Italy and France had reported 84 locally acquired dengue cases by Oct. 28, while France and Italy also recorded 205 local chikungunya cases. The figures show mosquito-borne viruses are being transmitted within Europe, although the European Centre for Disease Prevention and Control says chikungunya is not endemic in mainland EU/EEA countries.
The dengue total comprised 76 cases in Italy and eight in France, according to the ECDC’s weekly surveillance. The separate chikungunya count was 204 cases in France and one in Italy, the agency reported.
Local transmission can occur when a person infected abroad is bitten by a mosquito after returning to an area where the insect is established. The mosquito can then carry the virus to other people. The Asian tiger mosquito, a known carrier of dengue, chikungunya and Zika, has spread across several European countries.
Portugal tests a mosquito-control method
In Lisbon, Portugal began an experimental programme on Sept. 10 by releasing 30,000 sterile male mosquitoes. The trial planned 90,000 releases in total and is intended to assess the method in an urban setting, according to ULS Santa Maria. The sterile males can mate but are not expected to produce offspring.
Health officials are also using surveillance to detect infections and track mosquito spread. HERA, the European Union’s Health Emergency Preparedness and Response Authority, has a €10 million funding line for developing diagnostics for vector-borne diseases.
Measures to limit breeding include removing standing water and using insecticide-treated screens. The ECDC’s assessment says local cases alone do not mean chikungunya has become endemic in mainland Europe.
Clayton Ward