Equine infectious anemia (EIA) is a highly infectious disease in members of the Equidae family, caused by equine infectious anemia virus (EIAV). The disease severity ranges from subclinical to acute or chronic, and causes significant economic losses in the equine industry worldwide. Serologic tests for detection of EIAV infection have some concerns given the prolonged seroconversion time. Therefore, molecular methods are needed to improve surveillance programs for this disease. We attempted detection of EIAV in 6 clinical and 42 non-clinical horses in Nuevo Leon State, Mexico, using the agar gel immunodiffusion (AGID) test for antibody detection, and nested and hemi-nested PCR for detection of proviral DNA. We found that 6 of 6, 5 of 6, and 6 of 6 clinical horses were positive by AGID, nested PCR, and hemi-nested PCR, respectively, whereas 0 of 42, 1 of 42, and 9 of 42 non-clinical horses were positive by these tests, respectively. BLAST analysis of the 203-bp 5′-LTR/tat segment of PCR product revealed 83–93% identity with EIAV isolates in GenBank and reference strains from other countries. By phylogenetic analysis, our Mexican samples were grouped in a different clade than other sequences reported worldwide, indicating that the LRT/tat region represents an important target for the detection of non-clinical horses.

马传染性贫血（EIA）是马科成员的一种高度传染性疾病家族，由马传染性贫血病毒（EIAV）引起。该疾病的严重程度从亚临床到急性或慢性不等，并在全球马业造成重大经济损失。鉴于血清转换时间延长，检测 EIAV 感染的血清学检测存在一些问题。因此，需要分子方法来改进这种疾病的监测计划。我们尝试在墨西哥新莱昂州的 6 匹临床马和 42 匹非临床马中检测 EIAV，使用琼脂凝胶免疫扩散 (AGID) 测试进行抗体检测，并使用巢式和半巢式 PCR 检测前病毒 DNA。我们发现 AGID、巢式 PCR 和半巢式 PCR 分别为 6 头、6 头中的 5 头和 6 头临床马中的 6 头，而 42 头中的 0 头、42 头中的 1 头和 42 头中的 9 头非临床马这些测试分别为阳性。PCR 产物的tat片段与 GenBank 中的 EIAV 分离株和其他国家的参考株有 83-93% 的同一性。通过系统发育分析，我们的墨西哥样本与世界范围内报道的其他序列不同，这表明 LRT/ tat区域代表了检测非临床马的重要目标。