A 10-year retrospective study on listeriosis in Latvia, 1998-2007

This study was undertaken to describe the trends in human listeriosis in Latvia over the 10-year period from 1998 to 2007 as a means of characterizing the epidemiological and clinical features of this disease. A total of 90 listeriosis cases were identified for the period from 1998 to 2007. During the 10-year study period the overall incidence of listeriosis was 0.4 per 100 000 of the population. Overall, 77% of all described clinical cases were characterized by meningoencephalitis and/or sepsis. The overall mortality, including abortions and perinatal infant deaths, was 6.7% (6/90). A marked clustering of listeriosis cases was observed from September to December 2000 possibly indicating one large outbreak. The lack of serotyping and molecular typing methods for subtyping of Listeria (L.) monocytogenes isolates in the present laboratory-based surveillance system is one of the main reasons why there were no officially documented listeriosis outbreaks in Latvia up to the present date. Therefore, serotyping and molecular typing should be introduced for all clinical isolates of L. monocytogenes to identify any listeriosis outbreaks as early as possible. Such measures will allow the application of appropriate actions at the food industry level, thus either preventing or significantly reducing the real burden of listeriosis in Latvia.