P. De Wals

Meningococcal disease in Belgium. Secondary attack rate among household, day-care nursery and pre-elementary school contacts

During a recrudescence of meningococcal disease mainly due to serogroup B, 1913 notified cases were investigated in Belgium from 1971 to 1976. From 1971 to 1973, 76 secondary cases were reported out of a total of 1455 cases (5.2 per cent); and from 1974 to 1976, nine secondary cases were reported of a total of 458 cases (2.0 per cent). Seventy per cent of the secondary cases occurred within seven days after the Index case. The 4.7 per cent fatality rate among secondary cases was lower than the 9.8 per cent fatality rate among primary cases. The estimated secondary attack rate was 685 per 100 000 among household contacts, 404 per 100 000 among day-care nursery contacts and 77 per 100 000 among pre-elementary school contacts. These attack rates were significantly higher (P less than 0.001) than the incidence rates in the corresponding age-groups in the general community, indicating the need for prophylaxis in these contacts.

Evaluation of routine ultrasound examination for the prenatal diagnosis of malformation

In 1986, a retrospective survey was undertaken in the southern part of the province of Hainaut, Belgium, in order to measure the frequency of ultrasound examinations during pregnancy and to evaluate the effectiveness of the routine practice of echography screening for the detection of congenital malformations in an unselected population. The reference populations comprised 8316 pregnancies covered by the EUROCAT Registry of Hainaut. In 1986, 190 congenital malformations cases were registered. For each of the 190 cases, one control ending in the birth of a non-malformed infant was retrospectively selected. The analysis showed that an average of four ultrasound examinations were performed during pregnancy. When all malformations are considered, the sensitivity of the screening is 14% (27/190). Sensitivity of detection varied from 100% for gross malformations such as anencephaly to 0% for defects of a minor size such as facial clefts. In these 27 cases, obstetrical interventions following prenatal diagnosis were termination of pregnancy in 14 cases and induction of labor in 3 cases. Antenatal care was planned in 8 cases, 5 of which had early surgical repair. In the control group, a malformation was suspected in 3 of the 144 pregnancies (specificity of detection, 98%).

Longitudinal study of asymptomatic meningococcal carriage in two Belgian populations of schoolchildren

In Brussels, a 15-month longitudinal survey was conducted in two primary schools, from March 1975 to May 1976, in order to analyse the dynamic of asymptomatic meningococcal carriage, during an epidemic mainly caused by serogroup B, serotype 2 Neisseria meningitidis. In the first school, which is situated in a suburban area with upper-middle socio-economic status of residents, a mean prevalence of carriers of 10 per cent, an acquisition rate of eight per 1000 months, and a mean duration of carriage of 12.4 months were observed among 158 schoolchildren aged six to 11 years old. In the second school, which is situated in a densely populated area with low socio-economic status of residents, a mean prevalence of carriers of 33 per cent, an acquisition rate of 28 per 1000 months, and a mean duration of carriage of 11.7 months were observed among 203 schoolchildren aged three to 14 years old. For both schools, the median duration of carriage was estimated at 9.4 months. The differences of prevalence and incidence of acquisition between the two schools cannot be explained by age, sex or ethnic factors and are probably related to socio familial variables. The theoretical relationship between prevalence, incidence and duration of meningococcal carriage was for the first time demonstrated in this study. The results also suggest that populations of low socio-economic status and living in densely populated areas constitute a target population for meningococcal disease prevention.

Mortality in meningococcal disease in Belgium

A survey of children admitted with meningococcal disease to 53 paediatric units in Belgium between 1975 and 1979 was made in order to assess the case mortality rate (CMR) and to identify risk factors associated with death. A total of 309 cases (226 bacteriologically confirmed and 83 unconfirmed) was recorded. The overall CMR was 6.1 per cent. It was 4.4 for bacteriologically confirmed cases and 10.8 for unconfirmed cases. The CMR was higher for septicaemia without meningitis (22.2 per cent) than for meningitis with or without signs of septicaemia (3.4 per cent). The risk of death was not related to the sex or nationality of the patients. Age was a major determinant of the CMR, independently of the clinical picture. The highest risk of death was in children under one year of age. Poor socio-economic conditions were a significant risk factor. Failure to recognise the severity of the disease by some poorly educated mothers, and the admission of the patient to a hospital lacking adequate facilities for managing severely affected children, were the two significant causes of delay of adequate treatment.

Validity of the recording of meningococcal disease according to various sources of information

A study was made in Belgium in order to assess the completeness and specificity of the recording of meningococcal disease by routine sources of information. Ninety-three cases identified in a hospital survey were linked with those recorded in mortality statistics, in the notification of communicable diseases, and by the National Reference Laboratory for meningococci. Statistics based on mortality data appeared to be of low validity. The overall completeness of recording was 44% for the notification of communicable disease, and 40% for the reference laboratory. When these two sources were used for surveillance, the completeness of case-finding increased to 56%. When the analysis was restricted to bacteriologically-confirmed cases, the completeness of recording was 62% for the notification system, 70% for the laboratory, and 84% for both sources. The surveillance of communicable diseases should rely on various sources of information. Laboratory data should be systematically used in order to improve both the completeness of recording and the specificity of case-ascertainment.

Incidence of congenital rubella syndrome in 19 regions of Europe in 1980-1986.

Twenty-five cases of congenital rubella syndrome were recorded in 1,458,126 live births in 19 EUROCAT birth defects registries from 1980 to 1986. During the study period, the incidence declined steadily from 3.50 to 0.41 per 100,000 births. Rubella infection occurred in 12 multiparous women indicating failure in immunization programme.

Quality of perinatal death registration

The quality of national perinatal mortality statistics was evaluated from a survey in nine maternity hospitals in Hainaut, Belgium (total births: 7862). The overall completeness of perinatal death registration was 86%. Under-registration was especially frequent in low birth weight babies. In 69% of cases, the birth weight value reported on death certificates was in exact agreement with the value in hospital records. Using detailed categories of causes, there was, in 37% of cases, agreement between the underlying cause on death certificates and the main cause identified in hospital records. Using gross categories of causes, the level of agreement was 56%. Disagreement was mostly due to the lack of specificity of the underlying cause on death certificates. The authors suggest ways to improve the quality of registration.

FREQUENCY OF BIRTHS WITH POTENTIALLY AVOIDABLE SERIOUS CHROMOSOMAL-ANOMALIES IN EEC COUNTRIES, 1979-1982

Child bearing at an early age and prenatal cytogenetic diagnosis in pregnant women of advanced age, combined with selective abortion, make it possible to avoid the birth of many children with serious chromosomal anomalies. To see how many of such births were still avoidable in Europe, data from 16 regional EUROCAT registers of congenital anomalies in nine EEC countries were analysed. In the period 1979-1982 about 30% of children with unbalanced anomalies of autosomes were born (live- and still-births) to mothers over 35 years of age. This amounts to an estimated 1300 cases yearly in the entire population of the nine countries. The approach shows the possible use of registry data for monitoring effects of avoidance strategies.

Home care as an alternative to hospitalization: A case study in Belgium

In Belgium, primary health care services are well developed. Their efficiency is, however, handicapped by a general lack of coordination at a local level. Recently, pilot projects have been conducted to improve the integration of the various activities related to the practice of family medicine and especially those activities associated with the home care of chronic diseases and disabilities of the elderly. In one municipality where the coordination of primary care services is organized from a health centre, a retrospective study was carried out to measure the possible effect of such coordination on the use of health services. Indicators of the use of medical services were measured before and after the establishment of the coordinating centre, and were compared with the evolution observed in control areas. It is shown that the establishment of a health centre and the coordination of existing activities do not result in an inflationary use of primary care services. Moreover, the use of secondary care services seems to be reduced, indicating a net benefit in terms of costs.