人兽共患病数学模型及其应用

发布时间：2018-03-01 07:13

本文关键词： 人兽共患病自然宿主中间宿主跨物种传播模型有效政策措施　出处：《北京建筑大学》2017年硕士论文　论文类型：学位论文

【摘要】：人兽共患病是指由同一种病原体引起,且能够在人类与动物之间进行自然传播的疫病.人类与动物越来越频繁的接触增加了人类患人兽共患病的概率.而人兽共患病的爆发,不仅威胁着人类身体健康,重创养殖业发展,同时也会造成巨大经济损失,对人类生产生活产生极大影响.目前,我们还不能对人兽共患病病原体传播机制完全掌控,也没有制定出对其进行有效干预的防控措施.了解人兽共患病的传播机理,将有利于其防治工作的进一步展开.人兽共患病是一种能够在不同物种间进行传播的传染性疾病.大多数人兽共患病是动物源的,人类能够直接地从自然宿主感染疾病或间接地通过中间宿主感染疾病.不同物种在人兽共患病传播过程中起到不同作用.本文构建三种常见类型的跨物种人兽共患病传播模型,分别为自然宿主—人类模型(TYPE 1),自然宿主—中间宿主—人类模型(TYPE 2),自然宿主—中间宿主(变异)—人类模型(TYPE 3).对于三种传播形式,当没有中间宿主介入时(TYPE 1),自然宿主决定疾病爆发与否,以及爆发后的流行趋势.当RN01时(RN0指自然宿主中疾病传播基本再生数),人兽共患病能够在人群中爆发;而随着自然宿主种群规模增大,疾病流行程度也会增强.但如果有中间宿主介入(TYPE 2、TYPE 3),当RN01时,人兽共患病同样能够在人群中爆发,并不受RI0(RI0指中间宿主中疾病传播基本再生数)是否大于1的影响;但中间宿主介入后,自然宿主对人兽共患病流行趋势的影响降低,而中间宿主对疾病流行趋势的影响反而更强,随着中间宿主种群规模的增大,疾病流行程度会增强.为应对突发人兽共患病危机,本文还在原有模型基础上,针对不同物种构建相应政策措施模型,并对不同措施效果进行分析.三种政策措施均可以对人兽共患病流行产生抑制作用,降低基本再生数.无论是否采取政策措施,疾病爆发的条件均是自然宿主基本再生数大于1;而疾病消亡的条件是各物种种群中的基本再生数均小于1.同时,饲养动物(中间宿主)的介入,使得在疾病流行时,对饲养动物的防控效果优于对野生动物(自然宿主)的防控.最后,本文选取几类常见的甲型流感传播类型,用以补充说明无人际传播人兽共患病模型.四种模型分别为无中间宿主且具有人际传播模型(TYPE 1-1)、无中间宿主且无人际传播模型(TYPE 1-2)、有中间宿主且具有人际传播模型(TYPE 2-1)、有中间宿主且无人际传播模型(TYPE 2-2).其中,TYPE 1-2、TYPE 2-2因病原体无人际传播能力,在相同条件下,疾病流行程度较其他两种低.
[Abstract]:Zoonosis is a disease that is caused by the same pathogen and can spread naturally between humans and animals. More frequent contact between humans and animals increases the probability of zoonosis in humans. Not only does it threaten human health and damage the development of aquaculture, but it also causes huge economic losses and has a great impact on human production and life. At present, we cannot fully control the transmission mechanism of zoonotic pathogens. There is no effective intervention to prevent and control the disease. Understand the transmission mechanism of zoonosis. Zoonosis is an infectious disease that can spread between different species. Most zoonosis is animal origin. Human beings can infect diseases directly from natural hosts or indirectly through intermediate hosts. Different species play different roles in the transmission of zoonosis. They are natural host human model TYPE 1, natural host intermediate host human model TYPE 2, natural host human model TYPE 3, respectively. When there is no intermediate host intervention, the natural host determines the disease outbreak or not, and the epidemic trend after the outbreak. But if an intermediate host is involved in TYPE2TYPE3, when RN01 occurs, zoonosis can also erupt in people. It was not affected by whether the number of basic regeneration of disease transmission in intermediate host of RI0(RI0 was greater than 1, but the influence of natural host on epidemic trend of zoonosis was decreased after intervention of intermediate host. However, the intermediate host has a stronger effect on the epidemic trend. With the increase of the population size of the intermediate host, the epidemic degree of the disease will increase. In order to deal with the crisis of zoonotic disease, this paper is still based on the original model. The corresponding models of policies and measures were constructed for different species and the effects of different measures were analyzed. The three kinds of policies and measures can inhibit the prevalence of zoonosis and reduce the number of basic regeneration. The condition of disease outbreak is that the basic regeneration number of natural host is greater than 1, and the condition of disease extinction is that the number of basic regeneration in each species population is less than 1. At the same time, the intervention of breeding animals (intermediate host) makes the disease prevalent. The control effect of breeding animals is better than that of wild animals (natural hosts). Finally, this paper selects several common types of influenza A transmission. The four models are non-intermediate host and interpersonal transmission model (TYPE 1-1), no intermediate host and no interpersonal transmission model (TYPE 1-2), with intermediate host and interpersonal transmission model. TYPE 2-1, with intermediate host and no interpersonal transmission model, TYPE 2-2. TYPE 1-2 TYPE 2-2 is not capable of interpersonal transmission due to pathogens. Under the same conditions, the prevalence of the disease was lower than that of the other two.
【学位授予单位】：北京建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O175

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