West Nile Virus outbreak in Sardinia, Italy, in 2011

Abstract

West Nile Virus (WNV) is an enveloped, positive-sense RNA virus belonging to the genus Flavivirus, antigenically related to the Japanese encephalitis complex in the family Flaviviridae. The principal vectors are mosquitoes, in particular Culex spp, and virus amplification seems to occur in susceptible birds that are the principal vertebrate reservoir hosts, whereas humans, horses and other vertebrates are considered incidental or dead-end hosts. The first Italian equine outbreak was reported in late summer of 1998 in Tuscany, in the area surrounding the Fucecchio marshes, where 14 clinical cases of WND in housed equines were recorded. In 2011 WNV appeared for the first time in Sardinia, representing the first clinical cases in equines in Italy in 2011. The outbreak occurred both in humans and in equines. The serological survey performed on 253 equines living in the province of Oristano detected a total of 87 IgG-positive subjects. Among them, 46 horses showed neurological signs such as ataxia, paresis, paralysis, hyperesthesia, muscle fasciculations, seizures, or fever. Nine of them died or were euthanized. In forthcoming years, surveillance of wild birds and insects will be used to forecast the extension and spread of WNV. The information gathered will be used to direct or optimise strategies intended to prevent virus transmission.

The West Nile Virus-Like Flavivirus Koutango Is Highly Virulent in Mice due to Delayed Viral Clearance and the Induction of a Poor Neutralizing Antibody Response

“…With the increasing global activity of West Nile virus, including the emergence of lineage II strains, causing widespread disease across Europe (8,9), and the emergence of the first virulent strain of WNV to cause an outbreak in Australia (4), there is a growing need to better understand the ability of different WNV strains to cause disease. This knowledge will lay the foundation for more effective therapeutics or vaccine candidates.…”

“…However, in recent times strains of WNV have caused large outbreaks of encephalitis in the New World, involving humans and equines in the United States and equines in Australia (2-10). There have also been recent incursions of new, virulent strains in Europe (8)(9)(10). In the summer of 2012, the United States saw the second highest number of WNV cases on record with concurrent outbreaks in several European countries, highlighting the continuing public health threat of WNV to humans (11).…”

“…Lineage II comprises WNV isolates from west, central, and east Africa and Madagascar (14,15). Historically, lineage II strains were associated with fever and mild symptoms until 2008, when the emergence of lineage II strains was responsible for outbreaks of neurological disease in Greece, Hungary, and Italy (6,8,10,16).…”

The Changing Epidemiology of Kunjin Virus in Australia

“…West Nile virus (WNV) has emerged as a global public health concern, causing large outbreaks in the Americas, Europe and more recently Australia [1,2,3,4,5,6,7,8,9]. Kunjin virus (WNV KUN ) is classified within a clade of the WNV group and has traditionally been associated with mild and rare disease in humans and horses in Australia.…”

Development of multiplex suspension microarrays for the detection of alphaviruses and flaviviruses of public health significance

“…These include the CHIKV outbreak, which commenced on the Reunion Islands and has since spread to many continents, causing disease in millions of people . Likewise, we have seen the continued introduction of exotic viruses into new regions, with subsequent disease outbreaks, such as WNV in Sardinia, Turkey and Greece (Spissu et al, 2013, Kalaycioglu et al, 2012, Danis et al, 2011. Finally, closer to home, we have seen the emergence of a more pathogenic strain of the endemic virus KUNV, which has resulted in unprecedented neurological disease outbreaks in equines (Studdert, 2013).…”