Schistosoma_bovis_genome_sequencing-sc-4972
Schistosoma_bovis_genome_sequencing
Flatworm parasites of the Schistosoma genus are trematodes well known for their serious threat on human health and livestock in many tropical and subtropical areas, and recently also in Europe. Schistosomes are endoparasites with a complex lifecycle including two obligatory hosts. One is a freshwater mollusc, used as intermediate host, and Humans or mammals represent definitive hosts. These bloodflukes cause schistosomiasis, a neglected disease ranking second to malaria in terms of morbidity and mortality in humans (King, 2010). Animal schistosomiasis has a wide distribution throughout Africa, Asia, and the Mediterranean Basin, and high prevalence with more than 165 million animals affected (Moné, Mouahid, & Morand, 1999) (De Bont & Vercruysse, 1997). Out of the 10 different Schistosoma species affecting cattle, Schistosoma bovis is of particular veterinary significance considering its pathogenicity for domestic ruminants (Vercruysse & Gabriël, 2005) (Taylor, 1987).   Schistosomes are known to hybridize and natural hybrids are increasingly detected in human hosts (Léger & Webster, 2017). In Africa, natural hybrids have been observed between animal- and human-infecting schistosomes including hybrids between S. bovis and S. haematobium, the parasite responsible for the urogenital schistosomiasis (Huyse et al., 2009) (B. L. Webster, Diaw, Seye, Webster, & Rollinson, 2013). In Senegal, up to 88% of patients with urogenital schistosomiasis harbour this hybrid form of the parasite. Current global changes (environmental and anthropogenic) are expected to promote the spread and transmission of pathogens, and increase the potential for hybridizations. The recent outbreak of S. bovis x S. haematobium hybrids in Europe (Corsica, France) with more than 100 people infected (Moné et al., 2015) (Boissier et al., 2016) (Berry et al., 2016) clearly demonstrates this invasive capacity and raises the risk of zoonotic transmission (Boissier et al., 2015). Thus, in addition to its veterinary importance, the hybridization events with S. haematobium increase the threat S. bovis represents for public health, opening up new questions such as the importance of hybrid vigour in such disease emergence. The genome of S. haematobium was recently published (Young et al., 2012) and improvements of the assembly are underway (Neil Young pers. comm.). However, the S. bovis draft genome is extremely fragmented and in the current form cannot be used for approaches (e.g. introgression and recombination event mapping of hybrids) that will allow researchers to understand, and potentially control, its infectivity and capacity to make hybrids.  1 This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/
For the scientific community working on schistosomiasis in human and livestock, the absence of a S. bovis reference genome represents a serious obstacle that prevents rapid advancement in this field. In addition, those working also on parasite evolution and comparative genomics will greatly benefit from an improved S. bovis genome assembly.