The early sporogonic cycle of Plasmodium falciparum in laboratory-infected Anopheles gambiae: an estimation of parasite efficacy
The early sporogonic cycle of Plasmodium falciparum in laboratory-infected Anopheles gambiae: an estimation of parasite efficacy
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DOI：
10.1046/j.1365-3156.1998.00156.x
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发表时间：
1998-01-01
影响因子：
3.3
通讯作者：
Boudin, C
中科院分区：
文献类型：
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作者：
Gouagna, LC;Mulder, B;Boudin, C
本研究调查了实验室饲养的冈比亚按蚊在孢子生殖早期恶性疟原虫阶段的寄生虫密度的连续损失，冈比亚按蚊通过膜喂养自然感染的配子体载体的血液（>50配子体/mm（3））感染。用免疫荧光法研究了恶性疟原虫Mm在蚊体内从受精卵到卵囊的发育阶段，方法是使用抗新形成配子表面上的Pfs 25蛋白的单克隆抗体。该方法允许在通过中肠壁之前、期间和之后评估各种孢子发生阶段。在感染后3 h（合子和巨配子）和24 h（动合子）测定整个血粉中的寄生虫密度。在蚊子血餐后48小时，检查中肠是否存在早期卵囊。对于中等大小的卵囊计数，在感染后第7天使用经典的显微镜检查。根据冈比亚按蚊孢子生殖周期不同早期阶段寄生虫密度的连续损失来估计寄生虫的效力。在高配子体密度下实现了37次实验感染，从64到2392配子体/mm（3），所有配子体载体均显示100%的圆形感染;在91.9%中发现动合子。卵囊感染率在第2天（年轻卵囊）为48.6%，在第7天（中型卵囊）为37.8%。各虫态的平均密度为：圆形12.6只，动卵5.5只，幼卵囊1.8只，中型卵囊2只。两个连续的寄生虫阶段（圆形形式/动合子，动合子/年轻的卵囊，年轻的卵囊/中型卵囊）和圆形和中型卵囊之间的显着相关性。平均寄生虫密度显着下降之间的圆形形式和动合子（产量Y1 = 41.6%）和动合子和年轻的卵囊（Y2 = 61.4%）。相比之下，未观察到年轻卵囊和中等大小卵囊之间的显著降低（Y3 = 91.2%）。的总产率：早期孢子生殖周期（在第7天从圆形到卵囊）等于25.7%，表明在孢子生殖周期的早期阶段，从感染后3小时到第7天，几乎3/4的总寄生虫丢失。
This study investigated the successive losses in the parasite densities of Plasmodium falciparum stages during the early sporogony in laboratory-reared Anopheles gambiae infected by membrane feeding with blood from naturally infected gametocyte carriers (>50 gametocytes/mm(3)). The developmental stages of P. falciparum Mm in the mosquito were studied from zygote to oocyst, by immunofluorescent method using monoclonal antibodies against the Pfs25 protein present on the surface of newly formed gametes. This method allows for assessment of the various sporogonic stages before, during and after passage of the midgut wall. Parasite densities were determined within the entire blood meal at 3 h (zygotes and macrogametes) and 24 h (ookinetes) post-infection. At 48 h after the mosquito blood meal, midguts were checked for the presence of early oocysts. For the mid-size oocysts count, classic microscopy examination was used at day 7 post-infection. The parasite efficacy was estimated by following successive losses in parasite densities between different early stages of the sporogonic cycle in A, gambiae, Thirty-seven experimental infections were realized with high gametocyte densities, ranging from 64 to 2392 gametocytes/mm(3), All gametocyte carriers showed infection with round forms 100%; ookinetes were found in 91.9%. The prevalences of infections with oocysts were 48.6% at day 2 (young oocyst) and 37.8% at day 7 (mid-size oocyst). The mean densities per mosquito for each parasite stage were 12.6 round forms, 5.5 ookinetes, 1.8 young oocyst and 2 mid-size oocysts. Significant correlations were found between two consecutive parasite stages (round forms/ookinetes, ookinetes/young oocysts, young oocysts/mid-size oocysts) and between round forms and mid-size oocysts. The mean parasite density significantly decreased between round forms and ookinetes (yield Y1 = 41.6%) and between ookinetes and young oocysts (Y2 = 61.4%). By contrast, no significant decrease was observed between young oocysts and mid-size oocysts (Y3 = 91.2%). The overall yield of the: early sporogonic cycle (from round form to oocyst at day 7) was equal to 25.7%, indicating that almost 3/4 of the total parasites were lost during the early step of the sporogonic cycle, from 3 h post-infection to day 7.