Eurosurveillance - Volume 13, Issue 8, 21 February 2008

Since November 2006, Switzerland has been experiencing the largest measles outbreak registered in the country since the introduction of mandatory notification for this disease in 1999. The first eight months of this outbreak have already been described in this journal [1]. From November 2006 to 13 February 2008, 1,405 measles cases were reported by physicians or laboratories in Switzerland (1,106 of them in 2007). Of these, 976 cases (69%) occurred in the cantons of Lucerne (29% of the total), Basel-Land (16%), Zurich (11%) Bern (7%), and Aargau (7%). The incidence for the whole country and all ages, calculated for this 15-month period, was 19 cases per 100,000 inhabitants (15 cases per 100,000 for the year 2007). For children under the age of 16 years living in the canton of Lucerne, it was 500 per 100,000.

Since January 2008, public health authorities in the state of Baden-Württemberg, south-west Germany, have observed an increased number of measles cases (16 cases in weeks 1-7 in 2008, compared to three cases in the same weeks in 2007) with epidemiological links to an ongoing measles epidemic in Switzerland [1]. So far only unvaccinated children, adolescents and young adults have been affected. .

Measles elimination in Europe is hindered by recurrent outbreaks, typically in non-immunised specific sub-populations. In 2003 and 2004, two measles outbreaks occurred in Jewish ultra-orthodox communities in Jerusalem, Israel. In 2007, another measles outbreak emerged in Jerusalem. Epidemiological investigation and control activities were initiated. Three measles cases (15 years old, 22 years old and an infant; all unvaccinated) were diagnosed in Jerusalem in August 2007. All three belonged to Jewish ultra-orthodox communities in London, United Kingdom, and had had contact with patients in London. The epidemiological investigation did not reveal any connection between these cases other than their place of origin. The disease spread rapidly in extremely ultra-orthodox sub-groups in Jerusalem. Until 8 January 2008, 491 cases were reported. Most patients (70%) were young children (0-14 years old), 96% unimmunised. Frequently, all the children in a large family were infected; two thirds of the cases belonged to family clusters of more than two patients per family (in part due to non-compliance with post-exposure prophylaxis recommendations). The high age-specific incidence among infants 0-1-year- (408.5/100,000) and 1-4-year-olds (264.1/100,000) is a cause for concern. The hospitalisation rate was 15% (71/491), mainly due to fever, vomiting and dehydration. The median age of hospitalised patients was 3.6 years; 19 patients (26.7%) presented with pneumonitis or pneumonia and two patients presented with encephalitis. There have not been any deaths to date. The outbreak was apparently caused by measles importation into unprotected groups. Despite a high national immunisation coverage (94-95%), programmes to increase and maintain immunisation coverage are essential, with special focus on specific sub-populations.

Influenza surveillance provides information on virus activity and is necessary for the selection of vaccine strains and early warning in the case of the threat of an epidemic or pandemic. To improve this surveillance in Poland, a sentinel surveillance system was introduced in 2004-5 (""SENTINEL""). This paper presents results from SENTINEL during three seasons of its existence. Voivodship Sanitary-Epidemiological Stations (VSESs), physicians and the National Influenza Center (NIC) participate in SENTINEL. Laboratory course was performed by the NIC for VSESs. Stations were provided with procedures, report forms, etc. Physicians register number of influenza-like illnesses (ILI) and collect swabs. VSESs perform diagnostic tests. On the basis of information from VSESs, the NIC prepares weekly reports for the entire country. In 2004-5 epidemiological reports were received from 50% of VSESs, while in 2005-6 and 2006-7 from all VSESs. Virological reports were obtained from 37.5% of VSESs (2004-5), 75% (2005-6) and 94% (2006-7). Weekly number of reporting physicians ranged in three consecutive seasons from 165 to 219, 98 to 949 and 696 to 1,054. A total of 399 specimens were tested during the 2004-5 winter; 63 (16%) were positive for influenza and 21 (5%) for other respiratory viruses. In 2005-6, 949 specimens were tested. Influenza infections were confirmed in 47 cases (5%) and infections with other respiratory viruses in 36 cases (4%). A total of 1,195 specimens were tested during the 2006-7 winter; 37 (3%) were positive for influenza and 26 (2%) for other respiratory viruses. SENTINEL provided improvement of influenza surveillance when compared with seasons before 2004. Nevertheless, due to decreasing rate of positive specimens, virological surveillance is the most important part to improve in the next years.

Between October 2007 and January 2008, 12 cases of a disease subsequently termed progressive inflammatory neuropathy (PIN) have been reported among workers in a swine slaughterhouse in Minnesota, United States.

The International Summer School "Infectious Disease Epidemiology" will be held from 15 to 19 September 2008 at the University of Bielefeld, Germany.

On request of the authors, four numbers were corrected in Table 2 of the article Mumps outbreak in young adults following a festival in Austria, 2006, published on 14 February 2008.