Detection of PRRSV-1 in tongue fluids under experimental and field conditions and comparison of different sampling material for PRRSV sow herd monitoring

BACKGROUND

Infection with porcine reproductive and respiratory syndrome virus (PRRSV) leads to significant economic losses worldwide. One of the initial measures following an outbreak is to stabilise the herd and to prevent vertical transmission of PRRSV. The objective of this study was to detect PRRSV in different sampling material, both in an experimental model and on a commercial piglet producing farm, with a focus on evaluating the suitability of tongue fluid samples.

RESULTS

In the experimental model, PRRSV negative pregnant gilts were infected with PRRSV-1 AUT15-33 on gestation day 85 and necropsy of gilts and foetuses was performed three weeks later. 38.3% of individual foetal serum and 39.4% of individual foetal thymus samples were considered PRRSV RT-qPCR positive. Tongue fluids from individual foetuses showed a 33.0% positivity rate. PRRSV RNA was detected in all but one sample of litter-wise pooled processing fluids and tongue fluids. In the field study, the investigated farm remained PRRSV positive and unstable for five consecutive farrowing groups after the start of the sampling process. Tongue fluid samples pooled by litter in the first investigated farrowing group had a 54.5% positivity rate, with the overall highest viral load obtained in the field study. In this farrowing group, 33.3% of investigated litter-wise pooled processing fluid samples and all investigated serum samples (pools of 4-6 individuals, two piglets per litter) were considered positive. Across all investigated farrowing groups, tongue fluid samples consistently showed the highest viral load. Moreover, tongue fluid samples contained the virus in moderate amounts for the longest time compared to the other investigated sampling material.

CONCLUSION

It can be concluded that the viral load in individual foetuses is higher in serum or thymus compared to tongue fluid samples. However, litter-wise pooled tongue fluid samples are well-suited for detecting vertical transmission within the herd, even when the suspected prevalence of vertical transmission events is low.

Pluck-pools as diagnostic samples for detecting porcine reproductive and respiratory syndrome virus and porcine circovirus type 2 in porcine abortion material and stillbirths

Investigating infectious agents in porcine abortion material and stillborn piglets poses challenges for practitioners and diagnostic laboratories. In this study, pooled samples of individual reference organs (thymus and heart) from a total of 1000 aborted fetuses and stillborn piglets were investigated using quantitative PCR protocols for porcine reproductive and respiratory syndrome virus 1 (PRRSV-1) and porcine circovirus type 2 (PCV2). Simultaneously, a pluck-pool containing equivalent portions of fetal thymus, heart, and lung tissue was collected, frozen at - 20 °C, and re-analyzed when a certain amount of either PRRSV-1 RNA or PCV2 DNA was detected in individual reference organs. Thirteen pluck-pools were assessed for PRRSV-1, all being PCR-positive. For PCV2, 11 of 15 pluck-pools investigated were PCR-positive. In all pluck-pools testing negative, viral loads in individual pools were low. This study indicates that pluck-pools can be valuable diagnostic material and the consolidation of multiple organs through a single RNA/DNA extraction optimizes the utilization of available laboratory resources. Additional research is required to assess the feasibility of follow-up investigations and to accurately define criteria for interpretation of viral loads in a clinical context.

Retrospective Analysis of the Detection of Pathogens Associated with the Porcine Respiratory Disease Complex in Routine Diagnostic Samples from Austrian Swine Stocks

The diagnostic workup of respiratory disease in pigs is complex due to coinfections and non-infectious causes. The detection of pathogens associated with respiratory disease is a pivotal part of the diagnostic workup for respiratory disease. We aimed to report how frequently certain viruses and bacteria were detected in samples from pigs with respiratory symptoms in the course of routine diagnostic procedures. Altogether, 1975 routine diagnostic samples from pigs in Austrian swine stocks between 2016 and 2021 were analysed. PCR was performed to detect various pathogens, including porcine reproductive and respiratory syndrome virus (PRRSV) (n = 921), influenza A virus (n = 479), porcine circovirus type 2 (PCV2) (n = 518), Mycoplasma (M.) hyopneumoniae (n = 713), Actinobacillus pleuropneumoniae (n = 198), Glaesserella (G.) parasuis (n = 165) and M. hyorhinis (n = 180). M. hyorhinis (55.1%) had the highest detection rate, followed by PCV2 (38.0%) and Streptococcus (S.) suis (30.6%). PRRSV was detected most frequently in a pool of lung, tonsil and tracheobronchial lymph node (36.2%). G. parasuis was isolated more frequently from samples taken after euthanasia compared to field samples. PRRSV-positive samples were more likely to be positive for PCV2 (p = 0.001), M. hyopneumoniae (p = 0.032) and Pasteurella multocida (p < 0.001). M. hyopneumoniae-positive samples were more likely to be positive for P. multocida (p < 0.001) and S. suis (p = 0.046), but less likely for M. hyorhinis (p = 0.004). In conclusion, our data provide evidence that lung samples that were positive for a primary pathogenic agent were more likely to be positive for a secondary pathogenic agent.

Presence of Equine and Bovine Coronaviruses, Endoparasites, and Bacteria in Fecal Samples of Horses with Colic

Acute abdominal pain (colic) is one of the major equine health threats worldwide and often necessitates intensive veterinary medical care and surgical intervention. Equine coronavirus (ECoV) infections can cause colic in horses but are rarely considered as a differential diagnosis. To determine the frequency of otherwise undetected ECoV infections in horses with acute colic, fresh fecal samples of 105 horses with acute colic and 36 healthy control horses were screened for viruses belonging to the Betacoronavirus 1 species by RT-PCR as well as for gastrointestinal helminths and bacteria commonly associated with colic. Horses with colic excreted significantly fewer strongyle eggs than horses without colic. The prevalence of anaerobic, spore-forming, gram-positive bacteria (Clostridium perfringens and Clostridioides difficile) was significantly higher in the feces of horses with colic. Six horses with colic (5.7%) and one horse from the control group (2.8%) tested positive for Betacoronaviruses. Coronavirus-positive samples were sequenced to classify the virus by molecular phylogeny (N gene). Interestingly, in three out of six coronavirus-positive horses with colic, sequences closely related to bovine coronaviruses (BCoV) were found. The pathogenic potential of BCoV in horses remains unclear and warrants further investigation.

Litters of Various-Sized Mummies (LVSM) and Stillborns after Porcine Reproductive and Respiratory Syndrome Virus Type 1 Infection-A Case Report

Diverse origins and causes are described for papyraceous mummifications of porcine foetuses, but the porcine reproductive and respiratory syndrome virus (PRRSV) is not one of them. In contrast, PRRSV is unlikely to cause mid-term placental transmission but may cause late-term abortions and weakness of piglets. This case report describes a sudden occurrence of mummified foetuses of various sizes and stillborns and delayed birth (>115 days) in more than 50% of sows from one farrowing batch, while newborn piglets were mostly vital. Neither increased embryonic death nor infertility was reported. Three litters with mummies, autolysed piglets and stillborn piglets were investigated, and infections with porcine parvoviruses, porcine teschoviruses, porcine circoviruses, encephalomyocarditis virus, Leptospira spp. and Chlamydia spp. were excluded. Instead, high viral loads of PRRSV were detected in the thymus pools of piglets at all developmental stages, even in piglets with a crown-rump length between 80 and 150 mm, suggesting a potential mid-term in utero transmission of the virus. Genomic regions encoding structural proteins (ORF2-7) of the virus were sequenced and identified the virulent PRRSV-1 strain AUT15-33 as the closest relative. This case report confirms the diversity of PRRSV and its potential involvement in foetal death in mid-gestation.

A single, episodic event of unilateral/bilateral scrotal swelling in a group of adult boars at an Austrian boar stud

BACKGROUND

Scrotal swelling is a clinical situation which can be caused by different aetiologies. In this case report, we describe a multi-week episode of unilateral and bilateral scrotal swelling in boars at an Austrian boar stud and its diagnostic work-up.

CASE PRESENTATION

In the summer of 2020, the herd veterinarian of an Austrian boar stud reported that over a period of six weeks, five out of 70 boars presented with unilateral severe swelling of the left scrotum and three out of 70 boars with bilateral severe swelling of the left and moderate swelling of the right scrotum, respectively. A complete history was obtained and an on-site evaluation of the facility was done. Five boars were necropsied, and a variety of samples harvested for further diagnostic investigations. Infectious differential diagnoses associated with unilateral swelling of the scrotum or the testis were excluded through serological and tissue testing. In three of the five boars, histopathology revealed complete acute haemorrhagic necrosis of the left testis concurrent with strongly congested blood vessels. Review of the collected information with a group of experts in the field of boar stud management resulted with consensus that, most likely, trauma was the etiologic event causing the clinical signs and pathology. Coincident with discussion of implementing video recording cameras in the boar housing area, no further clinical cases followed. As this case occurred during the first lockdown of the COVID-19 pandemic, we propose that the distress and travelling restrictions may have contributed to frustration among boar stud workers, which was consequently expressed as misbehaviour against boars.

CONCLUSIONS

Once all known infectious causes of unilateral swelling of the scrotum were excluded, a critical diagnostic work-up focused on non-infectious causes. Non-infectious causes, such as trauma, need to be carefully evaluated, as it may also include human misbehaviour against boars. Summarizing all findings of this case report, the authors hypothesize that a blunt trauma was the reason for the series of mainly unilateral swelling of the scrota of boars.

A Conserved Stem-Loop Structure within ORF5 Is a Frequent Recombination Hotspot for Porcine Reproductive and Respiratory Syndrome Virus 1 (PRRSV-1) with a Particular Modified Live Virus (MLV) Strain

The emergence of recombinant PRRSV strains has been observed for more than a decade. These recombinant viruses are characterized by a genome that contains genetic material from at least two different parental strains. Due to the advanced sequencing techniques and a growing number of data bank entries, the role of PRRSV recombinants has become increasingly important since they are sometimes associated with clinical outbreaks. Chimeric viruses observed more recently are products of PRRSV wild-type and vaccine strains. Here, we report on three PRRSV-1 isolates from geographically distant farms with differing clinical manifestations. A sequencing and recombination analysis revealed that these strains are crossovers between different wild-type strains and the same modified live virus vaccine strain. Interestingly, the recombination breakpoint of all analyzed isolates appears at the beginning of open reading frame 5 (ORF5). RNA structure predictions indicate a conserved stem loop in close proximity to the recombination hotspot, which is a plausible cause of a polymerase template switch during RNA replication. Further research into the mechanisms of the stem loop is needed to help understand the PRRSV recombination process and the role of MLVs as parental strains.

Successful treatment of coagulation disorders and hypoalbuminaemia in a puppy with Infectious Canine Hepatitis

Due to high vaccination coverage of the dog population in Western and Middle Europe, veterinarians are usually not familiar with clinical signs and treatment of Infectious Canine Hepatitis (ICH). This case report describes a 4-month-old female mixed breed dog that was imported from Bulgaria. According to the history, the puppy was presented with lethargy, pyrexia, icterus and melaena. On clinical examination, the dog additionally exhibited a painful abdomen and bleeding tendency at the venous puncture sites. Blood analysis revealed anaemia, left shift without leucocytosis, increased liver enzymes and prolonged coagulation times. Polymerase Chain Reaction (PCR) and subsequently sequence analysis performed out of urine confirmed Canine Adenovirus 1 (CAV-1) as the causative agent of the disease. Peripheral oedema developed on the dog´s head and limbs during the progression of the disease due to severe hypoalbuminaemia. Initial treatment of the puppy included transfusion of whole blood and fresh frozen plasma. Hypoalbuminaemia was treated by transfusion using human albumin. On day eight after starting the treatment, the dog was released from the hospital due to an unremarkable clinically condition. This case report indicates that ICH might become a re-emerging disease by means of rising dog imports. Especially, the severe form of ICH can be associated with several life-threatening complications that require hospitalisation and intensive care treatment.

Reproductive failure in an Austrian piglet-producing farm due to porcine circovirus genotype 2d

Infections of pigs with porcine circovirus type 2 (PCV2) can lead to various clinical conditions including reproductive disorders (PCV2-RD). In general, a transplacental infection of fetuses leads to mummification and stillbirth. So far, PCV2-RD has mainly been described in specific-pathogen-free (SPF) herds or farms with a high proportion of gilts. From December 2018 to February 2019, a high abundance of mummified fetuses (15.5%) was observed in two farrowing groups in an Austrian piglet-producing farm. PCV2 DNA was detected using qPCR in organs of all six investigated fetuses (2.07 × 108-1.09 × 1012 PCV2) genome equivalents/g tissue and via in situ hybridisation in organs from five fetuses, while histologic lesions were not observed in a single fetal heart. All isolates were sequenced and identified as PCV2d. After the implementation of a regular vaccination of all sows against PCV2, the abundance of mummified fetuses dropped to 3.5% in May 2019. In contrast to previous reports about PCV2-RD, this farm was neither an SPF herd nor a start-up herd with a high proportion of gilts. The implementation of regular PCV2 vaccination helped to reduce the abundance of mummified fetuses substantially.

[Challenges in Influenza diagnostics in a swine herd - a case report]

In a gilt producing farm in Lower Austria, respiratory diseases occurred over the previous years in self-reared gilts after being introduced into the sow herd. In addition, fertility disorders in terms of late abortions and re-breeders were observed in the fall of 2019. Nasal swabs of 3 gilts with respiratory signs and fever were tested positive for influenza A virus (IAV) subtype H1avN1 by PCR. However, examination of serum samples from these animals at 2 different time points did not detect antibodies using the standard hemagglutination inhibition (HI) test of the laboratory. Examination of additional age groups likewise failed to detect H1avN1 antibody titers. In consequence to the extension of the diagnostic panel of the HI test by 7 additional H1avN1 test antigens, a clear seroconversion of the PCR positive sows against 2 different H1avN1 isolates could be measured. In addition, high antibody titers against these 2 H1avN1 strains were also detectable in the majority of the remaining age groups tested. Following the administration of the trivalent influenza vaccine, which has been approved throughout Europe, a significant improvement of the clinical presentation in the herd was achieved. The present case report illustrates that direct and indirect pathogen detection should be used in combination for targeted influenza diagnostics. In addition, it was shown that the continuous adaptation of test antigens to the isolates circulating in the field would be extremely crucial for the significance of the HI test.

Reconsideration of the diagnostic criteria required for PCV2 reproductive disease

Porcine circovirus type 2 (PCV2) causes a variety of clinical conditions including PCV2-associated reproductive disease (PCV2-RD) characterized by late term abortions and mummifications. The generally accepted diagnostic triad includes the presence of reproductive disorders, the histopathological finding of myocarditis, and detection of moderate to high viral loads within the heart tissue. A new threshold of 10⁹ PCV2 genome equivalents (GE)/g heart tissue is suggested to fulfil the third criterion using the diagnostic settings of quantitative real time PCR and in situ hybridization of 30 fetal heart tissues. The need to identify histopathological lesions in fetal heart tissue appears to be invalid or overestimated in confirming a diagnosis of PCV2-RD, at least at the individual fetus level. The highest viral loads (10¹² GE/g tissue) were detected in autolyzed and mummified piglets and were identified as PCV2d, although concurrent detection of PCV2d + a and PCV2d + b also occurred.

Active equine parvovirus-hepatitis infection is most frequently detected in Austrian horses of advanced age

BACKGROUND

Equine parvovirus-hepatitis (EqPV-H) research is in its infancy. Information regarding prevalence, geographical distribution, genetic diversity, pathogenesis and risk factors enhances understanding of this potentially fatal infection.

OBJECTIVES

Determining the prevalence of EqPV-H in Austrian equids. Investigating factors increasing probability of infection, liver-associated biochemistry parameters, concurrent equine hepacivirus (EqHV) infection and phylogenetic analysis of Austrian EqPV-H variants.

STUDY DESIGN

Cross-sectional study.

METHODS

Sera from 259 horses and 13 donkeys in Austria were analysed for anti-EqPV-H VP1-specific antibodies by luciferase immunoprecipitation system (LIPS) and EqPV-H DNA by nested polymerase chain reaction (PCR). Associations between infection status, sex and age were described. Glutamate dehydrogenase (GLDH), gamma-glutamyl transferase (GGT), bile acids and albumin concentrations were compared between horses with active infection and PCR-negative horses. PCR targeting partial EqPV-H NS1 was performed and phylogenetic analysis of Austrian EqPV-H variants was conducted. Complete coding sequences (CDS) of four Austrian variants were determined by next-generation sequencing (NGS) and compared with published sequences.

RESULTS

Horses' EqPV-H seroprevalence was 30.1% and DNA prevalence was 8.9%. One horse was co-infected with EqHV. Significantly, higher probability of active EqPV-H infection was identified in 16- to 31-year-old horses, compared with 1- to 8-year-old horses (P = 0.002; OR = 8.19; 95% CI = 1.79 to 37.50) and 9- to 15-year-old horses (P = 0.03; OR = 2.96; 95% CI = 1.08 to 8.17). Liver-associated plasma parameters were not significantly different between horses with active infection and controls. Austrian EqPV-H variants revealed high similarity to sequences worldwide. No evidence of EqPV-H was detected in donkeys.

MAIN LIMITATIONS

Equids' inclusion depended upon owner consent. There was only one sampling point per animal and the sample of donkeys was small.

CONCLUSIONS

EqPV-H antibodies and DNA are frequently detected in Austrian horses, without associated hepatitis in horses with active infection. The risk of active EqPV-H infection increases with increasing age. Phylogenetic evidence supports close relation of EqPV-H variants globally, including Austrian variants.

Mechanism of the historical and the ongoing Vulcanian eruptions of Ebeko volcano, Northern Kuriles

Ebeko is one of the most active volcanoes of the Kurile island arc, producing frequent mild Vulcanian explosions with eruption clouds up to 5 km high. The volcano poses a serious threat to the Severo-Kurilsk town with a population of around 2500 inhabitants, located at a distance of only 7 km on a fan of the volcano's laharic deposits. Here, we report an overview of the activity of the volcano in the 20th-21st centuries and the results of our geological and petrological investigations of the ongoing Vulcanian eruption that started in 2016. We have found that eruptions of Ebeko span a range of mechanisms from purely magmatic to phreatic/hydrothermal. Three of its historical eruptions (the 1934-1935, 1987-1991, and the 2016-ongoing) involved fresh magma, while during the others (1967-1971, 2009-2011) fresh magma was not erupted. Juvenile material of the ongoing eruption represents highly crystalline and highly viscous (more than 10⁸ pa s) low-silica (56-58 wt% SiO₂) andesite. Historical data and our observations of the ongoing eruption allowed us to suggest a functional model of the volcano where Vulcanian explosions are caused by shallow intrusions of small diapir-like batches of strongly crystallized and highly viscous andesitic magma ascending into water-saturated, hydrothermally altered rocks composing the volcano summit. We suggest that the diapir's ascent is governed by their positive buoyancy. Some of the diapirs reach and breach the ground surface producing magmatic eruptions of Ebeko, while the others are stuck at the shallow subsurface level and feed intensive hydrothermal activity as well as phreatic eruptions of the volcano. Positive buoyancy of the diapirs is too weak to allow them to extrude high above the ground surface to form lava domes.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s00445-020-01426-z.

The first RT-qPCR confirmed case of tick-borne encephalitis in a dog in Scandinavia

Background

Tick-borne encephalitis (TBE) is a zoonotic neurological disease caused by tick-borne encephalitis virus (TBEV), a flavivirus endemic in parts of Europe and Asia. Seroconversion without signs of clinical disease is common in dogs and most of the cases previously described have been tentatively diagnosed by combining neurologic signs with serum antibody titres. Here, the first Scandinavian RT-qPCR-confirmed clinical case of TBE in a dog is reported.

Case presentation

A 4-year old castrated male Pointer Labrador cross was presented with acute-onset ataxia. During hospitalisation, the dog developed seizures. Despite aggressive treatment with steroids, antimicrobials and sedation/anaesthesia, there was continued deterioration during the following 24 h after admission and the dog was euthanised and submitted for necropsy. Histopathological changes in the brain were consistent with lymphoplasmacytic and histiocytic meningoencephalomyelitis. RT-qPCR examination of the brain was positive for TBEV, confirming infection.

Conclusions

Meningoencephalomyelitis caused by TBEV should be a diagnostic consideration in dogs presenting with clinical signs of central nervous system disease such as acute-onset ataxia and seizures in areas where TBEV-positive ticks are endemic. Clinical TBE may be underdiagnosed in dogs due to lack of specific testing.

Development and validation of a portable, point-of-care canine distemper virus qPCR test

Canine distemper virus (CDV) is a multi-host pathogen that can cause significant mortality in domestic, wild terrestrial and marine mammals. It is a major conservation threat in some endangered species. Infection can result in severe respiratory disease and fatal encephalitis. Diagnosis and disease monitoring in wildlife, and differentiation of CDV from rabies (a life-threatening zoonotic disease that can produce similar neurologic signs), would benefit from the availability of a portable, point-of-care (POC) diagnostic test. We therefore developed a quantitative RT-PCR assay for CDV using shelf-stable, lyophilized reagents and target-specific primers and probes for use with the handheld Biomeme two3™ qPCR thermocycler. Biomeme's extraction methodology, lyophilized reagents, and thermocycler were compared to our standard laboratory-based methods to assess sensitivity, efficiency and overall test performance. Results using a positive control plasmid for CDV showed comparable sensitivity (detection of 50 copies) and PCR efficiency between the two platforms, and CDV detection was similar between platforms when tested using a modified live CDV vaccine. Significantly higher Ct values (average Ct = 5.1 cycles) were observed using the Biomeme platform on known CDV positive animal samples. CDV detection using the Biomeme platform was similar in 25 of 26 samples from suspect CDV cases when compared to standard virology laboratory testing. One false positive was observed that was negative upon retest. The Biomeme methodology can be adapted for detection of specific targets, and this portable technology saves time by eliminating the need for local or international sample transport for laboratory-based diagnostics. However, results of our testing suggest that decreased diagnostic sensitivity (higher Ct values) relative to laboratory-based methods was observed using animal samples, so careful validation and optimization are essential. Portable qPCR platforms can empower biologists and wildlife health professionals in remote and low-resource settings, which will greatly improve our understanding of CDV disease ecology and associated conservation threats in wildlife.

Single centre versus multi-centre pooled morbidity data in PCNL and the implications for informed consent

Background: National and international outcome data following PCNL have been available for many years, but multi-centre data may not reflect the outcome from an individual surgeon or hospital.Methods: A combination of retrospective and prospective single centre data was collated from 2000-2016 and are compared to large single and multi-centre series.Results: Data were available on 801 unique cases performed between 2000 and 2016, mean age = 55.2 (SD = 14.8) (range = 17-93). The mean change in haemoglobin after PCNL was 1.65 g/dL ± 0.05, n = 630. Twenty-seven patients required a blood transfusion (3.37%). In 470 cases, data on pre-operative urine culture was available. One hundred and nineteen (25%) demonstrated evidence of bacteriuria pre-operatively. The most common isolated species were E. Coli and Proteus Mirabilis. Pre-operative urine infection was associated with a greater drop in haemoglobin following surgery, but this difference was not found to be statistically significant. Changes in serum creatinine and eGFR rise following surgery were calculated. The mean rise was found to be 15.21 µmol/L (SE = 2.08, n = 208). The mean drop in eGFR was estimated to be 7.35 ml/min/1.73 m² (± 0.895, n = 205). Eight cases of 801 (1%) required admission to higher level care. There was one small bowel puncture and one pleural perforation recorded. Sub-selective embolization due to bleeding occurred in six cases (0 .75%) and there were no peri-operative deaths in this series. Published data comparing single centres with > 500 cases are presented.Conclusion: To facilitate transparent consent, single-centre rather than pooled outcome data should be utilized.

No Evidence of Mosquito Involvement in the Transmission of Equine Hepacivirus (Flaviviridae) in an Epidemiological Survey of Austrian Horses

Prevalence studies have demonstrated a global distribution of equine hepacivirus (EqHV), a member of the family Flaviviridae. However, apart from a single case of vertical transmission, natural routes of EqHV transmission remain elusive. Many known flaviviruses are horizontally transmitted between hematophagous arthropods and vertebrate hosts. This study represents the first investigation of potential EqHV transmission by mosquitoes. More than 5000 mosquitoes were collected across Austria and analyzed for EqHV ribonucleic acid (RNA) by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Concurrently, 386 serum samples from horses in eastern Austria were analyzed for EqHV-specific antibodies by luciferase immunoprecipitation system (LIPS) and for EqHV RNA by RT-qPCR. Additionally, liver-specific biochemistry parameters were compared between EqHV RNA-positive horses and EqHV RNA-negative horses. Phylogenetic analysis was conducted in comparison to previously published sequences from various origins. No EqHV RNA was detected in mosquito pools. Serum samples yielded an EqHV antibody prevalence of 45.9% (177/386) and RNA prevalence of 4.15% (16/386). EqHV RNA-positive horses had significantly higher glutamate dehydrogenase (GLDH) levels (p = 0.013) than control horses. Phylogenetic analysis showed high similarity between nucleotide sequences of EqHV in Austrian horses and EqHV circulating in other regions. Despite frequently detected evidence of EqHV infection in Austrian horses, no viral RNA was found in mosquitoes. It is therefore unlikely that mosquitoes are vectors of this flavivirus.

Detection of selected viral pathogens in dogs with canine infectious respiratory disease in Austria

Objectives

To assess the prevalence of canine parainfluenza virus, canine adenovirus type 2, canine distemper virus, canine respiratory coronavirus and influenza virus A infections in: (1) privately‐owned or, (2) kennelled dogs showing signs consistent with canine infectious respiratory disease and, (3) clinically healthy dogs in Vienna, Austria.

Materials and Methods

Prospectively, nasal and tonsillar swabs from 214 dogs affected with infectious respiratory disease, and 50 healthy control dogs were tested for nucleic acids specific to the various viral infections. Concurrent bronchoalveolar lavage fluid from 31 dogs with chronic respiratory disease was investigated for the same viral pathogens. Additionally, anti‐canine respiratory coronavirus antibody concentrations were measured in paired blood samples from 30 acutely diseased dogs.

Results

Canine respiratory coronavirus (7.5%) and canine parainfluenza virus (6.5%) were the most commonly detected viruses in samples from the upper airways of dogs with respiratory infections. Serological results showed a significant seroconversion in response to coronavirus in 50% of the examined cases. None of the samples was positive for influenza virus A‐specific nucleic acid. Canine coronavirus‐specific nucleic acid was detected in 4.0% of healthy dogs.

Clinical Significance

Canine coronavirus should be considered as a clinically relevant cause of infectious respiratory disease in crowded dog populations. For sample collection, the nasal mucosa can be recommended as the favoured site. Analysis of paired serum samples aids verification of canine coronavirus infection in respiratory disease.

Ensuring selectivity using retention time modulation by solvent composition, applied to the analysis of phenol in e-liquids

A gas chromatographic method for the determination of volatile contaminants (halogenated solvents, benzene, toluene, ethyl-benzene, xylenes, styrene) and phenol in e-liquids was developed and validated with a working range of 0.01 (limit of quantification) to 0.5 mg/l, and variation coefficients between 2 and 14%. Selectivity performing MS/MS-detection was sufficient for all analytes except for phenol: e-liquids contain high amounts of aroma compounds in excess of 10⁵ compared to phenol. A number of these compounds potentially interfere at the retention time of phenol, showing all masses (including daughter ions and transitions) of phenol. To allow the detection of phenol in this matrix, a novel approach of adding a polar molecule to the injection solvent was used, modulating the polarity of the column, and thus the retention time of phenol. By adding 3 μl/ml and 10 μl/ml of 1,2-propanediol the retention time of phenol was shifted by 0.06 and 0.11 min respectively, while interfering peaks have not been shifted. This allowed a reliable confirmation of the presence of phenol. The introduced approach is an easy way to generate an additional chromatographic dimension for confirmation purposes, not requiring additional equipment.

246 IN VITRO PRODUCTION OF SPRINGBOK (ANTIDORCAS MARSUPIALIS) EMBRYOS

The objective of this experiment was to develop in vitro embryo production (IVP) technologies in springbok (Antidorcas marsupialis), a southern African antelope. Springbok, a fairly common species on game farms in parts of South Africa, may be used as a model species for gamete rescue and IVP techniques to be applied to the conservation of other threatened antelope species. Springbok belong to the family bovidae, subfamily antilopinae, tribe antilopini, which comprises about twenty species in genera Gazella, Antilope, Procapra, Antidorcas, Litocranius, and Ammodorcas. In this tribe alone, there are 4 species or subspecies that are critically endangered, 3 that are endangered, and 10 that are considered vulnerable, demonstrating the need for antelope conservation efforts. In addition, our studies contributed to the South African biological resource bank, so that banked springbok semen and embryos might be used in the future for managed genetic contribution to isolated captive or wild populations via assisted reproductive technologies. Oocytes were recovered (3 replicates) from ovaries obtained at supervised culls for management purposes in South Africa, and cultured in defined Gmat or undefined TCM-199 with FCS maturation medium for 28-30 h (Brad et al. 2004 Reprod. Fertil. Dev. 16, 223). Oocytes were fertilized with frozen-thawed springbok epididymal spermatozoa in modified SOF fertilization medium with caffeine (Herrick et al. 2004 Biol. Reprod. 71, 948–958). Eighteen hours after insemination, a randomly selected subset of the zygotes were fixed to determine fertilization success. The remaining zygotes were cultured in G1/G2 media. On Day 7 of culture, embryos were analyzed for development to the morula or blastocyst stage. A total of 259 selected oocytes were collected from 50 females (5.2 selected oocytes/female on average). There was no difference in the percentage of oocytes normally fertilized (2 pronuclei, PN) between oocytes matured in Gmat (n= 43; 12%) and those matured in TCM-199 (n= 42; 10%). There were significantly (P &lt; 0.05) more oocytes penetrated (e2 PN) when matured in TCM (50%) compared to Gmat (23%). There were no differences in embryonic cleavage or morula/blastocyst development (of total oocytes inseminated) between treatments (Gmat,n= 89, 54%, 9.0%; TCM-199, n= 85, 68%, 9.4%, respectively). In both treatments, the average blastocyst grade was 2.125 using the standard bovine grading system (Curtis, Cattle Embryo Transfer Procedure, 1991). In conclusion, in vitro oocyte maturation, fertilization, and embryo culture to the blastocyst stage is possible in springbok. Importantly, blastocysts can be produced in vitro under semi-defined conditions, demonstrating that oocyte maturation without serum does support developmental competence. This is important for the potential international movement of IVP embryos to be used for genetic management in the conservation of antelope species.

[Magnetic resonance angiography in inflammatory brain diseases]

In this review, we discuss the diagnostic potential of time of flight (TOF) MRA and contrast enhanced (CE) MRA in inflammatory disorders of the meninges and the brain. Cerebrovascular complications are frequently observed during infectious meningoencepalitis. 3D TOF-MRA and CE-MRA are complementary for the detection of basal intracranial artery stenosis and septic cerebral vein and sinus thrombosis due to secondary vasculitis. MRA reveals stenosis and occlusion as indirect signs of vasculitis, whereas MRI shows the inflammation of the brain and meninges and occasionally the vessel wall, together with the ischemic or hemorrhagic complication. In case of septic emboli MRA can detect peripheral occlusions and "mycotic" aneurysms. For the diagnosis of noninfectious vasculitides of the intracranial vessels, high resolution 3D TOF-MRA is superior to CE-MRA for the detection of multiloculated segmental stenoses. However, there are presently no prospective studies on the sensitivity and specificity of MRA for these indications. Therefore, only positive MRA results can directly influence clinical management. In case of normal MRA, confirmation by catheder angiography may still be required.

Virtual endoscopy for planning endoscopic third ventriculostomy procedures

Virtual endoscopy was used to plan 10 endoscopic third ventriculostomy procedures in 9 patients suffering from occlusive hydrocephalus due to idiopathic aqueductal stenosis and tumors. The patients were 4 children (4-14 years, mean age: 9 years) and 5 adults (21-38 years, mean age: 29 years). The aim of the study was to preoperatively evaluate the individual intraventricular and vascular endoscopic anatomy at the floor of the third ventricle based on virtual endoscopic images. The virtual views were correlated with the real endoscopic images, intraoperatively obtained by a standard ventriculoscope (Wolf, Knittlingen, Germany) during endoscopic third ventriculostomy procedures. Contrast-medium-enhanced MR images (3D-MPRAGE; Siemens, Germany) were semiautomatically segmented with a surface-rendering technique ('Navigator' software; General Electric Medical, Buc, France) to produce the virtual endoluminal views. The virtual endoscopic images were comparable with the real intraoperative endoscopic view in 8 of 9 patients. Virtual endoscopy can display the position of the basilar artery, the posterior cerebral arteries and the posterior communicating arteries in their relationship to the mammillary bodies and the clivus. Preoperative virtual endoscopy planning can intraoperatively assist the neurosurgeon to find a safe location for third ventriculostomy.

[Epignathus: prenatal diagnosis by sonography and magnetic resonance imaging]

Prenatal diagnosis of a teratoma of the oral cavity (epignathus) is presented using ultrasonography and magnetic resonance imaging as complementary techniques. Chromosome analysis from amniotic fluid revealed an inverted duplication of chromosome 1 that was confined to the tumour, whereas the constitutional karyotype was normal. The development of polyhydramnios, presumably reflecting impaired fetal swallowing, led to premature rupture of membranes and spontaneous delivery at 23 + 4 weeks of pregnancy. The premature neonate succumbed to acute respiratory distress secondary to airway obstruction by the tumour, and died immediately after birth.

[Transcranial Doppler ultrasonography: stereotactically guided examinations using magnetic resonance angiography]

The accurate localization of specific intracranial blood vessels is a major difficulty with transcranial Doppler sonography (TCD). It was the purpose of this study to develop a system enabling stereotactic navigation during a TCD examination on the basis of high-resolution three-dimensional magnetic resonance angiographic (MRA) data. During TCD, the examiner is provided--on a computer screen--with a projected view of the respective intracranial vessel anatomy. With the aid of an optoelectronic localization system, the spatial orientation and localization of the US probe is determined in real time, and correlated with the patient's MRA data using a dedicated stereotactic mask. Subsequently, the US beam and the points of insonation are displayed on the screen overlaid on the vessel anatomy. In this way the examiner gains real time control of the localization of the respective intracranial vessel insonated. Points of insonation can be stored and recalled for follow-up examinations. In addition to the successful verification of the system, it was shown that, in comparison with conventional TCD, stereotactic navigation distinctly improves the reproducibility of repeat TCD examinations.

[MRI characteristics of spontaneous intracerebral hemorrhage]

We review the signal characteristics of intracerebral hematomas (ICH) on magnetic resonance imaging (MRI), with special emphasis on the diagnosis of intracerebral hemorrhage within the first hours after stroke.The detection of peracute ICH was evaluated in 42 patients of a prospective, MR randomized stroke trial. These patients underwent a protocol of T1 and T2 weighted sequences, diffusion weighted sequences and MR - angiography within 6 hours after onset of acute hemiparesis. The signal behaviour of ICH in any stage after bleeding was additionally reviewed in a retrospective series of 63 patients, who were submitted for MRI over a 12 months period because of known ICH.MRI correctly identified 4 hyperacute ICH in the prospective group and 4 hyperacute ICH in the retrospective group. These ICHs had high signal on T2 weighted images, were isointense in T1 weighted images and had signal voids on the diffusion weighted sequences. The signal intensities of acute, subacute and chronic ICHs correlated to previous experiences as reported in the literature.In conclusion, MRI reliably identified all hematomas even in the hyperacute stage. Diffusion weighted images were most sensitive to the presence of deoxyhemoglobine and helpful for the differentiation and characterization of acute ischemia. Therefore, MRI at 1.5 T can be employed as an alternative to CT for the emergency diagnosis of acute stroke.

Transcranial Doppler sonography guided by magnetic resonance angiography for improved monitoring of intracranial arteries

Transcranial Doppler (TCD) sonography combines the advantages of real-time hemodynamic information, cost-effectiveness, and bedside application. However, measurements can be difficult to reproduce because the spatial resolution and the determination of insonation angles are limited. The purpose of this study was to use the high anatomic resolution of three-dimensional (3D) magnetic resonance angiography (MRA) images for the stereotactic guidance of TCD in order to improve the accuracy and reproducibility of TCD examinations. The MRA examinations were performed on a 1.5 T scanner using a 3D flow compensated gradient-echo sequence. A noninvasive stereotactic mask was used for image registration. The MRA data were then transferred to a personal computer. An infrared tracking system registered the position of the head and the ultrasound probe during TCD. This enabled the authors to superimpose a virtual ultrasound beam onto the MRA projections of the intracranial arteries displayed on the monitor of the personal computer. This allows the examiner to easily identify the insonated intracranial artery and displays the insonation angle. In volunteer examinations (n = 10), the accuracy and reproducibility for the localization of specific vessel segments was 2.48 mm for the middle cerebral artery and 2.81 mm for all insonated intracranial arteries (middle cerebral artery, anterior cerebral artery, internal carotid artery, and posterior cerebral artery). Without navigation the reproducibility of vessel segment insonation dropped to 4.7 mm for the middle cerebral artery and to 4.84 mm for all vessels. The authors conclude that 3D MRA, acquired as an initial procedure in patients with intracranial vascular disorders, can be used to provide stereotactic guidance for repeated TCD examinations. This facilitates the reproducible insonation of specific vessel segments.

Seat belt-related injury to the common iliac artery: case report and review of the literature

Blunt trauma to the common iliac artery is a rare phenomenon. Although seat belt injuries to the abdominal aorta and the carotid artery have been reported, there is only one previous report in the literature of seat belt injury to the common iliac artery. We report a case of common iliac arterial injury directly related to use of the lap belt and not associated with pelvic or lumbar fractures. The literature related to blunt trauma of the common iliac artery is reviewed.

Magnetic resonance angiographic and clinical features of extracranial vertebral artery dissection

OBJECTIVES

Clinical data and neuroradiological findings of 19 patients with 20 vertebral artery dissections were analysed to describe the features of time of flight magnetic resonance angiography (MRA) for the diagnosis and follow up of this vascular disorder.

METHODS

All patients underwent a combined MRI and MRA protocol with 1.5 T scanners, using a three dimensional flow compensated gradient echo sequence for MRA. Duplex sonography was performed on all patients and selective angiography was available from 17 vertebral artery dissections.

RESULTS

MRI showed ischaemic lesions of the brain in 18 of 19 patients (95%). In the acute and subacute stage, MRA detected signal abnormalities within the dissected vertebral artery in 94% (16/17) and MRI was specific for a dissection in 29% (5/17). Sensitivity of selective angiography was 100% and specificity was 35% (6/17). Combination of the results of both methods increased the specificity to 50%. Duplex sonography was sensitive in 79% (15/19), but lacked specific results. Follow up magnetic resonance in 16 patients showed recanalisation of the dissected vessel in 10 (63%), persistent occlusion in five (31%), and a dissecting aneurysm in one (6%) patient.

CONCLUSIONS

Magnetic resonance improves the triage for selective angiography and discloses complementary information for the diagnosis of vertebral artery dissection. If magnetic resonance identifies a double lumen or a mural haematoma with a stenosis or aneurysmal dilatation, invasive procedures can be omitted.

[Magnetic resonance angiography and magnetic resonance tomography in dissection of the vertebral artery]

Vertebral artery dissection (VAD) is an important cause of posterior circulation stroke in young adults. Initial symptoms are often non-specific and diagnostic arteriography is not performed until neurological deficits are obvious. Since magnetic resonance tomography (MRT) is superior in the diagnosis of vertebrobasilar ischemia, we retrospectively analyzed the role of MRT and MR angiography (MRA) in the detection of dissections of the vertebral artery. Between 1989 and 1995 we identified 24 patients with a vertebral artery dissection and 1 patient with a basilar artery dissection (8 females and 17 males, 23-60 years of age, mean 41.2 years). The diagnosis of VAD (14 left VAD, 9 right VAD, 1 bilateral VAD, 1 basilar artery dissection) was established by specific arteriographical findings (DSA) or clinical and neuroradiological course. All patients underwent a combined MRT/MRA examination protocol at 1.5T that consisted of spin-echo imaging and time of flight MRA of the intra- and extracranial arteries using 2D Flash and 3D Fisp sequences. The MRT/MRA findings were correlated to DSA and ultrasound results. During the acute and subacute stage, MRT/MRA revealed abnormal findings in 21 of 22 dissected vessels (95.5%). There was one false-negative MRT/MRA in a patient with a V1 dissection (intimal flap without peripheral flow disturbances). In 7/22 VAD the MRT/MRA findings were rated specific (double lumen n = 1, mural hematoma n = 4, pseudoaneurysm n = 2). DAS was sensitive in 100% and ultrasound in 77.3%. Specific results were obtained by DSA in 8/ 22 VAD (36.4%) and in 7/22 VAD (30.4%) by MRT/MRA. When MRT/MRA and DSA results were combined, the specific findings increased to 43.5%. Follow-up examinations revealed recanalization in 52% of initially stenosed or occluded vertebral arteries; four patients developed a pseudoaneurysm, and two of them underwent ligation of the VAD. With this retrospective approach, we were able to show a high sensitivity of MRT/ MRA for the presence of disturbed flow in the dissected vertebral artery. The MRA projections tended to overestimate stenosis and were inferior to DSA in the appreciation of irregularities of the vessel wall. Identification of high-grade stenosis, especially in the presence of distal occlusion, was improved on the MRA source images. During the acute and subacute stage, the diagnosis of luminal thrombus can be difficult, because signal ambiguities exist between hemoglobin breakdown products and flow effects and adjacent fat tissues. The differentiation between luminal thrombus and mural hematoma requires interpretation of MRA source images, together with flow compensated spin-echo images. Additional fat suppressed images and flow presaturation may be required at the appropriate levels. The identification of mural hematoma is important, because this finding is considered specific and cannot be obtained with DSA. There is a complementary role of MRT/MRA and DSA for an improved overall specificity for vertebral artery dissection. A negative MRT/MRA result in a patient with appropriate symptoms, however, cannot exclude a dissection and should prompt DSA. On the other hand, a suggestive MRT/MRA result in the appropriate clinical context can replace DSA. The advantage of MRT/MRA is that the method offers a simultaneous diagnosis of posterior fossa ischemia and vertebral artery abnormalities. Therefore, MRT/MRA should be recommended in patients with suspected VAD and especially in those who have no definite neurological deficit. These patients will benefit greatly from early diagnosis and therapy. The fact that all our patients were diagnosed after neurological symptoms and that 64% of them have residual deficits gives an ethical and economical rationale for advocating early MRT/MRA in these patients.

Cardiovascular parameters: sensitivity to detect autonomic dysfunction and influence of age and sex in normal subjects

In 137 healthy volunteers between 18 and 85 years of age, blood pressure (BP) and heart rate (HR) were measured continuously with the Finapres device during active change of posture (ACP), i.e. standing upright, passive tilt (PT, i.e. head-up tilt), Valsalva manoeuvre (VM), deep breathing (DB), isometric muscle exercise (IME) and a mental arithmetic task (MA). Mean HR activation was attenuated with increasing age in all manoeuvres, but was unrelated to sex. In non-orthostatic challenge procedures like MA and IME mean BP increases were independent of age and sex, despite lower increases in HR in the elderly. This points to a preserved sympathetic efferent activity. Following a forced fall in BP during ACP, PT and VM, the initial responses and maintenance values of BP showed a significant age-related decrease. This finding was strongly related to lower BP values in males compared with females, which became more pronounced with increasing age. Further studies to investigate age-related changes in the activation of the various components of the cardiovascular regulation need to consider the mode of activation of the autonomic nervous system and sex as factors of influence. Normal ranges, and also some new points in time not previously measurable, were calculated for all standard autonomic tests based on the continuous measurement of BP and HR. The minimum length of time necessary to assess the cardiovascular responses during ACP and PT was found to be 60 s. The upper time limits for reaching maximum activation during IME and MA were 3.5 min and 1 min, respectively. Age had a relevant influence on the lower limits of normal of all HR parameters and of some BP measurements during PT, ACP and VM. Sex was found to have no relevant impact on normal ranges. Over 65 years of age the normal values for HR activation during VM and DB hardly exceeded baseline values. The possibility of increasing the sensitivity of detection of autonomic dysfunction by measuring BP continuously must be approached with caution, as sufficient sensitivity was only reached at the lower limits of normal during late phase II of the VM. The initial increase of HR after ACP and the BP values after 60 s standing time proved to be the parameters with the best sensitivity for detecting an affection of the regulation of HR and BP over the whole range of age.

Emergency department nursing vascular assessment: a retrospective study

Nursing documentation in any area is essential, but in the patient with severe trauma and vascular injury it may be critical in evaluating change. In vascular trauma the nursing assessment and documentation provides a baseline for comparison of pulses in the emergency department, the intensive care unit, and the general or vascular floor. A retrospective review of vascular trauma charts performed at St. John's Mercy Medical Center in St. Louis, Missouri, revealed serious documentation omissions. In view of this study a new flow sheet for documentation was proposed, inservices were given, and a follow-up study is proposed for 2 years for implementation date. This study underscores the need to assess current documentation in every institution and regular review of records.

Pesticide exposures, cholinesterase depression, and symptoms among North Carolina migrant farmworkers

OBJECTIVES

We conducted a clinic-based study of erythrocyte cholinesterase levels, pesticide exposures, and health effects among farmworkers and nonfarmworkers to determine risks for exposure and associated morbidity.

METHODS

Two hundred two farmworkers and 42 nonfarmworkers were recruited sequentially at two community health centers. Erythrocyte cholinesterase levels were measured colorimetrically. Questionnaires obtained data on demographics, occupational history, exposures, and symptoms.

RESULTS

Cholinesterase levels were significantly lower among farmworkers (30.28 U/g hemoglobin) than among nonfarmworkers (32.3 U/g hemoglobin). Twelve percent of farmworkers, but no nonfarmworkers, had very low levels. Farmworkers applying pesticides also had lower cholinesterase levels. One half of farmworkers reported being sprayed by pesticides and working in fields with an obvious chemical smell. Of reported symptoms, only diarrhea was associated with cholinesterase levels. Reported exposures, however, were strongly associated with symptoms.

CONCLUSIONS

Farmworkers reported many pesticide exposures that violate state and federal regulations. Farmworkers had cholinesterase levels significantly lower than those of nonfarmworkers, although only spraying pesticides was associated with very low levels.

Qualitative diatom analysis as a tool to diagnose drowning

Since the 1950s, quantitative diatom analysis has been used successfully at the Department of Forensic Medicine at the University of Helsinki as a supportive method for diagnosing deaths by drowning. The reliability of the method was firmly established in 1986 by a study involving 107 probable cases of drowning. Since 1982, the quantitative analysis has been complemented with qualitative diatom analysis. This report presents potential applications of the latter method by describing its use in six cases of drowning.

Diatoms and drowning

An examination is made of the applicability of quantitative and qualitative diatom analysis to the diagnosis of death by drowning, definition of the environment in which drowning occurred, and delimitation of the area where it occurred. the material comprises 107 bodies of subjects known or suspected to have died by drowning together with a control series of 15 bodies of subjects over 30 years of age who had died of various diseases on land. Whenever diatoms were found in the greater circulatory organs they were also found in the lungs, and when none were present in the lungs none were found in the other organs either. No diatoms or fragments of diatoms were found in the samples from the control subjects. All the fresh, well-preserved bodies for which death by drowning could be regarded as certain from the macroscopic autopsy findings and police reports, the cases used to test the method, gave quantitative diatom results that supported a diagnosis of water aspiration. The diatoms identified in the qualitative analyses served well to describe the ecological properties of the environments in which death had taken place, and the site of drowning could be defined by means of comparative water samples provided that sufficient diatoms were present, the local environment was not too homogeneous or the diatoms were not of quite different species due to a completely unknown location of death.

[Fetal indication for the termination of pregnancy from an ethical viewpoint]

The author goes into five ethical problems involved in foetal indication for termination of pregnancy: 1. The method of prenatal diagnosis is considered to be ethically neutral. 2. Arguments and indication for termination of pregnancy in case of foetal indication are critically reviewed. Four degrees of severity are distinguished in the field of prenatal damage. 3. After expounding the arguments for a continuation of pregnancy, the only case in which termination is declared as ethically justifiable is the occurrence of "total malformation" of the foetus (anencephaly). 4. In everyday practice, great importance must be attached to a differentiation between judgement of what can be considered as correct from the viewpoint of morals as tolerated by society on the one hand, and the moral value attached to a concrete action on the other. 5. Termination of pregnancy in case of foetal indication, which has largely become a matter of course, is examined and reflected with regard to its importance for the development of (medical and social) moral awareness.