Evaluation of Loop-Mediated Isothermal Amplification Suitable for Molecular Monitoring of Schistosome-Infected Snails in Field Laboratories

Abstract

Abstract. We previously described loop-mediated isothermal amplification (LAMP) for detection of Schistosoma haematobium and S. mansoni DNA in infected snails. In the present study, we adapted the LAMP assay for application in field laboratories in schistosomiasis-endemic areas. Isolation of DNA was simplified by blotting snail tissue (extracted in NaOH/sodium dodecyl sulfate) onto treated membranes, which enabled preservation at ambient temperatures. A ready-mix of LAMP reagents, suitable for shipment at ambient temperature and storage in minimal refrigeration, was used. Local survey teams without experience in molecular biology acquired operational expertise with this test within a few hours. Fifty-four field-caught snails were tested locally by LAMP and 59 were tested at similar conditions in Jerusalem. The LAMP results were consistent with those of a polymerase chain reaction; only four samples showed false-negative results. Results indicate that LAMP assays are suitable for detection of S. haematobium and S. mansoni in low-technology parasitology laboratories in which schistosomiasis elimination activities are undertaken.

Biompha-LAMP: A New Rapid Loop-Mediated Isothermal Amplification Assay for Detecting Schistosoma mansoni in Biomphalaria glabrata Snail Host

“…mansoni DNA corresponding to less than the equivalent to one single miracidium or a single parasite cell. A high sensitivity has also been previously reported when using other LAMP assays to detect schistosomes in infected snails [10, 29], but a long time of 120 min was required to complete the reaction, whereas our LAMP assay ( Biompha -LAMP) takes only 50 min to obtain the same limit of DNA detection.…”

“…haematobium and S . mansoni [10] and potentially later adaptation in a large-scale screening of snails pooled samples to be used as method for snails control [28, 29]. The "development of inexpensive, field-applicable diagnostic assays for the large-scale screening of individual or pooled snails from transmission sites to detect the presence of schistosomes" has been listed as an important point to consider in an agenda for snail control interventions related to schistosomiasis elimination [30].…”

Urogenital schistosomiasis transmission on Unguja Island, Zanzibar: characterisation of persistent hot-spots

“…While these infection levels seem rather low considering the S. haematobium prevalence in children in the persistent hot-spot shehias, previous work conducted in Zanzibar has shown that the cercariae shedding method misses many prepatent infections [35]. If more advanced, molecular techniques are used for screening snails instead, it is likely to detect a considerably higher number of infected snails [35, 40, 42–44]. Rapid detection of schistosome cercariae ribosomal DNA in environmental samples using new methods could also aid in uncovering transmission sites that may have previously been missed following classic snail ‘shedding’ methods [45].…”

Decline in transmission of schistosomiasis mansoni in Oman

“…Such procedures include molecular detection of S. mansoni cercariae in snail intermediate hosts [20], as well as assessment of current infection in human populations, through detection of antigens to S. mansoni (e.g. by circulating cathodic antigen (CCA) tests) [21, 22], or through stool sedimentation coupled with miracidia hatching test [23]. …”