Torben W Schou

Followers

Following

Co-authors

Public Views

Ebru Soytemel

Aston University

David Seamon

Kansas State University

Armando Marques-Guedes

UNL - New University of Lisbon

Noe Cornago

University of the Basque Country, Euskal Herriko Unibertsitatea

Alexandra Magnolia Dias

Faculty of Human and Social Sciences - New University of Lisbon

Thomas Marois

McMaster University

Viacheslav Kuleshov

Stockholm University

Tomasz Kamiński

The University of Lodz

Ronald Raminelli

UFF - Universidade Federal Fluminense

HiSTOReLo Revista de Historia Regional y Local

Universidad Nacional de Colombia (National University of Colombia)

Interests

Uploads

Papers by Torben W Schou

Effects of artemisinin and Artemisia annua extracts on xenic bacteria isolated from clonal cultures of Histomonas meleagridis

Comparative genetic resistance to Ascaridia galli infections of 4 different commercial layer-lines

British Poultry Science, Jun 1, 2003

1. The objective of the study was to compare the establishment and effect of Ascaridia galli infe... more 1. The objective of the study was to compare the establishment and effect of Ascaridia galli infections in 4 different layer-lines. 2. A total of 160 birds comprising 4 different commercial layer-lines, ISA Brown, New Hampshire, Skalborg and a cross of New Hampshire(NH) and Skalborg (Sk), were infected with A. galli eggs. The birds were examined for the presence of parasite eggs and parasites at weeks 3, 6 and 9 post infection (pi). 3. At week 6 pi the chickens of the NH line harboured more larvae compared with the three other lines. The Sk line chickens excreted more A. galli eggs throughout the study compared with the other lines. Female worms in the Sk line were more fecund than the worms in the other lines. Male and female worms recovered from the Sk line at week 9 pi were longer. Male worms recovered from the NH line 6 weeks pi were shorter than male worms from the other lines. Female worms recovered from the NH line were shorter than the female worms from the ISA line and the Sk line. No differences were seen in weight gain among the 4 lines. 4. The results suggest that genetic factors are involved in the establishment and survival of A. galli in the intestine of layers. Further studies are needed to elucidate the genetic mechanisms behind the observed parasitological findings.

Download

Screening of Artemisia annua compounds against Histomonas meleagridis

Resumen La infección con Histomonas meleagridis causa severa tiflohepatitis e incrementa la morta... more

Hepatic toxicity of artemisinin in turkeys

Antihistomonal effect of artemisinin and Artemisia annua extracts in experimentally infected chickens and turkeys

Effects of artemisinin and Artemisia annua extract on clinical caecal coccidiosis ( Eimeria tenella ) in broilers

Parasitology, 2015

Toxicity of artemisinin in one week old turkey poults

ABSTRACT In a previous study on the effect of artemisinin on histomonosis in experimentally infec... more ABSTRACT In a previous study on the effect of artemisinin on histomonosis in experimentally infected turkeys, intoxication using high doses of artemisinin was suspected. Consequently, the bile duct epithelium was quantified stereologically in turkeys suspected of artemisinin intoxication. The parameters investigated included the volume fraction of bile duct epithelium and two different length densities of bile ducts, i.e. the length density of lumen-less bile ducts and the total length density of bile ducts. The ratio of length density of lumen-less bile ducts to the total length density was significantly higher in the artemisinin treated birds when compared to control birds. However, no differences between the artemisinin treated group and control group were observed concerning the volume fraction of bile duct epithelium per liver parenchyma volume. Epithelial anisocytosis and anisokaryosis of bile epithelium was observed in the artemisinin treated group. The present findings suggest that artemisinin treatment modifies the development of the biliary duct system in post-natal turkey poults. This is the first study that uses stereological microscopy for quantification of bile duct epithelium in turkey livers. Artemisinin-induced cholehepatic toxicity has not previously been described in such detail. To our knowledge, comparable investigations on bile duct changes due to other liver toxicites have not yet been reported in domestic animals.

Quantitative assessment of bile ducts in turkeys treated with artemisinin: A model for liver toxicity?

Protective effects of artemisinin and Artemisia annua extracts on clinical caecal coccidiosis in broiler chickens

Acquisition of resistance after continuous infection with Ascaridia galli in chickens

Parasitology, Jan 8, 2014

SUMMARY Acquired resistance against Ascaridia galli infection was studied in seventy-two 18-week-... more SUMMARY Acquired resistance against Ascaridia galli infection was studied in seventy-two 18-week-old white Leghorn chickens allocated to six groups (G1-G6). In order to understand the population dynamics following trickle-infection (100 eggs per chicken twice weekly), chickens of subgroups of G1 were necropsied 3 days after 1, 6 or 12 inoculations (G1A, G1B and G1C respectively), while G2-G4 were inoculated for 6 weeks. G2 was necropsied 4 weeks after the last inoculation. The number of established larvae increased initially (between G1A and G1B) but decreased after repeated inoculations (G1C, G2). G3, G4 and G5 were used to measure the efficacy of anthelminthic treatment and to monitor the acquisition of resistance following a challenge infection. At week 7 G3, G4 and G5 were treated with flubendazole for 7 days in the feed. Two weeks after treatment the chickens in G4 and G5 were challenged with 500 eggs. G6 was left as uninfected control. Necropsy at week 10 after first inoculati...

Schistosoma japonicum in the pig: the influence of age on the host/parasite relationship

The Southeast Asian journal of tropical medicine and public health, 1999

The current study sought to elucidate a possible association between age and susceptibility to a ... more The current study sought to elucidate a possible association between age and susceptibility to a primary infection with Schistosoma japonicum in pigs. Sixteen Landrace/Yorkshire crossbred specific pathogen-free pigs in three different age groups (group A-C), aged approximately 7, 24 and 37 weeks at the beginning of the experiment, were infected by intramuscular injections of 1,000, 1,500 or 2,400 cercariae, respectively. Fecal egg counts were obtained twice weekly from six to eight weeks post infection (wpi), and the pigs were killed 11 wpi. The number of worms collected were counted and sexed subsequent to perfusion. Tissue egg counts were estimated on samples from the liver. The worm recoveries for group A, B and C were 3.2%, 8.1% and 3.8%, respectively. No differences were observed between the male/female ratios of the three groups. The fecundity parameters, ie, fecal egg counts per mature female and liver egg counts per mature female, showed no significant differences between th...

Download

Immune gene expression in the spleen of chickens experimentally infected with Ascaridia galli

Veterinary Immunology and Immunopathology, 2015

Ascaridia galli is a gastrointestinal nematode infecting chickens. Chickens kept in alternative r... more Ascaridia galli is a gastrointestinal nematode infecting chickens. Chickens kept in alternative rearing systems or at free-range experience increased risk for infection with resulting high prevalences. A. galli infection causes reduced weight gain, decreased egg production and in severe cases increased mortality. More importantly, the parasitised chickens are more susceptible to secondary infections and their ability to develop vaccine-induced protective immunity against other diseases may be compromised. Detailed information about the immune response to the natural infection may be exploited to enable future vaccine development. In the present study, expression of immune genes in the chicken spleen during an experimental infection with A. galli was investigated using the Fluidigm ® BioMark TM microfluidic qPCR platform which combines automatic high-throughput with attractive low sample and reagent consumption. Spleenic transcription of immunological genes was compared between infected chickens and non-infected controls at week 2, 6, and 9 p.i. corresponding to different stages of parasite development/maturation. At week 2 p.i. increased expression of IL-13 was observed in infected chickens. Increased expression of MBL, CRP, IFN-␣, IL-1␤, IL-8, IL-12␤ and IL-18 followed at week 6 p.i. and at both week 6 and 9 p.i. expression of DEF␤1 was highly increased in infected chickens. In summary, apart from also earlier reported increased expression of the Th2 signature cytokine IL-13 we observed only few differentially expressed genes at week 2 p.i. which corresponds to the larvae histotrophic phase. In contrast, we observed increased expression of pro-inflammatory cytokines and acute phase proteins in infected chickens, by week 6 p.i. where the larvae re-enter the intestinal lumen. Increased expression of DEF␤1 was observed in infected chickens at week 6 p.i. but also at week 9 p.i. which corresponds to a matured stage where adult worms are present in the intestinal lumen.

Download

Quantitative assessment of bile ducts in turkeys treated with artemisinin: A model for liver toxicity?

Toxicity of artemisinin in one-week-old turkey poults

In vitro maintenance of Schistosoma japonicum and surgical transfer from donor to naïve recipient pigs

Veterinary Parasitology, 1997

An objective of this study was to find a culture medium and a temperature range suitable for in v... more An objective of this study was to find a culture medium and a temperature range suitable for in vitro maintenance of adult Schistosoma japonicum during surgical transplantation experiments. Adult S. japonicum were cultivated in four different media (NCTC 135, NCTC 109, RPMI 1640 and 0.85% physiological saline) supplemented with 10% heat-inactivated normal pig serum (hiNPS) at either 4 degrees C, 22-25 degrees C (room temperature) or 37 degrees C. Based on survival and morphologic evaluation, NCTC 135 at room temperature was found to be the best medium/temperature combination for maintenance of worms. An additional objective was to develop a method for transplanting adult S. japonicum from experimentally infected donor pigs to naïve recipient pigs. Six Landrace/Yorkshire crossbred pigs were used as donors to supply worms for two recipient pigs. Worms for transplantation were obtained by perfusion of the mesenteric veins of the donor pigs and maintained for a maximum of 3 h in NCTC 135 + 10% hiNPS at room temperature. A total of 148 and 132 worms were surgically transferred by way of an infusion tube into caecal veins of the two recipients. Six weeks after transplantation, 14% and 36% of the transferred worms were recovered by perfusion and subsequent manual inspection of the mesenteric veins of the two recipient pigs, respectively. The successful results suggest that surgical transfer of S. japonicum worms from donor to naïve recipient pigs may be useful for future studies on population genetics, dynamics and regulation in the pig/S. japonicum model.

Cytokine gene expression profiles in chicken spleen and intestinal tissues during Ascaridia galli infection

Veterinary Parasitology, 2014

In the poultry production industry, chickens with access to outdoor areas are exposed to a wide r... more In the poultry production industry, chickens with access to outdoor areas are exposed to a wide range of parasites e.g. the helminth Ascaridia galli. By real-time quantitative RT-PCR, the relative gene expression of the T helper 1 (Th1) cytokine IFN-␥, the T helper 2 (Th2) cytokine IL-13, the anti-inflammatory cytokines IL-10 and TGF-␤4 and the proinflammatory cytokine IL-17F were determined over a period of 3 weeks in A. galli and non-A. galli-infected chickens. A characteristic Th2 response was observed in the jejunum of A. galli-infected chickens with increased expression of IL-13 and decreased expression of IFN-␥ from day 14 post infection. At the putative time of larvae invasion into the intestinal mucosa (day 7), an increased expression of IFN-␥, IL-10, and TGF-␤4 was observed in the spleen. At the putative onset of the innate immune response (day 10), a decreased expression of jejunal IFN-␥ and IL-13 was observed. Finally, at the expected period of an adaptive immune response (days 14-21) a general decreased expression of IFN-␥ and TGF-␤4 in spleen and IFN-␥ in jejunum was followed by a decreased expression of IFN-␥ and IL-10 at day 21 in caecal tonsils.

Download

Comparison of parasite-specific immunoglobulin levels in two chicken lines during sustained infection with Ascaridia galli

Veterinary Parasitology, 2013

Increasingly large numbers of poultry are held in production systems with access to outdoor areas... more Increasingly large numbers of poultry are held in production systems with access to outdoor areas. In these systems intestinal helminths are found with flock prevalences of up to 100%. Helminth infections influence chicken health negatively, which is why the following investigation has been performed.

Download

MHC haplotype and susceptibility to experimental infections (Salmonella Enteritidis, Pasteurella multocida or Ascaridia galli) in a commercial and an indigenous chicken breed

Veterinary Immunology and Immunopathology, 2010

Download

Ascaridia galli infection influences the development of both humoral and cell-mediated immunity after Newcastle Disease vaccination in chickens

Vaccine, 2014

Potent vaccine efficiency is crucial for disease control in both human and livestock vaccination ... more Potent vaccine efficiency is crucial for disease control in both human and livestock vaccination programmes. Free range chickens and chickens with access to outdoor areas have a high risk of infection with parasites including Ascaridia galli, a gastrointestinal nematode with a potential influence on the immunological response to vaccination against other infectious diseases. The purpose of this study was to investigate whether A. galli infection influences vaccine-induced immunity to Newcastle Disease (ND) in chickens from an MHC-characterized inbred line. Chickens were experimentally infected with A. galli at 4 weeks of age or left as non-parasitized controls. At 10 and 13 weeks of age half of the chickens were ND-vaccinated and at 16 weeks of age, all chickens were challenged with a lentogenic strain of Newcastle disease virus (NDV). A. galli infection influenced both humoral and cell-mediated immune responses after ND vaccination. Thus, significantly lower NDV serum titres were found in the A. galli-infected group as compared to the non-parasitized group early after vaccination. In addition, the A. galli-infected chickens showed significantly lower frequencies of NDV-specific T cells in peripheral blood three weeks after the first ND vaccination as compared to non-parasitized chickens. Finally, A. galli significantly increased local mRNA expression of IL-4 and IL-13 and significantly decreased TGF-␤4 expression in the jejunum two weeks after infection with A. galli. At the time of vaccination (six and nine weeks after A. galli infection) the local expression in the jejunum of both IFN-␥ and IL-10 was significantly decreased in A. galli-infected chickens. Upon challenge with the NDV LaSota strain, viral genomes persisted in the oral cavity for a slightly longer period of time in A. galli-infected vaccinees as compared to non-parasitized vaccinees. However, more work is needed in order to determine if vaccine-induced protective immunity is impaired in A. galli-infected chickens.

Download

Antibacterial and antiprotozoal effect of Artemisia annua extracts

Planta Medica, 2012