Praziquantel: its use in control of schistosomiasis in sub-Saharan Africa and current research needs

Abstract

S U M M A R YTreatment with praziquantel (PZQ) has become virtually the sole basis of schistosomiasis control in sub-Saharan Africa and elsewhere, and the drug is reviewed here in the context of the increasing rate that it is being used for this purpose. Attention is drawn to our relative lack of knowledge about the mechanisms of action of PZQ at the molecular level, the need for more work to be done on schistosome isolates that have been collected recently from endemic areas rather than those maintained in laboratory conditions for long periods, and our reliance for experimental work mainly on Schistosoma mansoni, little work having been done on S. haematobium. There is no evidence that resistance to PZQ has been induced in African schistosomes as a result of its large-scale use on that continent to date, but there is also no assurance that PZQ and/ or schistosomes are in any way unique and that resistant organisms will not be selected as a result of widespread drug usage. The failure of PZQ to produce complete cures in populations given a routine treatment should therefore solicit considerable concern. With few alternatives to PZQ currently available and/or on the horizon, methods to monitor drug-susceptibility in African schistosomes need to be devised and used to help ensure that this drug remains effective for as long a time as possible.

Schistosomiasis Sustained Control Program in Ethnic Groups Around Ninefescha (Eastern Senegal)

“…2010 86 2011 171 2012 192 2013 208 2014 78 2015 22 Total 757 and cannot prevent reinfection; its efficacy had therefore only temporary effect on transmission, and treatment has to be backed up by constant health education campaigns. 13 To respond to this point, we organized and took part in health education campaigns to raise awareness of the ethnic groups about the risks of contaminated waters, and we began building latrines in the 53 villages.…”

Control of infection of Biomphalaria alexandrina (Ehrenberg, 1831) with Schistosoma mansoni Sambon, 1907 using Eucalyptus camaldulensis

“…Up to date, no effective vaccine has been found against schistosomiasis and the disease control depends entirely on praziquantel. Laboratory tests have shown an emerging resistance to the drug (Fallon & doenHoFF 1994, doenHoFF et al 2009). Therefore, there is a continuous need for new control methods such as blocking the parasite's development within snails to decrease disease transmission.…”

Cross-disciplinary approaches for measuring parasitic helminth viability and phenotype

“…Currently, praziquantel is the only effective treatment against the three major species (S. mansoni, S. haematobium and S. japonicum) of schistosome that causes human schistosomiasis. The heavy reliance on this chemotherapy and its inability to protect from reinfection is causing real fears that praziquantel resistant schistosomes may be developing (Doenhoff et al 2009). With the recent sequencing of this parasite's genome (Berriman et al 2009, Zhou et al 2009) providing insight into new gene families and the availability of several functional genomics tools providing the technology useful in characterising them (Brindley andPearce 2007, Hokke et al 2007), there is now a strong belief within the schistosome community that novel chemotherapies and immunoprophylactics will be found (Loukas and Bethony 2008).…”