engleski

Molecular characterization of the first autochthonous Dengue virus cases in Croatia

In 2004 the first larvae of Aedes albopictus were discovered in Croatia. During the following years the species spread and established all over the country. The first imported Dengue (DENV) infection was confirmed in Dubrovnik in August 2007 in a Spanish tourist after returning from India. So far, five imported cases have been reported. However, no autochthonous DENV cases have been reported in Croatia until 2010. The first autochthonous case in Croatia, a 33-year-old woman, with fever, headache, myalgia, leukopenia, thrombocytopenia and elevated liver transaminases, appeared in August 11th, 2010, but was undiagnosed. On October 22nd, the 54-year-old mother of the previously hospitalized patient was hospitalized with similar symptoms including papular rash. About two weeks before, ECDC informed us about a German patient with confirmed DENV infection after he returned from Croatia spending his holiday in the same village on the Pelješac peninsula where both female Croatian patients lived. A retrospective molecular analysis confirmed DENV infection in two female Croatian patients. The obtained sequences from the E-NS1 gene junction of two Croatian patients were identical and showed 98% similarity with the first imported case from India in 2007. Phylogenetic analyses revealed these sequences as Genotype V within DENV serotype 1. In addition, we screened 100 blood samples from regular blood donors from the region and 97 sera from patients with fever of unknown origin hospitalized at the General Hospital in Dubrovnik for the presence of IgG antibodies. No specific DENV IgG antibodies have been detected. Immediately upon realization of autochthonous transmission trapping of Aedes albopictus was undertaken. Trapped individuals have been pooled and tested for the presence of viral RNA, but none was detected. This is the first evidence of the autochthonous DENV infections in Croatia in a small isolated endemic niche. Strong public-health measures are necessary to monitor and prevent possible spread of DENV in other parts of Croatia.

Dengue virus; autochthonous cases; Croatia; Phylogeny

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