The relationships between the burden of adult parasites, host age and the microfilarial density in human onchocerciasis
The relationships between the burden of adult parasites, host age and the microfilarial density in human onchocerciasis
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DOI：
10.1016/j.ijpara.2003.11.008
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发表时间：
2004-03-29
影响因子：
4
通讯作者：
Eichner, M
中科院分区：
文献类型：
--
作者：
Duerr, HP;Dietz, K;Eichner, M
我们调查的微丝蚴密度在皮肤和成年女性盘尾丝虫扭转的负担之间的关系，通过分析前控制结节切除术的数据，允许一个直接的方法，独立的曝光。布基纳法索169名患者和利比里亚182名患者的数据分别代表西非的萨凡纳和森林盘尾丝虫病。在布基纳法索，微丝蚴密度和蠕虫负担之间的饱和关系表明，在人类宿主中存在依赖密度的过程，而利比里亚的数据显示出线性关系，表明不存在密度依赖性。这种差异可能来源于两种寄生虫株之间的差异，即O.肠扭转一致的寄生虫菌株和独立的蠕虫负担，微丝蚴密度随着宿主年龄的增加，强调收购免疫耐受的概念。在利比里亚的男性宿主中，微丝蚴密度随着蠕虫负荷的增加而增加，比女性宿主更强，而在布基纳法索不能发现这种性别特异性差异。在本次调查的方法学部分，我们建议β分布是最适合描述微丝蚴密度的变化，我们提出了一种方法来考虑的不确定性，在成虫寄生虫负担，不能准确地确定蠕虫感染。密度依赖的影响进行了讨论，在人类宿主的免疫过程和控制程序的成功。所描述的关系表明，寄生虫和人类宿主之间的调节过程是多维度的，在高度的生物变异性内操作。(C)2003年澳大利亚寄生虫学会由爱思唯尔有限公司出版。保留所有权利。
We investigate the relationship between the microfilarial density in the skin and the burden of adult female Onchocerca volvulus by analysing pre-control nodulectomy data which allow for a direct approach, independent of exposure. The data of 169 patients in Burkina Faso and 182 patients in Liberia represent savannah and forest onchocerciasis in West Africa, respectively. Whereas in Burkina Faso, a saturating relationship between microfilarial density and worm burden suggests the operation of density-dependent processes within human hosts, the Liberian data show a linear relationship implying no density dependence. The differences may derive from differences between both parasite strains, i.e. the savannah or the forest strain of O. volvulus. Consistently for both parasite strains and independent of the worm burden, the microfilarial density increases with host age emphasising the concept of the acquisition of immunological tolerance. In male hosts in Liberia, the microfilarial density increases stronger with the worm burden than in female hosts, whereas such sex-specific differences cannot be found in Burkina Faso. In the methodological part of this investigation, we suggest the beta-distribution to be most appropriate for describing variability in microfilarial densities and we present an approach to consider the uncertainty in the adult parasite burden which cannot be determined precisely in helminth infections. Implications of density dependence are discussed with respect to immunological processes in the human host and with respect to the success of control programs. The relationships described show that regulatory processes between the parasite and the human host are multi-dimensional, operating within a high degree of biological variability. (C) 2003 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.