm phospholipase Cgamma (PLCgamma) is a potential candidate. In this study, cation-exchange chromatography with a Heparin column was used for the fractionation of porcine sperm cytosolic extracts. Oocyte activation potential of the resulting fractions was tested and active fractions were subjected to Western blot analysis using antibodies specific to PLCgamma1. PLCgamma1 was detected in fractions other than those supporting oocyte activation (Ca(2+)-release and pronuclear formation). The active Heparin fraction was then purified on a Mono Q anion-exchange column. One of the resulting fractions still contained Ca(2+)-releasing activity, but pronuclear formation did not occur. We conclude that sperm PLCgamma1 is not involved in oocyte activation and that Ca(2+)-release and pronuclear formation requires multiple factors from sperm cytosol.

Haemolytic complement activity and C3c serum concentration in pigs

Abstract. Because of the importance of the complement system in disease resistance through direct lysis of target cells and support of other mechanisms of the immune System, individual Variation in haemolytic complement activity and C3 concentration in pigs prior and after vaccination were evaluated. Possible effects on the variation of these parameters were investigated. Total complement activity was determined based on complement-mediated haemolysis of antibody-sensitised erythrocytes and C3c levels were measured by immunonephelometry in Gemian Landrace pigs and an experimental pig population. Both methods revealed remarkable individual differences. The arithmetic means of total haemolytic complement activity including all pigs were 42.3 ± 28.2 U/ml before vaccination and 59.1 ± 50.6 U/ml after three immunisations. Mean plasma concentrations of C3c were between .102 ± .035 g/1 before immunisation and .126 ± .038 g/1 on day 4 after Aujeszky vaccination. Existing phenotypic variation may be in part influenced by pig genetic factors. Both haemolytic complement activity as well as C3c semm levels are potentially useful measures of complement capacity on the way to improve defence power against many pathogens by breeding.

Application of microsatellite analysis to group chicken according to their genetic similarity

Abstract. When estimating genetic variability of groups of local chicken from Nigeria we had to deal with the problem that the groups could not be regarded as distinct breeds or strains. The original sample groups obviously just represent individuals sampled in the same geographical region. The aim was to arrange these chicken in new groups according to their genetic similarity. Therefore 60 chicken from Nigeria and 10 Dahlem Reds (RIR) were genotyped at 20 microsatellite loci. In order to build up new groups "allele sharing" was calculated as the proportion of shared alleles between each pair of individuals and was used to construct a dendrogram of all individuals including Dahlem Reds as a reference group which represents a well defined line. All Dahlem Reds clustered in this dendrogram indicating that this is an adequate approach to group individuals according to their common genetic make-up. The Nigerian chicken were arranged in 7 new groups. CHORD genetic distances between these new groups ranged from 0.07 to 0.27 and were higher than the values revealed by the original local sample groups (0.05–0.16).

OMEC II: a new ovine mammary epithelial cell line

We have established three independent ovine mammary epithelial cell lines which arose from primary cultures of ovine mammary epithelial cells by spontaneous immortalization. One of them, OMEC II, was characterised in greater detail. The cells grow on plastic dishes in medium containing 10% FCS without any requirement for additional growth factors or hormones. Immunofluorescence staining of this cell line showed expression of cytokeratin (46 kDa) and ZO-1, a tight-junction associated protein, but negative immunostaining for an anti-vimentin antibody. In confluent cell monolayers 'domes' because visible indicating the development of a polarised phenotype and the ability of directed secretion. When grown in collagen gels typical ducts with end-buds were observed. Treatment with lactogenic hormones increased the frequency of dome formation, but no expression of beta-lactoglobulin was found. To our knowledge this is the first report on an ovine mammary epithelial cell line.

Corona radiata density as a non-invasive marker of bovine cumulus-corona-oocyte complexes selected for in vitro embryo production

The density of the corona radiata as a marker for the quality of cumulus-corona-oocyte complexes (CCOC's) for in vitro embryo production was tested. The CCOC's in which the corona radiata appeared as a dark rim surrounding the zona pellucida (Group 1) and CCOC's in which the corona had the same density as the rest of the cumulus investment (Group 2) were assessed with respect to nuclear ultrastructure, corona-cumulus expansion and capacity for sustaining embryonic development in vitro. An intermediate Group 3 with characteristics between Groups 1 and 2 was also assessed for in vitro development capacity. The CCOC's in Group 1 were typically meiotically unactivated and presented a nonundulating nuclear envelope. More than half of the CCOC's in Group 2 showed some degree of meiotic activation, and those that were nonactivated displayed "holes" in the nuclear envelope or dilatations of the perinuclear cisterna. The CCOC's in Group 2 were characterized by partial corona-cumulus expansion already at collection. The CCOC's from Groups 1 and 3 sustained embryonic development in vitro at a significantly higher rate than CCOC's from Group 2. It is concluded that CCOC's in which the corona radiata has the same density as the rest of the cumulus investment are less competent candidates for in vitro embryo production.

Comparison of aggregation and injection techniques in producing chimeras with embryonic stem cells in mice

We analyzed embryonic stem cell lines for their capacity to produce aggregation chimeras with diploid or developmentally compromised tetraploid embryos. Descendants of embryonic stem cells which contributed to midgestation fetuses at high levels were capable of supporting fetal development also with tetraploid partners. Different numbers of embryonic stem cells were introduced into diploid and tetraploid morulae as well as into blastocysts by microinjection. There were no differences in the frequency of embryonic stem cell-containing fetuses when comparing aggregation or injection into morulae versus blastocysts. However, the distribution pattern of embryonic stem cell derivatives in chimeric fetuses suggested that pre-compaction embryos are more suitable for generating fetuses with high embryonic stem cell contribution. Injection of embryonic stem cells into tetraploid embryos showed that completely embryonic stem cell-derived fetuses can also be produced by this technique. Totally embryonic stem cell derived fetuses were observed in each group, when embryonic stem cells were injected into diploid embryos. However, the rate of chimeras and chimerism was lower when 1 or 3 embryonic stem cells were used versus 8 or 15 cells. This suggests that the number of embryonic stem cells introduced might play a role in the colonization ability.

Evaluation of seven microsatellite loci in Simmental cattle

Seven microsatellite loci were evaluated for their suitability for parentage control. The polymerase chain reaction (PCR) was used to amplify the short tandem repeat (STR) loci in separate reactions. The microsatellite polymorphisms were visualized by radioisotopic autoradiographic detection. The microsatellite loci showed extensive polymorphism with allele numbers ranging from 4-23 and polymorphism information content (PIC) values in the range of 0.57-0.87. The analysis of these loci also revealed that they have a 99.9% combined probability of exclusion (PE) of erroneous parentage. The results of this study revealed that a very high probability of exclusion could be reached with only four microsatellite loci.

Granulosa-cumulus-corona expansion and aromatase localization in preovulatory follicles in superovulated heifers

Granulosa-cumulus and cumulus-corona expansion as well as aromatase localization within ovarian follicles were monitored during the preovulatory period in superovulated cattle that were blood sampled every 2'nd h for LH analyses. Granulosa-cumulus as well as cumulus-corona expansion were studied by means of transmission electron microscopy and computerized image analysis. Localization of aromatase, an enzyme involved in estrogen synthesis, was determined immunocytochemically using anti-human placental aromatase cytochrome P-450 antisera. Nuclear oocyte maturation was determined by aceto:orcein staining. Significant cell dissociation within the granulosa-cumulus stalk occurred before the breakdown of the germinal vesicle, i.e. the oocyte nucleus, during the period up to 5-7 h after the LH peak, i.e. the highest LH concentration during the surge. Significant increase in intercellular spacing between the cumulus-corona cells occurred at 13-15 and 19-21 h after the LH peak. Before the LH peak all layers of granulosa cells were immunocytochemically stained for aromatase. At 5-7 h after the LH peak, however, only the granulosa cell layers located near the basal lamina were stained, and at all later intervals staining was absent. The granulosa cells of primary and secondary follicles, the interstitial gland cells, the theca interna cells and the oocytes in all follicles were immunocytochemically unstained.

Effects of different cryoprotectants and carbohydrates on freezing of matured and unmatured bovine oocytes

Cumulus cell-enclosed bovine oocytes in germinal vesicle (GV) and in metaphase II (MII) stages were cryopreserved. Different concentrations (1 M; 1.5 M) of various cryoprotectants (glycerol, PROH, DMSO) were tested. After thawing, the oocytes were exposed to various carbohydrates (sucrose, lactose, trehalose) at a concentration of 0.1 M and 0.25 M for cryoprotectant removal. Developmental capacity of the frozen-thawed oocytes was studied by in vitro maturation, fertilization and culture. We found no difference in subsequent development using glycerol or PROH for GV and MII oocytes. The DMSO treatment led to significantly better cleavage and development up to 4-cell stage in MII oocytes. Development beyond the 8-cell stage was obtained only when unmatured oocytes were frozen. No difference in the efficiency of the 3 cryoprotectants was detected in MII oocytes. However, in GV oocytes, glycerol and PROH yielded significantly better cleavage and 4-cell rate compared to DMSO (P<0.001). Influence of the concentration of a cryoprotectant on development was not observed in GV or MII oocytes. Among the 3 cryoprotectants, DMSO was less suitable, at both concentrations, than PROH and glycerol for the development of 6- to 8-cell stage embryos in the GV group. In the MII group, 1.5 M DMSO was as efficient as PROH and as glycerol at a 1.5-M concentration, and it was more efficient than 1 M glycerol. The use of carbohydrates during rehydration did not render a beneficial effect at either of the 2 concentrations, and when no carbohydrates were used in the MII group the oocytes cleaved better than GV oocytes.