Trends in de-lousing of Norwegian farmed salmon from 2000-2019-Consumption of medicines, salmon louse resistance and non-medicinal control methods

The salmon louse Lepeophtheirus salmonis has been a substantial obstacle in Norwegian farming of Atlantic salmon for decades. With a limited selection of available medicines and frequent delousing treatments, resistance has emerged among salmon lice. Surveillance of salmon louse sensitivity has been in place since 2013, and consumption of medicines has been recorded since the early 80’s. The peak year for salmon lice treatments was 2015, when 5.7 times as many tonnes of salmonids were treated compared to harvested. In recent years, non-medicinal methods of delousing farmed fish have been introduced to the industry. By utilizing data on the annual consumption of medicines, annual frequency of medicinal and non-medicinal treatments, the aim of the current study was to describe the causative factors behind salmon lice sensitivity in the years 2000–2019, measured through toxicity tests–bioassays. The sensitivity data from 2000–2012 demonstrate the early emergence of resistance in salmon lice along the Norwegian coast. Reduced sensitivity towards azamethiphos, deltamethrin and emamectin benzoate was evident from 2009, 2009 and 2007, respectively. The annual variation in medicine consumption and frequency of medicinal treatments correlated well with the evolution in salmon louse sensitivity. The patterns are similar, with a relatively small response delay from the decline in the consumption of medicines in Norway (2016 and onward) to the decline in measured resistance among salmon louse (2017 and onward). 2017 was the first year in which non-medicinal treatments outnumbered medicinal delousing treatments as well as the peak year in numbers of cleanerfish deployed. This study highlights the significance of avoiding heavy reliance on a few substance groups to combat ectoparasites, this can be a potent catalyst for resistance evolution. Further, it demonstrates the importance of transparency in the global industry, which enables the industry to learn from poor choices in the past.

A selection study on a laboratory-designed population of salmon lic (Lepeophtheirus salmonis) using organophosphate and pyrethroid pesticides

Resistance towards antiparasitic agents in the salmon louse (Lepeophtheirus salmonis) is a widespread problem along the Norwegian coast, reducing treatments efficacies and slowing down the envisioned expansion of Norwegian salmon production. The present study was conducted in order to assess the efficacies of two of the most widely used anti-parasitic substances–azamethiphos and deltamethrin–as well as assessing the benefit of having a resistant genotype compared to being fully sensitive when exposed to one of these substances. Atlantic salmon were exposed to a mix of salmon lice copepodids from a fully sensitive, a double resistant and a multi-resistant strain. Once the lice reached pre-adult stages, one group was exposed to 100 μg/L azamethiphos for 60 minutes, the other to 2 μg/L deltamethrin for 30 minutes, and the last was kept in a seawater control. Detached lice were collected at a series of time points following exposure, and all lice (immobilized and surviving) were analysed for both pyrethroid (sensitive “S” and resistant “R”) and azamethiphos (fully sensitive “SS”, heterozygous resistant “RS” and fully resistant “RR”) resistance markers. We found that the efficacies of deltamethrin on parasites with genotype S and R were 70.3 and 13.2%, respectively. The overall efficacy of the deltamethrin treatment was 32.3%. The efficacies of azamethiphos on parasites with genotype SS, RS and RR were 100, 80 and 19.1%, respectively. The overall efficacy of the azamethiphos treatment was 80.4%. Survival analyses revealed that the median survival time in deltamethrin-sensitive and–resistant parasites were 16.8 and >172 hours, respectively. The differences were even more pronounced in the azamethiphos-treated group, where SS, RS and RR parasites survived for 0.26, 6.6 and >172 hours, respectively. The substantial differences in survival between sensitive and resistant lice following treatment demonstrate the ability of medicinal treatments to drive genetic selection towards a much more resistant salmon lice population within a very short time span if there is no influx of sensitive genotypes.

Diagnosing patients with longstanding shoulder joint pain

OBJECTIVE

To examine the interobserver agreement of commonly used clinical tests and diagnoses in patients with shoulder pain, and the accuracy of these tests and ultrasonographic findings in comparison with arthroscopic findings.

METHODS

Eighty six patients with longstanding shoulder joint pain were "blindly" examined by two trained doctors using several clinical tests. In all patients an ultrasonographic examination was performed, and in 42 (49%) an arthroscopy.

RESULTS

Tests for impingement showed poor to moderate agreement. Tenderness of muscles, muscle weakness, and tests for labral lesion also showed poor agreement. Pain during muscle contraction showed moderate agreement. The agreement of clinical diagnoses was poor and the accuracy was low in comparison with arthroscopy. Ultrasonography was accurate in full thickness supraspinatus tendon tears, but inaccurate for partial tears and labral lesions.

CONCLUSIONS

Most clinical tests showed poor agreement. Clinical and ultrasonographic diagnoses had low accuracy in comparison with arthroscopy.

Treatment of "frozen shoulder" with distension and glucorticoid compared with glucorticoid alone. A randomised controlled trial

This study is a comparison of treatments of idiopathic "Frozen Shoulder" (adhesive capsulitis), distension combined with steroid is compared with steroid alone. Evaluation was based on pain scales, analgesic usage, and range of motion outcome scales. Out of one-hundred twenty patients (age, mean 51, range 21-70) that were referred under the diagnosis FS, twenty-six fulfilled the criteria for inclusion in the study, but four patients did not want to participate in the trial, giving a total of 22 patients (age, mean 53, range 40-65) in the study. Patients were randomised by the envelope method. Two patients dropped-out, one in each treatment group thus leaving the study with 20 patients for the final statistical analysis. Eight were treated with steroid alone and 12 with distension combined with steroid. Patients received one treatment per week for a six weeks period with a follow-up at 12 weeks. They were evaluated by pain VAS on function and at rest within the study period, the different ranges of motion (ROM) were measured at inclusion time and subsequent afterwards at 3, 6, and 12 weeks. The VAS outcomes showed no difference between the treatments (VAS-function p=0,1; VAS-rest p=0.1), while in the distension group ROM showed significant improvement in all directions except extension (external p=0.0007, flexion p=0.03, extension p=0,01). The analgesic usage was significantly lower in the group treated with distension at the end of the study (p=0.008). A blinded clinical assessment of ROM also showed significant improvement (p=0.002). It is concluded that distension with steroid can seem to help in management of "Frozen Shoulder". Other studies seems to support the conclusion.

Intra-articular hyaluronan injections in the treatment of osteoarthritis of the knee: a randomised, double blind, placebo controlled multicentre trial. Hyaluronan Multicentre Trial Group

OBJECTIVE

To assess the effects of intra-articular injections of hyaluronan on symptoms of knee osteoarthritis (OA).

METHODS

Two hundred and forty patients with symptomatic, radiological knee OA were randomly assigned to treatment with weekly injections for five weeks with either 25 mg of high molecular weight hyaluronan or vehicle. Results were evaluated at weeks 1, 2, 3, 4, 5, 13, and 20 by visual analogue scales (pain, function, motion, activity), algofunctional index, and global evaluation by patient and investigator. Analysis was by "intention to treat', "per protocol', and area under the curve principles on unstratified patient groups and for patients stratified into four groups of equal size by age and baseline algofunctional index.

RESULTS

No serious side effects were reported. At 20 weeks both treatment groups were improved compared with baseline, with no difference between unstratified groups treated with placebo or hyaluronan. Comparison of treatment groups stratified by age and baseline algofunctional index revealed a significant difference in favour of hyaluronan over placebo (pain, activity, algofunctional index, global evaluations by patient and investigator) for patients older than 60 years and with a baseline algofunctional index greater than 10. There was no clinically relevant difference between the two treatments for the other three stratified subgroups of younger age or fewer symptoms. Similar results were obtained by area under the curve, intention to treat, and per protocol analysis.

CONCLUSIONS

Patients older than 60 years with knee osteoarthritis and with significant symptoms corresponding to an index of severity of knee disease of 10 or more, comprise the group most likely to benefit from treatment with intra-articular hyaluronan injections.

Severe low-back pain. I: Clinical assessment of two weeks conservative therapy

A standard clinical examination was performed by two independent investigators, before and after two weeks of conservative therapy, on 33 patients with severe low-back pain. Kappa coefficients indicated a higher reproducibility of neurological tests than of e.g. muscular tenderness or scoliosis. All patients were diagnosed by CT-scan and a disc herniation was found in 20. The clinical diagnosis was more in agreement with the CT-diagnosis after than before treatment. By discriminant analyses six variables were found to classify the clinical diagnosis correctly in 32 of the 33 patients: sensory loss, ankle jerk, soreness of back extensors, lumbosacral soreness, radiating pain and back extension test. Similarly, the CT-diagnosis was classified in 25 of 33 patients by the variables: sensory loss and limping.

[Humero-scapular periarthrosis]

Humero-scapular periarthrosis (PH) is defined as an idiopathic painful condition in the shoulder with simultaneous limitation of active and passive movements in all directions. The condition is characterized by three phases: a painful period, a period dominated by stiffness and a period of recovery. PH is commonest between the ages of 40 and 60 years and the cumulated risk is estimated to be 2%. The incidence is higher in diabetics. The cause of PH is unknown and knowledge of the pathogenesis is very limited. Histological examination shows inflammation and fibrosis. Association with other pathological conditions of the upper limb or medical conditions, except diabetes mellitus, has not been documented with certainty. The average duration is 30 months but recovery without functional defects is common. Treatment is symptomatic and consists primarily of analgesics and rest during the painful phase. Local injections of steroids may be of effect. Exercises may be employed once the pain is under control and these have the object of improving mobility and increasing muscular strength.

Effect of osmotic pressure on uptake of chemotherapeutic agents by carcinoma cells

Intraperitoneal chemotherapy has been used to treat cancers which are confined to the abdominal cavity. Several variables which affect drug delivery into tumor cells have been identified, but the effect of osmotic pressure has not been studied. Tumor cell lines were used to evaluate the effect of fluid tonicity on drug uptake. HeLa cells and a murine teratoma cell line were suspended in solutions of tonicities 154, 308, and 616 mosM, each containing the same quantity of 5-fluorouracil, and uptake of the drug was measured at different intervals over 30 min. At all time points the amount of 5-fluorouracil taken up by cells in solutions of 154 mosM was greater than that in 310 mosM solutions, which was greater than the uptake in 616 mosM solutions, each by an average of 40-50%. Incorporation of drug into tumor cells was also assayed in vivo using a teratoma cell line propagated i.p. in mice. Tumor cell uptake of doxorubicin was increased to a similar extent when this drug was administered in hypotonic solutions of 154 mosM and was decreased by administration in hypertonic solutions of 465 mosM, as compared to solutions of 310 mosM. These results demonstrate that the uptake of chemotherapeutic agents into tumor cells is increased significantly when these drugs are infused in solutions of lower osmolalities, a finding which may be exploited in clinical situations.

Frozen shoulder: current concepts

The literature on frozen shoulder (FS) is reviewed. The etiology of FS is still not known and our understanding of the pathogenesis is limited. Studies on treatment programs under controlled conditions are few and incomplete. Further research is urgently needed.

[The rotator cuff syndrome--a frequent disease caused by loading]

The rotator cuff syndrome is defined as a cronical pain syndrome, originating from the rotator cuff with characteristic pain and referred pain. Disorders evolving from the rotator cuff and the rotator muscles comprise between 70 og 90% of the shoulder disorders. The rotator cuff syndrome may be of occupational origin, particularly in heavy work with tasks at or above shoulder level, e.g. shipyard welders and plate workers. Biomecanically surveys show that continuous blood flow in the rotator muscles ceases at about 30 degrees of flexion or abduction of the upper arm. Electromyographic examinations have shown high muscle tension in the same muscles in assembly plant employees. High prevalences of shoulder pain have been shown in these groups and it is considered that the workers are actually suffering from disorders in the rotator cuff and its muscles. The rotator cuff syndrome is on the list of occupational disorders in the Danish Workers' Compensation Act but, in the authors' experience knowledge on etiology, examination and treatment is insufficient. Diagnostic criteria are proposed with the object of improving clinical practice and medical insurance declarations.

[Alternative treatment of patients with rheumatism. The extent, effect and utilization of resources]

An anonymous questionnaire investigation involving 393 rheumatological patients showed that 185 patients (47%) had tried alternative treatment (52% of the women and 33% of the men). The three forms of treatment most commonly employed were chiropractor treatment, zone therapy and acupuncture. The 185 patients had, on an average, tried 2.2 types of treatment and 30% had tried more than two forms of treatment. One third of the patients had tried alternative treatment before or simultaneously with medical treatment while the remaining 2/3 had received medical treatment from weeks up to several years. The sources of information about alternative treatment were, most frequently, friends and relatives (70%) while in 16%, the general practitioner was the source. Only 58% replied to the question about the effect of the alternative treatment. Out of these, 56% had experienced improvement, 41% stated that there was no effect and 2% stated that deterioration had occurred. On an average, the patients had employed 2,444 Danish crows (approximately 200 pounds) for the alternative treatment. In addition, 6% stated that had spent more than 10,000 Danish crowns (approximately 833 pounds). It is concluded that alternative treatment frequently constitutes a considerable economical stress for the patients. Greater frankness and a increased level of information about the alternative forms of treatment are necessary.

Injection of steroids and local anaesthetics as therapy for low-back pain

Thirty patients with low-back pain of at least one month's duration were included in a double-blind controlled study with third-party administration and treated with either methylprednisolone acetate mixed with lignocaine or isotonic saline, injected at the site of the iliolumbar ligament. The treatment was evaluated by a visual analogue scale, range of spinal flexion ad modum Wright & Moll and of the patients' self-assessments. In the methylprednisolone group, significant decreases in pain score and in patients' self-assessments were found. The range of spinal flexion did not undergo any significant change. No significant changes were found in the control group. No side effects were observed during the study.

Calcified periarthritis at multiple sites including lumbar intervertebral discs. Report of a case

A case with calcified periarthritis at peripheral sites and calcification in intervertebral discs gives support to the perception of a distinct disease entity as proposed by SANDSTROM. The possible significance of genetic factors is discussed.

Steroid receptor analyses of nine human breast cancer cell lines

Nine human breast cancer cell lines in permanent tissue culture and currently available to researchers have been assayed for their content of cytoplasmic estrogen receptors, progesterone receptors, androgen receptors, and glucocorticoid receptors, as well as for the presence of unfilled or hormone-filled nuclear estrogen receptors. Receptor distribution varied considerably among the nine lines and differed from the expected distribution predicted from solid tumors. We find that estrogen receptor, when present, is usually localized in the nucleus as unfilled nuclear estrogen receptor. Progesterone receptor is correlated with presence of unfilled nuclear estrogen receptor. Glucocorticoid receptors are ubiquitous; they were found in all cell lines tested. The distribution of androgen receptor and progesterone receptor differed, suggesting that these proteins are dissimilar.

In vitro studies of chemical mutagens and carcinogens. I. Stability studies in cell culture medium

A quantitative microbial assay was used to study the stability of known mutagenic and carcinogenic compounds in cell culture medium. Ten direct-acting carcinogens, when incubated in culture medium with 15% fetal bovine serum at pH 7.2-7.4 and 37 degrees C, became inactive at varying rates. Biologic half-lives of the test compounds ranged from 8 minutes to 67 hours. In contrast, six procarcinogens showed no significant inactivation after 3 weeks' incubation. The biologic half-lives of each compound were presented, and the significance of these findings as they relate to cell culture carcinogenesis and mutagenesis assays was discussed.

Cytopathogenic test for feline leukemia virus infections

A mixed culture cytopathogenic effect with the development of multinucleated giant cells in feline leukemia virus-infected cultures after cocultivation with XC cells is described. This cytopathogenic effect has been utilized as a convenient visual marker for the detection and assay of feline leukemia virus in feline and canine embryo fibroblasts as well as in a canine tumor cell line, M-132-1. Comparison of the cytopathogenic reaction in the three cell lines indicates that the reaction is more rapid and pronounced in M-132-1 cells than in the embryo fibroblast cultures.

Virus containing lymphocyte cultures from cancer patients

Seven continuous cell cultures were established from 45 lymphoid tissue specimens from 43 cancer patients. All cultures were free-floating and appeared to be primarily lymphoblasts. Electron microscopic examination revealed herpesvirus-like particles in all the established cell lines and in one cell line that was maintained for only 1 month. The particles appeared identical to those observed in Burkitt's lymphoma and other lymphoma and leukemia cultures. In one instance virus particles were observed in the original tissue specimen before cultivation. The virus particles were not infectious for several cell lines known to be susceptible to herpes simplex virus and other members of this group.