Page 48 - Timeliness of Infectious Disease Notification & Response Systems - Corien Swaan

46 Chapter 2
Shigellosis and EHEC/STEC infections have short incubation periods and require time-consuming laboratory testing for diagnosis. These two disease categories consequently show remarkable delays in reporting; for shigellosis, we found even higher percentages of delay than were found in other studies [6-8]. We hypothesise that shigellosis patients in the Netherlands present to their gener- al practitioner at a later stage of the disease than patients in other countries, and that laboratory diagnosis is likewise requested at a later stage. However, we were not able to investigate these hypotheses. We did find that physicians and laboratories are not aware of the importance of rapidly reporting these cases, leading to an increase in the percentage of shigellosis and EHEC/STEC infections that are reported more than three days after diagnosis. This may be a cause for concern as has been found in other studies [18]. Public health re- sponse measures, such as improving hygiene and implementing fast exclusion policies in schools or institutions, are sometimes urgently required in order to avoid outbreaks of these two diseases. We must therefore conclude that Dutch surveillance is not sufficient with regard to these infections, and that additional approaches to control, such as public education on hygiene and raised aware- ness of urgency among physicians, must be considered.
The severity of illness of meningococcal disease generally creates a sense of urgency for the diagnosing physician, which no doubt extends to reporting. Chemoprophylaxis, preferably administered within 24 hours after identification of the index case, is the primary means for preventing meningococcosis, and the ability of health services to identify contacts in time, depends largely on timeliness of reporting. Nevertheless, we found that 13.3% of cases of meningo- coccosis are not reported within two incubation periods, a total of seven days. Other studies have likewise found suboptimal timeliness of reporting cases of this disease [9,10]. Optimising Pd, as shown in Table 1, by immediate laboratory reporting, can make an essential improvement and should be applied.
Using the time interval corrected for infectiousness before disease onset (Ic), we found that even diseases with longer incubation periods (measles, HAV infection) have a considerable percentage of cases notified after one Ic. Although overall vaccination coverage for measles is high in the Netherlands, unvaccinated subgroups persist. It is therefore cause for concern that 51.5% of cases are not notified within one Ic. For measles, a rapid vaccination campaign for contacts of infectious cases is essential for controlling an outbreak.
HAV infections occasionally cause outbreaks in the Netherlands in child day-care centres, schools, or other institutions. Most of these outbreaks are initiated by children of immigrants, who become infected when travelling to