Large human outbreak of West Nile virus infection in north-eastern Italy in 2012.

Human cases of West Nile virus (WNV) disease have been reported in Italy since 2008. So far, most cases have been identified in north-eastern Italy, where, in 2012, the largest outbreak of WNV infection ever recorded in Italy occurred. Most cases of the 2012 outbreak were identified in the Veneto region, where a special surveillance plan for West Nile fever was in place. In this outbreak, 25 cases of West Nile neuroinvasive disease and 17 cases of fever were confirmed. In addition, 14 WNV RNA-positive blood donors were identified by screening of blood and organ donations and two cases of asymptomatic infection were diagnosed by active surveillance of subjects at risk of WNV exposure. Two cases of death due to WNND were reported. Molecular testing demonstrated the presence of WNV lineage 1 in all WNV RNA-positive patients and, in 15 cases, infection by the novel Livenza strain was ascertained. Surveillance in other Italian regions notified one case of neuroinvasive disease in the south of Italy and two cases in Sardinia. Integrated surveillance for WNV infection remains a public health priority in Italy and vector control activities have been strengthened in areas of WNV circulation.

Estimated imported infections of Chikungunya and Dengue in Italy, 2008 to 2011.

BACKGROUND: In temperate countries, where the competent vector is present, the risk of introduction and transmission of Chikungunya (CHIKV) and Dengue (DENV) cases is particularly high. Thus, epidemiological surveillance is crucial to rapidly identify imported cases in order to introduce measures to reduce mosquito density in the area. METHODS: We analyze imported cases of CHIKV and DENV reported to the National Institute of Health (ISS) and the Ministry of Health, from January 2008 through October 2011 within the National Surveillance system in Italy. Moreover, considering the worldwide spread of DENV and CHIKV and the consequent importation of cases in Italy we estimate the number of imported cases using data on airport arrivals of travelers to the Italian international airports. RESULTS: From January 2008 to October 2011 a total of 130 cases of DENV/CHIKV were reported in travelers returning to Italy. In our study, 42.8% of CHIKV cases were imported from Indian Ocean Islands (Mauritius, Maldives, Bali, and Sri Lanka), whereas, for DENV 40.4% of imported cases reported to have visited Asia within the incubation period. The estimated number of exposed travelers to CHIKV and DENV arriving in Italy was higher compared to notified cases, suggesting a possible underestimation of the real number of imported cases. CONCLUSIONS: Integrated human and entomological surveillance is crucial to monitor the spread of emerging vector-borne diseases and to implement public health measures in order to avoid transmission and control such diseases in humans.

[West Nile disease: review of clinical features and risk factors associated with severe disease]. / Malattia da virus West Nile: caratteristiche cliniche e associazione tra fattori di rischio e sviluppo di forme cliniche gravi. Una revisione dei dati di letteratura.

West Nile Disease (WND) is an acute viral disease that is transmitted by a mosquito vector. Birds are the virus reservoirs and the natural amplifying hosts for the life cycle of the virus. Mammals, such as horses and humans, are secondary accidental hosts. In human cases the disease can be asymptomatic or show mild systemic symptoms, such as fever, headache, myalgia, fatigue, anorexia and lymphoadenopathy, and a non-pruritic maculo-papular rash can occur. In the elderly and immunocompromised severe clinical manifestations include the West Nile Neuro-invasive Disease (WNND): encephalitises, meningitises, meningo-encephalitises, Guillain-Barre-like syndromes, polyradiculoneuritis and acute flaccid paralyses. In the last 10 years many European countries have experienced outbreaks in animals and in humans (Romania, the Czech Republic, France, Italy). The increasing number of human cases indicates the public health threat of WND and the importance of achieving a better case definition of this disease at international level. The aim of this article is to scrutinise the available literature for the most frequently occurring clinical features of WNND and detect any associations with pre-existing risk factors.