de Almeida Pedro Morais, Belas Adriana, Bragança Mauro, de Oliveira Joana, Viegas Carlos
Faculty of Veterinary Medicine, Lusófona University- Lisbon University Centre, Lisbon, Portugal.
Animal and Veterinary Research Center (CECAV), University of Trás-os-Montes and Alto Douro (UTAD), Vila Real, Portugal.
BMC Vet Res. 2025 Mar 26;21(1):205. doi: 10.1186/s12917-025-04691-2.
With its large stray population, Portugal had the highest prevalence of the Feline Leukemia Virus (FeLV) infection in Europe. Progressive infection is still high, especially in southern Europe. In addition to the viral load, the subgroup is a determining factor in the development of the various syndromes associated with this disease, which can be fatal, justifying the morbidity and mortality of this retrovirus. The aim of the study was to determine the prevalence of FeLV, the viral load and to identify the subgroup of circulating virus in stray cats in the Lisbon metropolitan area. This prospective study was conducted at the Veterinary Teaching Hospital of the FMV-ULusófona, from November 2022 to January 2023. Blood samples from 129 stray cats from the Lisbon metropolitan area were included. All samples were tested for p27 antigen detection and proviral DNA by qPCR. For the detection of FeLV subgroups (A, B and C) nested PCR was performed.
The results showed that at the time of enrollment, 8.5% (n = 11/129) of the cats tested positive for FeLV using p27 antigen and qPCR for proviral DNA. Considering the proviral DNA load, 90.9% (n = 10/11) of the FeLV infections were classified as "likely progressive infection" (> 4.0 × 10 copies/mL). In the remaining animal, the FeLV infection was classified as "likely regressive infection" (≤ 4.0 × 10 copies/mL). In this study, the most common FeLV subgroup was a combination of AB (54,5%, n = 6/11), followed by FeLV-A (45,5%, n = 5/11). FeLV-C subgroup was not detected.
To the best of our knowledge, this is the first study to research FeLV subgroups in Portugal. The prevalence of FeLV in this group was consistent with our expectations. However, the molecular characterization differed significantly from that observed in other countries. These results suggest that stray cats may not be the main epidemiological concern.
葡萄牙流浪猫数量众多，其猫白血病病毒（FeLV）感染率在欧洲最高。进行性感染率仍然很高，尤其是在南欧。除病毒载量外，病毒亚组是与该疾病相关的各种综合征发展的决定性因素，这些综合征可能是致命的，这也解释了这种逆转录病毒的发病率和死亡率。本研究的目的是确定里斯本大都市区流浪猫中FeLV的流行率、病毒载量，并识别循环病毒的亚组。这项前瞻性研究于2022年11月至2023年1月在FMV-ULusófona兽医学院教学医院进行。纳入了来自里斯本大都市区的129只流浪猫的血液样本。所有样本均通过qPCR检测p27抗原和前病毒DNA。为检测FeLV亚组（A、B和C），进行了巢式PCR。
结果显示，在入组时，使用p27抗原和前病毒DNA的qPCR检测，8.5%（n = 11/129）的猫FeLV检测呈阳性。考虑到前病毒DNA载量，90.9%（n = 10/11）的FeLV感染被归类为“可能的进行性感染”（>4.0×10拷贝/mL）。在其余动物中，FeLV感染被归类为 “可能的消退性感染”（≤4.0×10拷贝/mL）。在本研究中，最常见的FeLV亚组是AB组合（54.5%，n = 6/11），其次是FeLV-A（45.5%，n = 5/11）。未检测到FeLV-C亚组。
据我们所知，这是葡萄牙第一项研究FeLV亚组的研究。该组中FeLV的流行率与我们的预期一致。然而，分子特征与其他国家观察到的有显著差异。这些结果表明，流浪猫可能不是主要的流行病学关注点。
