Arthropod-borne Infectious Disease Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, 1692 Campus Delivery, Fort Collins, CO 80523-1692, USA.
Parasit Vectors. 2012 Jun 28;5:131. doi: 10.1186/1756-3305-5-131.
Over two dozen mermithid nematodes have been described parasitizing mosquitoes worldwide, however, only two species were found in Africa. Mermithid nematodes kill their mosquito host upon emergence, which suggests that they could be developed as biological control agents of mosquitoes. Both Romanomermis culicivorax and Romanomermis iyengari have been reared for mass release to control numerous Anopheles species vector populations, and in one instance this may have led to reduced malaria prevalence in a human population.
Anopheles mosquitoes were collected during a malaria study in southeastern Senegal. Two different adult blood fed mosquitoes had a single mermithid nematode emerge from their anus while they were being held post-capture. Primers from the 18 S rDNA were developed to sequence nematode DNA and screen mosquitoes for mermithid DNA. 18 S rDNA from the Senegalese mermithid and other mermithid entries in GenBank were used to create a Maximum Parsimony tree of the Mermithidae family.
The mermithid was present in 1.8% (10/551) of the sampled adult Anopheles species in our study area. The mermithid was found in An. gambiae s.s., An. funestus, and An. rufipes from the villages of Ndebou, Boundoucondi, and Damboucoye. Maximum parsimony analysis confirmed that the nematode parasites found in Anopheles were indeed mermithid parasites, and of the mermithid sequences available in GenBank, they are most closely related to Strelkovimermis spiculatus.
To our knowledge, this is the first report of mermithids from adult Anopheles mosquitoes in Senegal. The mermithid appears to infect Anopheles mosquitoes that develop in diverse larval habitats. Although maximum parsimony analysis determined the mermithid was closely related to Strelkovimermis spiculatus, several characteristics of the mermithid were more similar to the Empidomermis genus. Future mermithid isolations will hopefully allow: formal taxonomic identification, laboratory colonization, determination of life history traits and species specificity, and characterize its usefulness as a biological control agent.
全世界已经描述了二十多种寄生蚊子的蛭形线虫，但仅在非洲发现了两种。蛭形线虫在孵化后会杀死其蚊子宿主，这表明它们可能被开发为蚊子的生物控制剂。Romanomermis culicivorax 和 Romanomermis iyengari 已被大量繁殖并用于大规模释放，以控制许多疟蚊种群，并且在一种情况下，这可能导致人群中疟疾患病率降低。
在塞内加尔东南部的疟疾研究中收集了疟蚊。两只不同的成年吸血蚊子在被捕获后从肛门中出现了一只单一的蛭形线虫。从 18S rDNA 中开发了引物来对线虫 DNA 进行测序，并筛选蚊子中的蛭形 DNA。使用塞内加尔蛭形线虫和 GenBank 中其他蛭形线虫的 18S rDNA 为 Mermithidae 科创建最大简约树。
在所研究地区的 551 只成年疟蚊中，有 1.8%（10/551）的样本中存在蛭形线虫。在 Ndebou、Boundoucondi 和 Damboucoye 村庄的 An. gambiae s.s.、An. funestus 和 An. rufipes 中发现了蛭形线虫。最大简约分析证实，在疟蚊中发现的线虫寄生虫确实是蛭形线虫寄生虫，并且在 GenBank 中可用的蛭形线虫序列中，它们与 Strelkovimermis spiculatus 最为密切相关。
据我们所知，这是塞内加尔首次从成年疟蚊中报告蛭形线虫。蛭形线虫似乎感染了在不同幼虫栖息地中发育的疟蚊。尽管最大简约分析确定蛭形线虫与 Strelkovimermis spiculatus 密切相关，但蛭形线虫的几个特征与 Empidomermis 属更为相似。未来的蛭形线虫分离有望实现：正式的分类鉴定、实验室定殖、生活史特征和种特异性的确定，并确定其作为生物控制剂的有用性。
