Biology subjects

Huyse, T.

Publications and source records attributed to Huyse, T..

7 recordsLinked to original sources

bioRxiv2025

Improving eDNA filtration and purification for qPCR detection of Schistosoma mansoni in lakes Albert and Victoria

BackgroundSchistosomiasis, a parasitic disease caused by Schistosoma trematodes, remains a significant public health burden in sub-Saharan Africa, particularly in regions with limited access to clean water, sanitation and hygiene. Effective disease control strategies rely on large-scale surveillance to accurately identify and target high-risk populations. However, traditional methods such as malacological surveys and stool/urine microscopy in humans often lack sensitivity and scalability. Environmental DNA (eDNA) is emerging as a promising tool for non-invasive surveillance of aquatic pathogens, offering enhanced sensitivity and feasibility for large-scale monitoring. MethodsThis study evaluated the efficacy of eDNA-based detection of Schistosoma mansoni in water samples from Lake Albert and Lake Victoria, Uganda. Three eDNA filtration techniques: open membrane, Waterra capsule and Sylphium capsule filters, were compared for DNA yield and detection efficiency. SYBR Green quantitative polymerase chain reaction (qPCR) targeting the mitochondrial cytochrome oxidase subunit I (COI) gene was performed to quantify S. mansoni eDNA, following in silico and in vitro optimisation of primers. Conventional malacological surveys were conducted in parallel to validate eDNA findings, and statistical analyses examined the influence of environmental factors (turbidity and total dissolved solids (TDS)) on eDNA yield and detection rates. ResultsThe SYBR Green S. mansoni qPCR assay had a practical limit of detection (LOD), defined as amplification in >95% of 33 technical replicates, of 100 copies per reaction. The assay amplified in 82% of reactions with 10 DNA copies and 76% with a single copy. The theoretical LOD, determined via amplification probabilities in RStudio, was 83 copies per reaction, which was also the calculated limit of quantification (LOQ). Schistosoma mansoni eDNA was detected in 58.1% (25/43) of filters from Lake Albert and 19.2% (10/52) from Lake Victoria. The Waterra capsule filter yielded the highest eDNA concentrations, while the Sylphium-coupled capsule filter exhibited comparable detection efficiency. Among the DNA purification methods tested, the Sylphium precipitation-based protocol produced significantly higher eDNA yield than column-based kits (DNeasy Blood and Tissue and Zymo Research). Despite significant variation in eDNA recovery across filtration methods, qPCR detection rates were consistent. No significant correlation was observed between turbidity and S. mansoni eDNA detectability. ConclusionOur findings highlight the potential of eDNA as a sensitive, scalable tool for schistosomiasis surveillance. While Waterra filters and Sylphium extraction maximised DNA yield, lower-yield filtration methods still enabled S. mansoni detection in high-transmission settings. These findings support the adaptability of eDNA approaches across varying resource contexts. Future work should prioritise protocol standardisation, ecological validation, and development of field-ready diagnostics such as LAMP to enable broader implementation in endemic regions.

molecular biology↗

bioRxiv2024

First evidence of a causal link between genetic variation and thermal adaptation in a schistosome host snail

Freshwater snails are pivotal in transmitting schistosomiasis, a tropical parasitic disease affecting over 150 million people. The adaptive potential of these snails is a critical factor in determining how climate change and other environmental factors influence disease transmission dynamics, yet it has remained unexplored. Bulinus truncatus is the schistosome intermediate host snail with the widest geographic distribution and therefore plays a pivotal role in determining the maximum range of urogenital schistosomiasis. In this study, we assessed the local adaptation capacity of B. truncatus to temperature through an integrative approach encompassing phenotypic, ecophysiological, and genomic data. Ten snail populations from diverse thermal environments were collected in three countries, with eight populations reared in a common garden. The F2 generation (total N= 2592) was exposed to eight chronic temperature treatments and various life-history traits were recorded for over 14 weeks. Subsequently, ecophysiological analyses were conducted on the ten last surviving snails per population. Genotyping the parental generation collected in the field using a genotyping-by-sequencing (GBS) approach, revealed 12,875 single nucleotide polymorphisms (SNPs), of which 4.91 % were potentially under selection. We observed a significant association between these outlier SNPs, temperature, and precipitation. Thermal adaptations in life-history traits were evident, with lower survival rates at high temperatures of warm- origin snails compensated for by higher reproduction rates. Cold-origin snails, on the other hand, exhibited higher growth rates adapted to a shorter growing season. Ecophysiological adaptations included elevated sugar and haemoglobin contents in cold-adapted snails. In contrast, warm-adapted snails displayed increased protein levels but also more oxidative damage. Furthermore, heightened phenoloxidase levels indicated a more robust immune response in snails from parasite-rich regions. The substantial local adaptation capacity of B. truncatus holds profound implications for its response to climate change, future schistosomiasis risk, and the effectiveness of schistosomiasis control measures. HighlightsO_LILocal adaptation influences species responses to climate change C_LIO_LIThe snail Bulinus truncatus showed a high thermal local adaptation (LA) potential C_LIO_LILA is apparent through variations in life history and ecophysiological traits C_LIO_LIWe identified a significant genetic basis underlying this LA C_LIO_LILA of the hosts could sustain schistosomiasis transmission under global warming C_LI

ecology↗

bioRxiv2023

Host-microbiome transplants of the schistosome snail host Biomphalaria glabrata reflect species-specific associations

Snail-borne diseases affect more than a quarter of a billion people worldwide and pose a high burden in the livestock industry. A fundamental understanding of the drivers of the epidemiology of these diseases is crucial for the development of sustainable control measures. The microbiome is increasingly being recognized as an important player in the tripartite interaction between parasitic flatworms, snail intermediate hosts and the snail microbiome. In order to better understand these interactions, transplant experiments are needed, which rely on the development of a reliable and reproducible protocol to obtain microbiome-disturbed snails. Here we report on the first successful snail microbiome transplants, which indicate that Biomphalaria glabrata can accrue novel bacterial assemblies depending on the available environmental bacteria obtained from donor snails. Moreover, the phylogenetic relatedness to the donor significantly affected the survival probability of the recipients, corroborating the phylosymbiosis pattern in freshwater snails. The transplant technique described here, complemented by field-based studies, could facilitate future research endeavors to investigate the role of specific bacteria or bacterial communities in parasitic flatworm resistance of B. glabrata and might ultimately pave the way for microbiome-mediated control of snail-borne diseases.

microbiology↗

bioRxiv2022

First record of monogenean fish parasites in the Upper Lufira basin (Democratic Republic of Congo): dactylogyrids and gyrodactylids infecting Oreochromis mweruensis, Coptodon rendalli and Serranochromis macrocephalus (Teleostei: Cichlidae)

BackgroundMonogenean parasites have never been formally reported on fish from the Lufira basin. Then it is hypothesised that multiple monogenean species are to be recorded that are new to the region. This study aimed to record the gill monogenean parasite fauna of three cichlid fish species in the Upper Lufira basin by inventorying their diversity (species composition) and analysing their infection parameters (prevalence, mean intensity and abundance). MethodsOreochromis mweruensis, Coptodon rendalli, and Serranochromis macrocephalus were selected for the study, given their economic value and their abundance in the Upper Lufira basin. Monogeneans were isolated from the gills and stomach, mounted on glass slides with either Hoyers medium or ammonium picrate-glycerin for further identification under a stereomicroscope, based on morphological analysis of genital and haptoral hard parts. Indices of diversity and infections parameters were calculated. ResultsA total of thirteen gill monogenean parasite species (Cichlidogyrus dossoui, C. halli, C. karibae, C. mbirizei, C. papernastrema, C. quaestio, C. sclerosus, C. tiberianus, C. tilapiae, C. zambezensis, Scutogyrus gravivaginus, S. cf. bailloni and Gyrodactylus nyanzae) and one stomach monogenean (Enterogyrus malmbergi) were reported. A species richness of S= 10 for O. mweruensis, S= 6 for C. rendalli and S= 2 for S. macrocephalus were recorded. Five parasite species were reported to be common amongst O. mweruensis and C. rendalli. The most prevalent parasite species were C. halli (P= 80.9%) on O. mweruensis, C. dossoui (P= 92.9%) on C. rendalli and C. karibae and C. zambezensis (both of which P = 9.1%) on S. macrocephalus with a respective mean infection intensity of 7.9 on O. mweruensis, 9.8 on C. rendalli and 5 and 15, respectively, on S. macrocephalus. Results of this study reported new host ranges for five parasites species (C. quaestio, S. cf. bailloni, E. malmbergi on O. mweruensis, C. halli on C. rendalli and C. karibae on S. macrocephalus) as well as new geographical records for three of them (S. cf. bailloni, E. malmbergi, C. karibae). ConclusionsThis study highlights the richness of monogenean communities in the Upper Lufira basin and is a starting point for future helminthological studies, e.g. on the use of fish parasites as indicators of anthropogenic impacts.

zoology↗

bioRxiv2022

A new species of Cichlidogyrus Paperna, 1960 (Platyhelminthes: Monogenea: Dactylogyridae) infecting tilapias in Lake Kariba (Zimbabwe), with a discussion on its phylogenetic position

Monogeneans dominate the external parasite fauna of bony fish. During recent years, examination of more populations of species of Cichlidogyrus Paperna, 1960 has led to the (re)description of several species. Cichlidogyrus halli (Price & Kirk, 1967) Price, 1968, for example, has been redescribed several times in the past and has been proposed to encompass many (pseudo)cryptic species. In Lake Kariba (Zimbabwe), specimens of a species of Cichlidogyrus were found that morphologically resemble C. halli. These specimens were found on the gills of native Oreochromis cf. mortimeri and Coptodon rendalli (Boulenger, 1897), and introduced Nile tilapia Oreochromis niloticus (Linnaeus, 1758). A detailed study of the morphology of these specimens, including morphometrics, and a thorough comparison with specimens of C. halli is presented. Part of the COI gene and 18S-ITS1 fragment were sequenced and analysed to provide insight into the phylogenetic placement of these specimens within the Cichlidogyrus-Scutogyrus monophylum. We found that C. halli and the new specimens sp. nov. are sister clades within the same monophyletic clade, and that clear morphological and morphometric differences are present in the dorsal bar of the haptor and accessory piece of the male copulatory organ. Based on these results, the new specimens are described as a new species: C. chloeae sp. nov. The role of introduced Nile tilapia as a potential reservoir for native parasites raises concern for potential spillbacks and stresses the need for further monitoring of monogeneans on native and introduced tilapias.

zoology↗

bioRxiv2020

A Darwinian outlook on schistosomiasis elimination

Schistosomiasis is a poverty-related chronic disease that affects over 240 million people across 78 countries worldwide. In order to control the disease, the World Health Organization (WHO) recommends the drug praziquantel against all forms of schistosomiasis. Mass Drug Administration (MDA) programs with praziquantel are successful on the short-term as they reduce the prevalence and infection intensity after treatment, and thus instantly relieve the patient from the burden of its disease. However, epidemiological and genetic studies suggest that current school-based interventions may have little or no long-term impact on parasite transmission. Here, we adopt a Darwinian approach to understand the impact of MDA on the neutral evolution of Schistosoma parasites and assess its potential to eliminate schistosomiasis. We develop a finite island model to simulate the impact of repeated treatments on the genetic diversity of schistosome populations locally (within each host, i.e. infrapopulation) and regionally (within all hosts combined, i.e. component population). We show that repeated treatments induced strong and lasting declines in parasite infrapopulation sizes, resulting in concomitant genetic bottlenecks within the treated individuals. However, parasite genetic diversity recovered quickly in a few generations due to re-infection, and there was little or no impact of treatment on the genetic diversity of the component population when treatment coverage was 95% or lower. This was mainly due to parasite infrapopulations of the untreated host individuals that acted as reservoirs of genetic diversity, sustaining the diversity of the component population. Hence, lasting declines in parasite genetic diversity were only observed when coverage of treatment was 100%, resulting in population crashes after a minimum of six treatment rounds. We argue that achieving a full coverage of treatment is highly challenging for most endemic regions in sub-Saharan Africa, and conclude that MDA alone has little potential to achieve elimination within a conceivable time frame. Our results raise skepticism about the current WHO goals of elimination of schistosomiasis by 2025.

genetics↗

bioRxiv2018

The first next-generation sequencing approach to the mitochondrial phylogeny of African monogenean parasites (Platyhelminthes: Gyrodactylidae and Dactylogyridae)

BackgroundMonogenean flatworms are the main ectoparasites of fishes. Representatives of the species-rich families Gyrodactylidae and Dactylogyridae, especially those infecting cichlid fishes and clariid catfishes, are important parasites in African aquaculture, even more so due to the massive anthropogenic translocation of their hosts worldwide. Several questions on their evolution, such as the phylogenetic position of Macrogyrodactylus and the highly speciose Gyrodactylus, remain unresolved with available molecular markers. Also, diagnostics and population-level research would benefit from the development of higher-resolution genetic markers. We aim to advance genetic work on African monogeneans by providing mitogenomic data of four species (two each belonging to the Gyrodactylidae and Dactylogyridae), and analysing their gene sequences and gene order from a phylogenetic perspective.\n\nResultsBased on Illumina technology, the first four mitochondrial genomes of African monogeneans were assembled and annotated for the cichlid parasites Gyrodactylus nyanzae, Cichlidogyrus halli, Cichlidogyrus mbirizei (near-complete mitogenome) and the catfish parasite Macrogyrodactylus karibae (near-complete mitogenome). The start codon TTG is new for Gyrodactylus and for the Dactylogyridae, as is the incomplete stop codon TA for the Dactylogyridae. The most variable markers are nad genes and these are under relaxed selection. Especially nad2 is promising for primer development. Gene order was identical for protein-coding genes and differed between the African representatives of these families only in a tRNA gene transposition. A mitochondrial phylogeny based on an alignment of nearly 12,500 bp including 12 protein-coding and two ribosomal RNA genes confirms that the Neotropical oviparous Aglaiogyrodactylus forficulatus takes a sister group position with respect to the other gyrodactylids, rather than the supposedly primitive African Macrogyrodactylus. Inclusion of the African Gyrodactylus nyanzae confirms the paraphyly of Gyrodactylus. The position of the African dactylogyrid Cichlidogyrus is unresolved, although gene order suggests it is closely related to marine ancyrocephalines.\n\nConclusionsThe amount of mitogenomic data available for gyrodactylids and dactylogyrids is increased by roughly one-third. Our study underscores the potential of mitochondrial genes and gene order in flatworm phylogenetics, and of next-generation sequencing for marker development for these non-model helminths for which few primers are available while they constitute a risk to tropical aquaculture.

evolutionary biology↗