Courchamp F, Suppo C, Fromont E, Bouloux C
UMR CNRS 5558 Biométrie, Génétique et Biologie des Populations, Université Claude Bernard Lyon I, Villeurbanne, France.
Proc Biol Sci. 1997 Jun 22;264(1383):785-94. doi: 10.1098/rspb.1997.0111.
We present a deterministic model of the dynamics of two microparasites simultaneously infecting a single host population. Both microparasites are feline retroviruses, namely Feline Immunodeficiency Virus (FIV) and Feline Leukaemia Virus (FeLV). The host is the domestic cat Felis catus. The model has been tested with data generated by a long-term study of several natural cat populations. Stability analysis and simulations show that, once introduced in a population, FIV spreads and is maintained, while FeLV can either disappear or persist. Moreover, introduction of both viruses into the population induces an equilibrium state for individuals of each different pathological class. The viruses never induce the extinction of the population. Furthermore, whatever the outcome for the host population (persistence of FIV only, or of both viruses), the global population size at the equilibrium state is only slightly lower than it would have been in the absence of the infections (i.e. at the carrying capacity), indicating a low impact of the viruses on the population. Finally, the impact of the diseases examined simultaneously is higher than the sum of the impact of the two diseases examined separately. This seems to be due to a higher mortality rate when both viruses infect a single individual.
我们提出了一个确定性模型，用于描述两种微寄生虫同时感染单一宿主种群的动态变化。这两种微寄生虫均为猫逆转录病毒，即猫免疫缺陷病毒（FIV）和猫白血病病毒（FeLV）。宿主为家猫（Felis catus）。该模型已通过对多个自然猫种群的长期研究产生的数据进行了测试。稳定性分析和模拟结果表明，一旦在种群中引入，FIV会传播并持续存在，而FeLV可能消失或持续存在。此外，将两种病毒引入种群会导致每个不同病理类别的个体达到平衡状态。这些病毒从未导致种群灭绝。此外，无论宿主种群的结果如何（仅FIV持续存在，或两种病毒都持续存在），平衡状态下的全球种群规模仅略低于未感染时的规模（即承载能力），这表明病毒对种群的影响较小。最后，同时研究的这两种疾病的影响高于分别研究这两种疾病的影响之和。这似乎是由于当两种病毒感染同一个体时死亡率更高。
