Eurosurveillance - Volume 9, Issue 5, 01 May 2004

The Republic of Serbia, with WHO support, has implemented an early warning system (ALERT) for priority communicable diseases, to complement the routine surveillance system which notifies individual confirmed cases. The results of its evaluation, conducted one year after implementation is presented here. ALERT relies on notification of 11 syndromes by primary care facilities. Data is analysed weekly at district level and transmitted to national epidemiologists. ALERT is perceived to be a simple and flexible tool. Acceptability is higher at national level than at district level. Some districts perceive ALERT as a parallel system poorly connected to control measures. Sensitivity of ALERT in detecting cases of meningitis is 93%, and 37% for cases of hepatitis. Retrospective analysis of ALERT data identified 9 outbreaks, 5 of which had been recognized by epidemiologists. ALERT was the timeliest system for detecting 4 outbreaks identified by both systems. ALERT was useful for triggering timely investigation and control of outbreaks of hantavirus and salmonellosis and for detecting the start of the influenza season. However, ALERT did not detect clusters of brucellosis and tularaemia targeted by the unexplained fever syndrome. This evaluation underlined the need for a global review of surveillance activities when implementing new components such as ALERT. While control measures based on notification of individual confirmed cases are well understood and implemented, the investigation and verification process that should result from an increase in ALERT syndromes is not fully understood. Field epidemiology training programmes, such as the EPIET programme, are best suited to bring about this change of perspective.

HIV infection in Spain was monitored in persons undergoing voluntary HIV testing in ten sentinel clinics between 1992 and 2002. Only patients on their first visit were considered for inclusion, and their numbers rose from 4426 in 1992 to 6649 in 2002. Most of them recognised their risk exposure as heterosexual. The proportion of injecting drug users decreased from 19% to 2% of the study population, and the proportion of female sex workers increased from 6% to 26%. The number of patients diagnosed with HIV infection declined from 604 in 1992 to 153 in 2002, and HIV prevalence fell from 13.6% to 2.3% in the same period. In all risk exposure categories, a decrease in HIV prevalence was observed, more pronounced during the first few years and stabilised in the later years. In 2002, the highest HIV prevalence was found in injecting drug users (IDUs) (14.2%), homo/bisexual men (7.5%) and individuals who had an HIV infected heterosexual partner (10.2%).

Diphyllobothriasis, a parasitosis caused by the flatworm Diphyllobothrium latum, is contracted by consuming raw or undercooked freshwater fish. The aim of this study was to evaluate the situation of this parasitosis during the past 20 years in Europe through the analysis of databases and search engines (Medline, Cabi Helminthological abstracts,Yahoo, Google), and through a questionnaire sent to a network of European parasitologists and to microbiological laboratories located on the shores of the large Alpine lakes. This study has shown that several dozen cases have been reported each year in Finland and Sweden, that there have been numerous cases in the French or Italian speaking areas of subalpine lakes, and that sporadic cases only have been observed in Austria, Spain, Greece, Romania, Poland and Norway. Over 30 cases have been identified on the Swiss shores of Lake Maggiore since 1990, and 70 cases on the Swiss and French shores of Lake Léman between 1993 and 2002. Eight to 12% of perch fillets from Lake Leman and 7.8 % of perch from Lake Maggiore were infested with larvae. Contamination sources include marinated fish fillets in northern Europe, 'carpaccio di persico' in northern Italy, and perch and charr consumed raw or undercooked around Lake Léman. Factors allowing the continuation of the parasitic cycle include the continued dumping of wastewater into lakes, yachtsmen who also fish, and a possible animal reservoir.

Measles vaccine was introduced in Gipuzkoa (Basque country, Spain) in 1978 and was replaced by the measles, mumps, and rubella (MMR) vaccine for children aged 12-15 months in 1981. A second dose of the MMR vaccine was introduced in 1992. Both doses of the MMR vaccine were well accepted by the population and high coverage was achieved (95% and 91% for the first and second doses respectively for the period 1993-2002). Measles virus circulation was interrupted in the second half of the 1990s: no cases of indigenous measles were notified between 1998 and 2003, and only imported cases have been confirmed during this period. These data indicate that the measles vaccination programme implemented has been effective. Nevertheless, to avoid measles outbreaks following viral introduction, high MMR vaccine coverage levels for the two doses have to be maintained (>95%).