Molluscicides against the snail-intermediate host of Schistosoma: a review

Abstract

Schistosomiasis, a neglected tropical disease (NTD), is one of the most prevalent parasitoses in the World. Certain freshwater snail species are the intermediate host in the life cycle of schistosome species. Controlling snails employing molluscicides is an effective, quick, and convenient intervention strategy to prevent the spread of Schistosoma species in endemic regions. Advances have been made in developing both synthetic molluscicides and molluscicides derived from plants. However, at present, the development of molluscicides is not adapted to the actual demand for snails and schistosoma controlling. We undertake a systematic review of exploitation and application of synthetic molluscicides and molluscicides derived from plants to combat intermediate host snails. The detailed molluscicidal activity, structure–activity relationship, structural feature, and possible mechanism of some molluscicides are also highlighted, which may afford an important reference for the design of new, more effective molluscicides with low environmental impact and realize the aim of controlling schistosome at transmission stages. Supplementary Information The online version contains supplementary material available at 10.1007/s00436-021-07288-4.

The Biosafety Evaluation for Crustaceans: A Novel Molluscicide PBQ Using against Oncomelania hupensis, the Intermediate Host of Schistosoma japonica

“…Niclosamide demonstrated outstanding molluscicidal activity against different kinds of freshwater snails [ 24 ]. However, niclosamide has the disadvantages of poor solubility in water and high toxicity to fish and other non-target biota, which can induce upward climbing movement for snails [ 10 ]. Niclosamide can easily cause environmental pollution and contradictions in aquaculture [ 18 ].…”

“…There is a general rule that in the areas where the epidemic situation has rebounded, the density of O. hupensis snails will pick up earlier [ 8 ]. Controlling the intermediate snail host has proved to be a very effective strategy of controlling S. japonicum [ 9 , 10 , 11 ]. However, since the 21st century, the total area of O. hupensis snails in China has always fluctuated between 3.519 billion and 3.863 billion m 2 , and it seems to be very difficult to further compress the area [ 12 ].…”

“…Niclosamide is the only molluscicide recommended by the World Health Organization (WHO) and has been widely used internationally because of its high efficiency [ 13 ]. However, niclosamide and its derivatives possess high toxicity to fish and other non-target biota, which hinders its applications in areas that are full of aquatic organisms [ 7 , 10 ]. Research and development of high-efficiency, ecofriendly, and cost-effective molluscicides is urgent.…”

Cenário epidemiológico da esquistossomose no estado de Sergipe

“…Sua transmissão no homem se dá pela penetração na pele das larvas de Schistosoma sp.(cercárias). Seis espécies do gênero Schistosoma, incluindo S. japonicum, S. mansoni, S. haematobium , S. mekongi , S. malayensis e S. intercalatum podem causar doenças em pessoas (Friani, et al, 2022;Zheng, et al, 2021). No Brasil, devido a presença de um hospedeiro propício, a biophalária, somente o S. mansoni prevaleceu.…”

“…(Katz, 2018) O ciclo de vida do parasita é complexo e requer a inter-relação de um hospedeiro intermediário (oncomelania caramujos), hospedeiro definitivo (humanos e mamíferos) e ecossistemas límnicos. São sete os estágios do ciclo de vida envolvendo o verme adulto, ovo, miracídio, esporocisto mãe, esporocisto filha, cercárias e esquistossomose (Zheng, et al, 2021). Ao penetrarem na pele humana, as larvas do Schistosoma invadem o sistema venoso e se espalham por órgãos tais como coração, pulmões, fígado e intestinos, sendo a hipertensão arterial pulmonar a complicação mais importante no contexto fisiopatológico desta doença de característica crônica (Posada-Martínez, et al, 2022).…”