Eurosurveillance - Volume 15, Issue 39, 30 September 2010

In September 2010, two cases of autochthonous dengue fever were diagnosed in metropolitan France for the first time. The cases occurring in Nice, south-east France, where Aedes albopictus is established, are evidence of dengue virus circulation in this area. This local transmission of dengue calls for further enhanced surveillance, active case finding and vector control measures to reduce the spread of the virus and the risk of an epidemic.

The Hajj has become the epicenter of mass migration of millions of Muslims of enormous ethnic diversity. No other mass gathering can compare, either in scale or in regularity. Communicable disease outbreaks of various infectious diseases have been reported repeatedly, during and following the Hajj. The Hajj 2010 starts in the first week of November 2010 and this report is a timely reminder that many infectious diseases can be avoided or averted by adopting appropriate prophylactic measures.

We report an outbreak of Legionnaires' disease in a nursing home in Slovenia in August 2010 affecting 15 of 234 residents. To date, Legionnaires' disease has been confirmed in four patients. Further serum analyses and genotyping of isolates are ongoing. The building's water distribution system with dead end sections has been identified as the probable source of infection.

A sudden reduction in the number of reported genital chlamydia cases was observed in Norrbotten County, Sweden, during October to November 2009. After exploring other possibilities, such as a reduction in the number of chlamydia tests analysed or a new Chlamydia trachomatis variant that had been undetected in standard laboratory tests, it was found likely that the decrease was an indirect effect of the 2009 influenza A(H1N1) pandemic due to reduced social interactions among young adults.

During the last decade, outbreaks of acute hepatitis C virus (HCV) infection have been reported among human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) in several European countries. To study this emerging infection in MSM in Antwerp, Belgium, we reviewed all cases of newly acquired HCV infection in HIV-positive MSM followed from 2001 to 2009 at the HIV/sexually transmitted infection (STI) reference clinic of the Institute of Tropical Medicine in Antwerp. Newly acquired HCV infection was considered as certain or probable according to local definitions. During the study period, 69 episodes of newly acquired HCV infection (40 certain and 29 probable) were diagnosed in 67 HIV-infected MSM. In only 10 episodes (14%) were the patients symptomatic. The annual incidence of HCV infection in our population of HIV-infected MSM rose steadily from 0.2% in 2001 to 1.51% in 2008, and then peaked to 2.9% in 2009. For 60 episodes (87%), another STI (mainly syphilis and lymphogranuloma venereum) had been diagnosed within the six months before the diagnosis of HCV infection. All but one patient with available genotyping (n=54) were found to be infected with the difficult-to-treat HCV genotypes 1 or 4. Our results therefore demonstrate the rising incidence of HCV infection in HIV-positive MSM in Antwerp, since 2001, which reached an alarming level in 2009. Targeted awareness campaigns and routine screening are urgently needed to limit further HCV spread and its expected long-term consequences.