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Biomedical subjects

Q Syed

Publications and source records attributed to Q Syed.

31 records · Page 2Linked to original sources
PubMed1999

Social factors associated with increases in tuberculosis notifications.

This study assessed the contribution of immigration and deprivation to the changes in tuberculosis notifications in Liverpool over the last 20 yrs. Ethnic origin was retrospectively assigned to all named cases from 1974 to 1995. Average tuberculosis rates were calculated for the 33 council wards in Liverpool for 1981-1985 and 1991-1995. Multiple regression was used to determine the independent effects of socioeconomic and population measures from the 1981 and 1991 censuses in explaining these ward-based rates. Since 1974, there has been a steady increase in the percentage of non-Caucasian cases of tuberculosis, from 8.7% in 1975-1977, 15.1% in 1981-1983, 17.5% in 1987-1989 to 28.0% in 1993-1995. Multiple regression analysis showed that in 1981 only unemployment had a significant independent relationship with tuberculosis rates, but in 1991 two indices of deprivation and ethnicity had a significant influence. The increasing proportion of non-Caucasian tuberculosis cases, both while the number of notifications was declining before 1987 and increasing afterwards, is not necessarily consistent with the concept that immigration has influenced the recent increase. However, the fact that ethnicity now independently explains some of the council ward variations but did not in the early 1980s suggests that immigration does influence the distribution of disease within the city.

Adolescent↗
PubMed1999

An outbreak of campylobacter food poisoning at a university campus.

Twelve cases of Campylobacter jejuni infection were identified on a university campus in the first 12 days of November 1997. Consumption of food from a single outlet, where poor food handling practices were identified, was statistically associated with infection. The epidemiological evidence suggested that what presented as a point source outbreak was a series of small cross contamination incidents associated with multiple strain types. The nature of this outbreak suggests that current surveillance systems are inadequate for the identification of campylobacter outbreaks. Enhanced surveillance should be introduced to identify case clusters of campylobacter infections and public health professionals should remember the risks of cross contamination associated with ubiquitously contaminated foodstuffs, especially raw meats and poultry. The role of strain typing in campylobacter epidemiology is as yet undefined.

Adolescent↗
PubMed1998

Hepatitis B and hepatitis C virus infections: risk factors among drug users in Northwest England.

OBJECTIVES: to identify the risk factors for hepatitis B (HBV) and hepatitis C (HCV) virus infections in drug users attending two drug treatment centres in Northwest England, and to evaluate the effect of both needle exchange and hepatitis B vaccination on the prevalence of hepatitis B and hepatitis C infections. METHODS: a retrospective, cross-sectional study performed at the Regional Infectious Disease Unit and a Primary Care Centre for drug users in Liverpool. The study population included 773 drug users who had hepatitis serology performed between January 1992 and April 1996. Information on risk factors was obtained from clinical records; hepatitis serology data were obtained from the Liverpool Public Health Laboratory database. RESULTS: the overall seroprevalences of exposure markers for HBV (anti-HBc antibody) and HCV (anti-HCV antibody) were 48% and 67%, respectively. Duration of injecting drug use was the strongest predictor of HCV infection, with a crude odds ratio of 8.9 (95% confidence interval (CI): 4.5-17) for >10 compared to <3 years of injecting, and was also a strong predictor of HBV infection, with an adjusted odds ratio (controlled for the effects of HBV vaccination) of 5.7 (95% CI: 3.2-10) for >10 compared to <3 years' injecting. Vaccination against HBV was associated with greatly reduced HBV seroprevalence (crude odds ratio 0.11, 95% CI: 0.06-0.18). Overall, HCV was acquired earlier in the injecting career than HBV, but drug users who were not vaccinated against HBV acquired markers for HBV even more rapidly than for HCV. We found no independent protective effect for either anti-HBc or anti-HCV acquisition after the introduction of a needle-exchange scheme. CONCLUSIONS: hepatitis C is highly prevalent among Merseyside drug users and is likely to prove difficult to control because of rapid acquisition early in the injecting career. Vaccination against hepatitis B is the best means of protecting drug users from hepatitis B, and should be offered before injecting is commenced.

Adolescent↗
PubMed1998

The use of serodiagnosis in the retrospective investigation of a nursery outbreak associated with Escherichia coli O157:H7.

AIMS: To use serology to investigate an outbreak of verocytotoxin (VT) producing Escherichia coli O157 in a hospital nursery, following the detection of faecal E coli O157 (phage type 49) producing VT type 2. METHODS: ELISA and immunoblotting techniques, based on lipopolysaccharide (LPS) purified from E coli O157; diagnostic bacteriology; serotyping and phage typing; DNA probes for VT. RESULTS: 29 of 126 sera contained antibodies to the LPS of E coli O157: 10 were from children, three were from staff, and 11 were from hospital kitchen staff. Five parents of children attending the nursery were antibody positive. Sixty four sera from other hospital staff and controls did not contain antibodies to the LPS of E coli O157. CONCLUSIONS: Serology detected evidence of infection with E coli O157 in 23% of sera examined. By bacteriology alone, only a single case of infection with E coli O157 would have been detected. Serology is valuable in providing evidence of infection with E coli O157.

Antibodies, Bacterial↗
PubMed1998

Long-term trends in tuberculosis. Comparison of age-cohort data between Hong Kong and England and Wales.

The caseload of tuberculosis in developing countries is increasingly associated with the elderly. This is possibly due to increased longevity today and a change in the lifetime risk of tuberculosis within birth cohorts. Published data for tuberculosis notifications for Hong Kong and England and Wales have been used to calculate age-specific rates of disease by different age groups for different birth cohorts. In Hong Kong, each birth cohort showed a similar pattern of disease by age, with rates peaking in the 25 to 39-yr age groups and gradually declining thereafter. After 1978, regardless of age at that time, all age cohorts showed an increase in tuberculosis rates with increasing age. This trend was more marked in males than females. A similar pattern was seen for birth cohorts in England and Wales except that the peak occurred earlier in life (before 25 yr of age) and the decline with age ceased in 1984. Thereafter, rates increased in males born before 1930 but showed only a leveling off in females. If these data represent a true increase in tuberculosis rates, rather than resulting from a change in reporting accuracy and completeness, the burden of tuberculosis in the elderly is likely to continue to increase substantially.

Adolescent↗
PubMed1998

Whooping cough surveillance in the north west of England.

The number of whooping cough notifications has declined in recent years, as vaccine coverage has recovered from the low levels seen in the 1970s and 1980s. Notification of infectious disease is often incomplete, and this study aimed to estimate the extent to which whooping cough is undernotified. We included all cases of whooping cough occurring in the North West Region between 1 April 1994 and 31 December 1996, identified by notification, hospital admission data, or laboratory reports. By combining the three sources, 1239 cases were identified, 69.6% of which were notified. The notification rate was 29.6% (131/442) for cases admitted to hospital and 45.6% (78/170) for laboratory reported cases. Completeness of notification was estimated to be 35.7% (863/2420; 95% confidence interval 30.3-43.4%) using the capture-recapture method. The study confirms that notification of whooping cough is incomplete and suggests that two thirds of cases are not notified.

Age Distribution↗
PubMed1996

Tuberculin testing in two Liverpool social clubs: the effects of a tuberculosis outbreak on background positivity.

BACKGROUND: Tuberculin testing remains the standard method for assessing infection due to tuberculosis in the UK. However, there are no data on the incidence of tuberculin positivity among the general adult population in the UK and consequently interpretation of Heaf test results is often difficult. METHODS: During the investigation of an outbreak of tuberculosis in a Liverpool social club 198 members were interviewed and Heaf tested and 171 members of a second social club in Liverpool were similarly screened as a control group. Comparisons between the results from the two populations provided both an estimate of baseline Heaf test positivity in indigenous white adults from a British inner city population, and a measure of the effect on this baseline of recent exposure to tuberculosis. RESULTS: In both club populations the proportion of positive Heaf tests increased with age. Independent of age, the tuberculosis exposed population had a higher proportion of positive Heaf grade results (40.9%) than those in the control group (26.9%). Multivariate analysis confirmed both the differences in Heaf results between clubs and between age groups but identified no other behavioural or medical factors which affected Heaf test results. CONCLUSIONS: Heaf test positivity increases with age at least up to 54 years, and recent exposure to tuberculosis increases the proportion of positive Heaf tests in each age group. Interpretation of positive Heaf tests when assessing the effects of a tuberculosis outbreak should take account of background levels of Heaf positivity.

Adolescent↗
PubMed1995

A hospital outbreak of Clostridium perfringens food poisoning--implications for food hygiene review in hospitals.

An outbreak of Clostridium perfringens (C. perfringens) food poisoning affected 17 of 44 (38.6%) patients interviewed on two hospital wards. A case-control study showed a statistically significant association between the consumption of roast pork and illness (P < 0.01). C. perfringens type A, untypable serotype, was isolated from samples of pre-cooked vacuum sealed pork supplied by a local meat producer. Faults were noted in the food production process at the factory. Cuts of meat were too large and equipment to ensure rapid cooling of cooked meat was not installed. Cost improvements taken by hospitals, such as the use of commercially cooked meat, may not be consistent with the highest standards of food safety. Amendments to the District Catering Policy were implemented to prevent further outbreaks.

Animals↗
PubMed1995

Outbreak of cryptosporidiosis associated with a disinfected groundwater supply.

In an outbreak of cryptosporidiosis in Warrington, a town in North-West England, 47 cases were recorded between November 1992 and February 1993, most within the first month. There was a strong statistical association between cases and residence in an area supplied from two groundwater sources. In a case-control study, a strong association between having drunk unboiled tap water from these sources, and a dose-response relationship were found. Oocysts were not detected in the water supply. During very heavy rainfall one source of water was found to drain surface water directly from a field containing livestock faeces, thereby bypassing natural sandstone filtration. Exceptionally heavy rainfall occurred at the probable time of infection. After withdrawal of the original water supply, the outbreak rapidly subsided. It was concluded that there was very strong evidence that this outbreak was waterborne. This, the second documented outbreak of cryptosporidiosis attributable to a groundwater supply, demonstrates that infection can be transmitted from a disinfected groundwater source despite apparently satisfactory treated water quality. We recommended that guidelines for protection of groundwater are implemented, raw groundwater should be routinely monitored for microbiological contamination, and the structure of all sources and waterworks should be assessed in risk surveys of water catchment areas.

Adult↗
PubMed1994

A pseudo outbreak of tuberculosis.

Three cases of suspected tuberculosis were diagnosed over a ten day period at an oncology unit. Case finding was carried out and six further cases were diagnosed. However, doubts were raised about these diagnoses and a review of the outbreak investigation was carried out. Investigation of laboratory procedures found that the 'outbreak' was likely to be due to a contaminated phenol red solution. This incident highlights the importance of a critical evaluation of outbreak investigations, and the need for close collaboration between clinicians, epidemiologists and laboratory staff.

Child↗