A heritable CRISPR knock-in in Schistosoma mansonigenerated a transgenic line that secreted a functional anti–SARS-CoV-2 antibody into mouse circulation. Virus neutralization by infected mouse sera de...

Freshwater snails act as intermediate hosts for parasites affecting both humans and livestock, including schistosomes. In Mauritania, however, the diversity, distribution, and infection status of these snails remain poorly documented. This study aimed to identify freshwater snail species collected from two schistosomiasis-endemic areas in southern Mauritania, characterize their spatial distribution, and assess their infection rates using molecular tools. Malacological surveys were conducted in Kankossa and Oued Rawdha during the 2023 rainy season. A total of 806 snail specimens were collected and preserved in 70% ethanol at 4 {degrees}C prior to analysis. Five species were identified morphologically and confirmed by molecular analysis: Bulinus truncatus, B. forskalii, B. senegalensis, B. umbilicatus, and Melanoidestuberculata. MALDI-TOF MS generated high-quality spectra for 99.0% of specimens and correctly identified 99.9% of analyzable samples after molecular confirmation of discrepant cases. Preservation in ethanol at 4 {degrees}C markedly improved spectral quality compared with previously reported room-temperature storage conditions. Distinct ecological distributions were observed according to water body type. B. senegalensis and B. umbilicatus were exclusively collected from temporary ponds, whereas B. truncatus, B. forskalii, and M. tuberculata were found in permanent water bodies. Real-time PCR screening detected Schistosoma haematobium complex DNA in 239/798 (29.9%) specimens, with substantially higher infestation rates in Kankossa than in Oued Rawdha. These findings demonstrate that MALDI-TOF MS is a rapid, accurate, and field-compatible tool for freshwater snail identification, including closely related species that are difficult to distinguish morphologically. This approach could facilitate large-scale epidemiological surveillance and improve monitoring of schistosomiasis transmission dynamics in endemic settings.

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A newly detected parasite in Portugal hints at an emerging and little-understood risk in freshwater ecosystems. Researchers in Portugal have identified parasites from the Trichobilharzia group, including T. franki, in Lake Alqueva. This is the first confirmed record of these avian schistosomes in the country and highlights a major recreational freshwater site as a potential location for cercarial dermatitis risk in Europe. Trichobilharzia species are parasitic flatworms that cycle between waterfowl and freshwater snails. Their free-swimming larvae can accidentally penetrate human skin, leading to cercarial dermatitis, also known as swimmer’s itch. While not typically dangerous, the condition can cause intense itching, red bumps, and blister-like lesions, with symptoms sometimes worsening after repeated exposure. Several species in this group have been linked to human infections across Europe, and T. franki is among the most commonly involved. A Notable Gap in Portugal Until this study, Trichobilharzia species had not been formally reported in Portugal. This absence was notable given Lake Alqueva’s status as the largest artificial reservoir in Western Europe and its growing popularity for recreation, including swimming, fishing, and birdwatching. The researchers also point out that swimmer’s itch has not been systematically monitored in the country. However, early survey data from...

A newly detected parasite in Portugal hints at an emerging and little-understood risk in freshwater ecosystems. Researchers in Portugal have identified parasites from the Trichobilharzia group, including T. franki, in Lake Alqueva. This is the first confirmed record of these avian schistosomes in the country and highlights a major recreational freshwater site as a potential [...]

Male regulation of female reproductive development in schistosomes depends on an intact reproductive neural network. You et al. identify a limbic system-associated membrane protein as essential for maintaining this network, enabling the efficient release of the pheromone β-alanyl-tryptamine dipeptide, which promotes female maturation.

Author summary Schistosomiasis is a major parasitic disease that affects over 200 million people. Schistosomes’ ability to thrive inside the hostile environment of the host bloodstream and reproduce i...

Schistosomes are parasitic flatworms that cause Schistosomiasis, a major Neglected Tropical Disease (NTD) that affects more than 250 million people worldwide. With two morphologically distinct sexes, a heterogametic female (ZW) and a homogametic male (ZZ), schistosomes are an exception among flatworms, which are largely hermaphroditic. Sexual dimorphism in schistosomes only becomes apparent by adulthood within the mammalian host. The cellular and molecular mechanisms underlying the sexual differentiation of these parasites are poorly understood, partly due to intrinsic challenges in assessing parasite development in vivo . Therefore, robust and reproducible approaches for maintaining and developing parasites in vitro may help to overcome these difficulties. However, to date, only a few studies have focused on protocols that allow cultured parasites to reach sexual dimorphic stages, and none have been reproduced, limiting the ability to understand the unique sexual biology of this major human parasite. Here, we refine a protocol for long-term culture of newly transformed cercariae that developed in vitro into sexually dimorphic forms. We assessed the effect of two different sera, Foetal Bovine Serum (FBS) and Human Serum (HS), added to the culture medium supplemented with human red blood cells. We found that in contrast to FBS-cultured worms, HS-cultured parasites digested red blood cells, a crucial step for long term parasite culture. Additionally, while most FBS-cultured parasites did not progress beyond an early liver stage, sexual dimorphism was clearly established in the HS-cultured worms, albeit delayed compared to in vivo development. Moreover, EdU pulse-chase experiments revealed a continuous proliferation of parasite cells over time in HS-cultured parasites, while a significantly lower number of proliferating cells were detected in FBS-cultured worms. This protocol paves the way to study parasite development in vitro , positively impacting the principles of the 3Rs (Replacement, Reduction and Refinement) for animal research, and allowing for in-depth studies of sexual dimorphism establishment as well as in vitro screening for novel control strategies across the life cycle of these major human parasites. ### Competing Interest Statement The authors have declared no competing interest. UKRI-Future Leaders Fellowship, UK, MR/W013568/2 Wellcome Sanger Institute, https://ror.org/05cy4wa09, 098051, 206194 European Union, 101080784 - WORMVACS2.0

Qu'est-ce que la bilharziose, cette maladie parasitaire qui commence à gagner l'Europe ? - Les schistosomes, de petits vers parasites, sont à l’origine d’une maladie aux conséquences potentiellement graves : la schistosomiase ou bilharziose. Une simple baignade dans des eaux infestées par leurs larves peut suffire à être contaminé. Longtemps cantonnée à certains pays tropicaux, la maladie s’étend. Elle aborde désormais le sud de l’Europe : des cas ont été recensés en Corse, ces dernières années.