Critical analysis of molluscicide application in schistosomiasis control programs in Brazil

Abstract

In Brazil, Biomphalaria glabrata, B. tenagophila, and B. straminea are naturally infected by the trematode Schistosoma mansoni, the causative agent of schistosomiasis. Despite decades of governmental efforts through official control programs, schistosomiasis remains an important public health problem in the country: thousands of people are infected with the trematode each year and millions live in endemic areas. The World Health Organization recommends using a combination of molluscicide (niclosamide) and mass chemotherapy to control the transmission of schistosomiasis, with this treatment successfully reducing the morbidity of the disease. In the past, niclosamide has been used in official schistosomiasis control programs in Brazil. However, as B. glabrata recolonizes even after molluscicide application, the use of molluscicides has gradually decreased in the country until they were discontinued in 2002, mainly due to the rising global pressure to preserve the environment and the difficulties of obtaining licenses from the Brazilian Ministry of Environment to use toxic substances in aquatic ecosystems. Therefore, the discovery of new molluscicides, which could be more selective to Biomphalaria species and less harmful to the aquatic ecosystem, is necessary. In addition, political efforts to sensitize funders to provide grants for this field of research are required. In this context, this article aims to make a critical analysis of molluscicide application in schistosomiasis control programs in Brazil.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-016-0153-6) contains supplementary material, which is available to authorized users.

Diagnosis of Schistosoma mansoni infections: what are the choices in Brazilian low-endemic areas?

“…Aiming to eliminate doubt concerning trace results and increase detection of low-intensity infections, Coelho et al 111 proposed an additional step for POC-CCA® in Brazilian endemic areas. The POC-CCA Lyo that uses 10-fold concentrated urine via lyophilisation improved conventional POC-CCA® sensitivity from 6% to 56% compared to sensitivity observed using a reference method (24 K-K slides plus two SG).…”

The Stakeholders’ Views on Planting Trees to Control Schistosomiasis in China

“…Various control measures have been used to cut off this transmission pathway. Spaying molluscicides in snail habitats to kill snails has been practiced widely [6,7]. In addition, chemicals have been used to kill cercariae in the water [8,9].…”

Molluscicidal activity and mechanism of toxicity of a novel salicylanilide ester derivative against Biomphalaria species

“…Its life-cycle requires aquatic snails of the genus Biomphalaria as obligate intermediate hosts. Biomphalaria straminea , an important intermediate host of S. mansoni [ 4 ], is considered a major invasive species involved in the transmission of schistosomiasis in some invaded habitats, including Brazil, Paraguay, Argentina, Uruguay and the Caribbean [ 5 , 6 ]. In addition to the Neotropics, B. straminea was found in Hong Kong in 1974 [ 7 ], and recently, this species has been widely reported in South China [ 8 , 9 ].…”