The “One Health” approach in West Nile disease surveillance: the
experience of Southern Italy
Abstract
West Nile Disease is a zoonotic vector-borne infection involving viral
pathogens, human and animal hosts, vectors and habitats with a complex
transmission cycle. Cooperation among different disciplines has been
promoted by the Italian Public Health Authorities to introduce a robust
surveillance system and an integrated West Nile Virus (WNV) Surveillance
Plan has been in force in Italy since 2016, in order to establish a
medical, veterinary and entomological network. This represents a unique
model in Europe. This study aims to present this “One Health” approach
applied following the first recorded autochthonous case of West Nile
Neuroinvasive Disease (WNND) in Sicily (Southern Italy). Serological and
molecular tests were conducted on the blood, liquor and urine of a
38-year-old man with encephalitis and meningitis: WNND was confirmed by
serological analysis on liquor and serum. Consequently, a veterinary and
entomological surveillance was started. Overall, 160 mosquito catches
were collected from six different sampling sites and 2704 adult
culicides were morphologically identified. Female mosquitoes were
analyzed in pools for WNV RNA detection. Serological and molecular
assays for WNV were carried out in 11 horses, 271 chickens and 2 dogs
sampled in farms around the man’s residence. Collected mosquito species
included Culex pipiens (93.6%), Aedes albopictus (5.25%), Culex
hortensis (0.6%), Culiseta longiareolata (0.55%) and Anopheles
maculipennis s.l. (0.04%). Mosquito pools were negative for WNV nucleic
acid presence. Two dogs (100%) and two horses (18.2%) resulted
positive for WNV-specific IgG antibodies. Since WNND epidemiology is
influenced by several ecological factors and by the presence of several
animal and vector species, the integrated surveillance system was
crucial for understanding whether the virus had circulated/was
circulating in the suburban, urban area and for preventing the spread of
infection.