Rolf Nijsse - Academia.edu (original) (raw)
Papers by Rolf Nijsse
Additional file 1: Table S1. Graphic image of all reports to the CMV, including Hyalomma (June 20... more Additional file 1: Table S1. Graphic image of all reports to the CMV, including Hyalomma (June 2019–December 2020). Table S2. Hyalomma sp. GenBank® accession numbers (n=77) used for the cluster analysis.
Additional file 3: Figure S1. Example of SSU-rDNA fragment with "double peaks" in the S... more Additional file 3: Figure S1. Example of SSU-rDNA fragment with "double peaks" in the Sanger sequence results.
Additional file 1: Table S1. Characteristics of multi-locus genotype nested PCRs.
Additional file 3: Table S3. Raw data. Table S4. Prevalence of gastrointestinal parasites, compar... more Additional file 3: Table S3. Raw data. Table S4. Prevalence of gastrointestinal parasites, compared to previous performed studies in similar dog populations.
Additional file 2: Table S2. Prevalence of gastrointestinal parasites for the different age groups.
Additional file 1: Table S1. Prevalence of gastrointestinal parasites for the different dog popul... more Additional file 1: Table S1. Prevalence of gastrointestinal parasites for the different dog populations.
Text. Experiment 1: Confirming true positivity of samples only positive with the qPCR. Figure S1.... more Text. Experiment 1: Confirming true positivity of samples only positive with the qPCR. Figure S1. SSU rDNA qPCR [5] performed as conventional PCR without probe. Figure S2. Serial dilution of template for SSU rDNA qPCR [5] performed as conventional PCR without probe. (DOCX 1781 kb)
Questionnaire. (PDF 483 kb)
Parasites & Vectors, 2015
Background: Environmental contamination with Toxocara eggs is considered the main source of human... more Background: Environmental contamination with Toxocara eggs is considered the main source of human toxocariasis. The contribution of different groups of hosts to this contamination is largely unknown. Current deworming advices focus mainly on dogs. However, controversy exists about blind deworming regimens for >6-month-old dogs, as most of them do not actually shed Toxocara eggs. We aim to estimate the contribution of different non-juvenile hosts to the environmental Toxocara egg contamination and to assess the effects of different Toxocara-reducing interventions for dogs. Methods: A stochastic model was developed to quantify the relative contribution to the environmental contamination with Toxocara eggs of household dogs, household cats, stray cats, and foxes, all older than 6 months in areas with varying urbanization degrees. The model was built upon an existing model developed by Morgan et al. (2013). We used both original and published data on host density, prevalence and inte...
Parasites & Vectors, 2020
Background In dogs, infections with Giardia duodenalis are mainly caused by assemblages C and D, ... more Background In dogs, infections with Giardia duodenalis are mainly caused by assemblages C and D, but also by the potentially zoonotic assemblages A and B. The aims of this study were to assess differences in assemblages (i) between dogs living mainly in close proximity to humans (synanthropic dogs) versus dogs living mainly among other dogs, (ii) between samples of dogs with or without loose stool, and (iii) related to the amount of cysts shedding. Methods One hundred eighty-nine qPCR Giardia positive fecal samples of dogs originating from four groups (household, sheltered, hunting, and dogs for which a veterinarian sent a fecal sample to a diagnostic laboratory) were used for genotyping. For this, multi-locus genotyping of beta-giardin, triose phosphate isomerase, and glutamate dehydrogenase and genotyping of SSU rDNA gene fragments were performed. Fecal consistency was scored (loose or non-loose stool), and cysts per gram of feces were determined with qPCR. Results Assemblage D wa...
Tijdschrift Voor Diergeneeskunde, 2008
Een onafhankelijke groep Europese parasitologen wil via de website www.esccap.org zonder winstoog... more Een onafhankelijke groep Europese parasitologen wil via de website www.esccap.org zonder winstoogmerk informatie verstrekken over parasitaire infecties bij hond en kat in Europa. Hierbij is het belangrijk dat de (ontwormings)adviezen uniform zijn, de informatie “up-to-date” wordt gehouden en dat deze in diverse talen beschikbaar is. De uitgebreide richtlijnen kunnen worden aangepast aan de regionale situatie. De organisatie, genaamd European Scientific Counsel Companion Animal Parasites (ESCCAP), wordt inmiddels ondersteund door het European Veterinairy Parasitology College (EVPC) en de World Association for the Advancement of Veterinary Parasitology (WAAVP). De vertegenwoordiger vanuit Nederland is Frans van Knapen, hoogleraar in veterinaire volksgezondheid en levensmiddelenhygiene te Utrecht
Text. Detection of Giardia duodenalis assemblages and other Giardia species with the qPCR. (DOCX ... more Text. Detection of Giardia duodenalis assemblages and other Giardia species with the qPCR. (DOCX 363 kb)
Parasites & Vectors
Background Ticks of the genus Hyalomma, which are vectors for several tick-borne diseases, are oc... more Background Ticks of the genus Hyalomma, which are vectors for several tick-borne diseases, are occasionally found in areas outside their endemic range including northern parts of Europe. The objective of this study was to analyse adult Hyalomma ticks that were recently found in the Netherlands. Methods Hyalomma ticks were morphologically identified. Cluster analysis, based upon sequence data (cox1 barcoding) for molecular identification, and pathogen detection were performed. Additionally, a cross-sectional survey of horses was conducted to actively search for Hyalomma ticks in summer 2019. Analysis of temperature was done to assess the possibility of (i) introduced engorged nymphs moulting to adults and (ii) establishment of populations in the Netherlands. Results Seventeen adult Hyalomma ticks (one in 2018, eleven in 2019, five in 2020) were found by citizens and reported. Fifteen ticks were detected on horses and two on humans. Twelve were identified as H. marginatum, one as H. r...
Parasites & Vectors, Nov 21, 2019
BackgroundThe aim of this study was to assess potential associations between Giardia duodenalis i... more BackgroundThe aim of this study was to assess potential associations between Giardia duodenalis infection in dogs, as determined by three diagnostic tests, and dog’s group of origin, fecal consistency, age, sex, neuter status, and co-infections with other gastrointestinal parasites.MethodsFecal samples from 1291 dogs from four groups (household, shelter, hunting and clinical dogs) were tested with qPCR, rapid enzyme immunochromatographic assay (IDEXX SNAP® Giardia), and direct immunofluorescence (DFA, Merifluor) for presence of G. duodenalis. Moreover, fecal samples were tested with centrifugation sedimentation flotation (CSF) coproscopical analysis for presence of gastrointestinal parasites. Associations were expressed as odds ratios (ORs).ResultsSeveral significant associations were found, of which a few were consistent for all three tests and Giardia positivity in general (positive with at least one of these tests). Dogs older than one year were significantly less likely to test positive for Giardia than younger dogs. Group-housed dogs, especially hunting dogs, were significantly more likely to test positive for Giardia compared to household and clinical dogs. A consistently significant association with Trichuris appeared to be driven by the high prevalence in hunting dogs. Although there was no significant association between loose stool and Giardia infection in the overall population, household dogs were significantly more likely to test Giardia-positive when having loose stool. Overall, Giardia-positive dogs with loose stool shed significantly more cysts, both determined semi-quantitatively with CSF and quantitatively by qPCR, than positive dogs with no loose stool. When other gastrointestinal parasites were present, significantly fewer cysts were detected with CSF, but this was not confirmed with qPCR.ConclusionGiardia is the most common gastrointestinal parasite in Dutch dogs, except for hunting dogs, in which Trichuris and strongyle-type eggs (hookworms) prevailed. Giardia infection was not significantly associated with loose stool, except for household dogs. Young dogs and group-housed dogs were significantly more often Giardia-positive. These associations were consistent across diagnostic tests. Young dogs, clinical dogs and dogs with loose stool shed Giardia cysts in the highest numbers. If another gastrointestinal parasite was present lower numbers of cysts were observed by microscope (CSF), but not with a molecular method (qPCR).
Advances in Parasitology
OBJECTIVES To provide an overview of Toxocara prevalences in dogs and cats in Europe from the las... more OBJECTIVES To provide an overview of Toxocara prevalences in dogs and cats in Europe from the last 25 years. METHOD Systematic review of the literature. RESULTS Over the past 25 years, prevalence studies of Toxocara spp. have been published from 26 European countries. The average prevalences were 14.6% for T. canis in all dogs and 24.5% for T. cati in all cats. Specified for young dogs until 6 months old this was 41.2%, for young cats until 6 months old 25%, adult owned dogs 11.1%, adult owned cats 16.3%, stray dogs 17.6%, and stray cats 33.5%. A recent study in seven European countries showed a prevalence of 3.4% for adult dogs and 4.2% for adult cats. The prevalences seem not to decrease over the years. CONCLUSION The prevalence of patent Toxocara infections over the last 25 years did not show a distinct declining trend. Prevalence data provided by recent modern antigen tests showed much lower results than from older studies. Results from studies using less diverse methods and well-defined study-populations could provide more clarity.
Advances in Parasitology
Embryonated Toxocara eggs in the environment are considered to be the most important source of hu... more Embryonated Toxocara eggs in the environment are considered to be the most important source of human toxocariasis. These eggs, however, are also a source of infection for the definitive and paratenic hosts. Most available literature focuses on Toxocara canis in dogs, or other canids. There are, however, other Toxocara species with their accompanying definitive hosts. Results from studies that modelled patent infections in dogs, cats and foxes show that although dogs are a very important source for environmental contamination with Toxocara eggs, other sources cannot be ignored. For a good understanding of the relative contributions of different definitive hosts to environmental contamination with Toxocara eggs, computational models should be built and fed with data from different fields of expertise as is discussed in this paper.
Parasites & vectors, Jan 31, 2018
To accurately diagnose giardiosis in dogs, knowledge of diagnostic test characteristics and expec... more To accurately diagnose giardiosis in dogs, knowledge of diagnostic test characteristics and expected prevalence are required. The aim of this work was to estimate test characteristics (sensitivity and specificity) of four commonly used diagnostic tests for detection of Giardia duodenalis in dogs. Fecal samples from 573 dogs originating from four populations (household dogs, shelter dogs, hunting dogs and clinical dogs) were examined with centrifugation sedimentation flotation (CSF) coproscopical analysis, direct immunofluorescence assay (DFA, Merifluor Cryptosporidium/Giardia®), a rapid enzyme immunochromatographic assay (IDEXX SNAP Giardia®) and qPCR (SSU rDNA) for presence of G. duodenalis. Bayesian latent class analysis was used to determine test performance characteristics and to estimate G. duodenalis prevalence of each of the four dog populations. All tests were highly specific. IDEXX SNAP Giardia® showed the highest specificity (99.6%) and qPCR the lowest (85.6%). The sensiti...
Additional file 1: Table S1. Graphic image of all reports to the CMV, including Hyalomma (June 20... more Additional file 1: Table S1. Graphic image of all reports to the CMV, including Hyalomma (June 2019–December 2020). Table S2. Hyalomma sp. GenBank® accession numbers (n=77) used for the cluster analysis.
Additional file 3: Figure S1. Example of SSU-rDNA fragment with "double peaks" in the S... more Additional file 3: Figure S1. Example of SSU-rDNA fragment with "double peaks" in the Sanger sequence results.
Additional file 1: Table S1. Characteristics of multi-locus genotype nested PCRs.
Additional file 3: Table S3. Raw data. Table S4. Prevalence of gastrointestinal parasites, compar... more Additional file 3: Table S3. Raw data. Table S4. Prevalence of gastrointestinal parasites, compared to previous performed studies in similar dog populations.
Additional file 2: Table S2. Prevalence of gastrointestinal parasites for the different age groups.
Additional file 1: Table S1. Prevalence of gastrointestinal parasites for the different dog popul... more Additional file 1: Table S1. Prevalence of gastrointestinal parasites for the different dog populations.
Text. Experiment 1: Confirming true positivity of samples only positive with the qPCR. Figure S1.... more Text. Experiment 1: Confirming true positivity of samples only positive with the qPCR. Figure S1. SSU rDNA qPCR [5] performed as conventional PCR without probe. Figure S2. Serial dilution of template for SSU rDNA qPCR [5] performed as conventional PCR without probe. (DOCX 1781 kb)
Questionnaire. (PDF 483 kb)
Parasites & Vectors, 2015
Background: Environmental contamination with Toxocara eggs is considered the main source of human... more Background: Environmental contamination with Toxocara eggs is considered the main source of human toxocariasis. The contribution of different groups of hosts to this contamination is largely unknown. Current deworming advices focus mainly on dogs. However, controversy exists about blind deworming regimens for >6-month-old dogs, as most of them do not actually shed Toxocara eggs. We aim to estimate the contribution of different non-juvenile hosts to the environmental Toxocara egg contamination and to assess the effects of different Toxocara-reducing interventions for dogs. Methods: A stochastic model was developed to quantify the relative contribution to the environmental contamination with Toxocara eggs of household dogs, household cats, stray cats, and foxes, all older than 6 months in areas with varying urbanization degrees. The model was built upon an existing model developed by Morgan et al. (2013). We used both original and published data on host density, prevalence and inte...
Parasites & Vectors, 2020
Background In dogs, infections with Giardia duodenalis are mainly caused by assemblages C and D, ... more Background In dogs, infections with Giardia duodenalis are mainly caused by assemblages C and D, but also by the potentially zoonotic assemblages A and B. The aims of this study were to assess differences in assemblages (i) between dogs living mainly in close proximity to humans (synanthropic dogs) versus dogs living mainly among other dogs, (ii) between samples of dogs with or without loose stool, and (iii) related to the amount of cysts shedding. Methods One hundred eighty-nine qPCR Giardia positive fecal samples of dogs originating from four groups (household, sheltered, hunting, and dogs for which a veterinarian sent a fecal sample to a diagnostic laboratory) were used for genotyping. For this, multi-locus genotyping of beta-giardin, triose phosphate isomerase, and glutamate dehydrogenase and genotyping of SSU rDNA gene fragments were performed. Fecal consistency was scored (loose or non-loose stool), and cysts per gram of feces were determined with qPCR. Results Assemblage D wa...
Tijdschrift Voor Diergeneeskunde, 2008
Een onafhankelijke groep Europese parasitologen wil via de website www.esccap.org zonder winstoog... more Een onafhankelijke groep Europese parasitologen wil via de website www.esccap.org zonder winstoogmerk informatie verstrekken over parasitaire infecties bij hond en kat in Europa. Hierbij is het belangrijk dat de (ontwormings)adviezen uniform zijn, de informatie “up-to-date” wordt gehouden en dat deze in diverse talen beschikbaar is. De uitgebreide richtlijnen kunnen worden aangepast aan de regionale situatie. De organisatie, genaamd European Scientific Counsel Companion Animal Parasites (ESCCAP), wordt inmiddels ondersteund door het European Veterinairy Parasitology College (EVPC) en de World Association for the Advancement of Veterinary Parasitology (WAAVP). De vertegenwoordiger vanuit Nederland is Frans van Knapen, hoogleraar in veterinaire volksgezondheid en levensmiddelenhygiene te Utrecht
Text. Detection of Giardia duodenalis assemblages and other Giardia species with the qPCR. (DOCX ... more Text. Detection of Giardia duodenalis assemblages and other Giardia species with the qPCR. (DOCX 363 kb)
Parasites & Vectors
Background Ticks of the genus Hyalomma, which are vectors for several tick-borne diseases, are oc... more Background Ticks of the genus Hyalomma, which are vectors for several tick-borne diseases, are occasionally found in areas outside their endemic range including northern parts of Europe. The objective of this study was to analyse adult Hyalomma ticks that were recently found in the Netherlands. Methods Hyalomma ticks were morphologically identified. Cluster analysis, based upon sequence data (cox1 barcoding) for molecular identification, and pathogen detection were performed. Additionally, a cross-sectional survey of horses was conducted to actively search for Hyalomma ticks in summer 2019. Analysis of temperature was done to assess the possibility of (i) introduced engorged nymphs moulting to adults and (ii) establishment of populations in the Netherlands. Results Seventeen adult Hyalomma ticks (one in 2018, eleven in 2019, five in 2020) were found by citizens and reported. Fifteen ticks were detected on horses and two on humans. Twelve were identified as H. marginatum, one as H. r...
Parasites & Vectors, Nov 21, 2019
BackgroundThe aim of this study was to assess potential associations between Giardia duodenalis i... more BackgroundThe aim of this study was to assess potential associations between Giardia duodenalis infection in dogs, as determined by three diagnostic tests, and dog’s group of origin, fecal consistency, age, sex, neuter status, and co-infections with other gastrointestinal parasites.MethodsFecal samples from 1291 dogs from four groups (household, shelter, hunting and clinical dogs) were tested with qPCR, rapid enzyme immunochromatographic assay (IDEXX SNAP® Giardia), and direct immunofluorescence (DFA, Merifluor) for presence of G. duodenalis. Moreover, fecal samples were tested with centrifugation sedimentation flotation (CSF) coproscopical analysis for presence of gastrointestinal parasites. Associations were expressed as odds ratios (ORs).ResultsSeveral significant associations were found, of which a few were consistent for all three tests and Giardia positivity in general (positive with at least one of these tests). Dogs older than one year were significantly less likely to test positive for Giardia than younger dogs. Group-housed dogs, especially hunting dogs, were significantly more likely to test positive for Giardia compared to household and clinical dogs. A consistently significant association with Trichuris appeared to be driven by the high prevalence in hunting dogs. Although there was no significant association between loose stool and Giardia infection in the overall population, household dogs were significantly more likely to test Giardia-positive when having loose stool. Overall, Giardia-positive dogs with loose stool shed significantly more cysts, both determined semi-quantitatively with CSF and quantitatively by qPCR, than positive dogs with no loose stool. When other gastrointestinal parasites were present, significantly fewer cysts were detected with CSF, but this was not confirmed with qPCR.ConclusionGiardia is the most common gastrointestinal parasite in Dutch dogs, except for hunting dogs, in which Trichuris and strongyle-type eggs (hookworms) prevailed. Giardia infection was not significantly associated with loose stool, except for household dogs. Young dogs and group-housed dogs were significantly more often Giardia-positive. These associations were consistent across diagnostic tests. Young dogs, clinical dogs and dogs with loose stool shed Giardia cysts in the highest numbers. If another gastrointestinal parasite was present lower numbers of cysts were observed by microscope (CSF), but not with a molecular method (qPCR).
Advances in Parasitology
OBJECTIVES To provide an overview of Toxocara prevalences in dogs and cats in Europe from the las... more OBJECTIVES To provide an overview of Toxocara prevalences in dogs and cats in Europe from the last 25 years. METHOD Systematic review of the literature. RESULTS Over the past 25 years, prevalence studies of Toxocara spp. have been published from 26 European countries. The average prevalences were 14.6% for T. canis in all dogs and 24.5% for T. cati in all cats. Specified for young dogs until 6 months old this was 41.2%, for young cats until 6 months old 25%, adult owned dogs 11.1%, adult owned cats 16.3%, stray dogs 17.6%, and stray cats 33.5%. A recent study in seven European countries showed a prevalence of 3.4% for adult dogs and 4.2% for adult cats. The prevalences seem not to decrease over the years. CONCLUSION The prevalence of patent Toxocara infections over the last 25 years did not show a distinct declining trend. Prevalence data provided by recent modern antigen tests showed much lower results than from older studies. Results from studies using less diverse methods and well-defined study-populations could provide more clarity.
Advances in Parasitology
Embryonated Toxocara eggs in the environment are considered to be the most important source of hu... more Embryonated Toxocara eggs in the environment are considered to be the most important source of human toxocariasis. These eggs, however, are also a source of infection for the definitive and paratenic hosts. Most available literature focuses on Toxocara canis in dogs, or other canids. There are, however, other Toxocara species with their accompanying definitive hosts. Results from studies that modelled patent infections in dogs, cats and foxes show that although dogs are a very important source for environmental contamination with Toxocara eggs, other sources cannot be ignored. For a good understanding of the relative contributions of different definitive hosts to environmental contamination with Toxocara eggs, computational models should be built and fed with data from different fields of expertise as is discussed in this paper.
Parasites & vectors, Jan 31, 2018
To accurately diagnose giardiosis in dogs, knowledge of diagnostic test characteristics and expec... more To accurately diagnose giardiosis in dogs, knowledge of diagnostic test characteristics and expected prevalence are required. The aim of this work was to estimate test characteristics (sensitivity and specificity) of four commonly used diagnostic tests for detection of Giardia duodenalis in dogs. Fecal samples from 573 dogs originating from four populations (household dogs, shelter dogs, hunting dogs and clinical dogs) were examined with centrifugation sedimentation flotation (CSF) coproscopical analysis, direct immunofluorescence assay (DFA, Merifluor Cryptosporidium/Giardia®), a rapid enzyme immunochromatographic assay (IDEXX SNAP Giardia®) and qPCR (SSU rDNA) for presence of G. duodenalis. Bayesian latent class analysis was used to determine test performance characteristics and to estimate G. duodenalis prevalence of each of the four dog populations. All tests were highly specific. IDEXX SNAP Giardia® showed the highest specificity (99.6%) and qPCR the lowest (85.6%). The sensiti...