疾病擴張之生物族群模式研究--以狂犬病為例

The Population Model of Disease Proliferation: the case of rabies

劉恬吟(Tien-Yin Liu)

指導教授 ： 程建中

高雄醫學大學/生命科學院/醫藥暨應用化學研究所/碩士(2005年)

摘要

狂犬病是種死亡率極高的的人畜共通傳染病。台灣地區自民國四十七年起即未再出現病例，是世界上極少數的狂犬病非疫區之一。為防止本病入侵，本研究結合複合族群和流行病學理論，建立狂犬病入侵犬族群不同情況的動態模式，模擬推演免疫策略以控制疾病。
首先以複合族群模式模擬健康族群的動態，其次與流行病學理論結合，建立模式分析罹病的族群動態。本研究發現一旦當狂犬病引進以後，隨著移動速率和感染率的增加，感受性的族群會趨於滅絕狀態，最終則全由感染性的族群所佔有。進而為瞭解對罹病族群的控制，本研究將免疫接種策略加入族群模式。結果發現當移動速率不高時，疾病雖無法在族群中擴散，但其複合族群的佔有比例亦無法提高。隨著移動速率的增加，其族群的佔有比例雖提高，但卻是僅剩感染性族群和免疫性族群共存，兩族群間呈一競爭函數關係。
由本研究結果知，降低移動速率雖可有效避免疾病擴散，但無法提高族群佔有比例。感染率和移動率的降低雖能有效控制疾病擴張，但成效有限。免疫接種率的提高可使得免疫性族群增加，故當疾病入侵時，即便是此複合族群具有高移動率的特性，高免疫接種率亦可以有效地控制住疾病的擴張。

關鍵字

複合族群 ； 流行病學 ； 狂犬病 ； 族群模式 ； 疾病擴張模擬

並列摘要

Rabies is a kind of lethal zoonosis. There is no rabies case occurred in Taiwan area from 1958. Taiwan is one of few areas as rabies-free zone in the world. In order to prevent rabies invasion, this research is trying to integrate the theories of meta-population and epidemiology, to construct the dynamic models for various status of the dog populations, and to simulate the development of vaccination strategy for the disease control.
Firstly, the classic meta-population model was applied to simulate the dynamics of the healthy population as a start. Secondly, the meta-population model was integrated with the epidemiology to construct a modified model system to analyze the infected population dynamics. The result suggests that as the population infected rabies, the higher movement rate and the transmission rate would make the susceptible population extinction and the infected population taken over the whole patches. Thirdly, for understanding the control of infected population, this research incorporates the control strategy of vaccination to the meta-population model system. The result implies that although the low movement rate make rabies could not proliferate in the population, the occupied ratio of the meta-population could not raise, either. As the movement rate increase, the occupied ratio of the meta-population could raise but only the infected and immune sub-populations co-existed. These two sub-populations have shown a competitive function relationship.
Although reducing movement rate might effectively keep the disease from outbreak, it might not raise the occupied ratios of patches by the meta-population. The reduction of infected rate and movement rate can control disease expanding, but the effects are rather limited. Increasing vaccination rate can boost the immune population; therefore, it can effectively control the rabid proliferation even in high movement rate as the disease invading.

並列關鍵字

epidemiology ； metapopulation ； rabies ； population model ； disease proliferation simulate

參考文獻

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