Barbic Ljubo, Stevanovic Vladimir, Mauric Maljkovic Maja, Miletic Gorana, Coric Ivona, Savic Vladimir, Masovic Viktor, Bogdanic Maja, Medic Alan, Vilibic-Cavlek Tatjana
Department of Microbiology and Infectious Diseases with Clinic, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia.
Department of Animal Breeding and Livestock Production, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia.
Front Vet Sci. 2025 Jun 2;12:1602706. doi: 10.3389/fvets.2025.1602706. eCollection 2025.
Surveillance is crucial in controlling and preventing vector-borne zoonotic diseases (VBDs). We analyzed the seroprevalence of selected vector-borne zoonotic pathogens in sheep from endemic areas and their role as possible sentinels for VBDs. A total of 300 sheep from seven farms at three micro-locations were tested for the presence of IgG antibodies against tick-borne encephalitis virus (TBEV), West Nile virus (WNV), Usutu virus (USUV), s.l., and Crimean-Congo hemorrhagic fever virus (CCHFV) using ELISA with confirmation of borderline/positive results by VNT. Seropositivity for at least one pathogen was observed in 18.0% (54/300) of sheep. The highest seroprevalence was confirmed for TBEV (9.7%; 29/300), followed by WNV (3.0%; 9/300) and s.l. (2.7%; 8/300), while USUV and inconclusive flavivirus (TBEV/WNV/USUV) infections had the same seroprevalence of 1.3% (4/300). None of the serum samples tested positive for CCHFV. Geographic micro-location was a significant risk factor for USUV ( = 0.045), TBEV ( = 0.03), and s.l. ( = 0.015) infections, but not for WNV. The farm distance from the household (TBEV < 0.001, s.l. = 0.005) and sheep breed (TBEV < 0.001, s.l. < 0.001) were found as risk factors for seropositivity to tick-borne (TBEV, s.l.), but not to mosquito-borne diseases (WNV, USUV). Of the other risk factors, sheep shearing was statistically significant, with unshared sheep showing a higher probability of tick-borne diseases ( = 0.048). Sex, age, herd size, and the presence of clinical signs were not associated with the seroprevalence. Serologic evidence of VBDs suggests their sentinel potential for mapping micro-foci of zoonotic pathogens' activity and identifying high-risk areas for public health. Further studies are needed to confirm this observation.
监测对于控制和预防媒介传播的人畜共患病（VBDs）至关重要。我们分析了来自流行地区绵羊中选定的媒介传播人畜共患病病原体的血清阳性率及其作为VBDs可能哨兵的作用。使用酶联免疫吸附测定法（ELISA）对来自三个微地点七个农场的300只绵羊进行检测，以确定其是否存在抗蜱传脑炎病毒（TBEV）、西尼罗河病毒（WNV）、乌苏图病毒（USUV）、狭义嗜吞噬细胞无形体（Anaplasma phagocytophilum s.l.）和克里米亚-刚果出血热病毒（CCHFV）的IgG抗体，并通过病毒中和试验（VNT）对临界/阳性结果进行确认。在18.0%（54/300）的绵羊中观察到至少一种病原体的血清阳性。TBEV的血清阳性率最高（9.7%；29/300），其次是WNV（3.0%；9/300）和狭义嗜吞噬细胞无形体（2.7%；8/300），而USUV和不确定的黄病毒（TBEV/WNV/USUV）感染的血清阳性率均为1.3%（4/300）。没有血清样本检测出CCHFV呈阳性。地理微地点是USUV（P = 0.045）、TBEV（P = 0.03）和狭义嗜吞噬细胞无形体（P = 0.015）感染的显著风险因素，但不是WNV的风险因素。发现农场与住户的距离（TBEV P < 0.001，狭义嗜吞噬细胞无形体P = 0.005）和绵羊品种（TBEV P < 0.001，狭义嗜吞噬细胞无形体P < 0.001）是蜱传疾病（TBEV、狭义嗜吞噬细胞无形体）血清阳性的风险因素，但不是蚊传疾病（WNV、USUV）的风险因素。在其他风险因素中，剪羊毛具有统计学意义，未共享的绵羊患蜱传疾病的可能性更高（P = 0.048）。性别、年龄、畜群规模和临床症状的存在与血清阳性率无关。VBDs的血清学证据表明它们在绘制人畜共患病原体活动的微病灶和确定公共卫生高风险地区方面具有哨兵潜力。需要进一步研究来证实这一观察结果。
