Biomedical subjects

W Schlosser

Publications and source records attributed to W Schlosser.

At least 19 recordsLinked to original sources

PubMed2004

Draft risk assessment of the public health impact of Escherichia coli O157:H7 in ground beef.

An assessment of the risk of illness associated with Escherichia coli O157:H7 in ground beef was drafted in 2001. The exposure assessment considers farm, slaughter, and preparation factors that influence the likelihood of humans consuming ground beef servings containing E. coli O157:H7 and the number of cells in a contaminated serving. Apparent seasonal differences in prevalence of cattle infected with E. coli O157:H7 corresponded to seasonal differences in human exposure. The model predicts that on average 0.018% of servings consumed during June through September and 0.007% of servings consumed during the remainder of the year are contaminated with one or more E. coli O157:H7 cells. This exposure risk is combined with the probability of illness given exposure (i.e., dose response) to estimate a U.S. population risk of illness of nearly one illness in each 1 million (9.6 x 10(-7)) servings of ground beef consumed. Uncertainty about this risk ranges from about 0.33 illness in every 1 million ground beef servings at the 5th percentile to about two illnesses in every 1 million ground beef servings at the 95th percentile.

Animals↗

PubMed2001

Considering uncertainty in comparing the burden of illness due to foodborne microbial pathogens.

The uncertainty attendant to burden-of-illness estimates should be taken into account in comparing the public health impact of different foodborne pathogens. In this paper, decision analysis concepts are applied to the comparisons of pathogen-specific burden-of-illness estimates. In situations wherein the magnitude of uncertainty varies, the rank order of pathogen-specific burden-of-illness estimates is sensitive to the decisional criteria applied. To illustrate the magnitude of attendant uncertainty in pathogen-specific foodborne-illness estimates, probabilistic risk assessment methods are used to characterize the uncertainty regarding the burden of illness due to Escherichia coli O157:H7. The magnitude of uncertainty about the burden of food-related illness due to E. coli O157:H7 is substantial, ranging from less than 50,000 to more than 120,000 cases/year. This example underscores the importance of considering the uncertainty attendant to burden-of-illness estimates in comparing the public health impacts of different pathogens. Although some would argue that the expected value of the number of illnesses provides the "best estimate" for decision-making, this merely reflects a decision-making rule of convention and not a scientific truism.

Decision Trees↗

PubMed2001

Use of a Markov-chain Monte Carlo model to evaluate the time value of historical testing information in animal populations.

Quantitative risk assessments are now required to support many regulatory decisions involving infectious diseases of animals. Current methods, however, do not consider the relative values of historical and recent data. A Markov-chain model can use specific disease characteristics to estimate the present value of disease information collected in the past. Uncertainty about the disease characteristics and variability among animals and herds can be accounted for with Monte Carlo simulation modeling. This results in a transparent method of valuing historical testing information for use in risk assessments. We constructed such a model to value historical testing information in a more-transparent and -reproducible manner. Applications for this method include trade, food safety, and domestic animal-health regulations.

Animal Diseases↗

PubMed2001

Common bile duct stenosis in complicated chronic pancreatitis.

BACKGROUND: Common bile duct stenosis (CBDS) is one of the most frequent and serious complications in patients with chronic pancreatitis. Due to improved diagnostic tools, the frequency of CBDS seems to occur more frequently, nevertheless the prevalence varies widely because of different selection criteria. METHODS: Between April 1982 and October 1996, 323 patients with chronic pancreatitis and inflammatory mass in the head of the pancreas (IMH) (286 patients) or CBDS alone (37 patients) were operated. Patients' data including US, CT, ERCP, endocrine and exocrine function tests were documented prospectively. Dividing patients into groups with and without CBDS, clinical data were comparable concerning distribution of sex, age, etiology of the disease and clinical feature. RESULTS: Regarding the subgroup of 286 patients with inflammatory mass in the head of the pancreas (IMH), 154 patients (51%) showed radiological proved CBDS; out of this group, 82 patients (57%) revealed cholestasis and 37 patients (26%) had one or several periods of jaundice. By means of ERCP, 104 patients (72%) revealed short stenosis of the common bile duct (CBD) (<2 cm). No significant differences could be found in terms of morphologic alterations like pancreatic main duct stenosis, pseudocysts, duodenum stenosis, vascular obstruction. Ten patients (7%) in the group with CBDS and 13 patients (9%) in the group without CBDS had cancer in the pancreatic head. Concerning the endocrine function, the group of patients with CBDS had a significantly elevated rate of impaired glucose metabolism (IGT or IDDM) compared to the group without CBDS (60% versus 38%; P < 0.003). These results demonstrate that patients with IMH bear the risk of developing a stenosis of the CBD even before they become symptomatic with cholestasis or jaundice. CONCLUSION: Due to the elevated morbidity and the significantly deteriorated endocrine function, patients of this group are candidates for early surgical treatment.

Adolescent↗

PubMed2001

Distributional and functional alterations of immunocompetent peripheral blood lymphocytes in patients with chronic pancreatitis.

OBJECTIVE: To investigate whether the chronic inflammatory process in patients with chronic pancreatitis affects their immune function. SUMMARY BACKGROUND DATA: Chronic pancreatitis is a chronic inflammatory disease of the exocrine pancreas. In approximately 30% of patients, an inflammatory mass of the pancreatic head is found, representing an indication for surgery. METHODS: This study comprised 28 patients with chronic pancreatitis. Sixteen patients were also reevaluated 1 year after resection of the pancreatic head for chronic pancreatitis. RESULTS: Compared with an age- and gender-matched control group, the number of CD3(+) cells was significantly increased in patients with chronic pancreatitis, with an increase of both CD3(+)CD4(+) and CD3(+)CD8(+) cells. The number of natural killer cells or B lymphocytes did not differ between the patients and the control group. After stimulation with phytohemagglutinin or anti-CD3 antibodies, the blastogenic response was significantly attenuated in the patients with chronic pancreatitis. One year after resection of the pancreatic head for chronic pancreatitis, the distribution and the blastogenic response to phytohemagglutinin and anti-CD3 antibodies had returned to normal compared with preoperative values. CONCLUSION: The chronic inflammatory process in chronic pancreatitis markedly affects the distribution and function of peripheral immunocompetent blood cells, and elimination of the chronic inflammatory focus by pancreatic head resection restores the suppressed immune function in these patients.

Adult↗

PubMed2001

Low serum levels of CD44, CD44v6, and neopterin indicate immune dysfunction in chronic pancreatitis.

INTRODUCTION: In autoimmune diseases, malignancies, and inflammatory conditions, a correlation of serum levels of CD44, interleukin-2 receptor (IL-2r), and neopterin with disease activity could be shown. AIMS: To assess the immune parameters in chronic pancreatitis in correlation to clinical data to evaluate the potential role of immune dysfunction as a risk factor. METHODOLOGY: Levels of IL-2r, sCD44, sCD44v6, and neopterin were measured using the enzyme-linked immunosorbent assay in 63 patients with chronic pancreatitis who underwent surgery between 1992 and 1995 in our institution. Clinical data were evaluated prospectively before surgery, and a follow-up investigation was conducted in 1997. RESULTS: Mean serum levels of CD44, CD44v6, and neopterin were significantly lower in patients with chronic pancreatitis compared with the control group. The mean level of IL-2r was also lower in chronic pancreatitis, but this difference was not significant. However, no influence of immunosuppressive factors such as alcohol consumption, cigarette smoking, or diabetes could be detected on the levels of IL-2r, CD44, CD44v6, and neopterin. CONCLUSION: In accordance with other diseases of reduced immunoreactivity, depressed serum levels of biomarkers in chronic pancreatitis are caused by reduced T-lymphocyte and macrophage activation. By ruling out a significant influence of concomitant immunosuppressive factors, we conclude that the inflammatory process itself is the source of the depressed immune function, which might be restored by surgical resection.

Alcohol Drinking↗

PubMed2000

Estimating the annual fraction of eggs contaminated with Salmonella enteritidis in the United States.

Using available data on the occurrence of Salmonella enteritidis (SE) in US layer flocks and eggs, and a probabilistic scenario tree method, an estimate of the fraction of SE-contaminated eggs produced annually is derived with attendant uncertainty. In lieu of a definitive prevalence survey, the approach presented here provides insight to the relative contribution of various pathways leading to contaminated eggs. A Monte Carlo model with four branches is developed. The first branch predicts the proportion of all US flocks that are SE-affected. The second branch apportions SE-affected flocks into three categories (high, moderate, and low level affected flocks) based on population-adjusted epidemiologic data. The third branch predicts the proportion of affected flocks that are molted and producing eggs during a high risk period subsequent to molt. The fourth branch predicts the fraction of contaminated eggs produced by flocks of the type described by the pathway (e.g. high level affected flocks that are not molted) based on egg sampling evidence from naturally infected flocks. The model is simulated to account for uncertainty in the data used to estimate the branch probabilities. Correlation analysis is used to estimate the sensitivity of model output to various model inputs. The output of this model is an uncertainty distribution for the fraction of all eggs that are SE-contaminated during 1 year of production in the US. The expected value of this distribution is approximately one SE-affected egg in every 20,000 eggs annually produced, and the 90% certainty interval is between one SE-contaminated egg in 30,000 eggs, and one SE-contaminated egg in 12,000 eggs. The model estimates that an average of 14% of all eggs (i.e. contaminated and not contaminated) from affected flocks are produced by high level, non-molted affected flocks, but these flocks are estimated to account for more than two-thirds of the total fraction of contaminated eggs produced annually. Sensitivity analysis also suggests that the proportion of affected flocks that are high level flocks - and the egg contamination frequency for these types of flocks - are the most sensitive model inputs. The model's pathways provide a framework for evaluating interventions to reduce the number of contaminated eggs produced in the US. Furthermore, sensitivity analysis of the model identifies those inputs whose uncertainty is most influential on the model's output. Future farm-level research priorities can be established on the basis of this analysis, but public policy decisions require a fuller exposure assessment and dose-response analysis to account for microbial growth dynamics, meal preparation, and consumption demographics among US egg consumers.

Animals↗

PubMed2000

Analysis of Salmonella serotypes from selected carcasses and raw ground products sampled prior to implementation of the Pathogen Reduction; Hazard Analysis and Critical Control Point Final Rule in the US.

In July 1996, the US Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS), published the Pathogen Reduction; Hazard Analysis and Critical Control Point (HACCP) Systems final rule to improve food safety of meat and poultry products. The final rule established, among other requirements, pathogen reduction performance standards for Salmonella for food animal carcasses and raw ground products. The final rule is to be fully implemented in three stages in successively smaller federally inspected meat and poultry slaughter and processing establishments. Implementation began in January 1998 and was completed in January 2000. Samples of carcasses of four species of food animals (cattle, swine, chickens, turkeys), and raw ground product from each of these species, were collected by FSIS from establishments prior to implementation of the final rule and cultured for Salmonella. This paper reports Salmonella serotype results of samples collected from June 1997 through August 1998. These results represent a baseline for future comparisons.

Animals↗

PubMed2000

Duodenum-preserving pancreatic head resection in patients with benign and borderline tumors of the pancreatic head.

BACKGROUND: Benign tumors of the pancreas are rare, accounting for only 1-2% of primary pancreatic lesions. Up to now, partial duodenopancreatectomy is still one of the established forms of treatment of benign tumors of the pancreas. We applied duodenum-preserving pancreatic head resection in 12 patients with benign pancreatic tumors to evaluate the feasibility, morbidity and recurrence rates after this less aggressive method. METHODS: Between April 1984 and December 1999, 12 patients with benign and borderline tumors of the pancreatic head were operated on by duodenum-preserving pancreatic head resection. RESULTS: All five patients with serous cystadenoma are free of recurrence 4.4 years after primary resection. One of two patients with mucinous cystadenoma and one of three patients with intraductal papillary mucinous tumor developed recurrent tumor within the former pancreatic head 5 years and 6 years, respectively, after the primary operation. Both patients were resected a second time. One of two patients with gastrinoma still has elevated serum gastrin levels. There was no hospital or long-term mortality. CONCLUSION: For a symptomatic serous cystadenoma, duodenum-preserving pancreatic head resection is a good alternative to partial duodenopancreatectomy. In borderline tumors with malignant potential, we would rather suggest a more radical duodenum-preserving segmental resection. A video clip (3 min) is attached demonstrating the basic steps of duodenum-preserving pancreatic head resection.

Adult↗

PubMed2000

Pharmacological identification of acetylcholine receptor subtypes in echinoderm smooth muscle (Sclerodactyla briareus).

Contractions of an echinoderm (sp. Sclerodactyla briareus) smooth muscle, the longitudinal muscle of the body wall (LMBW), were evoked by acetylcholine (ACh) and agonists: epibatidine, muscarine and nicotine (in order of force generation: ACh>muscarine=epibatidine>nicotine). ACh-induced contractions were blocked by atropine by 50%, and methoctramine, by 30%. ACh responses were also blocked by 25% by methyllycaconitine (MLA) but not by D-tubocurarine (dTC). Muscarine initiated large contractions that were completely blocked by atropine. To elucidate possible muscarinic ACh receptor (mAChR) subtypes, muscarinic agonists (oxotremorine, pilocarpine) and antagonists (methoctramine, pirenzepine) were tested. Oxotremorine, pilocarpine, and pirenzepine each enhanced resting tonus and potentiated ACh-induced contractions (order of potency: pilocarpine>oxotremorine=pirenzepine). Muscarine, oxotremorine or pirenzepine generated phasic, rhythmic contractions. Nicotine-induced contractions were almost completely blocked by dTC but were not altered by atropine. Large contractions evoked by epibatidine were potentiated by dTC whereas atropine had no effect on them. MLA blocked spontaneous rhythmicity. Cholinesterase inhibitors, neostigmine or physostigmine, caused marked potentiation of ACh-induced contractions and initiated rhythmic slow wave contractions in previously quiescent muscles. The present pharmacological evidence points to the co-existence of excitatory nicotinic ACh receptor (nAChRs) and mAChRs where nAChRs possibly modulate tone, and the mAChRs initiate and enhance rhythmicity.

Acetylcholine↗

PubMed1999

Duodenum-preserving head resection in chronic pancreatitis changes the natural course of the disease: a single-center 26-year experience.

OBJECTIVE: To present preoperative and early postoperative data for 504 patients who underwent duodenum-preserving pancreatic head resection (DPPHR) for severe chronic pancreatitis (CP). BACKGROUND: The pancreatic head is considered to be the pacemaker of the disease in alcohol-induced CP. Indications for surgery in CP are intractable pain and local complications. DPPHR offers the advantage of treating the complications related to the inflammatory process in the head, relieving the pain syndrome, and preserving the bilioduodenal anatomy, and it may have the potential to change the natural course of chronic pancreatitis. METHODS: Between November 1972 and December 1998, 504 patients with chronic pancreatitis and an inflammatory mass in the pancreatic head were treated surgically after medical pain treatment for a median of 3.6 years. The procedure resulted in a hospital mortality rate of 0.8%. A continuous follow-up investigation lasting up to 26 years was conducted, during which the patients were reevaluated four times (1983, 1987, 1994, 1996). Between November 1982 and October 1996, 388 patients treated surgically were reinvestigated to evaluate the late outcome; the follow-up rate was 94% (25 patients were lost to follow-up). The reinvestigation evaluation included glucose tolerance test, exocrine pancreatic function test, pain status, physical status, professional and social rehabilitation, and quality of life. RESULTS: After an observation period of up to 14 years, 78.8% of the patients were completely pain-free and 12.5% had (yearly) pain. 91.3% were considered as pain-free; 8.7% had continuing abdominal pain; 12% had abdominal complaints. During the 14 years of follow-up, only 9% were admitted to the hospital for acute episodes of chronic pancreatitis. Endocrine function was improved in 11%; in 21%, diabetes developed de novo. The rate of hospital admission for acute episodes decreased from 69% before surgery to 9% after surgery. In the clinical management period of 9 years (median), the frequency of hospital admission dropped from 5.4 per patient before surgery to 2.7 after surgery. Fourteen years after surgery, 69% of the patients were professionally rehabilitated; in 72%, the quality of life index (Karnofsky criteria) was 90 to 100 and in 18%, it was <80. CONCLUSION: In patients with alcoholic chronic pancreatitis in whom an inflammatory mass has developed in the pancreatic head, DPPHR results in a change in the natural course of the disease in terms of pain status, frequency of acute episodes, need for further hospital admission, late death, and quality of life.

Adult↗

PubMed1999

Distal pancreatectomy in chronic pancreatitis.

BACKGROUND: The indications for a resective procedure in chronic pancreatitis are severe pain and local complications. The aim of this study, based on prospectively assessed data, was to evaluate distal pancreatectomy in patients suffering from chronic pancreatitis localized in the corpus and cauda of the pancreatic gland. METHODS: Seventy-four patients undergoing distal pancreatectomy were evaluated pre- and postoperatively (after a median observation period of 58 months) for pain, professional status, alcohol consumption, and endocrine function as measured by the glucose tolerance test preoperatively. RESULTS: The indication for operation was severe therapy-resistant pain in nearly all patients and an inflammatory tumor or pancreatic pseudocysts in over 50% of the patients. One fourth of the patients were operated in order to exclude malignancy. Ninety-five percent of the patients underwent distal pancreatectomy, only in 4 cases (5%) was a subtotal (Child) resective procedure performed. In 34% of patients undergoing distal pancreatectomy a splenectomy could be avoided. The early postoperative complications were few and mostly due to the severe comorbidity of the patients. During the median observation period of 58 months 14.7% of the patients died due to diseases not related to distal pancreatectomy. Six percent of the patients could not be reevaluated and were lost to follow-up. In the remaining 59 patients 88% had significantly less pain and 66% had an increase in median body weight of 8 kg. Fifty percent of the patients had full or partial professional rehabilitation, one fourth was unemployed and 24% had retired due to age. 51.7% had a normal endocrine function as assessed by the glucose tolerance test, 16.2 and 21.6% had a latent or manifest diabetes mellitus, respectively. In 74.5% of all patients the endocrine function did not worsen during the observation period. CONCLUSION: In comparison to conservative treatment distal pancreatectomy is a suitable therapeutic measure in patients with severe pain and local complications. It significantly improves the quality of life of patients without compromising endocrine function. Postoperative lethality is lower than in conservatively treated patients and is not related to distal pancreatectomy.

Adult↗

PubMed1999

[Is a Whipple operation in chronic pancreatitis still a current procedure?].

Until the eighties, the surgical procedure of choice in chronic pancreatitis with an inflammatory mass in the head of the pancreas has been partial duodenopancreatectomy (pDP). Since neither stomach, duodenum nor the common bile duct are directly involved in the inflammatory process of the pancreas, the Whipple's procedure (pDP) might lead to overtreatment. Therefore, duodenum-preserving pancreatic head resection (DPPHR), developed by Beger in 1972, has become in several centers the standard procedure for patients with an inflammatory enlargement of the head of the pancreas. We reviewed the literature of the last ten years and evaluated the different surgical procedures for pancreatic head resection. Comparing pDP and DPPHR. Whipple procedure has a higher hospital mortality (3.2% versus 0.6%), a higher late mortality (22% versus 8.4%), a higher morbidity and a higher incidence of a new "surgical" diabetes (17.6% versus 2%). With regard to relief of pain long-term investigations show totally pain-free patients after pDP in 72%, after pylorus-preserving duodenopancreatectomy (PPDP) in 82% and after DPPHR in 89%. Furthermore, other disadvantages of PPDP are the high rate of gastric outlet dysfunction (17% on average with a range of 4-32%) and the high rate of marginal ulcers (8.4% on average with a range of 5-11%). In summary, we conclude that in patients with chronic pancreatitis and an inflammatory enlargement of the pancreatic head. DPPHR is the procedure of choice. Whipple's procedure should only be performed if a suspicion of malignancy is suspected or, secondly, if a patient suffers from persistent pain (5%) after DPPHR.

Chronic Disease↗

PubMed1999

The surgical management of chronic pancreatitis: duodenum-preserving pancreatectomy.

Duodenum-preserving pancreas resection for chronic pancreatitis results in a subtotal resection of the pancreatic head. Of 488 patients suffering from chronic pancreatitis with an inflammatory mass in the head, 48% had a common bile duct stenosis in the ERCP, 63% had a pancreatic main duct stenosis, 25% had a duodenum stenosis, and 17% showed vascular obstruction--mainly compression or occlusion of the portal vein. Hospital mortality after duodenum-preserving head resection was 0.9%. In the late follow-up, 88% of patients were free of pain and 60% were professionally rehabilitated. The incidence of diabetes mellitus in the late follow-up was 14%; however, 6% of the patients had a lasting improvement of endocrine function. Late mortality after a median follow-up of 6 years (1-22 years after surgical treatment) was 9%. Only 10% of the patients needed further hospitalization due to recurrent attacks of acute pancreatitis. Duodenum-preserving head resection should be the surgical procedure of choice in chronic pancreatitis with an inflammatory mass in the head of the pancreas and in cases with pancreas divisum after failure of medical and interventional treatment. Duodenum-preserving total pancreatectomy is a last-resort surgical treatment after failure of left resection for pain in chronic pancreatitis.

Chronic Disease↗

PubMed1998

The splice-pattern of CD44 is altered in chronic pancreatitis exhibiting dysplastic changes.

Recent studies have shown that several splice variants of CD44, might be involved in tumor progression. Since chronic pancreatitis is suggested to be a risk factor for pancreatic cancer we investigated the splice pattern of CD44 in chronic pancreatitis to elucidate the role of CD44 in pancreas tumorigenesis. The expression of CD44-isoforms was examined in 40 specimens of chronic pancreatitis and 12 specimens of normal pancreas by immunohistochemistry, Westernblotting and exon specific RT-PCR. Pancreatic cancer tissue from two patients who developed pancreatic cancer 2 and 3 years following surgery for chronic pancreatitis were analyzed. Strong expression of CD44s was found in all cells, whereas the expression of CD44v6 was restricted to ductal cells. Westernblotting revealed an overexpression of CD44v6 in chronic pancreatitis as compared to normal pancreas. Exon specific analysis revealed an altered splice pattern of CD44, similar to that in pancreatic cancer, in 12.5% of the chronic pancreatitis specimens. Both patients who developed pancreatic cancer after chronic pancreatitis exhibited this altered splice pattern in both, chronic pancreatitis and pancreatic cancer. These results suggest that variant forms of CD44-mRNA might be expressed in early dysplastic alterations in chronic pancreatitis.

Blotting, Western↗

PubMed1998

[Diagnosis and therapy of pancreatic pseudocysts in chronic pancreatitis].

Cystojejunostomy is the operation of choice in patients with pancreatic pseudocysts with pain and/or local complications if no resection procedure is necessary. This procedure can be performed safely after 6 weeks with a low morbidity and mortality and good long-term results compared to conservative treatment.

Chronic Disease↗

PubMed1997

[Duodenum preserving resection of the head of the pancrease in therapy of pancreas divisum].

In 1-6% of the patients who are investigated by endoscopic retrograde cholangio-pancreatography a pancreas divisum can be found. In some patients pancreas divisum can lead to an acute relapsing and finally chronic pancreatitis (CP). Surgical intervention in these cases seems to offer a good chance of recovery. We report our experience with the duodenum-preserving resection of the head of the pancreas in 12 patients with pancreas divisum and CP. In all patients the preoperative evaluation showed clinical, functional or radiological signs of CP. The duodenum-preserving resection of the head of the pancreas was carried out in all patients without perioperative mortality. Ten postoperative versus eight preoperative patients showed a pathological exocrine function of the pancreas. Endocrine function, measured by the oral glucose tolerance test (OGTT), improved postoperatively in two patients. Eleven patients who were investigated after a mean follow-up time of 31 months (3-75 months) were completely pain free. No late mortality occurred. OGTT revealed a diabetic endocrine function in two patients. Disturbed exocrine pancreatic function had to be substituted in nine patients. One patient had to be reoperated by duct incision and renewal of the pancreatico-jejunostomy 10 months after the first operation. In conclusion, the duodenum-preserving resection of the head of the pancreas reduced pain in all patients with pancreas divisum and CP and may lead to an improvement of endocrine pancreatic function. Other, nonresecting procedures or endoscopic interventional therapy should be avoided in these patients.

Adult↗

PubMed1997

Epidemiology and control of egg-associated Salmonella enteritidis in the United States of America.

The isolation rate for Salmonella enterica serotype Enteritidis (SE) in humans in the United States of America (USA) increased from 1,207 sporadic isolates identified in 1976 (0.6 isolates/100,000 population) to 10,201 identified in 1995 (4.0/100,000 population). The proportion of reported Salmonella isolates which were SE increased from 5% to 25% during the same time period. In 1990, 1994, and 1995, SE was the most commonly reported reported Salmonella serotype in the USA. Much of this increase has been associated with the consumption of contaminated shell eggs. An examination of the results of a United States Department of Agriculture (USDA) survey of spent hens at slaughter and unpasteurised liquid egg at breaker plants (liquid egg processors) in 1991 and 1995 reveals an increase in the prevalence of SE isolates overall and in most regions of the USA. SE phage type 4 (pt 4), the predominant SE phage type in other parts of the world, has emerged in the egg industry in the western USA concurrent with a sharp increase in the number of sporadic human SE pt 4 isolates in California and Utah. Research on the molecular structure and virulence of SE pt 4 isolates from the USA as compared with isolates from other parts of the world (human and poultry) should be a priority. A comparison of DNA from pt 4 isolates from the USA and Europe may provide information about the potential threat to public health and poultry in the USA from this phage type. Some regional success in the reduction of human illness as a result of SE control efforts is apparent. The Pennsylvania Egg Quality Assurance Program has shown progress in reducing SE infection in participating flocks. At a national level, however, neither the incidence of human illness due to SE nor the prevalence of SE in flocks and unpasteurised liquid eggs have decreased significantly, despite the implementation of the USDA 'trace back' regulation from 1990 to 1995, and intensified efforts to educate food handlers and to enforce safe food handling practices. More effort is needed to control SE at every stage of the egg continuum, from production through to consumption. A risk-reduction approach, with barriers to the introduction and multiplication of the pathogen throughout the farm-to-table continuum, is the most practical method for reducing human illness from SE in shell eggs at present. An effective long-term solution will require interdisciplinary efforts involving government, industry, consumers, and academics. Interventions should be developed and evaluated in compliance with the potential for reducing the risk to human health and cost-effectiveness.

Animal Husbandry↗