A total of 1485 adult ticks were collected from mammalian hosts in south-eastern Sardinia, Italy, during the years 2007–2008. Ticks were identified and tested by PCR analysis for presence of Rickettsia species of the spotted fever group, Ehrlichia canis, Anaplasma phagocytophilum, Coxiella burnetii, Bartonella species and Leishmania species. Among all tick species examined (Rhipicephalus sanguineus, Rhipicephalus turanicus, Rhipicephalus bursa, Rhipicephalus pusillus, Hyalomma marginatum marginatum, Haemaphysalis sulcata and Dermacentor marginatus), only Hyalomma marginatum marginatum produced negative results. A total of 22 pools belonging to the three tick species Rhipicephalus sanguineus (0.9 %), Rhipicephalus turanicus (4.5 %) and Rhipicephalus pusillus (100 %) were positive for Rickettsia species, while a total of five pools belonging to Rhipicephalus sanguineus (0.09 %), Haemaphysalis sulcata (16.7 %) and D. marginatus (7.8 %) were positive for E. canis. Five pools of Rhipicephalus turanicus (1.8 %) were positive for A. phagocytophilum. Positivity for C. burnetii was found in seven pools belonging to three tick species: Rhipicephalus sanguineus (0.5 %), Rhipicephalus turanicus (0.3 %) and Haemaphysalis sulcata (4.4 %). Finally, four pools belonging to Rhipicephalus sanguineus (0.09 %), Rhipicephalus turanicus (0.7 %) and Rhipicephalus bursa (1.1 %) were positive for Bartonella species. Leishmania species DNA was not detected in any of the tick pools examined. Data presented here increase our knowledge on tick-borne diseases in Sardinia, and provide a useful contribution to understanding their epidemiology.

Bluetongue (BT) epidemics have affected the Mediterranean island of Sardinia since 2000. While Culicoides imicola represents the main bluetongue virus (BTV) vector, other European Culicoides biting midges, possibly implicated in virus transmission, have been detected here. Understanding their distribution, seasonal abundance, and infection rates is necessary to predict disease incidence and spread across coastal and inland areas, and to define their role in virus overwintering. Biting midge abundance was determined by light traps on selected farms representing diverse climatic conditions of Sardinia. Livestock-associated Culicoides species were morphologically and molecularly identified. Infection rates in prevailing midge species captured in 2013 during a BTV-1 outbreak were determined using RT-qPCR based virus detection in insect body pools, supplemented by specific body region analyses. The seasonal infection prevalence in Culicoides samples collected in 2001 in a BTV-2 affected farm was also determined. The Newsteadi complex (C. newsteadi species A and species B) prevailed among all biting midge species (47.7 %), followed by C. imicola (27.8 %) and the Obsoletus complex (C. obsoletus and C. scoticus) (17.6 %). Whilst Culicoides imicola was more abundant along the coast, the Newsteadi complex was frequently collected at higher altitude and the Obsoletus complex was notably associated to cattle farms. Culicoides pulicaris and C. punctatus abundance was found to be marginal in all farms. BTV was detected in parous female samples of all these species, and the full dissemination of the virus within the body of C. imicola, C. obsoletus, C. scoticus, and Newsteadi complex species was confirmed by analyses of thorax and head, containing salivary glands. Higher infection rates were associated with C. scoticus, C. newsteadi species A and species B, compared to C. imicola. The virus was detected in C. newsteadi species A and C. obsoletus in winter and spring, whereas it was mainly found in summer and autumn in C. imicola. In Sardinia, bluetongue virus is transmitted by multiple Culicoides vectors, including C. imicola and the Newsteadi complex being the most important. The Newsteadi complex and other midge species can play an important role in internal areas and are likely to be directly involved in virus overwintering.

The distribution of Bluetongue virus (BTV) in Europe can be represented by two distinct and interconnected epidemiological systems (episystems), each characterized by different ecological characteristics and vector species. This study investigated the vector competence of Italian populations of Culicoides imicola and Culicoides obsoletus/scoticus to some representative BTV strains after artificial oral infection. The BTV strains were selected according to their ability to spread to one or both episystems and included BTV-4 ITA, responsible of the recent Italian and French BTV-4 outbreaks; the BTV-2 strain which caused the first BTV incursion in Italy, Corsica, and Balearic Islands; BTV-4 MOR, responsible for the epidemic in Morocco; and BTV-8, the strain which spread through Europe between 2006 and 2008. Blood-soaked cotton pledgets and Hemotek membrane feeder using Parafilm^® membrane were used to artificially feed midges. For each population/strain, recovery rates (positive/tested heads) were evaluated using serogroup- and serotype-specific RT-PCR. The trial demonstrated that, except for the Abruzzo population of C. obsoletus/C. scoticus, which was refractory to BTV-4 MOR infection, all the investigated Culicoides populations are susceptible to the selected BTV strains and that, if prompt vaccination programs and restriction measures had not been implemented, BTV-2 and BTV-4 MOR could have spread all over Europe.

Background and Objectives: Climate change is modifying the ecological and climatic conditions that influence the distribution and activity of arthropod vectors. Rising temperatures and prolonged warm seasons have favored the establishment of Aedes albopictus in Mediterranean regions, increasing the risk of autochthonous Dengue transmission. Therefore, this study describes the evolution of Dengue surveillance in Sardinia between 2018 and 2024, integrating human and entomological data to assess trends, system performance, and implications for prevention and control. Materials and Methods: Data on human cases were retrieved from national notification systems (namely PREMAL, arbo.iss.it) and the New Health Information System. Entomological surveillance data were obtained from the Experimental Zooprophylactic Institute of Sardinia. Mosquitoes were collected using BG-Sentinel^® traps and ovitraps, covering major cities and points of entry. Descriptive analyses were conducted for both datasets. Results: Sixteen Dengue cases were reported during the study period, all imported and laboratory-confirmed in 81% of cases. Most patients were adults (mean age 38 years), and 77% required hospitalization. The most frequent travel origins were Southeast Asia, Africa, and Latin America. No autochthonous cases were identified. Entomological surveillance showed a progressive increase in Aedes albopictus captures from 2020 onwards, with seasonal peaks between September and October. Despite intensified sampling and expanded geographic coverage, no mosquito pools tested positive for the Dengue virus. Conclusions: Although no locally acquired Dengue infections have been detected, the widespread and increasing presence of Aedes albopictus indicates that Sardinia meets the ecological prerequisites for possible autochthonous transmission. Strengthening the timeliness and completeness of human surveillance, improving clinicians’ awareness of reporting requirements, promoting vaccination for travelers, and maintaining continuous entomological monitoring are essential to prevent and promptly manage future outbreaks.

Schmallenberg virus (SBV), an Orthobunyavirus transmitted by Culicoides, causes congenital malformations and mild symptoms, such as fever, reduced appetite, decreased milk production, and occasional diarrhea, in ruminants. First detected in Central Europe in 2011, SBV spread across the continent, reaching Sardinia (Italy) in late 2012. This study evaluates the occurrence of SBV infections in Sardinian sheep from 2013 to 2024 by anatomo-pathological, virological, serological, and entomological data. The results suggest the presence of SBV infections in a continuous enzootic status over the years, without the cyclic waves observed in other countries, likely due to the unique sheep breeding management in Sardinia. Seroprevalence rates in the years 2022 and 2024 varied between 16.40% (C.I. = 12.28–20.52) and 21.53% (C.I. = 17.15–25.91) without significant differences between the two years analyzed. SBV was predominantly detected in C. imicola and C. newsteadi populations, while C. cataneii and C. sahariensis were identified as potential new vectors. Additionally, S- and M-segment sequences were obtained from two SBV isolates, S-sequences from a sample detected in 2020, and 21 archived cDNA samples from 2012. The S-segments showed high similarity among themselves and the reference strains, while the M sequences were significantly different, although potential artifacts from fetal samples must be considered. Overall, the results suggest widespread enzootic SBV circulation in Sardinia over the past decade, with a very low frequency of malformations in newly born sheep offspring.

Background: Lyme borreliosis (LB) constitutes a major challenge for Public Health, particularly in regions where surveillance and diagnostic systems are underdeveloped or fragmented. Despite its potential as a hotspot for tick-borne diseases, Sardinia (Italy) remains poorly explored in terms of LB epidemiology. Methods: A sero-prevalence study was conducted on serum samples stored in the biobank of a hospital in Northern Sardinia. The serum library consisted of serum samples collected on the basis of a diagnostic hypothesis of rheumatic disease. Serological testing for antibodies against Borrelia was performed using the indirect immunofluorescence assay (IFA) and enzyme-linked immunosorbent assays (ELISA), followed by confirmation by Western blot for positive results. The study analyzed 58 serum samples from patients selected based on clinical symptoms compatible with Borrelia spp. infection. Results: Among the 58 patients, 9 (15.5%) yielded positive results, with absorbance values higher than those of the positive control, suggesting that the pathogen is widespread but poorly recognized in Sardinia. The results are in line with broader trends in the Mediterranean, indicating that Sardinia can no longer be considered a marginal area for Borrelia spp. circulation. Conclusions: The status of Sardinia as a sentinel territory underlines the need for enhanced epidemiological surveillance within the One Health approach, including human, animal and environmental health.