HTLV-1 was the first described human retrovirus and was soon found to be associated with severe clinical diseases, including a devastating lymphoma/leukemia and other inflammatory diseases. Although HTLV-2 is not usually pathogenic, it is widely distributed among native Indian populations in Brazil, particularly in the Amazon region of the country. Presently, HTLV spreads mainly by the sexual route and from mother to child, and virus persistence is an active biological factor aiding its transmission. Recently, the use of illicit drugs has been shown to be an additional risk factor, showing the influence of new habits on the epidemiology of HTLV in the region. Despite the detection of the virus in several different populations in the Amazon region of Brazil for almost 30 years, the exact prevalence of HTLV-1/2 is not well defined. The original biases in sampling and the selection of epidemiologically unsuitable populations were commonly repeated in most prevalence studies, generating unreliable and conflicting figures that do not represent the actual prevalence of HTLV. The improvements in clinical and laboratory facilities have resulted in the description of several clinical manifestations that were previously unknown in the region. The extent of the spread of the virus must be defined in this region, which is the largest geographical area of the country. As prophylaxis advances toward the use of vaccines against HTLV-1, it is important to determine who is at risk of being infected and developing a disease to successfully implement preventive measures, particularly as proposals are made to eradicate the virus among humans.

中文翻译：

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描述巴西亚马逊地区 HTLV 流行病学的挑战

HTLV-1 是第一个被描述的人类逆转录病毒，很快被发现与严重的临床疾病有关，包括毁灭性的淋巴瘤/白血病和其他炎症性疾病。尽管 HTLV-2 通常不具有致病性，但它广泛分布于巴西的印度本土人群中，尤其是在该国的亚马逊地区。目前，HTLV主要通过性途径和母婴传播，病毒的持续存在是帮助其传播的活跃生物因素。最近，非法药物的使用已被证明是一个额外的危险因素，表明新习惯对该地区 HTLV 流行病学的影响。尽管近 30 年来一直在巴西亚马逊地区的几个不同人群中检测到该病毒，但 HTLV-1/2 的确切流行率尚未明确。在大多数流行研究中，最初的抽样偏差和选择流行病学上不合适的人群通常会重复出现，产生不可靠和相互矛盾的数字，不能代表 HTLV 的实际流行率。临床和实验室设施的改进导致描述了该地区以前未知的几种临床表现。必须在该地区确定病毒的传播范围，该地区是该国最大的地理区域。随着预防措施朝着使用针对 HTLV-1 的疫苗发展，确定谁有感染和发展疾病的风险以成功实施预防措施非常重要，特别是在提出在人类中根除该病毒的建议时。