1 1Department of Veterinary Sciences, University of Turin, Turin, Italy. 2Department of Veterinary Medicine, University of Bari, Valenzano (BA), Italy. *Corresponding author at: Department of Veterinary Sciences, University of Turin, Turin, Italy. E-mail: angela.fanelli@unito.it. Keywords Cattle, Buffalo, ELISA, Q fever, Zoonosis. Summary A cross‑sectional survey was carried out in dairy cattle and buffalo herds from the Southern Italy to detect antibodies against Coxiella burnetii. From 2014 to 2018, 402 herds were monitored and 50 mL of bulk‑tank milk (BTM) per farm was analyzed by indirect ELISA. Blood samples of animals from positive farms were also taken and analyzed with the same ELISA test. The overall seroprevalence was 35% [95% Confidence interval (CI):30‑39] at herd level and 13% (95%CI:13‑14) at animal level. Herd province seroprevalences ranged from 17% to 75%. The provinces of Matera (71%, 95%CI:38‑105) and Agrigento (75%, 95%CI:51‑100) showed the highest percentage of infected farms. These results describe the widespread distribution of C. burnetii in livestock from Southern Italy, highlighting the need to implement a monitoring program for Q fever. Angela Fanelli1*, Adriana Trotta2, Filena Bono2, Marialaura Corrente2 and Domenico Buonavoglia2 Seroprevalence of Coxiella burnetii in dairy cattle and buffalo from Southern Italy Veterinaria Italiana 2020, 56 (3), xxx‑xxx. doi: 10.12834/VetIt.2321.13237.1 Accepted: 10.10.2020 | Available on line: xx.xx.2020 Code. Therefore, Member Countries have the legal obligation to report information on the disease to the OIE. National regulations exist also at country level. In Italy, Q fever is a notifiable disease in humans and it has been listed in the Occupational disease list (Italian Republic, Ministry of Works Decree 14th January 2008). However, the epidemiological situation is not well‑known because of the scarce monitoring in both humans and livestock, as it has been demonstrated for other notifiable animal diseases (Fanelli et al. 2020, Fanelli and Tizzani 2020). Indeed, the occurrence of C. burnetii has been investigated in flocks and herds only in limited areas of the country (Masala et  al. 2004, Rizzo et  al. 2016, Guidi et  al. 2017, Galluzzo et  al. 2019). The major constraint is represented by the poor knowledge and awareness of Q fever in both farmers and veterinarians. Considering that monitoring and reporting the infection in livestock is crucial for the prevention of human disease, the objective of this study is to estimate the seroprevalence of C. burnetii in dairy cattle and buffalo herds from Southern Italy, an area characterized by a closed and interconnected farms network. From 2014 to 2018 402 semi‑intensive farms (herd Q fever is a zoonotic disease caused by Coxiella burnetii, a bacterium developing spore‑like forms that are highly resistant in the environment. Cattle, sheep, and goats are the main reservoirs of the bacteria. They can shed C. burnetii in urine, feces, milk, and birth products, and humans usually acquire the infection through inhalation of contaminated aerosols (Arricau‑Bouvery and Rodolakis 2005). Q fever is considered mainly as an occupational zoonosis, being farmers, laboratory workers, veterinarian at high risk of infection (Schimmer et al. 2014). Consumption of raw/unpasteurized milk and tick bites have also been claimed as possible routes of transmission, but they are probably far less frequent than the airborne one (Duron et  al. 2015, Gale et al. 2015). Q fever is frequently misdiagnosed and underreported. In human, the disease has been associated with a wide clinical spectrum, from asymptomatic to fatal disease. However, in most of the cases, it is characterized by flu‑like symptoms (Arricau‑Bouvery and Rodolakis 2005). In livestock, the infection can cause significant economic losses due to abortion, infertility and subclinical mastitis (Van Asseldonk et al. 2013). Q fever is listed in the OIE Terrestrial Animal Health SHORT COMMUNICATION 2 Veterinaria Italiana 2020, 56 (3), xxx-xxx. doi: 10.12834/VetIt.2321.13237.1 C. burnetii in southern Italy livestock Fanelli et al. positive if the OD percent was over 50, doubtful if it was between 40 and 50, and negative if it was under 40. The overall seroprevalence was 35% at herd level (95%CI:30‑39) and 13% (95%CI:13‑14) at animal level, with differences among provinces (Table I, Figure 2). Province seroprevalences ranged from 17% to 75%. When compared to the results from other Mediterranean regions, the majority of the provinces present a seroprevalence at the herd level in line with those reported in Spain (43%) and Portugal (61.1%) (Ruiz‑Fons et  al. 2010, Pimenta et  al. 2015). The high numbers of positive farms in the province of Matera (Basilicata) and Agrigento (Sicily) are similar to what described in cattle from central Italy (68.5%) (Barlozzari et  al. 2020), and it confirms the significant presence of C.  burnetii in the territory of Western Sicily (Galluzzo et al. 2019). Some authors have reported a higher risk of being seropositive for animals originating from larger herds (Agger et  al. 2013, Paul et  al. 2014). In this study, the risk factors of C. burnetii infection on each herd were not assessed, however, the differences detected are unlikely to depend on the herd‑size or management system, considering the similar features of the sampled farms (with the exception of the size of buffalo herds). size ranges from 20 to 50 heads for cattle and 230 to 800 for buffalo) were sampled in 18 Italian provinces (Figure 1). The sample collection does not represent a random sampling, as it is represented by farms in which abortions due to C. burnetii were detected by RT‑PCR or farms located in the surrounding area (within a radius of 5 km from an infected farm). A multiple sampling strategy was applied to assess the circulation of C. burnetii in the study area. Firstly, an ELISA test [LSI Qfever ruminant serum/milk ELISA kit (LSI, France] was performed on 50  mL of bulk tank milk (BTM). The use of ELISA to test BTM has been proved to a be cost‑effective and valuable tool to monitor herds (Ryan et  al. 2011). The test was repeated in the herds tested negative after 10 months, in order to consider also animals that were in dry period during the first sampling. Ten mL of serum per animal were assessed with the same ELISA test in each positive herd. The number of animals to be tested was determined considering the herd size, the expected seroprevalence (20%), the absolute precision desired (5%) and the confidence interval (CI) (95%) (Cannon and Roe 1982). The assay was performed according to the manufacturer’s instructions. For BTM, a sample was considered positive if the OD percent was over 40, doubtful if it was between 30 and 40, and negative if it was under 30. For serum, a sample was considered Figure 1. Map showing the provinces sampled to assess the seroprevalence of C. burnetii. Veterinaria Italiana 2020, 56 (3), xxx-xxx. doi: 10.12834/VetIt.2321.13237.1 3 Fanelli et al. C. burnetii in southern Italy livestock Table I. C. burnetii seroprevalence at both herd and animal level according to provinces. Region Province Herds sampled Positive herds Prevalence % (95%CI) Number of animals tested Positive Animals Prevalence % (95%CI) Apulia Bari 24 13 54 (34-74) 340 153 45 (40-50) Barletta-Andria-Trani1 1 1 NA* 22 9 41 (20-61) Brindisi1 1 0 NA* - - - Foggia 11 5 45 (16-75) 204 91 45 (38-51) Lecce1 1 1 NA* 16 11 69 (46-91) Taranto 46 21 46 (31-60) 560 246 44 (40-48) Basilicata Matera 7 5 71 (38-105) 60 13 22 (11-32) Potenza 11 6 55 (25-84) 62 18 29 (18-40) Campania Salerno2 104 19 18 (11-26) 247 77 31 (25-37) Sicily Agrigento 12 9 75 (51-100) 151 22 15 (9-20) Caltanissetta 6 2 33 (-4-71) 163 3 2 (0-4) Catania 11 2 18 (-5-41) 201 6 3 (1-5) Enna 26 11 42 (23-61) 784 27 3 (2-5) Messina 41 11 27 (13-40) 531 15 3 (1-4) Palermo 46 11 24 (12-36) 1259 24 2 (1-3) Ragusa 30 14 47 (29-65) 1092 101 9 (8-11) Syracuse 18 7 39 (16-61) 389 21 5 (3-8) Trapani 6 1 17 (-13-46) 99 1 1 (-1-3) 1Only one herd was sampled for the provinces of Barletta-Andria-Trani, Lecce and Brindisi, thus it was no possible to compute the seroprevalence at herd level. 2 The buffalo farms included in this study are all located in Salerno province. *Not applicable. Figure 2. Choropleth map displaying C. burnetii seroprevalence at herd-level in connection with the first level administrative boundaries. 4 Veterinaria Italiana 2020, 56 (3), xxx-xxx. doi: 10.12834/VetIt.2321.13237.1 C. burnetii in southern Italy livestock Fanelli et al. precautions (i.e. changing boots and/or clothes) significantly reduce the risk of the infection. Data from this study made an important contribution from both public and animal health perspectives. Baseline epidemiological data presented herein will be useful for comparative purposes during future studies in areas with circulation of the pathogen. A One Health approach, with an integrated surveillance system involving the systematic notification of cases in both humans and animals, is needed to better understand the spread of C. burnetii in the study area. As regards livestock, further investigations should be performed to assess the potential risk factors that could influence the exposure of C. burnetii. This information is crucial to improve the management of biosecurity at farm level, and to prevent the introduction into susceptible populations. Financial support This research received no specific grant from any funding agency, commercial or not‑for‑profit sectors. We focused on semi‑intensive farms, where animals are housed in winter and graze during spring and summer. Because of that, livestock is at high risk of C. burnetii infection due to both the transmission by infected aerosols derived from contaminated materials left in the environment (such as birth fluids) or by fomites and the exposure to large numbers of infected ticks by grazing pastures during spring and summer. We do believe that the rural reality and the cultural tradition of the livestock farming characterizing our study area have a great influence on the epidemiological framework of the disease. 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