Filip Volckaert
Katholieke Universiteit Leuven
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Featured researches published by Filip Volckaert.
Infection, Genetics and Evolution | 2011
F. Van den Broeck; S. Geldof; Katja Polman; Filip Volckaert; Tine Huyse
Genotyping individual larval stages and eggs of natural parasite populations is complicated by the difficulty of obtaining reliable genotypes from low quantity DNA template. A suitable storage and extraction protocol, together with a thorough quantification of genotyping errors are therefore crucial for molecular epidemiological studies. Here we test the robustness, handling time, ease of use, cost effectiveness and success rate of various fixation (Whatman FTA(®) Classic and Elute Cards, 70% EtOH and RNAlater(®)) and subsequent DNA extraction methods (commercial kits and proteinase K protocol). None of these methods require a cooling chain and are therefore suitable for field collection. Based on a multiplex microsatellite PCR with nine loci the success and reliability of each technique is evaluated by the proportion of samples with at least eight scored loci and the proportion of genotyping errors. If only the former is taken into account, FTA(®) Elute is recommended (83% success; 44% genotyping error; 0.2 €/sample; 1h 20 m handling time). However, when also considering the genotyping errors, handling time and ease of use, we opt for 70% EtOH with the 96-well plate technology followed by a simple proteinase K extraction (73% success; 0% genotyping error; 0.2 €/sample; 15m handling time). For eggs we suggest (1) to pool all eggs per person in 1.5 ml tubes filled with 70% EtOH for transport and (2) to identify each egg to species level prior to genotyping. To this end we extended the Rapid diagnostic PCR developed by Webster et al. (2010) with a S. mansoni-specific primer to discriminate between S. mansoni, S. haematobium and S. bovis in a single PCR reaction. The success rate of genotyping eggs was 75% (0% genotyping error). This is the first study to incorporate genotyping errors through re-amplification for the evaluation of schistosome sampling protocols and the identification of error-prone loci.
International Journal for Parasitology | 2013
Tine Huyse; F. Van den Broeck; B. Hellemans; Filip Volckaert; Katja Polman
It is generally accepted that Schistosoma mansoni and Schistosoma haematobium, causing intestinal and urinary schistosomiasis, respectively, are not able to hybridise, due to the high phylogenetic distance between them. Cloning of nuclear internal transcribed spacer rDNA and partial mitochondrial cytochrome c oxidase 1 fragments revealed two internal transcribed spacer rDNA genotypes within single eggs and miracidia, one identical to S. mansoni and the other identical to S. haematobium, suggesting hybrid ancestry. The cytochrome c oxidase 1 clones always belonged to only one of the parental species. This demonstrates that offspring of heterologous pairing between these two species is not (always) parthenogenetic.
Heredity | 2014
F. Van den Broeck; Lynn Meurs; Nele Boon; Tandakha Ndiaye Dieye; Filip Volckaert; Katja Polman; Tine Huyse
The size, structure and distribution of host populations are key determinants of the genetic composition of parasite populations. Despite the evolutionary and epidemiological merits, there has been little consideration of how host heterogeneities affect the evolutionary trajectories of parasite populations. We assessed the genetic composition of natural populations of the parasite Schistosoma mansoni in northern Senegal. A total of 1346 parasites were collected from 14 snail and 57 human hosts within three villages and individually genotyped using nine microsatellite markers. Human host demographic parameters (age, gender and village of residence) and co-infection with Schistosoma haematobium were documented, and S. mansoni infection intensities were quantified. F-statistics and clustering analyses revealed a random distribution (panmixia) of parasite genetic variation among villages and hosts, confirming the concept of human hosts as ‘genetic mixing bowls’ for schistosomes. Host gender and village of residence did not show any association with parasite genetics. Host age, however, was significantly correlated with parasite inbreeding and heterozygosity, with children being more infected by related parasites than adults. The patterns may be explained by (1) genotype-dependent ‘concomitant immunity’ that leads to selective recruitment of genetically unrelated worms with host age, and/or (2) the ‘genetic mixing bowl’ hypothesis, where older hosts have been exposed to a wider variety of parasite strains than children. The present study suggests that host-specific factors may shape the genetic composition of schistosome populations, revealing important insights into host–parasite interactions within a natural system.
Infection, Genetics and Evolution | 2013
Tine Huyse; F. Van den Broeck; Thibaut Jombart; Bonnie L. Webster; Oumar T. Diaw; Filip Volckaert; Francois Balloux; David Rollinson; Katja Polman
The Senegal River Basin (SRB) experienced a major epidemic of intestinal schistosomiasis in the early nineties, after the construction of a dam for irrigation purposes. Exceptionally low cure rates following praziquantel (PZQ) treatment at the onset of the epidemic raised concerns about PZQ resistant strains of Schistosoma mansoni, although they could also be attributed to the intense transmission at that time. A field study in the same region more than 15 years later found cure rates for S. mansoni still to be low, whereas Schistosomahaematobium responded well to treatment. We collected S. mansoni miracidia from children at base-line prior to treatment, six months after two PZQ treatments and two years after the start of the study when they had received a total of five PZQ treatments. In total, 434 miracidia from 12 children were successfully genotyped with at least six out of nine DNA microsatellite loci. We found no significant differences in the genetic diversity of, and genetic differentiation between parasite populations before and after repeated treatment, suggesting that PZQ treatment does not have an impact on the neutral evolution of the parasite. This is in stark contrast with a similar study in Tanzania where a significant decrease in genetic diversity was observed in S. mansoni miracidia after a single round of PZQ treatment. We argue that PZQ resistance might play a role in our study area, although rapid re-infection cannot be excluded. It is important to monitor this situation carefully and conduct larger field studies with short-term follow-up after treatment. Since PZQ is the only general schistosomicide available, the possibility of PZQ resistance is of great concern both for disease control and for curative use in clinical practice.
Canadian Journal of Fisheries and Aquatic Sciences | 2008
Kathryn R. Elmer; Jeroen Van Houdt; AxelMeyerA. Meyer; Filip Volckaert
Archive | 2011
Jan Vanaverbeke; Ab Braarup; Ulrike Braeckman; Wouter Courtens; Els Cuveliers; Klaas Deneudt; Annelies Goffin; Bart Hellemans; Tine Huyse; Geneviève Lacroix; Maarten Larmuseau; Jan Mees; Pieter Provoost; Marijn Rabaut; Thomas Remerie; Marie Savina; Karline Soetaert; Ewm Stienen; Hilbran Verstraete; Filip Volckaert; Magda Vincx
Aquaculture | 2017
J.E.J. Hillen; I. Coscia; Marc Vandeputte; Koen Herten; Bart Hellemans; F. Maroso; Alain Vergnet; François Allal; Gregory E. Maes; Filip Volckaert
Archive | 2018
Els Lea R. De Keyzer; Zoë De Corte; Maarten VanSteenberge; Federico Calboli; Nikol Kmentová; N'sibula Mulimbwa; Massimiliano Virgilio; Carl Vangestel; Pascal Masilya Mulungula; Filip Volckaert; Maarten Vanhove
Archive | 2016
Nele Boon; Linda Paredis; Filip Volckaert; Katja Polman; Tine Huyse
Archive | 2016
Nele Boon; Frederik Van den Broeck; Lynn Meurs; Filip Volckaert; Katja Polman; Tine Huyse