Safwat Mahmoud S, Bahr Amany D, Bakry Noha M, Amer Haitham M, Yousif Ausama A, Shehata Amir A, Mansour Othman N O, Shahen Nehal M, Karam Reham, Eid Samah, Khalil Ghada M, Refaei Omnia H
Department of Internal Medicine and Infectious Diseases (Infectious Diseases), Faculty of Veterinary Medicine, Cairo University, Giza, 12211, Egypt.
Department of Internal Medicine and Infectious Diseases (Infectious Diseases), School of Veterinary Medicine, Badr University in Cairo, Cairo, Badr City, 11829, Egypt.
BMC Vet Res. 2025 Jul 29;21(1):497. doi: 10.1186/s12917-025-04943-1.
Data on the epidemiology and molecular characterization of feline immunodeficiency virus (FIV) in Egypt are limited. This study aimed to estimate FIV prevalence in 240 Egyptian cats during 2022–2024 using three diagnostic techniques: two point-of-care antibody detection kits (Anigen and SNAP) and one end-point PCR targeting the gene. FIV infection is defined as positivity in at least two of the three diagnostic methods or PCR alone confirmed by sequencing, Additionally, FIV-associated clinicopathological abnormalities were assessed, and, for the first time in Egypt, circulating FIV subtypes were identified through partial sequencing and phylogenetic analysis of all gene-positive samples ( = 10), along with 4 additional gene-positive samples.
Using our diagnostic criteria, 76 of 240 cats (31.7%) were identified as FIV-infected. Of these 76 cases, 75 were positive on both rapid kits, yielding a sensitivity of 98.7% for sequential testing with Anigen and SNAP, whereas only 10 were positive on PCR and sequencing (13.2% sensitivity). FIV-infected cats exhibited lymphopenia, thrombocytosis, hyperglobulinemia, and reduced albumin/globulin ratios. On and gene-based phylogenetic analyses, Egyptian strains did not cluster with any known FIV subtype (A-F and U-NZ) but formed a distinct, previously uncharacterized clade. The Egyptian sequences displayed low intra-group diversity (2.8–3.7%) but high divergence from all known subtypes (21–25%), with no evidence of recombination observed. Moreover, these sequences were derived from both shelter-housed and client-owned cats across three Egyptian governorates within a one-year period.
Given their genetic distinctiveness and widespread detection, we propose a novel FIV subtype, tentatively designated “X-EGY.” Its dominance and limited variability among its strains suggest it represents an ancient lineage uniquely adapted to Egyptian cats, rather than a recently emerged variant. This subtype may partly contribute to Egypt’s notably high FIV prevalence. Serological testing, utilizing two point-of-care kits in screening and confirmation steps, is the most accurate FIV diagnostic approach, outperforming molecular testing, particularly in regions where genetic data on circulating strains are scarce. Overall, the findings enhance our understanding of FIV epidemiology and diagnostic strategies and offer new insights into viral diversity and evolution.
埃及猫免疫缺陷病毒（FIV）的流行病学和分子特征数据有限。本研究旨在利用三种诊断技术估计2022年至2024年期间240只埃及猫的FIV流行率：两种即时检测抗体检测试剂盒（Anigen和SNAP）和一种针对该基因的终点PCR。FIV感染定义为三种诊断方法中至少两种呈阳性，或仅PCR呈阳性并经测序确认。此外，评估了FIV相关的临床病理异常情况，并且在埃及首次通过对所有该基因阳性样本（n = 10）以及另外4个该基因阳性样本进行部分测序和系统发育分析，鉴定了循环FIV亚型。
根据我们的诊断标准，240只猫中有76只（31.7%）被鉴定为感染FIV。在这76例病例中，75例在两种快速检测试剂盒上均呈阳性，Anigen和SNAP连续检测的灵敏度为98.7%，而仅10例在PCR和测序上呈阳性（灵敏度为13.2%）。FIV感染的猫表现出淋巴细胞减少、血小板增多、球蛋白血症以及白蛋白/球蛋白比值降低。基于该基因和该基因的系统发育分析表明，埃及毒株未与任何已知的FIV亚型（A - F和U - NZ）聚类，而是形成了一个独特的、以前未被描述的进化枝。埃及的该基因序列在组内多样性较低（2.8 - 3.7%），但与所有已知亚型的差异较大（21 - 25%），未观察到重组迹象。此外，这些该基因序列来自埃及三个省份的收容所猫和客户拥有的猫，时间跨度为一年。
鉴于其遗传独特性和广泛检测到的情况，我们提出一种新的FIV亚型，暂定名为“X - EGY”。其在毒株中的优势地位和有限变异性表明它代表了一个古老的谱系，独特地适应了埃及猫，而不是最近出现的变体。这种亚型可能部分导致了埃及FIV流行率显著较高的现象。在筛查和确认步骤中使用两种即时检测试剂盒的血清学检测是最准确的FIV诊断方法，优于分子检测，特别是在循环毒株遗传数据稀缺的地区。总体而言，这些发现增进了我们对FIV流行病学和诊断策略的理解，并为病毒多样性和进化提供了新的见解。
