Pedram Bijan, Pasquetto Valérie, Drame Papa M, Ji Yongchang, Gonzalez-Moa Maria J, Baldwin Richard K, Nutman Thomas B, Biamonte Marco A
Drugs & Diagnostics for Tropical Diseases, San Diego, California, United States of America.
Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
PLoS Negl Trop Dis. 2017 Jul 27;11(7):e0005741. doi: 10.1371/journal.pntd.0005741. eCollection 2017 Jul.
Ivermectin-based mass drug administration (MDA) programs have achieved remarkable success towards the elimination of onchocerciasis and lymphatic filariasis. However, their full implementation has been hindered in Central Africa by the occurrence of ivermectin-related severe adverse events (SAEs) in a subset of individuals with high circulating levels of Loa loa microfilariae. Extending MDA to areas with coincident L. loa infection is problematic, and inexpensive point-of-care tests for L. loa are acutely needed. Herein, we present a lateral flow assay (LFA) to identify subjects with a serological response to Ll-SXP-1, a specific and validated marker of L. loa. The test was evaluated on serum samples from patients infected with L. loa (n = 109) and other helminths (n = 204), as well as on uninfected controls (n = 77). When read with the naked eye, the test was 94% sensitive for L. loa infection and was 100% specific when sera from healthy endemic and non-endemic controls or from those with S. stercoralis infections were used as the comparators. When sera of patients with O. volvulus, W. bancrofti, or M. perstans were used as the comparators, the specificity of the LFA was 82%, 87%, and 88%, respectively. A companion smartphone reader allowed measurement of the test line intensities and establishment of cutoff values. With a cutoff of 600 Units, the assay sensitivity decreased to 71%, but the specificity increased to 96% for O. volvulus, 100% for W. bancrofti, and 100% for M. perstans-infected individuals. The LFA may find applications in refining the current maps of L. loa prevalence, which are needed to eliminate onchocerciasis and lymphatic filariasis from the African continent.
基于伊维菌素的群体药物给药（MDA）计划在盘尾丝虫病和淋巴丝虫病的消除方面取得了显著成功。然而，在中非，由于一部分体内罗阿丝虫微丝蚴循环水平较高的个体出现了与伊维菌素相关的严重不良事件（SAE），其全面实施受到了阻碍。将MDA扩展到同时感染罗阿丝虫的地区存在问题，因此迫切需要用于检测罗阿丝虫的廉价即时检测方法。在此，我们展示了一种侧向流动分析（LFA），用于识别对罗阿丝虫特异性且经过验证的标志物Ll-SXP-1产生血清学反应的受试者。该检测方法在感染罗阿丝虫的患者（n = 109）、感染其他蠕虫的患者（n = 204）以及未感染对照（n = 77）的血清样本上进行了评估。肉眼读取时，该检测方法对罗阿丝虫感染的敏感性为94%，当使用来自健康流行区和非流行区对照或来自粪类圆线虫感染患者的血清作为对照时，特异性为100%。当使用盘尾丝虫、班氏丝虫或常现曼森线虫患者的血清作为对照时，LFA的特异性分别为82%、87%和88%。配套的智能手机阅读器可用于测量检测线强度并确定临界值。临界值设定为600单位时，该检测方法的敏感性降至71%，但对于盘尾丝虫感染个体，特异性提高到了96%，对于班氏丝虫感染个体为100%，对于常现曼森线虫感染个体为100%。LFA可能在完善当前罗阿丝虫流行地图方面找到应用，这对于从非洲大陆消除盘尾丝虫病和淋巴丝虫病是必要的。
