Cetacean strandings in Italy: an unusual mortality event along the Tyrrhenian Sea coast in 2013

Abstract

An unusual mortality event involving cetaceans, mainly striped dolphins Stenella coeruleoalba (Meyen, 1833), occurred along the Tyrrhenian Sea coast of Italy during the first 3 mo of 2013. Based on post-mortem analyses carried out according to body condition on 66 dolphins (54% of stranded animals), several hypotheses to explain the causes of this mortality event were proposed. Although no definitive conclusions can be drawn, dolphin morbillivirus was deemed the most likely cause, although other infectious agents (including Photobacterium damselae damselae and herpesvirus) or environmental factors may also have contributed to this recent mortality event.

Retrospective seroepidemiological investigations against Morbillivirus, Toxoplasma gondii and Brucella spp. in cetaceans stranded along the Italian coastline (1998–2014)

“…More in detail, the impact exerted by this viral pathogen on cetacean health and conservation has been particularly consistent in S. coeruleoalba and G. melas from the western Mediterranean, being also prominent in T. truncatus from the USA Atlantic seaboard (Van Bressem et al, 2009Fauquier et al, 2014). Additional concern has been recently raised for the Tyrrhenian B. physalus population, with at least four cases of DMV infection having been reported in this population between 2011 and 2013 (Mazzariol et al, 2012;Casalone et al, 2014). Interestingly, four morbilliviral infection's outbreaks have occurred in the western Mediterranean from 1990 to 2013, with two major epidemics having been observed in 1990-'92 and 2006-'08.…”

“…Thereafter, a die-off event was reported in 2011 along the Valencian coast of Spain, with several newborn striped dolphins and bottlenose dolphins (Tursiops truncatus) found stranded (Rubio-Guerri et al, 2013), as well as along the Italian coastline, involving fin whales (Balaenoptera physalus) (Mazzariol et al, 2012;. In Italy, an additional mortality outbreak associated with Morbillivirus occurred along the Tyrrhenian Sea during the first 3 months of 2013, mostly involving striped dolphins (Casalone et al, 2014;Van Bressem et al, 2014).…”

Initial characterization of novel beaked whale morbillivirus in Hawaiian cetaceans

“…Between 2006 and 2007, CeMV was detected in 9 long-finned pilot whales Globicephala melas that stranded along the southern Spanish Mediterranean coast and Balearic Islands (Fernández et al 2008). More recently, in 2013 CeMV was detected in 24 stranded cetaceans of various species along the Tyrrhenian coast of Italy (Casalone et al 2014), while another outbreak in 2013 along the east coast of the USA killed hundreds of bottlenose dolphins (Brown et al 2014).…”

Cetacean morbillivirus in Northern and Southern Hemispheres

“…Intriguingly, no peculiar inflammatory lesions nor immunohistochemical (IHC) evidence of morbilliviral antigen were observed in the brain of these two animals (Stephens et al, 2014), differently from CeMV-infected cetaceans (Di Guardo and Mazzariol, 2013; Di Guardo et al, 2013) but also similarly to experimentally RPV-infected cattle (Wohlsein et al, 1993). In this respect, while CeMV sequences could be demonstrated in the brain and lung from approximately 40% of the striped dolphins ( Stenella coeruleoalba ) found stranded during the first mid of 2013 along the Tyrrhenian coast of Italy, IHC evidence of morbilliviral antigen was obtained from the brain of only one of these animals (Casalone et al, 2014). Nevertheless, the isolate(s) characterized from these dolphins, apart from being identical to each other, were also very similar to those responsible for the three previous epidemic outbreaks occurred throughout the last 25 years in the Western Mediterranean (Di Guardo and Mazzariol, 2013; Casalone et al, 2014).…”

“…In this respect, while CeMV sequences could be demonstrated in the brain and lung from approximately 40% of the striped dolphins ( Stenella coeruleoalba ) found stranded during the first mid of 2013 along the Tyrrhenian coast of Italy, IHC evidence of morbilliviral antigen was obtained from the brain of only one of these animals (Casalone et al, 2014). Nevertheless, the isolate(s) characterized from these dolphins, apart from being identical to each other, were also very similar to those responsible for the three previous epidemic outbreaks occurred throughout the last 25 years in the Western Mediterranean (Di Guardo and Mazzariol, 2013; Casalone et al, 2014). …”