Otero Luisa, Schall Jos J, Cruz Virnaliz, Aaltonen Kristen, Acevedo Miguel A
Department of Biology, University of Puerto Rico, Río Piedras, Puerto Rico.
Department of Biology, University of Vermont, Burlington, Vermont, USA.
Parasitology. 2019 Apr;146(4):453-461. doi: 10.1017/S0031182018001750. Epub 2018 Oct 15.
Understanding the consequences of environmental fluctuations for parasite dynamics requires a long-term view stretching over many transmission cycles. Here we studied the dynamics of three malaria parasites (Plasmodium azurophilum, P. leucocytica and P. floridense) infecting the lizard Anolis gundlachi, in the rainforest of Puerto Rico. In this malaria-anole system we evaluated temporal fluctuations in individual probability of infection, the environmental drivers of observed variation and consequences for host body condition and Plasmodium parasites assemblage. We conducted a total of 15 surveys including 10 from 1990 to 2002 and five from 2015 to 2017. During the early years, a lizard's probability of infection by all Plasmodium species appeared stable despite disturbances ranging from two hurricanes to short droughts. Over a longer timescale, probability of infection and overall prevalence varied significantly, following non-linear relationships with temperature and rainfall such that highest prevalence is expected at intermediate climate measures. A perplexing result was that host body condition was maximized at intermediate levels of rainfall and/or temperature (when risk of infection was highest), yet we found no significant decreases in body condition due to infection. Plasmodium parasite species composition varied through time with a reduction and near local extinction of P. floridense. Our results emphasize the need for long-term studies to reveal host-parasite dynamics, their drivers and consequences.
要了解环境波动对寄生虫动态的影响，需要有跨越多个传播周期的长期视角。在此，我们研究了三种疟原虫（嗜天蓝疟原虫、白细胞疟原虫和弗罗里达疟原虫）在波多黎各雨林中感染变色蜥的动态情况。在这个疟疾-变色蜥系统中，我们评估了个体感染概率的时间波动、观察到的变异的环境驱动因素以及对宿主身体状况和疟原虫组合的影响。我们总共进行了15次调查，其中10次是在1990年至2002年期间，5次是在2015年至2017年期间。在早期，尽管经历了从两次飓风到短期干旱等各种干扰，但蜥蜴被所有疟原虫物种感染的概率似乎保持稳定。在更长的时间尺度上，感染概率和总体患病率有显著变化，与温度和降雨量呈非线性关系，因此预计在中等气候条件下患病率最高。一个令人困惑的结果是，宿主身体状况在中等降雨量和/或温度水平（即感染风险最高时）达到最佳，但我们发现感染并未导致身体状况显著下降。疟原虫物种组成随时间变化，弗罗里达疟原虫数量减少且近乎在当地灭绝。我们的研究结果强调了进行长期研究以揭示宿主-寄生虫动态、其驱动因素和后果的必要性。
