Relationship between transmission intensity and incidence of dengue hemorrhagic fever in Thailand.
Relationship between transmission intensity and incidence of dengue hemorrhagic fever in Thailand.
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DOI：
10.1371/journal.pntd.0000263
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发表时间：
2008-07-16
影响因子：
3.8
通讯作者：
Davies C
中科院分区：
文献类型：
--
作者：
Thammapalo S;Nagao Y;Sakamoto W;Saengtharatip S;Tsujitani M;Nakamura Y;Coleman PG;Davies C
登革热是最普遍的蚊媒病毒，潜在致命的登革出血热（DHF）主要发生在继发感染中。最近有人假设，由于交叉免疫的存在，在传播强烈的地区，登革出血热的发病率与传播强度之间可能呈负相关。我们以经验检验了这一假设，使用载体丰度作为传播强度的替代品。房屋指数（HI）的定义是被病媒幼虫/蛹侵染的住户百分比，该指数是2002年至2004年期间对泰国100万所房屋进行调查得出的。首先，由于HI与人群中DHF的平均年龄呈负相关，因此证实了HI作为传播强度替代品的效用。其次，研究DHF发病率与HI之间的关系。DHF的发病率只增加到HI约为30，但此后下降。将HI从目前的最高水平降低到30将使发病率增加40%以上。模拟采用了最近提出的交叉免疫模型，产生的结果与实际流行病学数据相似。据预测，交叉免疫在发病率上产生很大的变化，从而模糊了发病率与传播强度之间的关系。只有在较长时间内（例如100至10年）收集的数据取平均值时，这种关系才会变得明显。登革出血热发病率与登革热传播强度呈负相关，表明在传播强度较大的地区，媒介丰度降低不足可能会增加登革出血热的长期发病率。需要进行比目前研究持续时间长得多的进一步研究。登革热病毒感染可导致登革出血热（DHF），这是一种危险的疾病。这种最普遍的蚊媒病毒每年感染数千万（或更多）人，目前还没有批准的疫苗。因此，卫生当局一直把重点放在减少媒介蚊子伊蚊属上。然而，一个新的数学假设预测，在高度流行的国家减少伊蚊可能会“增加”登革出血热的发病率，这是相当矛盾的。为了根据实际数据验证这一假设，我们将从泰国1000个县收集的登革出血热发病率与通过调查100万户家庭获得的伊蚊丰度数据进行了比较。分析表明，将泰国伊蚊丰度从最高水平降低到中等水平将使发病率增加40%以上。此外，基于上述假设，我们开发了计算机模拟软件。模拟预测，流行病学研究应持续很长时间，最好超过十年，以清楚地发现伊蚊数量与登革出血热发病率之间的这种矛盾关系。这种长期研究是必要的，特别是因为在防治伊蚊方面已经（也许将）花费了巨大的努力和资源。
Dengue is the most prevalent mosquito-borne virus, and potentially fatal dengue hemorrhagic fever (DHF) occurs mainly in secondary infections. It recently was hypothesized that, due to the presence of cross-immunity, the relationship between the incidence of DHF and transmission intensity may be negative at areas of intense transmission. We tested this hypothesis empirically, using vector abundance as a surrogate of transmission intensity. House Index (HI), which is defined as the percentage of households infested with vector larvae/pupae, was obtained from surveys conducted on one million houses in Thailand, between 2002 and 2004. First, the utility of HI as a surrogate of transmission intensity was confirmed because HI was correlated negatively with mean age of DHF in the population. Next, the relationship between DHF incidence and HI was investigated. DHF incidence increased only up to an HI of about 30, but declined thereafter. Reduction of HI from the currently maximal level to 30 would increase the incidence by more than 40%. Simulations, which implemented a recently proposed model for cross-immunity, generated results that resembled actual epidemiological data. It was predicted that cross-immunity generates a wide variation in incidence, thereby obscuring the relationship between incidence and transmission intensity. The relationship would become obvious only if data collected over a long duration (e.g., >10 years) was averaged. The negative relationship between DHF incidence and dengue transmission intensity implies that in regions of intense transmission, insufficient reduction of vector abundance may increase long-term DHF incidence. Further studies of a duration much longer than the present study, are warranted. An infection with dengue virus may lead to dengue hemorrhagic fever (DHF), a dangerous illness. There is no approved vaccine for this most prevalent mosquito-borne virus, which infects tens of millions (or more) people annually. Therefore, health authorities have been putting an emphasis on reduction of vector mosquitoes, genus Aedes. However, a new mathematical hypothesis predicted, quite paradoxically, that reducing Aedes mosquitoes in highly endemic countries may “increase” the incidence of DHF. To test this hypothesis based upon actual data, we compared DHF incidence collected from each of 1,000 districts in Thailand to data of Aedes abundance, which was obtained by surveying one million households. This analysis showed that reducing Aedes abundance from the highest level in Thailand to a moderate level would increase the incidence by more than 40%. In addition, we developed computer simulation software based upon the above hypothesis. The simulation predicted that epidemiological studies should be continued for a very long duration, preferably over a decade, to clearly detect such a paradoxical relationship between Aedes abundance and incidence of DHF. Such long-term studies are necessary, especially because tremendous efforts and resources have been (and perhaps will be) spent on combating Aedes.
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影响因子：
15.8
作者：
Cazelles B;Chavez M;McMichael AJ;Hales S
通讯作者：
Hales S
影响因子：
64.8
作者：
HALSTEAD, SB;OROURKE, EJ
通讯作者：
OROURKE, EJ
DOI：
10.1016/s1201-9712(02)90072-x
发表时间：
2002-06-01
影响因子：
8.4
作者：
Guzman, Maria G.;Kouri, Gustavo;Halstead, Scott B.
通讯作者：
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影响因子：
168.9
作者：
Coleman, PG;Perry, BD;Woolhouse, MEJ
通讯作者：
Woolhouse, MEJ
影响因子：
7.7
作者：
DANTES, HG;KOOPMAN, JS;MIRELLES, ER
通讯作者：
MIRELLES, ER