Antibiotic prescribing during an outbreak of meningococcal disease.

During a prolonged outbreak of meningococcal disease caused by serogroup B serotype 15 sulphonamide-resistant strains in one British health district, there was considerable variation in attack rates by town. General practitioner (GP) antibiotic prescribing rates were compared in high and low incidence towns. The only significant difference found was that erythromycin prescribing was more frequent in the high incidence towns (rate ratio 4.0, 95% CI 3.2-4.8, in March 1987 and 3.0, 95% CI 2.4-3.7, in November 1987). This was probably due to increased GP consultation rates for upper respiratory tract infection (URTI), but higher erythromycin usage may have increased meningococcal acquisition rates or susceptibility to meningococcal disease. Antibiotic prescribing rates should be further investigated in defined areas of high and low incidence of meningococcal disease.

Incidence of episodes of acute asthma and acute bronchitis in general practice 1976-87.

The incidence of episodes of acute asthma and acute bronchitis was analysed for an 11-year period and studied in relation to epidemiological data on viral illness and virus isolation data. Between 1976 and 1987, the weekly returns service estimates of the incidence of acute asthmatic episodes in England and Wales increased from 10.2 to 27.1 per 100,000 patients per week (all ages). The increase was most marked in children up to the age of 14 years. Acute bronchitis attack rates (all ages) increased from 78.7 to 111.9 per 100,000 patients over the same period. Because of this rise in rates of acute bronchitis, it is unlikely that labelling shifts contributed to the increase in reported episodes of asthma. These data support the belief that the rise in the prevalence of asthma is real, and also that in the United Kingdom this rise may even be underestimated by partial concealment in the rates of acute bronchitis. In 1987, if 10% of attacks of acute bronchitis were attacks of asthma, this would represent a 41% underestimation of asthma attack rates. Rates for other respiratory illnesses showed a fall over the same period, apart from the common cold which showed an increase. The winter increase in acute bronchitis coincided with viruses with strong seasonal patterns (respiratory syncytial virus, parainfluenza viruses 1 and 2 and influenza A and B), but there was no evidence that these viruses were related to the overall increase in acute asthma attacks over this 11 year period.(ABSTRACT TRUNCATED AT 250 WORDS)

An outbreak of cryptosporidiosis associated with a swimming pool.

In August 1988 an increase was noted in the number of cases of cryptosporidiosis identified by the microbiology laboratory at Doncaster Royal Infirmary. By 31 October, 67 cases had been reported. Preliminary investigations implicated the use of one of two swimming pools at a local sports centre and oocysts were identified in the pool water. Inspection of the pool revealed significant plumbing defects which had allowed ingress of sewage from the main sewer into the circulating pool water. Epidemiological investigation confirmed an association between head immersion and illness. The pools were closed when oocysts were identified in the water and extensive cleaning and repair work was undertaken. The pool water was retested for cryptosporidial oocysts and found to be negative before the pool reopened.

Failure of influenza vaccine to prevent two successive outbreaks of influenza A H1N1 in a school community.

Forty nine of the 149 boys (33%) at a preparatory school fell ill at the beginning of the autumn term 1986 with symptoms of influenza. One hundred and eighty two of the 470 pupils (39%) in the senior part of the same school had similar symptoms of influenza at the beginning of the spring term 1987. A new variant of influenza A H1N1 virus was isolated from both outbreaks and shown to be antigenically similar to A/Taiwan/1/86. The attack rate among pupils who had previously received trivalent influenza vaccine containing A/Chile/1/83 H1N1 antigen was not significantly different from the rate among those who had never been vaccinated. It is concluded that annual vaccination of all boarding school pupils may be inappropriate.

Effect of smoking on meningococcal carriage.

A case-control study was done to examine whether certain environmental or medical factors were associated with meningococcal carriage. Questionnaires were posted to 138 meningococcal carriers and their controls, and to 52 carriers of Neisseria lactamica and their controls. Carriers were matched to controls by age, sex, and area of residence. The overall response rate was 89%. There were no differences in environmental or medical factors between N lactamica carriers and their controls, nor in household crowding, housing conditions, frequency of physical exercise, or upper respiratory disorders between meningococcal carriers and their controls. Active smoking and the presence of other smokers in the household were independently associated with meningococcal carriage; the risk of carriage increased significantly with heavier smoking.

An outbreak of puerperal fever caused by group C streptococci.

Between 19 February and 18 April 1987, 33 confirmed cases of puerperal fever caused by Streptococcus equisimilis serotype T204 occurred at three hospitals in and around Chelmsford. Most of the cases (70%) occurred on one ward, in which toilet seats and a shower are believed to have aided transmission, although insufficient data were obtained to exclude a role for person-to-person spread. Possession of M-protein antigen was demonstrated in the outbreak strain.

Hepatitis B infections after gynaecological surgery.

When acute hepatitis B developed in 3 patients who had had gynaecological surgery, the surgeon was found to be a carrier of hepatitis B e antigen. Of 268 patients operated on by this surgeon in one hospital, 247 were screened for markers of recent or current hepatitis B. 22 (9%) had such markers, associated with symptoms in 5. The operations carrying greatest risk of infection were hysterectomy (10/42) and caesarean section (10/51). These findings strengthen the case for vaccination of all surgeons and medical students against hepatitis B.

Immunity to rubella in women of childbearing age in the United Kingdom.

In the first three years of a surveillance scheme for susceptibility to rubella in women aged 15-44 the results of over 1.3 million serological tests were collected by 80 laboratories throughout the United Kingdom. Seventy eight per cent of the results, or an average of 340,000 a year, were from pregnant women, so that just under half of all pregnant women in the United Kingdom were reported on. Eighteen per cent of results were from women tested before vaccination and the remainder were from diagnostic and other tests. Pregnant women showed an overall downward trend in susceptibility to rubella (from 4.2% at the beginning of 1984 to 3.0% at the end of 1986), and a similar decline was seen in the two other categories. Regional data showed a significant negative correlation between the proportion of pregnant women aged 15-19 who were susceptible to the virus and rate of uptake of vaccine in 14 year old schoolgirls. Women aged 25-29 were least susceptible. This form of laboratory surveillance is feasible and representative; it should be continued to monitor the effect of introducing the measles, mumps, and rubella vaccine.

Epidemiology of chickenpox in England and Wales, 1967-85.

Routine sources of data on chickenpox morbidity and mortality in England and Wales were reviewed for 1967-85. Only two epidemics occurred, one in 1967 and one in 1980, both of which were immediately followed by two to three years of low incidence. The age distribution of the disease appears to be changing, with more cases now being reported in children aged 0-4 years. The number of deaths in adults have, however, increased, particularly those deaths that are associated with pneumonia and immunosuppression. At present in England and Wales more deaths are attributed to chickenpox than to whooping cough and mumps. Widespread use of selective immunisation against chickenpox might be justified in England and Wales, but before routine immunisation of the child population can be considered special surveys to determine the incidence and severity of chickenpox and the effect of the vaccine on the subsequent development of herpes zoster are needed as well as cost-benefit studies of immunisation.

An outbreak of meningococcal disease in Stonehouse: planning and execution of a large-scale survey.

In November 1986 a large-scale survey was undertaken in the Gloucestershire town of Stonehouse during an outbreak of meningococcal disease due to group B type 15 subtype P1.16 sulphonamide-resistant strains. There were 15 cases in Stonehouse residents during the 4 years from April 1983, an annual attack rate of 56.5 per 100,000. Four secondary cases occurred despite rifampicin prophylaxis. The objectives of this community survey were to investigate patterns of meningococcal carriage, transmission and immunity and to determine the proportion of non-secretors of blood group antigens in the Stonehouse population and amongst meningococcal carriers. A total of 6237 subjects participated including 75% of the 6635 Stonehouse residents. Over 97% of the participants provided all three of the requested specimens-nasopharyngeal swabs, saliva and blood samples. The co-operation between the many organizations involved in the detailed preliminary planning was instrumental in the success of the survey; in particular the value of effective collaboration between Departments of Community Medicine and Microbiology and of the Public Health Laboratory Service network of laboratories in undertaking investigations of this size and type was clearly demonstrated.

The Stonehouse survey: nasopharyngeal carriage of meningococci and Neisseria lactamica.

A total of 6234 nasopharyngeal swabs was collected during a survey of the population of Stonehouse, Gloucestershire in November 1986 as part of an investigation into an outbreak of meningococcal disease. The overall meningococcal carriage rate was 10.9%. The carriage rate rose with age from 2.1% in the 0- to 4-year-olds to a peak of 24.5% in the 15- to 19-year-olds, and thereafter declined steadily with age. Male carriers outnumbered female carriers of meningococci by 3:2. Group B (or non-groupable) type 15 sulphonamide-resistant strains which had caused the outbreak were isolated from 1.4% of subjects. The age distribution of carriers of these strains was similar to that of other meningococci apart from an additional peak in the 5-9-year age group and a more rapid decline in carriage with increasing age. Variations in the carriage rates of the outbreak strain were seen in children attending different schools and in the residents of different areas of the town. The low carriage rate of these strains in a community during a prolonged outbreak supports the hypothesis that these organisms are less transmissible but more virulent than other strains of pathogenic meningococci. Carriage of Neisseria lactamica, which is thought to be important in the development of meningococcal immunity, was most frequent in children under the age of 5 years and was six times commoner in this age group than carriage of Neisseria meningitidis. In older children and adults female carriers of N. lactamica increasingly outnumbered males in contrast to the male preponderance observed with meningococcal carriage.

Outbreak of fever caused by Streptobacillus moniliformis.

A large outbreak of streptobacillary fever, confirmed by the isolation of Streptobacillus moniliformis from blood culture, affected 304 people, 43% of the total population of 700 in a boarding school. Raw milk initially appeared to be the vehicle of infection, but detailed epidemiological investigation showed significant statistical associations between the development of illness and the consumption of both milk and water. Further analysis showed that the association with water was independent of that with milk and that water was therefore more likely to have been the vehicle of infection. Opportunity for contamination of water by rats existed, although contamination was not confirmed by the isolation of S moniliformis from either rats or the water supply.