Bioactivity of miltefosine against aquatic stages of Schistosoma mansoni, Schistosoma haematobium and their snail hosts, supported by scanning electron microscopy

<p>Abstract</p> <p>Background</p> <p>Miltefosine, which is the first oral drug licensed for the treatment of leishmaniasis, was recently reported to be a promising lead compound for the synthesis of novel antischistosomal derivatives with potent activity <it>in vivo </it>against different developmental stages of <it>Schistosoma mansoni</it>. In this paper an <it>in vitro </it>study was carried out to investigate whether it has a biocidal activity against the aquatic stages of <it>Schistosoma mansoni </it>and its snail intermediate host, <it>Biomphalaria alexandrina </it>, thus being also a molluscicide. Additionally, to see whether miltefosine can have a broad spectrum antischistosomal activity, a similar <it>in vitro </it>study was carried out on the adult stage of <it>Schistosoma haematobium</it>, the second major human species, its larval stages and snail intermediate host, <it>Bulinus truncutes</it>. This was checked by scanning electron microscopy.</p> <p>Results</p> <p>Miltefosine proved to have <it>in vitro </it>ovicidal, schistolarvicidal and lethal activity on adult worms of both <it>Schistosoma </it>species and has considerable molluscicidal activity on their snail hosts. Scanning electron microscopy revealed several morphological changes on the different stages of the parasite and on the soft body of the snail, which further strengthens the current evidence of miltefosine's activity. This is the first report of mollusicidal activity of miltefosine and its <it>in vitro </it>schistosomicidal activity against <it>S.haematobium</it>.</p> <p>Conclusions</p> <p>This study highlights miltefosine not only as a potential promising lead compound for the synthesis of novel broad spectrum schistosomicidal derivatives, but also for molluscicidals.</p

Approaches to genotyping individual miracidia of Schistosoma japonicum

Molecular genetic tools are needed to address questions as to the source and dynamics of transmission of the human blood fluke Schistosoma japonicum in regions where human infections have reemerged, and to characterize infrapopulations in individual hosts. The life stage that interests us as a target for collecting genotypic data is the miracidium, a very small larval stage that consequently yields very little DNA for analysis. Here, we report the successful development of a multiplex format permitting genotyping of 17 microsatellite loci in four sequential multiplex reactions using a single miracidium held on a Whatman Classic FTA indicating card. This approach was successful after short storage periods, but after long storage (>4 years), considerable difficulty was encountered in multiplex genotyping, necessitating the use of whole genome amplification (WGA) methods. WGA applied to cards stored for long periods of time resulted in sufficient DNA for accurate and repeatable genotyping. Trials and tests of these methods, as well as application to some field-collected samples, are reported, along with the discussion of the potential insights to be gained from such techniques. These include recognition of sibships among miracidia from a single host, and inference of the minimum number of worm pairs that might be present in a host