Equine West Nile encephalitis, United States

After the 1999 outbreak of West Nile (WN) encephalitis in New York horses, a case definition was developed that specified the clinical signs, coupled with laboratory test results, required to classify cases of WN encephalitis in equines as either probable or confirmed. In 2000, 60 horses from seven states met the criteria for a confirmed case. The cumulative experience from clinical observations and diagnostic testing during the 1999 and 2000 outbreaks of WN encephalitis in horses will contribute to further refinement of diagnostic criteria.

Effects of countercurrent scalding and postscald spray on the bacteriologic profile of raw chicken carcasses

In June and September 1988, the USDA Food Safety and Inspection Service sampled raw chicken carcasses at a federally inspected slaughter establishment in Puerto Rico to determine the effects of changing the scalding equipment on bacterial contents of raw poultry products. The scalding equipment was changed to a countercurrent configuration, with a postscald hot-water rinse cabinet that sprayed carcasses as they exited the scalder. Analysis of 250 carcass-rinse samples collected at preevisceration, prechill, and postchill sites over 7 days indicated that carcasses had mean aerobe plate counts of log(10)3.73 before evisceration, 3.18 before chilling, and 2.87 after chilling; Enterobacteriaceae counts of log(10)2.70 before evisceration, 2.25 before chilling, and 1.56 after chilling; and Escherichia coli counts of log(10)2.09 before evisceration, 1.61 before chilling, and 0.89 after chilling. Salmonellae were found on 24% of the carcasses before evisceration, on 28% before chilling, and on 49% after chilling. Although bacterial count reductions were significant at all 3 sites, the proportion of carcasses contaminated with salmonellae in this study was higher at the postchill than prechill site (49 vs 28%). This no doubt was caused by cross-contamination in the chiller. These percentages indicated that although simple scalder changes contributed substantially to the improvement of the bacterial quality of chicken carcasses, additional interventions in the chilling process (such as chlorination of chill water) are important to control cross-contamination and to preserve the positive effects obtained by the scalder changes.

Effects of chlorination of chill water on the bacteriologic profile of raw chicken carcasses and giblets

In March 1989, the USDA Food Safety and Inspection Service sampled raw chicken carcasses and giblets at a federally inspected slaughter establishment in Puerto Rico to determine the effects of adding chlorine to carcass and giblet chill water on bacterial contents of raw poultry products. Over four 8-hour workdays, 200 carcass rinse samples were collected at 3 sites in the establishment; 39 giblet rinse samples were collected at 1 site. Analyses of the carcass rinse samples indicated that carcasses had average aerobe plate counts of log10 3.20 before chilling and 2.51 after chilling; Enterobacteriaceae counts of log10 2.57 before chilling and 1.75 after chilling; and Escherichia coli counts of log10 2.04 before chilling and 1.20 after chilling. Salmonellae were found on 43% of the carcasses before chilling and on 46% after chilling. Analyses of the giblet and neck rinse samples indicated that raw giblets and necks after chilling had average aerobe plate count of log10 3.49, Enterobacteriaceae count of log10 2.57, and E coli count of log10 1.06. Salmonellae were found on 12% of the giblets and necks sampled. Results compared favorably with giblet and neck rinse sample results obtained during a baseline sampling study in November and December 1987. The baseline results indicated aerobe plate count of log10 3.72; Enterobacteriaceae count of log10 2.90; E coli count of log10 1.14; and salmonellae on 69% of the giblets and necks sampled. Placing raw chicken carcasses in chlorinated chill water reduced aerobe, Enterobacteriaceae, and E coli plate counts. Prevalence of carcasses with salmonellae remained nearly the same.(ABSTRACT TRUNCATED AT 250 WORDS)

Profile of selected bacterial counts and Salmonella prevalence on raw poultry in a poultry slaughter establishment

The USDA Food Safety and Inspection Service determined populations of bacteria on poultry during processing at a slaughter plant in Puerto Rico in November and December 1987. The plant was selected because of its management's willingness to support important changes in equipment and processing procedures. The plant was representative of modern slaughter facilities. Eight-hundred samples were collected over 20 consecutive 8-hour days of operation from 5 sites in the processing plant. Results indicated that slaughter, dressing, and chilling practices significantly decreased the bacterial contamination on poultry carcasses, as determined by counts of aerobic bacteria, Enterobacteriaceae, and Escherichia coli. Salmonella was not enumerated; rather, it was determined to be present or absent by culturing almost the entire rinse. The prevalence of Salmonella in the study decreased during evisceration, then increased during immersion chilling.

A survey of doctorates by thesis among general practitioners in the British Isles from 1973 to 1988

Doctors who were general practitioners in the period 1973-88 and had written a successful MD or PhD thesis were identified. Of 96 doctorates, 64 were MDs and 32 PhDs. Fourteen doctors had obtained their MD before becoming general practitioners and the remaining 50 after becoming general practitioners. Twenty of the 64 doctors were full time or part time members of a university department of general practice; six of these were professors. In this 16 year study the mean annual number of MDs written by doctors while in general practice was three, compared with five in the previous 15 years. Of the PhDs, 11 were obtained before starting a medical course, six during the pre-clinical period, three after qualifying but before entry into general practice and 12 after entry into general practice. Ninety two per cent of the 50 doctors who obtained their MDs while in general practice and 84% of all the doctors with MDs continued to do research afterwards. Further research was carried out by 81% of doctors with a PhD. The best way of producing good researchers in general practice is to encourage doctors to accept the challenge of writing a PhD or an MD thesis. This study has shown that writing such a thesis encourages rather than discourages a doctor to undertake further research.

A purely mechanical theory of muscular contraction

A simple mathematic model is constructed for the cross-bridge dynamics that govern muscular contraction, based on ideas introduced by Huxley and Simmons. The model differs from earlier ones in that it is based on distributions over time rather than displacement and uses a sharp disengagement rule. The constitutive functions of the model are set using classical experimental results and its predictions for the length-step experiment of Ford, Huxley, and Simmons are examined.

Medical researchers in general practice

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Bordetella pertussis isolation in general practice: 1977-79 whooping cough epidemic in West Glamorgan

Some of the factors influencing the isolation rate of Bordetella pertussis during a whooping cough epidemic in West Glamorgan, Wales, are reported. The organism was isolated from 39% of patients with clinical whooping cough, pernasal swabbing being much more successful than cough plates. Isolation rates were increased in the non-immunized, particularly in the first year of life. Erythromycin and co-trimoxazole significantly reduced the isolation rate of B. pertussis but this did not occur with penicillin. In this study 20% of patients were culture positive 6 weeks after the onset of their infection. It is suggested that the Department of Health and Social Security recommendation of a minimum period of three weeks exclusion of children from school is inadequate. During the epidemic, the proportion of strains of B. pertussis containing antigen 2 more than doubled.

A five-year study of influenza in families. Joint Public Health Laboratory Service/Royal College of General Practitioners working group

A five year collaborative study of influenza in volunteer families from 1973-78 covered a period in which there were outbreaks every year but no major epidemics of influenza. Volunteers over the age of 15 years were bled before and after each of the five winters, and virus isolation was attempted from as many as possible when they reported episodes of illness. Children under 15 in the volunteer families were also swabbed when they were ill. Although most families experienced one or more attacks by influenza viruses, there was little transmission within families.

Whooping cough in nursery school children

This paper describes an outbreak of whooping cough in a nursery school during a large epidemic in West Glamorgan. Explosive outbreaks of whooping cough occurred in nursery schools in the area when the majority of children had not been vaccinated. It is recommended that the period of quarantine for whooping cough should be four weeks.

Validation of sources of pertussis immunisation data

In this paper we describe the validation of three sources of immunisation data in a study of whooping cough in West Glamorgan. The least reliable source was that of the general practitioners and the best was that of the parents, but the area health authority source should be used in future studies provided that sufficient time is allowed for the relevant information to reach the computer.

Urinary MHPG levels and tricyclic antidepressant drug selection. A preliminary communication on improved drug selection in clinical practice

The 24-hour urinary 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) output was used as the basis for selection of tricyclic antidepressant drug therapy for the depressed patient population treated by one psychiatrist over a period of ten months in a psychiatric clinic. Use of MHPG output level as the criterion for drug selection resulted in significantly better clinical results than had been obtained previously by the same psychiatrist using more traditional selection methods on a similar depressed patient population. A correlation was noted between patients' pretreatment MHPG output levels and three symptoms of depression (guilt, agitation, and diurnal variation) as measured on the Hamilton Rating Scale for Depression.

A randomized controlled trial of aspirin in the prevention of early mortality in myocardial infarction

A randomized controlled trial is reported in which a single dose of aspirin (300 mg) was given to patients with myocardial infarction on first contact with a general practitioner. A total of 1,705 patients with confirmed infarction were studied, and survival ascertained. There was no evidence of benefit from the aspirin.

The changing pattern of general practitioner drug prescribing in the National Health Service in England from 1970 to 1975

We describe the changing pattern of general practitioner prescribing in the National Health Service in England between 1970 and 1975.The percentage increase in items of prescriptions had increased 10 times as much as the percentage increase in the population in the same period. One of the reasons given is that there may be a growing tendency to give a prescription when it would be better to give advice.The evidence seems to support other findings that the profession responds much more widely to reports on the good effects of a drug than it does to its adverse effects.

General practitioners and their staff

We describe the practices and staff of a random sample of 158 doctors. There has been a significant increase in ancillary staff since the Doctors' Charter of 1966. The study showed that there was no economy in staff as the number of doctors in a practice increased. In the selection of receptionists, doctors preferred married women over 35 with children, and were in favour of good personal qualities rather than good academic attainments. However, a high standard of work is important as well as a good understanding of human behaviour.

The assessment by doctors of the effectiveness of drugs

There was no significant difference between the assessments by two groups of randomly-selected general practitioners on the effectiveness of the drug treatment for 19 common clinical conditions. The treatment of simple iron deficiency anaemia was considered the most effective and gained the highest consensus. Least effective, but not matched by worst consensus, was the drug treatment for obesity. The most widespread disagreement among the practitioners was for the effectiveness of the drug treatment of gastroenteritis.

Aspects of the use of lithium for the non-psychiatrist

Lithium carbonate is commonly used in psychiatry, particularly in the management of the manic-depressive syndrome. It is also being increasingly tried in a variety of physical disorders. This essentially practical article summarizes important non-psychiatric aspects of the use of the drug, including its less common actions. Contra-indications to the use of lithium are discussed, and the management of lithium intoxication is outlined.