Nodular gill disease in Northeastern Italy: An investigation on the prevalence of the disease and the risks of introduction in rainbow trout farms.

Nodular Gill Disease (NGD) is an emerging pathogenic condition that causes gill damage and mainly affects farmed freshwater fish, rainbow trout (Oncorhynchus mykiss) in particular, and this inevitably generates noticeable economic losses for the industry. The present study aimed to assess the prevalence of NGD in the Autonomous Province of Trento, a highly productive area located in Northeastern Italy, traditionally suited to rainbow trout production, and to identify possible risk factors for the introduction of this disease in trout farms. The necessary data were obtained through a questionnaire and the collection of fish samples. According to the data analysis, 42% of the investigated farms tested positive for NGD. The two possible risk factors identified for its introduction in farms are the presence of other diseases in the same farm (OR = 17.5; 95% CI = 2.7; 111.5) and having farms located 5 km upstream (OR = 24.8; 95% CI = 2.9; 211.1). These results highlight (i) a possible impairment of the immune system caused by other diseases as a predisposing factor to the manifestation of the pathology and (ii) the role of water in spreading pathogens.

An electronic learning course on avian influenza in Italy (2008).

The success of emergency intervention to control contagious animal diseases is dependent on the preparedness of veterinary services. In the framework of avian influenza preparedness, the Italian Ministry of Health, in cooperation with the National Reference Centers for Epidemiology and Avian Influenza, implemented an electronic learning course using new web-based information and communication technologies. The course was designed to train veterinary officers involved in disease outbreak management, laboratory diagnosis, and policy making. The "blended learning model" was applied, involving participants in tutor-supported self-learning, collaborative learning activities, and virtual classes. The course duration was 16 hr spread over a 4-wk period. Six editions were implemented for 705 participants. All participants completed the evaluation assignments, and the drop out rate was very low (only 4%). This project increased the number of professionals receiving high-quality training on AI in Italy, while reducing expenditure and maximizing return on effort.

Koi herpesvirus disease outbreak: Input for the implementation of a surveillance program in South Tyrol - Italy.

A severe episode of high and abnormal mortality was observed in the population of Cyprinus carpio of Lake Caldaro (South Tyrol, Italy) in summer 2016. The diagnostic investigation carried out led to the identification of Koi Herpesvirus (KHV) as the etiologic agent. Following this disease outbreak and its socio-economic consequences, the local authorities, in agreement with the local Fishing Association, decided to implement a surveillance program for the achievement of KHV-free health status (Category I) in the Province, in accordance to the Implementing Decision (EU) 2015/1554. The selected area was a defined geographical compartment (the Monticolo lakes compartment, South Tyrol, Italy), which is located near Lake Caldaro, where the Koi Herpesvirus disease (KHVD) outbreak had occurred. This area is of particular interest because it supplies other water bodies with juvenile C. carpio individuals; with the achievement of a KHV-free health status, South Tyrol could possibly become independent in the breeding of this fish species. Suitable samples were collected and processed during a two-year period in order to detect the presence/absence of KHV. The same samples were tested for other viruses that can affect carp, namely spring viraemia of carp (SVCV) and carp edema virus (CEV). According to the results, the authors conclude that the Monticolo lakes area should be classified as KHV-free, as no sample has tested positively for the presence of this specific virus (KHV).

Low evolutionary rate of infectious pancreatic necrosis virus (IPNV) in Italy is associated with reduced virulence in trout.

Infectious pancreatic necrosis virus (IPNV) is a naked double-stranded RNA virus with a bi-segmented genome that is classified within the family Birnaviridae, genus Aquabirnavirus. IPNV was first detected in Italian trout farms in the late 1970s and ultimately became endemic. To characterize the evolution of IPNV circulating in Italy, particularly whether there is a link between evolutionary rate and virulence, we obtained and analyzed the VP1 (polymerase) and the pVP2 (major capsid protein precursor) sequences from 75 IPNV strains sampled between 1978 and 2017. These data revealed that the Italian IPNV exhibit relatively little genetic variation over the sampling period, falling into four genetic clusters within a single genogroup (group 2 for VP1 and genogroup V for pVP2) and contained one example of inter-segment reassortment. The mean evolutionary rates for VP1 and pVP2 were estimated to be 1.70 and 1.45 × 10-4 nucleotide substitutions per site, per year, respectively, and hence significantly lower than those seen in other Birnaviruses. Similarly, the relatively low ratios of non-synonymous (dN) to synonymous (dS) nucleotide substitutions per site in both genes indicated that IPNV was subject to strong selective constraints, again in contrast to other RNA viruses infecting salmonids that co-circulate in the same area during the same time period. Notably, all the Italian IPNV harbored a proline at position 217 (P217) and a threonine at position 221 (T221) in pVP2, both of which are associated with a low virulence phenotype. We therefore suggest the lower virulence of IPNV may have resulted in reduced rates of virus replication and hence lower rates of evolutionary change. The data generated here will be of importance in understanding the factors that shape the evolution of Aquabirnaviruses in nature.

Evaluation of the efficacy of intervention measures and vaccination for the control of LPAI epidemics in Verona province (Veneto, Italy).

Meat-type turkey farms in Verona province (Veneto, Italy) have been affected by three low-pathogenicity avian influenza (LPAI) epidemics between 2000 and 2004. Control measures implemented ranged from stamping out to controlled marketing in conjunction with restocking bans and movement restriction on live poultry, vehicles, and personnel. These measures were complemented with two emergency vaccination programs (2000-01, 2002-03) started after the beginning of the epidemics, while 2004 outbreaks occurred in vaccinated farms. The three epidemics differed in the number of outbreaks, duration, and economic impact. The aim of the investigation was to estimate the risk of infection and the effect of vaccination on the LPAI epidemics affecting turkey farms in Verona province. Farm probability to avoid infection (Ps) was calculated by Kaplan-Meier for each epidemic. The vaccination effect was evaluated for the 2000-01 and 2002-03 epidemics considering different risk before or after the emergency vaccination. The epidemics and vaccination entered as predictors in a Cox regression model and hazard ratios (HR) were calculated. Ps values at the end of the epidemics were as follows: 2000-01 = 0.66, 2002-03 = 0.51, and 2004 = 0.91. Vaccination reduced dramatically the risk of infection. The measures implemented had different effects on the three epidemics. The lower probability of being infected during the 2004 epidemic was most likely related to the protection level of the vaccinated farms acquired before the beginning of the epidemic, which was also responsible for the reduced spread of infection.

Intervention strategies for low-pathogenic avian influenza control in Italy.

Italian poultry production was affected by several outbreaks of low-pathogenicity avian influenza (LPAI) between 2000 and 2005. Intervention measures (IM), such as stamping out of infected and suspected farms, controlled marketing, restocking bans, movement restriction, and emergency vaccination, were put into force in the most affected areas of Lombardia and Veneto regions. These two regions also showed differences in terms of measures applied and timeliness of application. In this study we describe the epidemics and discuss the effectiveness of the IM put into effect. The regional surveillance systems provided the data on the epidemics and the IM description. The IM effectiveness was compared between the different epidemics and the Lombardia and Veneto regions, considering the number of farms involved, the duration of the epidemics, and the extension of the area affected. With regard to the IM applied, reductions in the number of outbreaks (from 388 in 2002-03 to 15 in 2005), the duration of the outbreaks (from more than 1 yr to approximately 1 mo), and the spatial extension of the outbreaks (from 89 to 8 municipalities involved) were observed. The emergency vaccination, depopulation, and pre-emptive slaughtering reduced significantly the spread of the epidemic. Comparing the dynamics of the epidemics, more effective results were observed in the Veneto region, where the IM were applied to a greater extent. Emergency vaccination and depopulation were effective in the eradication of the disease during an epidemic, but vaccination and farm density reduction showed the most effective results in controlling the spread of LPAI.

First report of a fish kill episode caused by pyrethroids in Italian freshwater.

INTRODUCTION: Fish kills are events of strong emotional impact on the population because of the frequent suspicion that they can be the result of serious pollution accidents. As a matter of fact, they are often due to natural occurrences, such as low levels of dissolved oxygen in the water, but in many cases the causes remain unknown. Fish are particularly sensitive to pesticides and pyrethroids are reported to be the most ecotoxicologically active in the aquatic environment. Nevertheless, the reported cases of massive wild fish mortalities due to these toxicants are very few. This paper describes a fish kill episode occurred in the Padua Province (Veneto Region - North Eastern Italy) which involved several fish species and for which it was possible to identify the cause in the presence of pyrethroids in the water. CASE PRESENTATION: When a whitish liquid coming from the rainwater drain of an industrial area was seen to be spilling into a drainage channel, a fish massive mortality was noticed and investigated. The collected water samples showed the presence of relevant concentrations of cypermethrin, permethrin, deltamethrin and tetramethrin. Analyses on the fish tissues revealed the presence of cypermethrin and permethrin at a concentration range of 476-2834µg/kg and 346-2826µg/kg on a lipid basis, respectively. DISCUSSION: According to the results of the performed analyses, we can reasonably state that the described episode had been caused by the exposure of biota to high concentrations of pyrethroids. The present case report significantly contributes to the limited literature available on pesticides-related fish kills. Moreover, it highlights the importance of sharing protocols for fish kill management at a national level, as this would help to better define the roles of the different institutions involved and to improve the investigation and the reporting of these events.

Epidemiology of animal poisoning: An overview on the features and spatio-temporal distribution of the phenomenon in the north-eastern Italian regions.

In the present paper we analyze and discuss about the records referring to animal poisonings and poisoned baits cases covering the period between 2007 and 2013 and submitted for diagnostic investigations to the Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), which is the public veterinary health institute competent for the north eastern Italian regions. All data were gathered by a passive surveillance system based on voluntary reporting, which became mandatory in 2009 after a decree of the Italian Ministry of Health had come into force. This prohibited the use and detention of poisoned baits and ordered to selected institutions and professionals to carry out standardized surveys to assess suspect and/or confirmed reported cases; all the necessary anatomopathological and toxicological investigations to confirm the reported cases were then performed for free by public veterinary health institutes whenever a veterinarian diagnosis or clinical suspicion were provided. Totally, 1831 suspected animals poisoning and 698 cases of supposed poisoned baits recovery episodes were registered. 642/1831 (35.1%) animal poisoning cases were confirmed and the presence of toxic agents was verified in 292/698 baits (41.8%). The most severely affected territories were the ones with the highest level of urbanization and those most densely populated in the study area. Dogs and cats seemed to be greatly affected by poisoning cases and a characteristic seasonal trend was noticed, with an increase of episodes in late Winter/early Spring and in Autumn. Carbamate insecticides resulted to be the main cause for animal poisoning, while anticoagulants rodenticides played a primary role among toxicants found in poisoned baits. The presented results emphasize that malicious animal poisoning is a widespread problem in north-eastern Italy. The still relevant number of reported poisoning events caused by some banned pesticides poses the problem of identifying where these substances come from and brings to light the popular knowledge about the high toxicity of these compounds. Moreover, the noticeable increase of the number of episodes registered in 2009 pointed out how the above mentioned decree may have contributed to reveal a number of hidden cases which had not been investigated before, probably due to economic reasons related to the costs of toxicological analyses.

Molecular Evolution and Phylogeography of Co-circulating IHNV and VHSV in Italy.

Infectious haematopoietic necrosis virus (IHNV) and viral haemorrhagic septicaemia virus (VHSV) are the most important viral pathogens impacting rainbow trout farming. These viruses are persistent in Italy, where they are responsible for severe disease outbreaks (epizootics) that affect the profitability of the trout industry. Despite the importance of IHNV and VHSV, little is known about their evolution at a local scale, although this is likely to be important for virus eradication and control. To address this issue we performed a detailed molecular evolutionary and epidemiological analysis of IHNV and VHSV in trout farms from northern Italy. Full-length glycoprotein gene sequences of a selection of VHSV (n = 108) and IHNV (n = 89) strains were obtained. This revealed that Italian VHSV strains belong to sublineages Ia1 and Ia2 of genotype Ia and are distributed into 7 genetic clusters. In contrast, all Italian IHNV isolates fell within genogroup E, for which only a single genetic cluster was identified. More striking was that IHNV has evolved more rapidly than VHSV (mean rates of 11 and 7.3 × 10(-4) nucleotide substitutions per site, per year, respectively), indicating that these viruses exhibit fundamentally different evolutionary dynamics. The time to the most recent common ancestor of both IHNV and VHSV was consistent with the first reports of these pathogens in Italy. By combining sequence data with epidemiological information it was possible to identify different patterns of virus spread among trout farms, in which adjacent facilities can be infected by either genetically similar or different viruses, and farms located in different water catchments can be infected by identical strains. Overall, these findings highlight the importance of combining molecular and epidemiological information to identify the determinants of IHN and VHS spread, and to provide data that is central to future surveillance strategies and possibly control.

Possible influence of natural events on heavy metals exposure from shellfish consumption: a case study in the north-East of Italy.

The objective of this study was the estimation of the exposure over time to heavy metals (cadmium, mercury, and lead) due to shellfish consumption in the Veneto Region, Italy. Shellfish consumption was investigated by a food frequency consumption survey. Altogether, 1949 households, stratified into the five most populated areas of the Veneto Region, were involved in the study. Exposure estimation to heavy metals was carried out taking into account the level of metal measured in samples of Manila clams (Ruditapes philippinarum) and grooved carpet shell (Ruditapes decussatus), collected in the frame of the monitoring activities of mollusk production areas of Veneto Region, between January 2007 and December 2012. A general high contribution of the considered shellfish to the Tolerable Weekly Intake was noticed in the case of cadmium, especially in 2011, when a considerable increase in cadmium intake was estimated. This was probably due to a heavy rainfall event that triggered catastrophic flooding with high impact on shellfish capture areas in November 2010. The results strongly emphasize the importance of dealing with food safety in a holistic way, taking into account the potential impact of extraordinary natural events on food chain contamination, in order to identify food hazards at an early stage, before developing into a real risk for consumers.

Model for ranking freshwater fish farms according to their risk of infection and illustration for viral haemorrhagic septicaemia.

We developed a model to calculate a quantitative risk score for individual aquaculture sites. The score indicates the risk of the site being infected with a specific fish pathogen (viral haemorrhagic septicaemia virus (VHSV); infectious haematopoietic necrosis virus, Koi herpes virus), and is intended to be used for risk ranking sites to support surveillance for demonstration of zone or member state freedom from these pathogens. The inputs to the model include a range of quantitative and qualitative estimates of risk factors organised into five risk themes (1) Live fish and egg movements; (2) Exposure via water; (3) On-site processing; (4) Short-distance mechanical transmission; (5) Distance-independent mechanical transmission. The calculated risk score for an individual aquaculture site is a value between zero and one and is intended to indicate the risk of a site relative to the risk of other sites (thereby allowing ranking). The model was applied to evaluate 76 rainbow trout farms in 3 countries (42 from England, 32 from Italy and 2 from Switzerland) with the aim to establish their risk of being infected with VHSV. Risk scores for farms in England and Italy showed great variation, clearly enabling ranking. Scores ranged from 0.002 to 0.254 (mean score 0.080) in England and 0.011 to 0.778 (mean of 0.130) for Italy, reflecting the diversity of infection status of farms in these countries. Requirements for broader application of the model are discussed. Cost efficient farm data collection is important to realise the benefits from a risk-based approach.

A distinct CDV genotype causing a major epidemic in Alpine wildlife.

Canine distemper virus (CDV) infection represents an important conservation threat to many carnivore species and has contributed to the population decline of several wild terrestrial and aquatic mammalian species. Since 2006, the Alpine region of North-Eastern (NE) Italy has been experiencing a severe and widespread outbreak of CDV affecting the wild carnivore population. In this study we performed an extensive phylogenetic and molecular evolutionary analysis of CDV identified during the recent wildlife epidemic in the Alpine region. Our analysis yielded data on the evolutionary dynamics of the Alpine wildlife CDV epidemic and revealed the emergence and spread of a single genetic cluster of CDV. The wide distribution of the novel cluster combined with the identification of a specific amino acid mutation, which is believed to increase the ability of the virus to replicate in a wider host range, raises concerns over the possible implications of the spread of this virus on the conservation of endangered wildlife species.