Static ocular counterroll reflex in skew deviation

OBJECTIVE

The static ocular counterroll (OCR) reflex generates partially compensatory torsional eye movements during head roll. It is mediated by the utricle in the inner ear. Skew deviation is a vertical strabismus thought to be caused by imbalance in the utriculo-ocular pathway. We hypothesized that if skew deviation is indeed caused by damage to this reflex pathway, patients with skew deviation would show abnormal OCR.

METHODS

Eighteen patients with skew deviation caused by brainstem or cerebellar lesions and 18 normal participants viewed a target at 1 m. Ocular responses to static passive head roll-tilts of approximately 20° were recorded using search coils. Static OCR gain was calculated as the change in torsional eye position divided by the change in head position during sustained head roll. Perception of the subjective visual vertical (SVV) was also measured.

RESULTS

Group mean OCR gain was reduced by 45% in patients. At an individual level, OCR gains were asymmetric between eyes and between torsional directions in 90% of patients. In addition, the hypotropic eye incyclotorting gain was lower than the hypertropic eye excyclotorting gain during head roll toward the hypotropic eye in 94% of patients. No consistent pattern of gain asymmetry was found during head roll toward the hypertropic eye. The SVV was tilted toward the hypotropic eye.

CONCLUSION

Static OCR gain is significantly reduced in skew deviation. Interocular and directional gain asymmetries are also prevalent. The asymmetries provide further evidence that disruption of the utriculo-ocular pathway is a mechanism for skew deviation.

Outbreak of respiratory infection on a cruise ship

On 27 July 2007, the Department of Communicable Disease Control and Prevention of Stockholm County Council (SCC), Sweden, was informed by one of the infectious diseases hospitals in Stockholm that three elderly women travelling on a cruise ship had been hospitalised due to severe pneumonia

Tuberculosis screening of asylum seekers: 1 years' experience at the Dover Induction Centres

OBJECTIVES

To describe the uptake and outcomes of a service for tuberculosis screening of asylum seekers.

STUDY DESIGN

Descriptive study.

METHODS

A tuberculosis screening service was established at the Dover Induction Centres for all asylum seekers entering the UK through ports in Kent. This study describes the uptake and completion of tuberculosis screening, the results of tuberculin skin testing and follow-up, and the cost of the service during its first year.

RESULTS

In 1 year, 8258 asylum seekers were screened: 94% of 8799 who were eligible. A total of 2.2% of those with completed screens were positive (on the basis of symptoms requiring further investigation or positive Heaf reaction). Eleven cases of active respiratory disease were diagnosed on the basis of symptoms, Heaf reaction plus chest X-ray, or both; three were confirmed microbiologically. One-quarter of Heaf tests were not read because of the rapid dispersal of asylum seekers. The follow-up of those requiring further investigations at their destinations was largely unknown. The service cost was 350,000 pounds.

CONCLUSIONS

Induction centre tuberculosis screening services for asylum seekers can achieve a high uptake, but their cost-effectiveness is questionable, particularly where the yield of active disease is low. Tuberculin skin testing is not an ideal screening procedure in this setting because it may be uncompleted and the benefit of detecting latent infections is uncertain.

Geographical distribution of variant CJD in the UK (excluding Northern Ireland)

BACKGROUND

The agent that causes variant Creutzfeldt-Jakob disease (variant CJD) is indistinguishable from the causative agent of bovine spongiform encephalopathy (BSE). The transmission route by which human beings are infected has not been established. One hypothesis is that cases of variant CJD have resulted from exposure to the BSE agent via rendering plants involved in the production of meat and bone meal, the main vehicle of the BSE epidemic.

METHODS

We identified cases of variant CJD through the National CJD Surveillance Unit, and obtained lifetime residential histories of cases by interviewing a relative. The addresses of all rendering plants in the UK (excluding Northern Ireland) in production in 1988 were available from a survey done in that year. We calculated the distance between each case's place of residence on Jan 1, 1988, and the nearest rendering plant from postcode data, and used data from the 1991 UK census to estimate the population living within various distances of rendering plants. We compared the observed number of cases of variant CJD within a particular distance of a rendering plant with the number expected if there is no association between residential proximity to a rendering plant and the risk of developing variant CJD.

FINDINGS

Up to Aug 31, 1998, 26 cases of variant CJD with onset in the UK (Northern Ireland not included) had been identified. The observed and expected numbers of variant CJD cases living within a specified distance of any rendering plant up to 50 km were almost the same. Two plants in the county of Kent each had four cases within 50 km in 1988, significantly more cases than expected (plant A, 1.04 expected; plant B, 0.74 expected). Multiple significance tests were done, so some tests would be expected to appear significant by chance alone. Computer simulations suggested that the observation of four cases of variant CJD living in an area with a population of 1.5 million (the size of Kent) is not unexpected.

INTERPRETATION

There is no evidence that people with variant CJD tended to live closer than the population as a whole to rendering plants in the 1980s. The reported cluster of variant CJD cases in Kent is most probably a chance finding.

Feasibility study for identifying adverse events attributable to vaccination by record linkage

To investigate the feasibility of using a record linkage method for identifying vaccine attributable adverse events, computerized hospital admissions and vaccination records from South East Kent district were linked and checked for accuracy. Records for 90% of children under 2 years of age admitted to hospital over a 2-year period were matched with vaccination records using a computer algorithm based on name, date of birth, sex, and post-code supplemented by visual inspection. Relative to this gold standard, matching on date of birth, sex and postcode alone had a sensitivity of 60% and an incorrect match rate of 0.2% after matches to more than one vaccine recipient were excluded. Manual checking of a sample of admissions showed that only 4% had been assigned incorrect International Classification of Disease (ICD) codes. Routine record linkage of ICD admission codes to vaccination records therefore yields data of good quality which may be used for surveillance purposes.

An investigation into sick building syndrome among local authority employees

Self-administered questionnaires were used to find out the prevalence among employees working in the three local authority premises in a Health District of self-reported illness which could be associated with sick building syndrome. Eye symptoms were found to be more common among employees working in a typing centre using VDUs. The symptoms tiredness, lethargy and influenza-like ('flu-like) illness, including aches in the limbs, were reported in significantly higher numbers by employees working in areas where there was evidence of increased pressure of work and worries over job losses. Dry throat and blocked or stuffy nose were symptoms reported in significantly higher proportions by employees working in certain buildings, where anecdotal evidence suggested that there could be problems with temperature regulation. This study also confirmed findings by other studies that for some symptoms women complain in significantly higher numbers than men. It was concluded that the type of work people do, in addition to the type of building they work in, play an important role in self-reported illnesses. Causation of sick building syndrome is complex and probably of multifactorial origin.