Surveillance strategies for foot and mouth disease to prove absence of disease and absence of viral circulation.

Free trade of animals and their products is based on the international or bilateral recognition of the health status of the animal populations being traded. This recognition is based on documentation of their health status by the exporting country, based on the results of continuing surveillance. According to the Terrestrial Animal Health Code of the World Organisation for Animal Health (OIE), this may be based on various methods of surveillance, such as: documenting non-specific surveillance (clinical surveillance, passive notification of suspect cases, etc.); documenting activities that increase the sensitivity of non-specific surveillance (training activities, rewards/sanctions for notification/failure to notify, etc.); documenting all specific surveillance and its results (random surveys, targeted and risk-based surveillance, convenience-testing activities, etc.). Usually, the infection is the subject of the declaration of freedom. While clinical and passive surveillance can provide a high level of confidence that foot and mouth disease (FMD) infection is absent, this is not the case in vaccinated populations. In these populations, specific surveillance becomes much more important than non-specific clinical surveillance. Specific surveillance is severely restricted by the performance of the test(s) employed. The imperfect specificity of any serological test is further complicated when techniques to differentiate infected from vaccinated animals (DIVA) are used, because imperfect purification of the antigen used for vaccination may foster the production of undesired antibodies in the vaccinated animals. The authors discuss various approaches to overcome this problem; their merits and flaws in documenting the absence of infection or virus circulation for animal diseases in general, and for FMD in particular. Particular attention is paid to finding methods that can be applied in a variety of epidemiological conditions and organisational structures, since these vary greatly among OIE Members.

Antibody response in cattle vaccinated against bluetongue serotype 8 in Italy.

To assess the immunogenicity of Zulvac 8 Bovis (a commercial inactivated vaccine against bluetongue virus serotype 8 - BTV8) under field conditions, 71 cattle vaccinated according to manufacturer schedule in Verona province (Italy) were tested for the presence of BTV8 neutralizing antibodies at 21, 29, 36, 43, 49, 102 and 201 days post-vaccination (dpv). Another group of 528 BTV8 vaccinated cattle in Mantova province (Italy) was also tested once between 113 and 174 dpv. The vaccine was able to elicit an immune response in 69 (97.2%) and 346 (65.5%) animals of the Verona and Mantova groups, respectively.

[Earthquake in Abruzzo, public health interventions. Preliminary report]. / Interventi sanitari in occasione del sisma in Abruzzo. Rapporto preliminare.

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.

Bluetongue control strategy, including recourse to vaccine: a critical review.

The bluetongue (BT) epidemic that has prevailed in Europe since 2000 is the first example of continental spread of the BT virus (BTV) in large naive populations of susceptible animals. Based on the results of intensive surveillance and research in countries of the southern Mediterranean that were affected by the infection early on in the epidemic, a new strategy for prevention and control of the disease was developed to limit direct losses and to reduce the consequences due to movement restrictions. The basic innovations that were introduced were the use of mass vaccination of all domestic ruminant species to limit the spread of BTV and the use of intensive active surveillance to limit, as far as possible, the zone where movement restrictions must be applied. The novel strategy that was adopted dramatically reduced the number of clinical outbreaks in southern Europe and the Mediterranean Basin and ensured safer animal trade. In 2006, the first BTV-8 epidemic occurred, this time in north-western Europe. During this epidemic, affected countries adopted a 'wait and see' approach. No vaccination was implemented until 2008 and, in many instances, the movement of animals was authorised within restricted areas, thereby facilitating the spread of infection. The delay in administering vaccination was due to the decision to avoid the use of modified live virus vaccines, although this type of vaccine performed satisfactorily in the previous BT epidemics in southern Europe. Bluetongue has demonstrated that the infectious agents present in southern Africa can easily spread to the Mediterranean Basin, which should be considered a single entity as far as the epidemiology of animal diseases is concerned. Therefore, any effective strategy for the prevention and control of animal disease in Europe must take into account this reality and recognise the need for regional surveillance networks that include all the countries that border the Mediterranean.

Assessment of efficacy of a bivalent BTV-2 and BTV-4 inactivated vaccine by vaccination and challenge in cattle.

The efficacy of a bivalent inactivated vaccine against bluetongue virus (BTV) serotypes 2 (BTV-2) and 4 (BTV-4) was evaluated in cattle by general and local examination, serological follow-up, and challenge. Thirty-two 4-month-old calves were randomly allocated into 2 groups of 16 animals each. One group was vaccinated subcutaneously (s/c) with two injections of bivalent inactivated vaccine at a 28-day interval, and the second group was left unvaccinated and used as control. Sixty-five days after first vaccination, 8 vaccinated and 8 unvaccinated calves were s/c challenged with 1 mL of 6.2 Log10 TCID50/mL of an Italian field isolate of BTV serotype 2, while the remaining 8 vaccinated and 8 unvaccinated animals were challenged by 1 mL of 6.2 Log10 TCID50/mL of an Italian field isolate of BTV serotype 4. Three additional calves were included in the study and used as sentinels to confirm that no BTV was circulating locally. At the time of the challenge, only one vaccinated animal did not have neutralizing antibodies against BTV-4, while the remaining 15 showed titres of at least 1:10 for either BTV-2 or BTV-4. However, the BTV-2 component of the inactivated vaccine elicited a stronger immune response in terms of both the number of virus neutralization (VN) positive animals and antibody titres. After challenge, no animal showed signs of disease. Similarly, none of the vaccinated animals developed detectable viraemia while bluetongue virus serotype 2 and 4 titres were detected in the circulating blood of all unvaccinated animals, commencing on day 3 post-challenge and lasting 16 days. It is concluded that administration of the bivalent BTV-2 and BTV-4 inactivated vaccine resulted in a complete prevention of detectable viraemia in all calves when challenged with high doses of BTV-2 or BTV-4.

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 IFNgamma 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, IFNgamma 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.

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.

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.

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.

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.

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.

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.

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).

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%).

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.

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.

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.