[Earthquake in Abruzzo, public health interventions. Preliminary report]

On 6th April 2009, at 3.32 AM, there was in L'Aquila and in some neighbouring villages, after an earthquake swarm last some months, an earthquake of M(L) = 5.8 (Richter magnitude scale) on depth of 8.8 km. The event was sensed in a very broad area, till in Rome and Ancon. The operative committee of the Civil Protection Department immediately gathered and a first operating group was despatched in the epicentre; the voluntary association of civil protection were in a pre-alarm situation and then were activated. This work want describe all the activities from 6th April 2009 till 31th August 2009, giving too a synthesis of the normative lines in case of catastrophic events typology C, otherwise all that events impossible to manage without national intervention.

Serological evidence of USUTU virus occurrence in north-eastern Italy

In the recent years, USUTU virus (USUV), a flavivirus of the Japanese encephalitis virus complex, has been reported in Central Europe. As part of a systematic surveillance programme to monitor possible entrance and/or circulation of vector-borne viruses, since 2001, sentinel-chicken flocks were placed throughout the Italian territory nearby areas considered at risk of virus introduction. They have been periodically checked for the presence of antibodies against flaviviruses by indirect ELISA, plaque reduction neutralization test for USUTU, West Nile and tick-borne encephalitis viruses. In July 2007, a sentinel chicken in a flock of 20 animals located within the Ravenna province seroconverted to USUV reaching neutralizing titres up to 1:5120. A second chicken seroconverted to the same virus 2 months later. Although no virus was rescued from these animals and from wild or farm birds sampled in the area, these results still provided evidence of the circulation of USUV in north-eastern Italy.

Clinical, humoral and IFN g responses of cattle to infection with Mycoplasma mycoides var. mycoides small colony and attempts to condition the pathogenesis of the infection

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides var. mycoides small colony (MmmSC), is one of the most important diseases of cattle in Africa. The role of innate or acquired cell mediated and humoral immunity in conferring protection against MmmSC infection has not yet been elucidated. On the other hand, the pathological lesions caused by the aetiological agent have been considered indicative of an immunopathological process. In this study ten naïve cattle were exposed to in-contact infection with animals infected by intubation with a strain of MmmSC. Clinical signs, antibody response, IFNg release and pathological changes at necropsy were analysed and compared with the events following in-contact infection of an equal number of animals kept under daily treatment with cyclosporine for the entire observation period of 84 days. Cyclosporine is a suppressor of the immune response related to the T-cell system. Under the conditions of the experiment, cyclosporine appeared to condition the pathogenesis of CBPP by delaying the events that follow infection, bringing further support to the possibility that the immune response may have an impact on the disease outcome.

The concept of compartmentalisation

The rationale for establishing trade 'regions' and 'zones' is based on principles of epidemiological science and risk analysis that assess and manage animal disease risks so that the safety of trade can be ensured. However, the boundaries of geographical regions and zones may readily be breached through numerous epidemiological pathways. The concept of a 'compartment' extends the application of a 'risk boundary' beyond that of a geographical interface and considers all epidemiological factors that can contribute to the creation of an effective boundary. The fundamental requirement for application of either concept (regions/zones or compartments) is that the population considered for trade is maintained within management or geographical boundaries which allow clear epidemiological differentiation to be made between those animals and surrounding populations of higher risk. Seven factors are presented that an exporting country might use to guide the identification and documentation of a compartment. Additionally, the steps that would be undertaken to implement trade based on the compartmentalisation concept are discussed.

Investigating on a foodborne outbreak: analysis of the critical points

The Authors describe an epidemiological survey performed after a cluster of cases of foodborne infection involving several participants at a wedding reception. The aim was to identify the food, the responsible pathogen and any shortcomings in the coordination between the various services and the territorial operating units involved in the outbreak investigation. The investigation involved 149 participants; fifty seven persons (38.3%) had a foodborne illness. The only food item that remained associated with illness after multiple regression analysis was the ricotta cheese (RR 3.58, I.C. 1.,72-7.48 ). The finding of B. cereus in samples of ricotta cheese collected at the dairy food supplier indicate its responsibility for the outbreak but diagnostic certainty could not be achieved as no leftovers were available. Thus, shortcomings in this epidemiological investigation are constituted by: delayed notification, which prevented the acquisition of food samples, lack of a reference laboratory and lack of a specific diagnostic protocols, which prevented the microbiological research for the rapid identification of new pathogens incriminated in foodborne diseases. Finally, environmental and sanitary inspections showed deficiencies in the hygienic measures of food storage, particularly regarding refrigeration and in the HACCP plan that was not properly implemented.

An indirect ELISA for the detection of antibody in milk from sheep experimentally infected with Brucella melitensis biovar 3

An indirect ELISA was evaluated for the detection of Brucella antibodies in milk (m-ELISA) from sheep experimentally infected with B. melitensis biovar 3. At the end of the second reproductive cycle (13 months post infection), the milk of 22 lactating sheep was tested using the m-ELISA. Sera from the same sheep were also tested for Brucella antibodies using the Rose Bengal test (RBT) and the complement fixation test (CFT). The first serum sampling after parturition showed 100% sensitivity in both the RBT and the CFT (confidence interval [CI] 94-100%), but in subsequent samplings the sensitivity of the RBT decreased to 73% (CI 55-85%). Similarly, the sensitivity of the CFT decreased two months after the first sampling, when respective sensitivities of 95% (CI 81-98%) and 81% (CI 61-93%) were recorded for the final two samplings. The sensitivity of the m-ELISA decreased initially (68% on the third sampling, CI 50-81%), but then increased to 95% (CI 81-98%) for the final sampling. When disease prevalence in a flock is below 5%, the estimated probability of not detecting an infected flock through m-ELISA bulk milk testing is over 25%. Under field conditions in Italy (average sheep flock size of 70), the probability that the infection will not be detected is over 25% when four (or less) infected milking sheep are present in the flock. The results show that the m-ELISA is not a reliable screening test for bulk milk samples when the prevalence of brucellosis in a sheep flock is low.

Human exposure to dioxins through diet in Italy

We have measured the content of polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans (together defined as "dioxins") in 269 samples of food of animal origin collected through the regional veterinary services, covering the national territory. Quantification of the dioxins was accomplished by isotope dilution method, and toxic equivalents (TEQ) were calculated. The average daily food intake was obtained from two main sources: national data collected by the National Institute of Nutrition, and data from an ongoing cohort study on diet and cancer including 40,000 Italian subjects. The mean value of dioxins measured in food of animal origin was 0.144 +/- 0.266 pg-TEQ/g (range: 0.003-1.655 pg-TEQ/g). Fish was the item with the highest content. The estimated intake of dioxins with main food items of animal origin is presented. The major contribution to dioxins intake with food comes from cow milk and fish consumption. These results are in agreement with what observed in studies conducted in other countries, such as Germany, Finland, Japan, Spain, and are below the limits set by the European legislation.

The Persistence of Brucella melitensis in Experimentally Infected Ewes Through Three Reproductive Cycles

The authors studied the persistence of infection in 46 ewes experimentally infected with Brucella melitensis biovar 3 and monitored through three subsequent reproductive cycles. The entire experimental period lasted for 151 weeks. Infection of ewes and elimination of Brucella in milk, or its presence in vaginal discharges, persisted throughout the duration of the trial, as demonstrated by recurrent elimination of Brucella in milk and vaginal discharges. Brucella melitensis was recovered from the tissues of one ewe killed at the end of the trial. The strain was recovered from vaginal swabs and milk following parturition in the third reproductive cycle from an ewe that had aborted in the first cycle but was not pregnant in the second cycle. From a public health point of view, the periodical recovery of Brucella from the milk during the entire trial period illustrated that brucellosis in sheep remains a continuous occupational risk and a significant public health problem for consumers of fresh milk and milk products. That risk may persist for at least 3 years following the initial infection of the flock. Lamb antibody titres became negative in all lambs within 5 months after birth. This suggested that serological tests on lambs may have no practical diagnostic significance if performed during the first 5 months of life. Nevertheless, the birth of three infected lambs suggested that the phenomenon of latent carrier state may represent another way for B. melitensis to persist in a flock.

Use of the complement fixation and brucellin skin tests to identify cattle vaccinated with Brucella abortus strain RB51

In the European Union, RB51 vaccine can be used only under strictly controlled conditions for the immunisation of cattle at risk of infection with Brucella abortus. A test is therefore necessary to distinguish vaccinated from unvaccinated animals. The complement fixation test with RB51 antigen (RB51-CFT), dot-blot and gamma-interferon used to identify vaccinated animals have been described, but sensitivity of the tests has been poor and positivity transient after calfhood vaccination. To avail of a rapid and accurate diagnostic tool, the authors produced, controlled and evaluated an experimental brucellin prepared from strain RB51 (RB51 brucellin). The potency of this brucellin was evaluated in guinea-pigs sensitised with RB51 and compared with a commercially available brucellin. Both allergens produced similar biological activity in guinea-pigs. The RB51 brucellin skin test was performed in 10 cattle 414 days after calfhood vaccination with RB51 when they were negative to the RB51-CFT. The skin test revealed 60% sensitivity (with a confidence interval of 95%, CI 30.8%-83.3%) and 100% specificity (CI 60.7%-100%). These findings limit the use of the skin test only for screening to detect RB51 vaccinated herds, not individual animals. Nevertheless, following intradermal inoculation of RB51 brucellin, a transient antibody increase to the RB51-CFT was observed, from day 9 to day 20 post inoculation with RB51 brucellin. This transient antibody increase, when evaluated in parallel with the RB51 brucellin skin test results, enables detection of individual vaccinated animals (sensitivity 100%; CI 76.2%-100%).

Bluetongue virus isolations from midges belonging to the Obsoletus complex (Culicoides, Diptera: Ceratopogonidae) in Italy

Between July and September 2002 there were outbreaks of bluetongue on three sheep holdings in the communities of San Gregorio Magno (Salerno, Campania), Laviano (Salerno, Campania) and Carpino (Foggia, Puglia), and the involvement of bluetongue virus (btv) was confirmed serologically and virologically. The mortality rate was at least 11 per cent and involved btv serotype 2 (btv-2) and serotype 9 (btv-9). These holdings were also surveyed for the Culicoides (Diptera: Ceratopogonidae) vectors; approximately 10,000 midges belonging to 15 species were captured, but they did not include a single specimen of the classical Afro-Asiatic bluetongue vector, Culicoides imicola. Species belonging to the Obsoletus complex dominated the light-trap collections, and Culicoides obsoletus Meigen, Culicoides scoticus Downes and Kettle and Culicoides dewulfi Goetghebuer constituted 90 per cent of all the Culicoides species captured. Fifty-six pools of the Obsoletus complex (excluding C dewulfi), each containing 100 individual midges and containing only parous and gravid females, were assayed for virus. btv-2 was isolated from three pools from San Gregorio Magno and Carpino, and btv-9 was isolated from one pool from Laviano. These results indicate that a species other than C imicola is involved in the current re-emergence of bluetongue in the Mediterranean Basin, but whether it is C obsoletus sensu stricto or C scoticus, or both, is uncertain.

Global perspectives on animal welfare: Europe

Effective implementation and enforcement of legislation is essential to ensure animal welfare. In the World Organisation for Animal Health (OIE) European Region the well-established body of national and European Union laws in existence is growing continuously. The growth is due to various factors, such as new technology in animal farming and experimentation, exploitation of wildlife, new understanding of animal needs, and increasing public awareness and concern. The latter, in particular, determines the need for new animal welfare legislation to regulate and discipline the 'use' of animals for different purposes, such as food production, companionship, work and leisure. This paper intends to provide an overview of the more relevant activities carried out by the Council of Europe and the European Union in the field of animal welfare. The authors identify eLearning as a tool to harmonise the interpretation and the implementation of animal welfare legislation.

Adverse events following hexavalent vaccine (Hexavac): Knowledge and informative sources

This report describes adverse events to vaccination in eight children in southern Italy. These children were seen in the Emergency Room of a hospital of the Local Health Unit SA2 (Salerno, Italy) after administration of hexavalent vaccine (Hexavac, Aventis-Pasteur). On analysing available documentation on the adverse reactions (label instructions, Medline), the Authors concluded the cases reported were to be expected. However, the label instructions did not give sufficient information on the type and frequency of adverse reactions. If the label instructions are to furnish complete, operative information for the vaccination units, the Italian instructions for the Hexavac vaccine can be considered inadequate.

The Use of Homologous Antigen in the Serological Diagnosis of Brucellosis Caused by Brucella melitensis

In the European Union the serological diagnosis of brucellosis caused by Brucella melitensis is performed using the heterologous antigen of B. abortus S99. The possible higher sensitivity or ability of an early detection of antibodies by a homologous antigen may prove very useful in the final phases of an eradication programme. Results obtained in sheep experimentally infected by B. melitensis biovar 3 were compared using B. abortus S99, B. melitensis M1, M2 and M3 antigens in the Rose Bengal plate test (RBPT), the complement fixation test (CFT) and an enzyme-linked immunosorbent assay (ELISA) test. Forty-six sheep from an officially brucellosis-free flock were experimentally infected intraconjunctivally with B. melitensis biovar 3. Prior to infection, all animals were tested first against Brucella antibodies, weekly for 2 months post-infection (PI) and then monthly for a further 7 months. All sera were tested against the antigens listed above using RBPT, CFT and ELISA. Using a Bayesian approach, test sensitivities were estimated and compared. Their ability for the early detection of antibodies was evaluated through a regression model based on a logit response model, using the number of days PI as the independent variable and the logit of the fraction of positive animals as the dependent variable. No significant differences were detected among the various antigens used, either in terms of sensitivity or in terms of antibody kinetics; however, the CFT was significantly less sensitive than the RBPT and ELISA and it also showed a lower rate of increase of percentage positive animals (beta-coefficient of regression analysis).

VP2 gene sequence analysis of some isolates of bluetongue virus recovered in the Mediterranean Basin during the 1998-2002 outbreak

Since 1998, five serotypes of bluetongue virus (BTV), BTV-1, BTV-2, BTV-4, BTV-9 and BTV-16, have been reported in countries surrounding the Mediterranean Basin. Preliminary data on the sequencing analysis of the VP2-genes of BTV isolates recovered during the 1998-2002 epizootic of BT in Italy, Greece and Israel were studied. The VP2-genes of the Italian BTV-2 and BTV-9, Greek BTV-4 and BTV-9, Israeli BTV-4 and BTV-16 and South African BTV-2, BTV-4, BTV-9 and BTV-16, together with those of their corresponding South African serotype reference and vaccine strains, were cloned and the sequences of their terminal ends determined. These sequences, as well as those of all BTV VP2-gene sequences currently available on GenBank, were used to compile a phylogenetic tree to determine the probable geographic origins of the BTV incursions into Europe. The Italian isolates included in this study were from different regions, animal hosts and years (2000-2002). The results demonstrated that sequencing of the terminal end of the VP2-gene of BTV can be used for topotyping. According to the phylogenetic analysis, the Italian BTV-2 and BTV-9 isolates were stable across all species, irrespective of geographic origin and year of isolation. The sequencing data of the Italian isolates were identical to those of a BTV-2 isolate from Corsica. There was 97% homology between the Italian and Corsican BTV-2 isolates and the BTV-2 vaccine and reference isolates from South Africa. Italian BTV-9 isolates were also identical to the Greek BTV-9 isolates (99% homology). Surprisingly these BTV-9 isolates had only 67% homology with the reference BTV-9 isolate from South Africa. Conversely, BTV-9 field isolates from Australia and elsewhere in Europe had 89% homology with the Italian isolate at the nucleic acid level. Greek and Israeli BTV-4 isolates were almost identical (98% homology) and shared a 90% homology with the BTV-4 South African reference and vaccine strains. Israeli BTV-16 and South African BTV-16 reference strains were also similar. From these results, it may be concluded that Italian and Corsican BTV-2, Israeli and Greek BTV-4, and South African and Israeli BTV-16 had a common origin. The Greek BTV-9 isolate had more than 99% homology with the isolates from Italy, indicating these isolates to have had a common origin. The European BTV-9 isolates, grouped as 'eastern isolates', were more similar to the Australian isolates than to the South African reference strains.

Effects of vaccination against bluetongue on milk production and quality in cattle vaccinated with live-attenuated monovalent type 2 vaccine

The first epidemic of bluetongue (BT) to affect the three regions of Sardinia, Sicily and Calabria (Italy) in 2000 induced high economic losses caused by the disease itself and by the cessation of ruminant movements both within, and out of, the infected areas. In order to reduce virus circulation, and to create a resistant livestock population, the Italian Ministry of Health ruled, in May 2001, that all sheep, cattle, goats and water buffalo, in infected and in neighbouring regions, be vaccinated. The live-attenuated BTV-2 monovalent vaccine produced by Onderstepoort Biological Products in South Africa was to be used. Accordingly, in 2002, 98.6% of the sheep and goats, and 88.1% of the cattle, on Sardinia were vaccinated. Included was the vaccination of >70% of the cattle in the province of Oristano where >18,000 dairy cows in >220 herds are concentrated in the municipality of Arborea (Oristano) and which account for 65-70% of the milk produced in Sardinia. Using data collected at the centralised dairy co-operative since 1999 the quantity and quality of milk produced before vaccination against bluetongue was compared to that produced after vaccination. The following variables were analysed: average milk production/cow/month, monthly average fat content (%), monthly average protein content (%), average monthly somatic cell count and average monthly platelet count. The findings indicate that vaccination against BTV-2 in Sardinian dairy cattle did not impact negatively upon milk quantity nor milk quality.

Molecular differentiation of field and vaccine strains of bluetongue virus serotype 2 using the real-time polymerase chain reaction and fluorescene resonance energy transfer hybridisation probes

As a consequence of the recent outbreaks of bluetongue (BT) disease amongst sheep in the Mediterranean Basin, and following the subsequent vaccination campaign to control further spread of the disease and its long-term maintenance, it has become most important to develop rapid and sensitive methods that can reliably differentiate between field and vaccine strains of the causative virus. The authors describe a new method to differentiate bluetongue virus serotype 2 (BTV-2) field and vaccine strains, using the VP2 gene sequence differences between the South African vaccine and the Italian field wild-type strains. The method is based on the principle that the melting temperature of a DNA duplex gives information on the sequence, which enables the identification of even single-base alterations in the amplicon. The real-time polymerase chain reaction the generation of melting curves and fluorescence detection were all performed using the light cycler system (Roche). Primers and probes were designed using VP2 gene sequences. After RT-PCR, the melting curves analysis, derived by the fluorescence resonance energy transfer (FRET) real-time PCR, was performed using the light cycler data analysis program (Roche). To assess the diagnostic value of the method, a BTV-2 vaccine strain (Onderstepoort Biological Products, South Africa) was first compared against a field strain of BTV-2 (isolated during an outbreak in 2000 in Sardinia). The ability of the method to reliably identify all the BTV-2 strains was tested using an array of eleven BTV-2 field strains isolated during outbreaks in various Italian regions between 2000 and 2002 and other serotypes (BTV-1, BTV-4, BTV-9 and BTV-16) that had been isolated during recent outbreaks of BT in the Mediterranean Basin. The method was clearly able to differentiate BTV-2 strains of vaccine virus from all wild-type strains of the same serotype tested. The resultant melting curves distinctly reveal the two strains to have differing peak values of 47.8 degrees C-/+0.6 degrees C and 60.5 degrees C-/+0.6 degrees C, respectively.

Bluetongue laboratory diagnosis: a ring test to evaluate serological results using a competitive ELISA kit

The occurrence of bluetongue (BT) in Italy prompted an increase in disease surveillance. Thus a competitive enzyme-linked immunosorbent assay (c-ELISA) to detect immunoglobulins to BT virus (BTV) was developed and distributed amongst 27 laboratories comprising the Italian veterinary diagnostic laboratories network to screen field sera. This ring test enabled comparison of the results and the evaluation of the reproducibility of the method. The c-ELISA developed by the National Reference Centre for Exotic Diseases (c-ELISA-IZSA&M) was compared also against a commercially available c-ELISA. In addition, results obtained by the Centre of Athens Veterinary Institutions are presented.

Risk analysis on the introduction into free territories of vaccinated animals from restricted zones

Between August 2000 and 14 May 2001 (defined as the 2000-2001 epidemic) bluetongue (BT) was reported in three regions of Italy: Sardinia, Sicily and Calabria. During the 2001-2002 epidemic (between 15 May and 14 April 2002), the disease spread to five additional regions (Puglia, Basilicata, Campania, Latium and Tuscany). In May 2001 the Italian Ministry of Health decided to restrict animal movements and to vaccinate all susceptible domestic ruminant populations in infected and in neighbouring regions. This action was taken to reduce virus circulation with the aim of decreasing direct losses in sheep and goats due to the disease, and indirect losses in cattle populations due to movement restrictions. Furthermore, the Italian authorities implemented an epidemiological surveillance system to monitor the spread of the virus and to provide more effective movement controls. In 2002, the vaccination campaign reached the set goal of vaccinating more than 80% of susceptible domestic ruminants in Abruzzo, Sardinia and Tuscany. The vaccination campaign successfully reduced clinical disease in Sardinia and Tuscany. Before the advent of BT, cattle had always been moved from Sardinia, Sicily and the southern regions for fattening and slaughter in northern Italy. During the tracing of animals that had left infected areas in 2000 it was found that 10 957 cattle had been exported from Sardinia between June and August 2000 and were scattered throughout continental Italy. In addition, most cows selected for culling from the southern regions and the islands were sent to northern Italy for slaughter. However, since August 2000 the animal trade between infected and free areas has come to a complete standstill. Sardinia, in particular, due to the climatic and epidemiological conditions (vectors survive almost throughout the year), was no longer able to export any ruminants to the mainland. Long-term standstill therefore led to heavy economic losses and had even greater social consequences. As farmers are not compensated, it is impossible to enforce these restrictions indefinitely. The Italian authorities and the European Commission thus decided to adopt a policy of risk management allowing some animal movement. This paper presents an analysis that assesses the risk associated with animal movement from restricted areas, according to the level of immunity of susceptible animal populations due to vaccination in the same areas. Results of the analysis indicate that when more than 80% of the susceptible population in the territory of origin is vaccinated, the risk associated with the movement of vaccinated animals to free areas appears acceptable and can be mitigated further by adopting ancillary control measures.

Monovalent modified-live vaccine against bluetongue virus serotype 2: immunity studies in cows

A challenge study was conducted to determine the efficacy of vaccination against bluetongue (BT) virus (BTV) serotype 2 in protecting cattle against infection. A group of 30 cows, vaccinated seven months previously with monovalent BTV-2 modified-live vaccine produced by Onderstepoort Biological Products in South Africa, were challenged subcutaneously with 2x 10(5.8)TCID50/ml of BTV-2 field isolate. All cattle originated from the same population in the Sardinian province of Oristano. Eight unvaccinated calves from a BTV-free herd also participated in this study; four were inoculated with BTV-2 and used as positive controls whilst the remaining four were used as negative controls to confirm that no BTV was circulating locally. Blood samples were taken from all animals three times a week for two months. Serum samples were tested for antibody against BTV using the competitive enzyme-linked immunosorbent assay (c-ELISA) and the virus neutralisation (VN) test. Virus isolation was attempted on the blood samples by intravenous egg inoculation followed by two blind passages in Vero cells. Virus titres following challenge were determined also. Of the 30 cows vaccinated, 29 were positive in the c-ELISA and demonstrated neutralising antibodies. At the time of challenge, 11 cows had no virus neutralising antibody while the remainder had low titres ranging from 1:10 (11 cows) to 1:20 (6 cows); two cows showed titres of 1:40 and 1:80, respectively. None of the cows showed signs of disease after challenge and no BTV was isolated from the blood of the 29 cows that had developed antibodies after vaccination. Commencing on day 9 post challenge, BTV-2 was isolated from the blood of the single cow that had not seroconverted following vaccination and from the blood of the unvaccinated controls. Viraemia lasted until day 21 post challenge. Neither BTV nor antibody was detected in the blood samples taken from the negative control group. These observations indicate that the monovalent BTV-2 modified-live vaccine protects most animals when challenged with field virus seven months post vaccination.

Implementation of a new contingency plan for bluetongue disease in Italy

Since the first appearance of bluetongue (BT) in Italy in late August 2000, the ecology of vectors and the environmental conditions affecting their distribution and survival proved to be the most difficult factors to monitor, and represented a serious challenge to the effectiveness of the National Contingency Plan promulgated in 1991. Moreover, the Italian Ministry of Health considered the national management plan of BT inadequate to prevent further spread of the disease. The authors describe the implementation of a new BT contingency plan, integrating an operations manual and an ad hoc information system, which operated also as a decision-support system both at local and central levels. The plan describes the national capacity for dealing with BT outbreaks, the composition and duties of the National Disease Control Centre and Local Disease Control Centres, the chain of command and the strategies adopted.

Bluetongue vaccination in Europe: the Italian experience

The incursion of bluetongue (BT) into Italy in August 2000 caused heavy economic losses, partly due to the disease itself, but mostly because of disruption caused to the national animal trade structure. To limit direct losses and the circulation of BT virus (BTV), the Italian Ministry of Health ordered, on 11 May 2001, the vaccination of all susceptible domestic ruminant species (i.e. sheep, goats, cattle and water buffalo) in both infected and surrounding areas. The vaccination strategy was based on a risk assessment that suggested it would prevent direct economic losses and significantly reduce virus circulation. Vaccination of the target animal populations commenced in January 2002, prior to the epidemic peak of BT that began in July 2002. The proportion of vaccinated animals differed between the various regions and the varying levels of vaccination of these populations had clear consequences on the occurrence of clinical disease and the spread of BTV infection. In those regions where more than 80% of the target population were properly vaccinated, the disease disappeared almost completely and virus circulation was reduced significantly. The importance of this reduced circulation of BTV (i.e. infection did not spread from affected areas) was immediately obvious in areas affected by the less virulent BTV serotype 9 where, despite the virtual absence of clinical disease, trade of animals to other areas was prohibited. The areas affected by the highly virulent BTV-2 also benefited from vaccination because it eliminated clinical disease while animal movements were prohibited. The main consequence of the reduction of virus circulation after vaccination, as documented by serological surveillance, was a significantly reduced expansion of the areas that were subjected to animal movement restrictions. Subsequently, analysis of surveillance data, coupled with specific risk assessments, led to a progressive relaxation of movement restrictions even in areas where the infection was still present but where most of the population had been adequately vaccinated. The effectiveness of the strategy used in Italy (i.e. vaccination of all domestic ruminants) was reinforced by extensive experimental and field studies. The aim of these studies was to: a) evaluate levels of individual and herd immunity and resistance to challenge conferred by vaccination, and b) quantify the frequency and severity of the adverse effects of vaccination on domestic ruminants. Ongoing research has focused on the ability of vaccination to suppress or reduce viraemia in ruminants following natural challenge by a virulent BTV strain. These studies address the issue of safety of the trade and movement of vaccinated animals that originate from areas in which BTV continues to circulate and could justify the reversal in current policy that restricts the international trade of animals vaccinated against BT.

Health management of large transhumant animal populations and risk of bluetongue spread to disease-free areas

Transhumance, or seasonal grazing, in central Italy is a husbandry practice that is over two thousand years old. It involves the seasonal movement of sheep, goats and cattle from the southern lowlands of mainly the Puglia and Lazio regions, to summer pastures in the mountains of Abruzzo and Molise. Bluetongue (BT) made its appearance in Italy in 2000. In the early summer of 2001, disease was present in three regions: Sardinia, Sicily and Calabria. Neither an effective surveillance system nor a vaccination campaign had been implemented. Movement of ruminants to the disease-free regions of Abruzzo and Molise was therefore banned. The Italian Veterinary Services had to meet the challenge of the movement of ruminants from surveillance to disease-free zones, given the impossibility of stopping transhumance. The General Directorate of Veterinary Public Health, Food and Nutrition of the Ministry of Health developed a plan for both the Puglia and Abruzzo regions based on serological, virological and entomological surveillance. The plan was implemented between May and June 2001 when 7,000 animals moved from the Puglia surveillance zone to the infection-free summer pastures. In the early summer of 2002, eight regions were infected (Sardinia, Sicily, Calabria, Basilicata, Puglia, Campania, Lazio and Tuscany). Simultaneously, a nationwide surveillance system and a vaccination campaign, were implemented in infected regions. In the provinces where vaccination was compulsory, deviation from the animal movement ban was allowed if at least 80% of susceptible stock had been vaccinated. However, this objective was not achieved in the provinces of Rome and Viterbo (Lazio) where a large transhumant population was present and where sporadic virus circulation had been detected. A specific control plan to allow transhumance from Lazio to Abruzzo, Marche and Umbria was designed and implemented to increase the number of animals that could be moved. Between May and June 2002, authorisation was granted to move 28,000 head, whereas prohibition of movement was ordered for 12,000 sheep (belonging to 21 flocks). Regional authorities financed feeding, watering and housing for these animals. Transhumance did not spread infection to disease-free areas either in 2001 or in 2002.

Neutralising antibody response in cattle after vaccination with monovalent modified-live vaccine against bluetongue virus serotype 2

The antibody response following bluetongue (BT) vaccination under both field and experimental conditions, and the duration of colostral antibodies in calves born from vaccinated dams, were evaluated. To this end, 1 005 animals of various breeds and ages were selected at random from 10 herds in the Sardinian province of Oristano. During the first year of the vaccination campaign, the animals selected were vaccinated against BT virus (BTV) serotype 2 between July and August 2002. Blood samples were taken from all animals monthly for three months after vaccination and tested for the presence of BT antibodies using the competitive enzyme-linked immunosorbent assay (c-ELISA) and the virus neutralisation (VN) test. Serological results from field vaccinated animals were compared with those obtained following the vaccination of five animals under experimental conditions. Out of 1,005 animals, 994 (98.1%) developed BT antibody following vaccination whereas antibody was detected in all cows vaccinated under experimental conditions. Both groups showed the highest median titres of 1:160 after two months. To assess the duration of colostral antibodies in calves born from vaccinated dams, the sera of 47 calves were screened using the c-ELISA and VN test. Calves were divided into three age groups: Group A included 22 calves aged 1 to 25 days, Group B 13 calves aged 26 to 39 days and Group C 12 calves aged 40 to 60 days. Antibody was detected in calves in Groups A and B (68.2% and 46.1%, respectively) whereas the calves in Group C were serologically negative.

Efficacy and safety studies on an inactivated vaccine against bluetongue virus serotype 2

An inactivated vaccine was produced from an Italian field isolate of bluetongue virus serotype 2 (BTV-2) with a titre of 10(7.8)TCID50/ml. The virus was purified through a molecular cut cassette membrane, inactivated with beta-propriolactone and emulsified with ISA 206 (Seppic) adjuvant. The vaccine was then tested for sterility, toxicity and safety in laboratory and target animals according to European Pharmacopoeia standards. Immunogenicity was assessed by inoculating subcutaneously 10 sheep and 10 goats each with 2 ml of the vaccine and 10 bovines each with 5 ml of the vaccine. A booster dose was inoculated after 14 days and no side-effects were reported following vaccination. Fourteen days after the booster dose, all vaccinated animals developed virus neutralising (VN) bluetongue (BT) antibody titres that on day 60 post vaccination ranged between 1/20 and 1/1 280. After one year, goats still had high VN antibody titres. Sheep were challenged 138 days after vaccination by subcutaneously inoculating 1 ml of 10(5.6)TCID50/ml of an Italian field isolate of BTV serotype 2; four unvaccinated animals were also inoculated and used as controls. Starting from day 6 post challenge, control animals developed a fever, with temperature ranging from 39.9 degrees C to 40.6 degrees C and lasting 48 h on average. BTV-2 was also isolated from the blood of control animals between days 4 and 20 post challenge. Conversely, neither fever nor viraemia were detected in the vaccinated animals that were challenged. A new trial with a larger number of animals, including all target species, has been planned and is in progress.

Antibody response and antigen-specific gamma-interferon profiles of vaccinated and unvaccinated pregnant sheep experimentally infected with Brucella melitensis

It is well known that the immune response in sheep against Brucella melitensis is subject to individual variation, depending on diverse factors. It bears asking whether these factors (e.g. clinical disease, active infection, state of previous immunity), when affecting a group, can cause variation in the performance of different diagnostic tests. To clarify some of the circumstances in which this immune response can vary, we examine the immune-response profile of sheep protected against the clinical disease by prior vaccination with strain Rev. 1 in comparison with the profile of unprotected females showing the classical brucellosis symptoms. An experimental infection was provoked at midpregnancy under controlled conditions of both non-vaccinated (n=7) and previously Rev.1-vaccinated ewes (n=5). Their immune response was monitored from 7 to 9 weeks before abortion or normal birth to 30 weeks afterwards. Antibody response was assessed by classical tests (Rose Bengal test, complement fixation test (CFT)) in comparison with other diagnostic tests (indirect ELISA (iELISA), competitive ELISA (cELISA), fluorescence polarization assay (FPA), immunocapture test (ICT)). In addition, the cell-mediated immune response was indirectly evaluated by the in vitro antigen-specific release of gamma-interferon. The antibody levels and antigen-specific gamma-IFN profile of the non-vaccinated ewes having the disease and excreting the pathogen was notably high and differed significantly (P<0.05 or P<0.01) from those of vaccinated ewes that neither contracted brucellosis nor excreted the pathogen. In general, all the tests detect the infection in the non-vaccinated ewes with substantial effectiveness. It can be concluded that the high levels of circulating antibodies and of antigen-specific gamma-IFN are related to active Brucella infection. Similarly, the state of protection against the disease, but not necessarily against infection, due to a previous immunization with the Rev. 1 vaccination, appears to be responsible for a low level of detectable immune response. Nevertheless, the design of the study limits conclusions to pregnant ewes and cannot be extrapolated to non-pregnant ewes or rams. Likewise, the study provides no information on animals which are carriers of B. melitensis.

Use of a Montecarlo simulation model for the re-planning of bluetongue surveillance in Italy

Since August 2000, Italy has lost almost 500,000 sheep to the largest incursion of bluetongue (BT) yet to affect Europe. The national BT surveillance system includes serological and entomological programmes. The main objective of the serological programme is the early detection of BT virus (BTV) circulation by periodical testing of more than 30,000 sentinel cattle distributed across Italy. The sentinel network has been in force since October 2001 and since its inception has provided accurate and timely detection of viral circulation. However, the repeated testing of such a large number of animals required significant effort from the Veterinary Services and was costly for farmers. Consequently, a Montecarlo simulation model was developed to simulate different sentinel system scenarios and the results from each were compared. The model was validated using data derived from the serological surveillance activities in Sardinia from October 2001 to December 2002.

Surveillance system of bluetongue in Italy

The authors provide details of the bluetongue surveillance and the Internet-based information systems that were implemented in Italy. The systems were structured with the aim of gathering and spreading information and data to support decision-making, management of control activities and provide an early warning system. Information and data generated by the surveillance system enabled the detailed analysis of bluetongue epidemiology, vector distribution and vector population dynamics. This information and data also allowed the analysis of risk factors associated with vector spread and animal movements, which resulted in and increased the flexibility and the efficiency of the enforcement of control measures.

Bluetongue in Italy: Part I

The eastern focus of the current outbreak of bluetongue (BT) in the Mediterranean Basin commenced in late 1998, infecting Turkey and some of the eastern islands of Greece. In the summer of 1999 it moved to continental Greece and for the first time to Bulgaria. By the late summer of 2000, BT spread progressively through Greece and to the Balkan states. The BT virus (BTV) serotypes involved were BTV-4, BTV-9 and BTV-16. The west-central focus of the outbreak, involving BTV-2, appeared in Tunisia in December 1999 and the following summer also in Algeria. In August 2000, BTV-2 was reported for the first time in Italy (in Sardinia) and soon thereafter in France (Corsica) and in Spain (the Balearic Isles). In the autumn of 2000, a second serotype (BTV-9) emerged in southern peninsular Italy. Eventually this incursion of virus into the central Mediterranean region resulted in the largest epidemic of BT ever to affect Europe. Some features of this epidemic differ significantly from those observed previously, namely: a) its deep penetration northwards (reaching 44 degrees N both in Italy and in the Balkans) b) its persistence across four seasons in various zones of Italy and the Balkans, implying that BT could become endemic over a wide geographic area c) its successful invasion of areas separated from previously infected ones by fairly large distances (Sardinia, Sicily, Calabria, and the Balearic islands). The pattern of the spread of BT across Italy, before the introduction of vaccination, is described. The possible role of climate, soil and insect vectors on the incidence of the disease, and the overwintering of the virus, are discussed. Some hypotheses on the possible origins and modes of introduction of BTV into Italy are postulated.

Bluetongue virus surveillance in a newly infected area

The occurrence of bluetongue virus (BTV) in areas in which intensive animal production is practised and where there is extensive movement of animals may have a substantial impact on both animal trade and husbandry. This situation occurred in Italy after the detection of bluetongue (BT) in August 2000. In such situations, surveillance can be used to delineate with precision those areas in which the virus is circulating and, consequently, to enforce the appropriate animal movement restrictions. Furthermore, surveillance can provide the data required to assess the risk associated with animal movement and trade. A structured surveillance system for the detection of BTV has been in place in Italy since August 2001. The system is based on the periodical testing of unvaccinated sentinel cattle that are uniformly scattered throughout Italy in a grid of 400 km(2) cells. The initial number of sentinel sites and sentinel animals, together with the width of the restricted area generated by the finding of a single seroconversion in a sentinel animal, were based on conservative criteria. Animal movement was restricted in a 20 km radius buffer zone around any positive serological result. This buffer area extends about 1,257 km(2), equivalent to the area of three grid cells. After the commencement of the BT vaccination campaign in Italy, the sentinel surveillance system was the only way in which the effectiveness of vaccination and the incidence of infection in the non-immunised strata of ruminant animals could be estimated. Data collected over two years was used to assess the risks posed by the adoption of less conservative criteria for the delineation of infected areas and by the progressive relaxation of movement restrictions of vaccinated animals. In regard to the delineation of restricted areas, a new approach was tested and validated in the field, based on a Bayesian analysis of the positive and negative results obtained by the testing of sentinel animals from defined regions. For the risks related to animal movement, the surveillance data was used in risk assessment analyses to address the movement of slaughter and breeding animals from vaccinated/infected and surrounding areas to free areas. These risk assessments led to an amendment of the relevant European Union legislation. Finally, a Montecarlo simulation model was developed to simulate different sentinel system scenarios and to decrease the total number of sentinel animals and sites required by the surveillance system. The sentinel surveillance system was complemented by an entomological surveillance system based on the use of a number of permanent blacklight traps run weekly year-round and a number of mobile blacklight traps moved through the grid cells during the summer and autumn of each year. The aim of entomological surveillance was to define the maximum distribution of vectors and their seasonal population dynamics. Furthermore, the permanent trap system provides an early warning of the start of new epidemics. The data from the entomological surveillance system were also analysed to generate probability maps of the presence of the principal BTV vector (Culicoides imicola) and to define the geographical risk of BT on a nationwide basis, and to predict the geographical distribution and the short-term spread of C. imicola in Sardinia, using spatio-temporal data. The detection, since 2001, of BT outbreaks in the absence of C. imicola and the recent identification of BTV in midges of the Obsoletus Complex also stimulated investigations on other vector Culicoides, including C. obsoletus and C. pulicaris.

The isolation of bluetongue virus from field populations of the Obsoletus Complex in central Italy

Between July and September 2002, bluetongue (BT) virus (BTV) serotypes 2 and 9 caused mortalities amongst sheep in the communities of San Gregorio Magno (Salerno, Campania), Laviano (Salerno, Campania) and Carpino (Foggia, Puglia), central Italy. On three of the affected farms, approximately 10,000 specimens of Culicoides were captured, representing fifteen species. Not a single specimen of the classical Afro-Asiatic BT vector, C. imicola Kieffer, was found; species of the Obsoletus Complex dominated the light-trap collections (90%) and included C. obsoletus (Meigen), C. scoticus Downes and Kettle and C. dewulfi Goetghebuer. Fifty-eight pools of the Obsoletus Complex (excluding C. dewulfi), each numbering 100 individuals per pool, and containing only parous and gravid females, were assayed for virus. BTV serotype 2 (BTV-2) was isolated from three pools (San Gregorio and Carpino) and BTV-9 from one (Laviano). These results indicate clearly that a species other than C. imicola is involved in the current re-emergence of BT in the Mediterranean Basin, but whether this is only C. obsoletus sensu stricto, or only C. scoticus, or both together, has yet to be established.

Bluetongue in Italy: Part II

In summer 2000, bluetongue (BT) infection was reported in Italy and caused a widespread epidemic involving a total of ten southern and central regions and is still in progress after three years. From the date of the first case (18 August 2000) to 14 May 2001, when the lowpoint in the first epidemic curve was reached, a total of 310,234 animals in 6,869 flocks of three regions had been involved. From 15 May 2001 to 14 April 2002, when a second epidemic wave swept through central and southern Italy, a total of 323,635 animals in 6,807 flocks in seven regions were involved. During 2000 and 2001 virtually no susceptible ruminants were vaccinated. On 11 May 2001, the Italian Ministry of Health ordered the vaccination of all susceptible domestic ruminant species (i.e. sheep, goats, cattle and water buffalo) in the infected and surrounding areas. The vaccination strategy stemmed from a risk assessment that demonstrated the possibility of such a strategy preventing most of the direct economic losses and decreasing the level of virus circulation. Vaccination of the target populations commenced in January 2002. In July 2002, when the new epidemic peak was reached, the percentage of vaccinated populations varied between the regions with direct consequences on the spread of BT. The relationship between vaccination coverage of the target populations and animal losses due to disease and virus circulation, and as detected by the sentinel surveillance system, was analysed. The effectiveness of the vaccination campaign in limiting virus circulation and consequently indirect losses due to animal movement restrictions was analysed and evaluated. At the end of 2002, a second risk assessment led to the authorization of the movement of vaccinated animals from infected areas (where at least 80% of the susceptible population was vaccinated) directly to slaughter in unvaccinated areas free from infection. This risk assessment also generated new criteria to define zones where animal movement restrictions should be applied. Following the second vaccination campaign (January to May 2003), a third risk assessment was performed and the results from vaccination trials performed in controlled and in field conditions studied. These studies indicated that procedures to move vaccinated breeding animals from zones where infection exists to unvaccinated infection free zones could be contemplated.

Kinetics of the antibody response in ewes experimentally infected with Brucella melitensis biovar 3

The authors evaluated the kinetics of antibody response in 46 ewes coming from officially brucellosis free flocks that were experimentally infected with Brucella melitensis biovar 3, and monitored through three subsequent reproductive cycles. In this study, results of Rose Bengal test (RBT) and complement fixation test (CFT) were considered. Test results of 2nd and 3rd reproductive cycle show a peak in the antibody production at parturition, followed by a drop in the following months. The peak at parturition is significantly lower in the 3rd reproductive cycle compared to the 2nd. The drop in antibody production observed after parturition of the 3rd reproductive cycle is significantly higher than that observed after parturition of the 2nd reproductive cycle. Nevertheless, the infection can still be revealed at flock level after three years post infection.

Comparison of serological and milk tests for bovine brucellosis using a Monte Carlo simulation model

European Union (EU) Directive 97/12/EC allows the trade of cattle within the EU of animals originating from an 'officially brucellosis-free herd'. To qualify for this status, a number of different programmes must be implemented. Each EU Member Country is free to decide which procedure to use to qualify herds. The authors conducted a study to compare the merits and costs of testing programmes given in the Directive and of some alternative testing strategies. The effectiveness of testing programmes was evaluated by a Monte Carlo simulation model. Programmes listed in the Directive do not appear to have identical sensitivity and specificity. Simulations of the programmes showed that milk testing may be more effective and efficient than blood testing to identify infected herds. Results indicated that it could be advisable that legislation, rather than defining very detailed procedures both for laboratory tests and testing programmes, should establish minimal requirements in terms of efficacy of testing procedures (i.e. the probability of detecting an infected herd).

Vaccination in the control strategy of bluetongue in Italy

The incursion of bluetongue (BT) in Italy, in August 2000, caused heavy economic losses, partly due to the direct effect of the disease on the animals, but mostly due to indirect losses due to ruminant movement restrictions conducive to heavy losses to the cattle and sheep industry. To limit losses due to both disease and virus circulation, which was the cause of movement restrictions, the Italian Ministry of Health in May 2001 ordered the vaccination of animals of all domestic ruminant species in infected and "at risk" areas. The vaccination strategy derived from a risk assessment that suggested that the vaccination of all domestic ruminants could reduce both direct losses and virus circulation significantly. The different levels of vaccination coverage, achieved in the various regions of Italy, had clear consequences on the spread of both disease and infection. In regions where more than 80% of the target populations were vaccinated properly, the disease disappeared almost completely and virus circulation was significantly reduced, as documented by the serological surveillance system, after a single vaccination cycle. This led to a significant decrease in the areas subject to movement restrictions. Data generated by both field and controlled experiments contributed to modify the EU approach to BT and to some of the conclusions of the Third OIE International Symposium on Bluetongue that will probably lead to a modification of the Office International des Epizooties (OIE) standard.

The distribution of Culicoides imicola in Italy: application and evaluation of current Mediterranean models based on climate

In August 2000 bluetongue (BT) disease appeared amongst sheep on the island of Sardinia spreading later to Sicily and to mainland Italy. The majority of areas affected by BT were surveyed for Culicoides imicola, the only proven vector of the disease known to occur in the Mediterranean region. The data from 1456 light-trap collections, made in months with a mean temperature of 12.5 degrees C, were used to test the accuracy of current models predicting the prevalence and abundance of C. imicola across the region. For Italy, the distribution of C. imicola was found to be very irregular and did not fit the modelled predictions. The possible reasons for this are discussed, and suggestions made as to which variables may improve this fit in the development of future risk models. In Italy, past surveys failed to reveal the presence of C. imicola, and so could be construed as evidence of its recent invasion, and thus rampant spread northwards. Although equivocal, historical records indicate that C. imicola was overlooked in the past. Six recommendations are made as to the possible future course of Culicoides research in southern Europe.

Evaluation of a new immunocapture test for the diagnosis of ovine brucellosis caused by Brucella melitensis

A new immunocapture technique has been applied to the diagnosis of ovine brucellosis under experimental conditions. The tests were made on a serum bank derived from both young and adult ewes vaccinated conjunctivally with the Rev 1 strain at a dose of 10(8) to 10(9) colony-forming units. Adult ewes were infected experimentally two-and-a-half years after they had been vaccinated and the results were compared with an unvaccinated control group. The condition of each animal in terms of infection with Brucella melitensis was determined by clinical and bacteriological investigations. The development of the immune response was compared by the rose bengal test, the complement fixation test, the Coombs' test and the immunocapture technique for 180 days after the vaccination and for 410 days after the experimental infection, that is, the two following gestations. The results suggest that the new technique is more specific in animals vaccinated conjunctivally, regardless of their age when they were vaccinated. After the experimental infection, significantly (P < 0.05) fewer of the vaccinated sheep which were free of clinical signs and were not excreting B melitensis reacted positively to the test.

Importance of the traceability of animals and animal products in epidemiology

Traceability of animals and animal products has become a priority for governments of the developed countries, due to consumer demand for comprehensive and integrated food safety policies. In addition to analysing the differences between traceback and traceability systems, the authors describe some applications of animal traceback systems and the principal characteristics of an animal identification and registration system. The importance of a traceability system for food-borne risk assessment and management, and the most recent approaches towards a comprehensive and integrated animal health and food safety policy are reported.

Spatial risk factors related to outbreaks of contagious bovine pleuropneumonia in northern Italy (1990-1993)

In October 1990, an outbreak of contagious bovine pleuropneumonia (CBPP) was reported in Italy after an absence of approximately one century. Since October 1990, ninety-four outbreaks have occurred in Italy, of which forty-seven were concentrated in three areas of northern Italy (Lombardy region). The disease was eradicated in September 1993. The data used for the analysis were obtained from the epidemiological investigations undertaken during the outbreaks of 1990-1993. The unit of interest for the analysis is the farm. Spatial segregation of infected and uninfected farms within the study area was determined through the Pielou index of segregation. Data from herds within the same set of outbreaks were analysed through logistic regression to identify factors which could be used to discriminate between infected and uninfected herds. The study indicated a clear spatial segregation between infected and uninfected herds. The results of the analysis do not indicate the mode of disease spread. However, the study demonstrated that both aerosol and indirect transmission of the infection could have occurred, as previously documented in Africa. The possibility that indirect transmission played a prominent role in the spread of CBPP in the region of Lombardy is a completely new suggestion. Further studies are required to understand the epidemiology of CBPP in regions with intensive farming and a relatively cold climate. In particular, three aspects require consideration; firstly, animal movement among neighbouring herds could produce a pattern of disease similar to the one produced by indirect transmission (this possibility was excluded in the epidemiological outbreak investigations conducted by field veterinarians). Secondly, the methods of spatial analysis used in this study have not been previously used in the field of veterinary epidemiology. Further validation of the efficacy of these methods is thus required. Thirdly, the epidemiology of CBPP under conditions of high animal density and a relatively cool climate, as encountered in Lombardy, requires further investigation.

Implementation of a system for the regional management of animal health emergencies

A telematic system to support decisions and operations in case of animal health emergencies has been designed and implemented in the Abruzzo region of Italy. The system aims to improve decision-making by Veterinary Services in the event of an outbreak of exotic disease. The system has been tested, first by a simulated outbreak of foot and mouth disease, and then during an outbreak of swine vesicular disease. Critical problems were detected and corrected in both cases.

Quality assurance of veterinary services at the international level: a proposed approach

A proposal for the harmonization of quality assurance of Veterinary Services at the international level is made. This proposal is based on the hypothesis of accreditation of Veterinary Services according to the 9000 series of the International Standards Organisation (ISO) standards. An example of a way in which ISO 9000 standards can be used within the context of management of Veterinary Services is given, together with an explanation of the possible role of the Office International des Epizooties in ensuring fairness of evaluations of Veterinary Services at the international level.

Import risk analysis: the experience of Italy

The authors propose a contribution to the possible revision of Chapters 1.4.1. and 1.4.2. of the International Animal Health Code (Code) of the Office International des Epizooties (OIE). In particular, data are presented to illustrate some of the inadequacies of both the rationale and the results of the method for risk assessment reported in the Code. The method suggested by the Code for risk assessment is based on the calculation of the 'probability of the occurrence of at least one outbreak' of a given disease following the importation of a given quantity of either live animals or animal products (unrestricted risk estimate). This is usually undertaken when dealing with rare events. For a country such as Italy, this method may not be particularly useful as the frequency of disease outbreaks is what should be estimated, so as to provide decision makers with appropriate and relevant information. Practical use of risk information generated by the use of the OIE risk assessment method for swine vesicular disease (SVD) would have encouraged the Chief Veterinary Officer of Italy to prohibit all imports of swine from the Netherlands and Belgium for at least two years in the early 1990s, with the consequential heavy economic losses for both Italy and the exporting countries. On the contrary, the number of actual outbreaks of the disease due to direct imports of swine from Member States of the European Union (EU), which occurred in Italy in 1992, 1993 and 1994 was very low (two to five outbreaks due to direct imports of swine from the Netherlands and one to two from Belgium). An example of a method for assessing the risks associated with high volumes of trade in commodities is also described. This method is based on the Monte Carlo simulation and provides the information required to evaluate the costs of the strategies compared. The method can be used to predict the number of outbreaks which are likely to occur following importation and enables a comparison to be made of alternative safeguards. This would lead to the selection of the most cost-effective one. The comparison is conducted using risk curves and allows a quantitative evaluation and comparison to be made of various scenarios, varying from an absence of safeguards to combinations of various safeguards.

Sensitivity and specificity of serological and bacteriological tests for contagious bovine pleuropneumonia

In 1990 an outbreak of contagious bovine pleuropneumonia (CBPP) occurred in Italy. Subsequent surveillance for CBPP was based on random sampling in bovine herds, serological controls on all animals moved from the herd of origin and controls on slaughtered animals. Official tests employed were the complement fixation test (CFT) and bacteriological isolation and typing. A total of 33,856 serum samples collected from herds in CBPP-free regions were used to define CFT specificity, while samples from 595 animals from infected herds were employed to define the sensitivity. Ninety-nine animals from three infected herds were used to estimate the sensitivity of the isolation technique. Results showed the specificity of CFT (threshold +1:10) to be 98% and sensitivity to be 63.79%. The sensitivity of the test did not change significantly, regardless of whether the lesions were caused by acute or chronic infection. The sensitivity of the isolation technique was 54.1%.

Quality assurance in veterinary diagnostic laboratories

The authors discuss the responsibility of veterinary diagnostic laboratories as suppliers of analytical data for tests on animals and animal products. The guarantee of the quality of analytical data is a basic quality requirement for veterinary certification. It is therefore important for the laboratory to adopt operational quality assurance standards which are recognised internationally. The management and quality assurance criteria contained in the International Standardisation Organisation/International Electrotechnical Commission Guide 25, or in directives or guidelines established by international organisations such as the Office International des Epizooties and the Codex Alimentarius of the Food and Agriculture Organisation, are reviewed. These documents provide procedures for adopting the principles of quality assurance in order to acquire the recognition of competence to execute the laboratory tests required for national and international veterinary certification.

Characterisation of Aujeszky's disease viruses isolated from domestic animals and from a wild boar (Sus scrofa) in Italy between 1972 and 1995

Following the isolation of a group I Aujeszky's disease virus from a wild boar in 1993, an investigation was carried out on 30 Italian Aujeszky's disease viruses (ADV's), isolated over a 23-yr period in 12 Italian regions, by means of restriction endonuclease analysis. All strains isolated between 1972 and 1984 belong to group I. From 1984 onwards group II isolates (II and II intermediate) replace group I isolates. The isolation of a group I virus in 1993 from a wild boar supports the hypothesis that ADV's may persist for several years in wild boar populations and that wild boars should therefore be considered reservoirs of Aujeszky's disease virus.

Manifestation and epidemiology of contagious bovine pleuropneumonia in Europe

The authors describe the clinical profile and epidemiology of contagious bovine pleuropneumonia in Europe. This disease, once considered to have been eradicated several years ago, has now become endemic in southern countries of Europe. The status of contagious bovine pleuropneumonia in Portugal and Italy, and the evolution of the disease during the last ten years, are analysed in detail, in addition to the measures undertaken for control and eradication. The authors also refer to hosts and possible reservoirs of the infection.

Unexpected isolation of virulent Newcastle disease virus from commercial embryonated fowls' eggs

The authors report a case of causal isolation of virulent Newcastle disease virus (NDV) from embryonated eggs. The virus was isolated from uninfected chicken embryo liver and fibroblast cultures prepared from commercial embryonated fowls' eggs. A serological and virological investigation carried out on the breeders which had laid those eggs showed high titres against NDV, and virus isolation from cloacal swabs. The virus was also isolated from the progeny of the same breeders which showed no clinical signs of ND, following episodes of mortality. Vertical transmission of the virus is discussed.