Unité de la Génétique Fonctionnelle des Maladies Infectieuses, Institut Pasteur , Paris , France ; URA3012, Centre National de la Recherche Scientifique , Paris , France.
Sustainable Sciences Institute , Managua , Nicaragua.
Front Immunol. 2014 Jun 11;5:280. doi: 10.3389/fimmu.2014.00280. eCollection 2014.
Dengue is a major international public health concern, and the number of outbreaks has escalated greatly. Human migration and international trade and travel are constantly introducing new vectors and pathogens into novel geographic areas. Of particular interest is the extent to which dengue virus (DENV) infections are subclinical or inapparent. Not only may such infections contribute to the global spread of DENV by human migration, but also seroprevalence rates in naïve populations may be initially high despite minimal numbers of detectable clinical cases. As the probability of severe disease is increased in secondary infections, populations may thus be primed, with serious public health consequences following introduction of a new serotype. In addition, pre-existing immunity from inapparent infections may affect vaccine uptake, and the ratio of clinically apparent to inapparent infection could affect the interpretation of vaccine trials. We performed a literature search for inapparent DENV infections and provide an analytical review of their frequency and associated risk factors. Inapparent rates were highly variable, but "inapparent" was the major outcome of infection in all prospective studies. Differences in the epidemiological context and type of surveillance account for much of the variability in inapparent infection rates. However, one particular epidemiological pattern was shared by four longitudinal cohort studies: the rate of inapparent DENV infections was positively correlated with the incidence of disease the previous year, strongly supporting an important role for short-term heterotypic immunity in determining the outcome of infection. Primary and secondary infections were equally likely to be inapparent. Knowledge of the extent to which viruses from inapparent infections are transmissible to mosquitoes is urgently needed. Inapparent infections need to be considered for their impact on disease severity, transmission dynamics, and vaccine efficacy and uptake.
登革热是一个重大的国际公共卫生问题，疫情爆发的数量急剧增加。人类迁移以及国际贸易和旅行不断将新的病媒和病原体引入新的地理区域。特别值得关注的是，登革病毒（DENV）感染的无症状或隐匿程度。无症状感染不仅可能通过人类迁移导致 DENV 在全球范围内传播，而且在新出现的地区，幼稚人群中的血清流行率可能最初很高，尽管可检测到的临床病例很少。由于二次感染时发生重症疾病的概率增加，因此人群可能会被预先致敏，新血清型的引入可能会带来严重的公共卫生后果。此外，无症状感染产生的预先存在的免疫力可能会影响疫苗接种率，并且临床表现明显与无症状感染的比例可能会影响疫苗试验的解释。我们对隐匿性 DENV 感染进行了文献检索，并对其频率和相关危险因素进行了分析性综述。无症状感染率差异很大，但所有前瞻性研究中“无症状”都是感染的主要结局。流行病学背景和监测类型的差异在很大程度上解释了无症状感染率的差异。然而，四项纵向队列研究中有一个特定的流行病学模式是共有的：无症状 DENV 感染的发生率与前一年疾病的发病率呈正相关，这强烈支持短期异型免疫在决定感染结局方面的重要作用。初次感染和二次感染同样可能是无症状的。急需了解无症状感染的病毒传播给蚊子的程度。需要考虑无症状感染对疾病严重程度、传播动力学以及疫苗效力和接种率的影响。
