Vector-borne zoonoses surveillance in Piedmont region, northwestern Italy (2011-2016)

Vector-Borne Diseases (VBDs) represent a threat for humans and animals, that is emerging worldwide due to climate and environmental changes and international trade/ travel. Given the complex epidemiology, a multidisciplinary approach is required for their surveillance. Aim This work reports the integrated surveillance system enforced in Piedmont region (northwestern Italy), on mosquito and tick borne diseases. Methods An information network was activated between local veterinary and human health authorities, to connect the surveillance of VBDs human clinical cases with entomological surveillance and veterinary monitoring in order to implement control measures in case of outbreak. Since 2011 a systematic entomological surveillance was carried out during the vector season: mosquitoes were collected by georeferenced traps, then identified and pooled by species, data and collection site and analyzed by PCR to detect viruses belonging to the Flavivirus genus. Ticks removed from bitten humans of different regional areas were identified and tested by biomolecular essays for the detection of Borrelia burgdorferi sl, Rickettsia spp., Anaplasma spp and Tick Borne Encephalitis Virus (TBEV). Results Through entomological surveillance, Usutu virus was detected in mosquitoes since 2011. West Nile virus was firstly detected in 2014 in mosquitoes of a regional southeastern area, then in following years an expansion of its activity was observed. Control and preventive measures were immediately applied, according to the national legislation and in collaboration with regional veterinary and human health services. Since 2011, 1070 ticks were collected from humans, mainly identified as Ixodes ricinus. Preliminary biomolecular tests performed on 504 ticks showed their infection with Borrelia burgdorferi s.l. (6.5% prevalence), Rickettsia spp. (16.6%) and Anaplasma spp. (2.4%). No TBEV was detected. Conclusion According to the One Health concept, interactions between different disciplines are needed for an effective early warning and management of VBDs. The integrated surveillance on arthropods of medical importance provides useful information to public health authorities, in order to apply control measures in collaboration with local veterinary and human health services and valuable data to medical centers, to address patients’ diagnosis and therapy.