Department of Clinical Studies, University of Guelph, Guelph, ON, Canada.
Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada.
J Feline Med Surg. 2023 Jul;25(7):1098612X231183297. doi: 10.1177/1098612X231183297.
A total of 1692 medical records from a primary care feline practice and a veterinary referral hospital were evaluated retrospectively to assess discordant feline leukemia virus (FeLV) test results. In total, 73 cats were positive for FeLV using serum in a lateral flow immunoassay (LFI) or laboratory-based ELISA. Of these cats, 21 subsequently tested negative for FeLV proviral DNA by non-quantitative PCR on EDTA whole blood (16/21, 76.2%), bone marrow (4/21, 19%) or both (1/21, 4.7%). The proportional morbidity (an estimate of prevalence in a sample of the total population) for FeLV by LFI/ELISA and PCR assays was 3.1%, consistent with that reported in previous studies for cats in North America. Cats with discordant LFI/ELISA and PCR results had either primary bone marrow disease (18 autoimmune, one neoplastic), a bone marrow insult (hemotrophic mycoplasmosis) or systemic inflammation (pyothorax with a marked neutrophilic leukocytosis). The percentage of cats with a positive LFA/ELISA result and negative PCR assay surviving to discharge was 85.7% (18/21). Of these, 88.9% (16/18) survived 4 months to 6 years. Seven cats (33.3%) were re-tested with LFI or ELISA once primary disease was controlled, and all tested negative.
These findings indicate that in cats with bone marrow disease that shares features of progressive FeLV infection, positive LFI and ELISA FeLV test results should be followed up with FeLV proviral DNA PCR testing, particularly in populations where disease prevalence is low.
回顾性评估了来自初级保健猫科动物诊所和兽医转诊医院的总共 1692 份病历，以评估不一致的猫白血病病毒 (FeLV) 检测结果。总共有 73 只猫在侧向流动免疫分析 (LFI) 或基于实验室的 ELISA 中使用血清检测为 FeLV 阳性。在这些猫中，21 只随后通过 EDTA 全血（16/21，76.2%）、骨髓（4/21，19%）或两者（1/21，4.7%）的非定量 PCR 检测为 FeLV 前病毒 DNA 阴性。LFI/ELISA 和 PCR 检测的 FeLV 比例发病率（总人群样本中的患病率估计）为 3.1%，与北美猫之前的研究报告一致。LFI/ELISA 和 PCR 结果不一致的猫要么患有原发性骨髓疾病（18 例自身免疫性疾病，1 例肿瘤性疾病），要么骨髓受损（噬血支原体感染）或全身性炎症（伴有明显中性粒细胞增多的脓性胸膜炎）。存活至出院的 LFA/ELISA 结果阳性和 PCR 检测阴性的猫的百分比为 85.7%（18/21）。其中，88.9%（16/18）在 4 个月至 6 年内存活。在原发性疾病得到控制后，有 7 只猫（33.3%）再次进行了 LFI 或 ELISA 检测，结果均为阴性。
