Major difference in clinical outcome and replication of a H3N1 avian influenza strain in young pullets and adult layers.

In this study, we investigated the pathogenicity, replication and tropism of the low pathogenic avian influenza (LPAI) strain A/chicken/Belgium/460/2019(H3N1) in adult SPF layers and young SPF males. The inoculated hens showed 58% mortality and a 100% drop in egg production in the second week post inoculation. The high viral loads in the cloacal samples coincided with the period of the positive immunohistochemistry of the oviduct, acute peritonitis and time of mortality, suggesting that the replication of H3N1 in the oviduct was a major component of the onset of clinical disease and increased level of excretion of the virus. In the inoculated young birds, the clinical signs were very mild with the exception of one bird. The results suggest that the time of replication of the virus was much shorter than in the adult layers; some of the young males did not show any proof of being infected at all. To conclude, the results of the study in young birds confirmed the intravenous pathogenicity test results but also showed that the clinical signs in adult layers were very severe. Based on the mortality without a bacterial component, complete drop of egg production and post mortem findings, this H3N1 strain is a moderately virulent strain, the highest category for LPAI strains. It is important to realize that if HPAI did not exist, this moderately virulent H3N1 virus would most likely to be considered as a very virulent virus.

Towards high quality real-time whole genome sequencing during outbreaks using Usutu virus as example.

Recently, protocols for amplicon based whole genome sequencing using Nanopore technology have been described for Ebola virus, Zika virus, yellow fever virus and West Nile virus. However, there is some debate regarding reliability of sequencing using this technology, which is important for applications beyond diagnosis such as linking lineages to outbreaks, tracking transmission pathways and pockets of circulation, or mapping specific markers. To our knowledge, no in depth analyses of the required read coverage to compensate for the error profile in Nanopore sequencing have been described. Here, we describe the validation of a protocol for whole genome sequencing of USUV using Nanopore sequencing by direct comparison to Illumina sequencing. To that point we selected brain tissue samples with high viral loads, typical for birds which died from USUV infection. We conclude that the low-cost MinION Nanopore sequencing platform can be used for characterization and tracking of Usutu virus outbreaks.

Field and laboratory findings following the large-scale use of intermediate type infectious bursal disease vaccines in Denmark.

Following a period of clinical outbreaks of very virulent infectious bursal disease virus (vvIBDV) in Denmark, the histological bursal lesion score (HBLS) was used on a national scale to screen broiler flocks vaccinated with intermediate IBD vaccines for lesions indicative of IBDV challenge. High lesion scores were detected in a high percentage of healthy and well performing flocks despite the lack of other indications of the presence of vvIBDV. RT-PCR and subsequent sequencing showed the frequent presence of H253Q and H253N IBDV strains that were genetically close to the sequence of the intermediate vaccines with a relative risk ratio of 13.0 (P < 0.0001) in intermediate vaccine A or B vaccinated flocks compared to unvaccinated flocks. The relevance of these H253Q and H253N strains was tested under experimental conditions using a protocol derived from the European Pharmacopoeia for safety of live IBD vaccines. The results confirmed the higher pathogenicity for the bursa of these strains compared to intermediate vaccines as well as the negative effect on antibody response to a Newcastle disease (ND) vaccination performed at the peak of the bursa damage. The efficacy of the ND vaccination was still 100% showing that the H253N and H253Q IBDV strains would be considered as safe vaccine viruses. In conclusion, the use of the HBLS to screen commercial broiler flocks vaccinated with intermediate IBD vaccines for the presence of vvIBDV does not seem to be a reliable method due to the frequent occurrence of H253N and H253Q strains in those flocks. For screening of IBD vaccinated flocks for the presence of vvIBDV or other field strains, the RT-PCR with subsequent sequencing seems to be most suitable.

Prevalence of histopathological intestinal lesions and enteric pathogens in Dutch commercial broilers with time.

Intestinal disease has a major impact on the broiler industry due to economic and welfare reasons. Intestinal disease might occur due to a large number of reasons varying from well-defined pathogens to non-specific enteritis and complex syndromes. However, knowledge about the nature of intestinal disease and presence of enteric viruses in the Dutch broiler industry is largely absent. Therefore, a large-scale field study, in which 98 broiler flocks from 86 farms were sampled weekly, was started to assess the prevalence of histopathological lesions in the jejunum, a number of enterotropic viruses by real-time quantitative reverse transcriptase PCR (RT-qPCR) and coccidia by lesion scoring. Histopathological lesions indicative of intestinal disease were found in all flocks examined. The pathogens investigated were chicken astrovirus (99% of flocks positive), avian nephritis virus 3 (100%), rotavirus A (95%), rotavirus D (52%), reovirus (100%), Eimeria acervulina (94%), E. maxima (49%) and E. tenella (40%). The enteric viruses were more prevalent in the first weeks of the growing period, while coccidiosis was more frequently found at 4 and 5 weeks of age. The abundant presence of the enteric viruses and enteric disorders stresses the need to elucidate the role of these viruses in intestinal disease. Furthermore, the high prevalence of coccidiosis despite the use of anticoccidials shows that the current coccidial management programmes might be insufficient in controlling this disease.

Heartworm in a mute swan (Cygnus olor).

A severely emaciated female adult mute swan (Cygnus olor) was euthanized after a period of intensive supportive care in a wild bird rehabilitation centre. Necropsy revealed severe myocardial haemorrhages in the right ventricular free wall associated with the presence of adult heartworm (Sarconema eurycerca). On histological examination, multifocal randomly scattered blood-filled cavities without endothelial or epithelial lining (migration tracts) and surrounded by necrotic debris mixed with fibrinoid deposits and a mixed inflammatory infiltrate were seen, as well as mild multifocal degeneration and necrosis of adjacent myocardial fibres. In some of the lesions, cut sections of adult female filarial nematodes revealed numerous microfilariae in their uteri. This report is the first published case of Sarconema eurycerca in a mute swan in The Netherlands.

A clinicopathological study of 52 feline epulides.

A retrospective study was performed to characterize 52 new cases of feline epulides between 1995 and 2001, with clinical and pathological results classified according to Head's histopathologic criteria for canine epulides. The incidence of the fibromatous, acanthomatous, ossifying, and giant cell epulis were respectively 57.7% (30/52), 7.7% (4/52), 5.8% (3/52), and 28.8% (15/52). Giant cell epulides presented significant differences in clinical behavior compared with the fibromatous type, including rapid growth (P < .0001), presence of ulcerative changes (P < .01), and rapid recurrence after surgery (P < .01) from which euthanasia was judged necessary in 4 cases. Fifteen giant cell epulides were additionally examined in order to characterize the lesion both histochemically and immunohistochemically and to investigate the origin of the multinucleated giant cells (MGCs). Van Gieson staining showed osteoid and woven bone formation in 11 cases. Both the MGCs and a fraction of the mononuclear cells were positive for vimentin, tartrate-resistant acid phosphatase (TRAP), a commonly accepted marker for osteoclasts, and the polyclonal antibody receptor activator of nuclear factor kappabeta (RANK), a cytokine leading to the differentiation of osteoclast progenitors into mature osteoclasts in presence of its ligand. MGCs were negative for smooth muscle actin, MIB-1, and factor VIII. The giant cell epulis may be a variant of the fibromatous and ossifying epulis in which extensive ulceration and inflammation results in increased osteoclastic activity. The osteoclast-like giant cells are most likely formed from a monocyte/macrophage-like osteoclast precursor that differentiates into osteoclasts under the influence of mononuclear osteoblast-like stromal cells.

A probabilistic and decision-theoretic approach to the management of infectious disease at the ICU.

The medical community is presently in a state of transition from a situation dominated by the paper medical record to a future situation where all patient data will be available on-line by an electronic clinical information system. In data-intensive clinical environments, such as intensive care units (ICUs), clinical patient data are already fully managed by such systems in a number of hospitals. However, providing facilities for storing and retrieving patient data to clinicians is not enough; clinical information systems should also offer facilities to assist clinicians in dealing with hard clinical problems. Extending an information system's capabilities by integrating it with a decision-support system may be a solution. In this paper, we describe the development of a probabilistic and decision-theoretic system that aims to assist clinicians in diagnosing and treating patients with pneumonia in the intensive-care unit. Its underlying probabilistic-network model includes temporal knowledge to diagnose pneumonia on the basis of the likelihood of laryngotracheobronchial-tree colonisation by pathogens, and symptoms and signs actually present in the patient. Optimal antimicrobial therapy is selected by balancing the expected efficacy of treatment, which is related to the likelihood of particular pathogens causing the infection, against the spectrum of antimicrobial treatment. The models were built on the basis of expert knowledge. The patient data that were available were of limited value in the initial construction of the models because of problems of incompleteness. In particular, detailed temporal information was missing. By means of a number of different techniques, among others from the theory of linear programming, these data have been used to check the probabilistic information elicited from infectious-disease experts. The results of an evaluation of a number of slightly different models using retrospective patient data are discussed as well.

A probabilistic approach to improved antibiotic therapy.

PTA is a decision-theoretic expert system that aims to assist clinicians in diagnosing and treating patients with pneumonia in the intensive care unit. Its underlying probabilistic network model includes knowledge for diagnosing pneumonia on the basis of the likelihood of tracheobronchial-tree colonisation by pathogens, and symptoms and signs actually present in the patient. Optimal antibiotic therapy is selected by balancing the expected efficacy of treatment, which is related to the likelihood of pathogen-specific pneumonias, against costs and side effects of treatment. In this article, the model underlying the system and results of a preliminary evaluation are described.

Intraoperative transesophageal Doppler color flow imaging used to guide patient selection and operative treatment of ischemic mitral regurgitation.

BACKGROUND: Intraoperative transesophageal Doppler color flow imaging (TDCF) affords the opportunity to assess mitral valve competency immediately before and after cardiopulmonary bypass (CPB). The purpose of this study was to assess the utility of TDCF to assist in the selection and operative treatment of ischemic mitral regurgitation (MR). METHODS AND RESULTS: Two hundred forty-six patients undergoing surgery for ischemic heart disease were prospectively studied. All had preoperative cardiac catheterization. Catheterization and pre-CPB TDCF were discordant in their estimation of MR in 112 patients (46%). Compared with patients in whom both techniques agreed in estimation of MR, patients with discordance in MR were more likely to have had unstable clinical syndromes at the time of catheterization (79% versus 40%, p less than 0.05) or to have received thrombolytics (16% versus 8%, p less than 0.05). Pre-CPB TDCF resulted in a change in the operative plan with respect to the mitral valve in 27 patients (11%). Because less MR was found by TDCF than catheterization, 22 patients had only coronary bypass grafting when combined coronary bypass and mitral valve surgery had been planned. Because more MR was found by TDCF than catheterization, five patients had combined coronary bypass and mitral valve surgery when coronary bypass alone had been planned. Unsatisfactory results noted by TDCF following mitral valve surgery in five patients resulted in immediate corrective surgery. Cox regression analysis identified residual MR at the completion of surgery to be an important predictor of survival (chi 2 = 21.4) after surgery--more important than patient age (chi 2 = 8.3) or left ventricular ejection fraction (chi 2 = 5.3). CONCLUSIONS: These results indicate that TDCF is useful in guiding patient selection and operative treatment of ischemic MR and that in such patients, intraoperative TDCF should be performed routinely.

"Heparin-free" cardiopulmonary bypass: first reported use of heparinoid (Org 10172) to provide anticoagulation for cardiopulmonary bypass.

Org 10172 provided adequate anticoagulation for this patient. An excellent correlation between anti-factor Xa activity and ACT was observed at the doses used for CPB. If high-dose Org 10172 is used, these data suggest that it may be possible to circumvent the measurement of anti-factor Xa activity by using the ACT as an index of this heparinoid's anticoagulant effect. Because postoperative bleeding may be excessive, however, development of a method of reversal of Org 10172 is desirable. Although the optimal ACT, dose, plasma concentration, and means of reversal (e.g., protamine vs. heparinase) remains to be determined, heparinoids provide an alternate means of anticoagulation for CPB in patients unable to receive standard heparin.

The utility of transesophageal echocardiography and Doppler color flow imaging in patients undergoing cardiac valve surgery.

To assess the value of intraoperative transesophageal echocardiography during cardiac valve surgery, 154 consecutive patients who had a valve operation in conjunction with pre- and postcardiopulmonary bypass transesophageal imaging were studied. Prebypass imaging yielded unsuspected findings that either assisted or changed the planned operation in 29 (19%) of the 154 patients. Imaging immediately after bypass revealed unsatisfactory operative results that necessitated immediate further surgery in 10 (6%) of the 154 patients. Postbypass left ventricular dysfunction, prompting administration of inotropic agents, was identified in 13 patients (8%). Transesophageal echocardiography proved most useful when both two-dimensional and Doppler color flow imaging were employed in patients undergoing a mitral valve operation, where surgical decisions based on echocardiographic results were made in 26 (41%) of 64 cases. Postbypass echocardiographic findings identified patients at risk for an adverse postoperative outcome. Of 123 patients whose postbypass valve function was judged to be satisfactory, 18 (15%) had a major postoperative complication and 6 (5%) died, whereas of 7 patients with moderate residual valve dysfunction, 6 (86%) had a postoperative complication and 3 (43%) died (p less than 0.05 for both). Likewise, of 131 patients with preserved postbypass left ventricular function, 12 (9%) had a major complication and 7 (5%) died, whereas of 23 patients with reduced ventricular function, 17 (73%) had a postoperative complication and 6 (26%) died (p less than 0.05 for both). These data indicate that intraoperative transesophageal echocardiography is useful in formulating the surgical plan, assessing immediate operative results and identifying patients with unsatisfactory results who are at increased risk for postoperative complications.

General anesthesia during percutaneous transluminary coronary angioplasty for acute myocardial infarction: results of a randomized controlled clinical trial.

Acutely ill patients with myocardial infarction may require immediate cardiac catheterization and coronary angioplasty to achieve myocardial reperfusion. To determine the feasibility of using general anesthesia under these circumstances, a randomized clinical trial was performed. Of 50 patients, 25 received anesthesia and 25 receive intravenous sedation. There were transient increases in heart rate and blood pressure after tracheal intubation in the anesthetized patients, followed by significant and sustained decreases below baseline values once steady state anesthesia was attained. Arterial oxygenation was significantly improved in anesthetized patients. There were no serious complications due to anesthesia, but the small sample size limited the power of the study to detect differences in morbidity or mortality. Patients strongly preferred anesthesia. These results show that general anesthesia is feasible in patients undergoing interventional cardiac catheterization during acute myocardial infarction, when pain, anxiety or agitation do not respond adequately to conventional measures.

Noninvasive cardiac monitoring.

During the past few years a number of technological developments have made new methods of noninvasive cardiac monitoring available for use in the intensive care unit. Some of these can be used almost continuously some repeatedly, but intermittently, to manage critically ill patients. In addition to avoiding the risks of pain, bleeding, and infection associated more with invasive studies, a major advantage of many noninvasive studies is that one is able to conduct them at the bedside. Echocardiography has been most useful in this regard, but now even nuclear imaging can be carried out with commercially available portable scanners. Doppler techniques, formerly understood only by those with considerable background in cardiology have now evolved to provide the clinician with a simple method of measuring cardiac output. ECG monitoring too has undergone recent refinements to automate the detection of ST segment changes that escape routine observation of the bedside monitor.

Effect of hypothermia on median nerve somatosensory evoked potentials.

Median nerve somatosensory evoked potentials (SEP) were monitored in ten patients undergoing cardiac surgery with hypothermic cardiopulmonary bypass (CPB). Anesthesia was induced and maintained with sufentanil, oxygen, and pancuronium. Esophageal, nasopharyngeal, rectal, and blood temperatures were continuously monitored. SEPs were recorded before induction of anesthesia, after induction, and during cooling and rewarming on CPB. There was a strong negative correlation between SEP latencies and temperature (except rectal) (r = -.91, P < .001). for cortical latency and esophageal temperature. A decrease in esophageal temperature of 1 degrees C resulted in an increase in SEP latency of 1 ms. There was also a weak positive correlation between evoked potential amplitude and temperature (r = .19) for cortical amplitude and esophageal temperature.

Sufentanil pharmacokinetics in pediatric cardiovascular patients.

The pharmacokinetics of sufentanil were studied in 28 pediatric patients undergoing cardiovascular procedures. Patients were divided into four groups on the basis of age: neonates (0-1 month, n = 9), infants (1-24 months, n = 7), children (2-12 yr, n = 7), and adolescents (12-18 yr, n = 5). Sufentanil 10-15 micrograms/kg, was administered by IV bolus and plasma concentrations measured for up to 20 hr. A tri-exponential equation best described the time-concentration data in all patients. Clearance rate (Cl) was 6.7 +/- 6.1 ml.kg-1.min-1 (+/- SD) in neonates, which was significantly lower than the values of 18.1 +/- 2.7, 16.9 +/- 3.2, and 13.1 +/- 3.6 ml.kg-1 min-1 observed in infants, children, and adolescents, respectively. The volume of distribution at steady state (Vdss) was 4.15 +/- 1.0 L/kg in neonates, significantly greater than the values of 2.73 +/- 0.5 and 2.75 +/- 0.5 L/kg observed in children and adolescents, respectively. The elimination half-life (T1/2 beta) was 783 +/- 346 min in neonates, significantly longer than the values of 214 +/- 41, 140 +/- 30, and 209 +/- 23 min observed in infants, children, and adolescents, respectively. The plasma concentration of sufentanil at the time of additional anesthetic supplementation to suppress hemodynamic responses to surgical stimulation was 2.51 ng/ml in neonates, significantly higher than the levels of 1.58, 1.53, and 1.56 ng/ml observed in infants, children, and adolescents, respectively. The authors conclude that age-related differences in pharmacokinetic and pharmacodynamic properties of sufentanil are evident in pediatric patients with major cardiovascular disease who are undergoing cardiovascular surgery.

Comparison of hemodynamic responses to isoproterenol infusion and surgical stress in patients given cardioselective and noncardioselective beta-adrenergic antagonists.

Recent studies have demonstrated the presence of physiologically active beta 2 receptors in the myocardium. We hypothesized that activation of cardiac beta 2 receptors by endogenously released epinephrine and norepinephrine during surgical stress would add to the positive chronotropic response mediated by beta 1 stimulation. Twenty patients scheduled for coronary artery bypass grafting were studied. Ten patients received a beta 1-selective antagonist (atenolol, 6; metoprolol, 4) and ten patients received a nonselective beta 1 and beta 2 antagonist (propranolol) preoperatively. An isoproterenol dose-heart rate response test was performed. After stabilization, general anesthesia was induced followed by tracheal intubation and surgery. Hemodynamic data were recorded before induction, 1 min after induction, 5 min after intubation, 1 min before and after skin incision, 1 min before and after sternotomy. The ten patients on cardioselective beta-blocker drugs had significantly greater increases in heart rate during isoproterenol administration than did the non-cardioselectively blocked group of patients. Heart rate responses to tracheal intubation and surgical stress were not significantly different between the two groups at any point. We conclude that changes in heart rate during perioperative stress are primarily mediated through activation of beta 1 receptors in the myocardium and that patients on either cardioselective or noncardioselective beta-blockers have similar protection to adrenergic-mediated stressful hemodynamic events.