Temporal Dynamics of European Bat Lyssavirus Type 1 and Survival of <em>Myotis myotis</em> Bats in Natural Colonies

Many emerging RNA viruses of public health concern have recently been detected in bats. However, the dynamics of these viruses in natural bat colonies is presently unknown. Consequently, prediction of the spread of these viruses and the establishment of appropriate control measures are hindered by a lack of information. To this aim, we collected epidemiological, virological and ecological data during a twelve-year longitudinal study in two colonies of insectivorous bats (Myotis myotis) located in Spain and infected by the most common bat lyssavirus found in Europe, the European bat lyssavirus subtype 1 (EBLV-1). This active survey demonstrates that cyclic lyssavirus infections occurred with periodic oscillations in the number of susceptible, immune and infected bats. Persistence of immunity for more than one year was detected in some individuals. These data were further used to feed models to analyze the temporal dynamics of EBLV-1 and the survival rate of bats. According to these models, the infection is characterized by a predicted low basic reproductive rate (R0 = 1.706) and a short infectious period (D = 5.1 days). In contrast to observations in most non-flying animals infected with rabies, the survival model shows no variation in mortality after EBLV-1 infection of M. myotis. These findings have considerable public health implications in terms of management of colonies where lyssavirus-positive bats have been recorded and confirm the potential risk of rabies transmission to humans. A greater understanding of the dynamics of lyssavirus in bat colonies also provides a model to study how bats contribute to the maintenance and transmission of other viruses of public health concern.近年来，科研人员在蝙蝠体内陆续检测出多种受公共卫生重点关注的新型RNA病毒（RNA）。然而，这类病毒在自然蝙蝠种群中的传播动态目前仍未明确。因此，由于缺乏相关数据支撑，对这类病毒传播趋势的预测以及针对性防控措施的制定均受到极大阻碍。为此，我们针对西班牙境内的两个食虫性大鼠耳蝠（Myotis myotis）种群开展了为期12年的纵向研究，采集了流行病学、病毒学及生态学相关数据；该种群感染了欧洲地区最为常见的蝙蝠狂犬病毒（lyssavirus）——欧洲蝙蝠狂犬病病毒1亚型（EBLV-1）。本次主动监测结果显示，蝙蝠狂犬病毒呈现周期性循环感染态势，易感、免疫及感染个体的种群数量均呈现周期性波动。部分个体的免疫保护时长可超过一年。研究团队进一步将上述数据用于模型构建，以分析欧洲蝙蝠狂犬病病毒1亚型的时间动态变化规律以及蝙蝠的存活率。基于上述模型，该病毒感染的预测特征为较低的基本再生数（R0=1.706）以及较短的传染期（D=5.1天）。与多数感染狂犬病病毒的非飞行类动物的观测结果不同，该生存模型显示，大鼠耳蝠（Myotis myotis）感染欧洲蝙蝠狂犬病病毒1亚型后，死亡率未出现显著变化。上述研究结果对于已检出蝙蝠狂犬病毒阳性个体的种群管理具有重要的公共卫生指导意义，同时证实了狂犬病病毒向人类传播的潜在风险。对蝙蝠种群中狂犬病毒动态的深入研究，同时也可为解析蝙蝠如何维持并传播其他受公共卫生关注的病毒提供优质研究模型。