EEEva Olsson Engvall

Eva Olsson Engvall

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

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Eva Olsson Engvall has a total of 34 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Lipooligosaccharide locus classes and putative virulence genes among chicken and human Campylobacter jejuni isolates

    by Patrik Ellström, Ingrid Hansson, Anna Nilsson, Hilpi Rautelin, Eva Olsson Engvall

    Campylobacter cause morbidity and considerable economic loss due to hospitalization and post infectious sequelae such as reactive arthritis, Guillain Barré- and Miller Fischer syndromes. Such sequelae have been linked to C. jejuni harboring sialic acid structures in their lipooligosaccharide (LOS) layer of the cell wall. Poultry is an important source of human Campylobacter infections but little is known about the prevalence of sialylated C. jejuni isolates and the extent of transmission of such isolates to humans. Genotypes of C. jejuni isolates from enteritis patients were compared with those of broiler chicken with pulsed-field gel electrophoresis (PFGE), to study the patterns of LOS biosynthesis genes and other virulence associated genes and to what extent these occur among Campylobacter genotypes found both in humans and chickens. Chicken and human isolates generally had similar distributions of the putative virulence genes and LOS locus classes studied. However, there were significant differences regarding LOS locus class of PFGE types that were overlapping between chicken and human isolates and those that were distinct to each source. The study highlights the prevalence of virulence associated genes among Campylobacter isolates from humans and chickens and suggests possible patterns of transmission between the two species.


  • Monitoring Campylobacter in the poultry production chain — From culture to genes and beyond

    by Mathilde H. Josefsen, Arun K. Bhunia, Eva Olsson Engvall, Mette S.R. Fachmann, Jeffrey Hoorfar


  • Open Access

    Prevalence of thermophilic Campylobacter species in Swedish dogs and characterization of C. jejuni isolates

    by Mia Holmberg, Thomas Rosendal, Eva O Engvall, Anna Ohlson, Ann Lindberg

    The aims of this study were to investigate the prevalence of Campylobacter species in Swedish dogs, to identify the species of the Campylobacter isolates and to genotype the C. jejuni isolates. Young and healthy dogs were targeted and the sampling was performed at 11 veterinary clinics throughout Sweden from October 2011 to October 2012. Faecal swab samples were collected and sent to the laboratory at the National Veterinary Institute (SVA) for isolation of Campylobacter, speciation and genotyping. Campylobacter spp. were isolated from 67 of the 180 sampled dogs which yields an overall prevalence of 37%. The most prevalent species of Campylobacter among the participating dogs was C. upsaliensis with 52 of the 67 identified isolates. A lower prevalence was observed for C. jejuni with seven identified isolates and one isolate was identified as C. helveticus. Multi-locus sequence typing (MLST) was carried out on the seven C. jejuni isolates and all sequence types that were found are also commonly found in humans. The dogs were divided into three age groups; 1) under 12 months, 2) 12 to 23 months and 3) 24 months and older. The highest prevalence was found in the two younger age groups. Dogs shedding C. jejuni were between 3–12 months of age while dogs shedding C. upsaliensis were found in all ages. The present investigation finds that Campylobacter spp. known to cause campylobacteriosis in humans are present in Swedish dogs. The results suggest an age predisposition where dogs under 2 years of age are more likely to shed Campylobacter spp. than older dogs. The most commonly isolated species was C. upsaliensis followed by C. jejuni, which was only detected in dogs up to 12 months of age. All C. jejuni isolates identified in the present study were of the same MLST types that have previously been described both in humans and in animals. The awareness of the Campylobacter risk of healthy young dogs may be an important way to reduce the transmission from dogs to infants, young children and immunocompromised adults.


  • Open Access

    Leptospira seroprevalence and associations between seropositivity, clinical disease and host factors in horses

    by V Båverud, A Gunnarsson, E Olsson Engvall, P Franzén, A Egenvall

    A cross-sectional study was carried out to determine the seroprevalence of different serovars of Leptospira spp. and their association with clinical disease and host factors in Swedish horses.


  • Open Access

    Identification of nine sequence types of the 16S rRNA genes of Campylobacter jejuni subsp. jejuni isolated from broilers

    by Ingrid Hansson, Marianne Persson, Linda Svensson, Eva Olsson Engvall, Karl-Erik Johansson

    Campylobacter is the most commonly reported bacterial cause of enteritis in humans in the EU Member States and other industrialized countries. One significant source of infection is broilers and consumption of undercooked broiler meat. Campylobacter jejuni is the Campylobacter sp. predominantly found in infected humans and colonized broilers. Sequence analysis of the 16S rRNA gene is very useful for identification of bacteria to genus and species level. The objectives in this study were to determine the degree of intraspecific variation in the 16S rRNA genes of C. jejuni and C. coli and to determine whether the 16S rRNA sequence types correlated with genotypes generated by PFGE analysis of SmaI restricted genomic DNA of the strains.


  • Isolation and Identification of Thermophilic Campylobacter Species in Faecal Samples from Swedish Dogs

    by Eva Olsson Engvall, Boel Brändström, Linda Andersson, Viveca Båverud, Gunilla Trowald-Wigh, Lena Englund

    To investigate the role of Swedish dogs as potential reservoirs of thermophilic Campylobacter species, faecal samples were analysed from 91 dogs in 2001. The majority of dogs (n = 84) were healthy family dogs. Campylobacter spp. were isolated from 51 of the 91 dogs (56%). A significant difference in isolation rates was observed between younger and older dogs: 76% of the younger dogs (5–12 months) were positive, compared with 39% of dogs ≥ 13 months (p <0.01). Two different selective media, Preston and CAT, were used for isolation of Campylobacter species. 104 Campylobacter isolates were identified to species level using polymerase chain reaction and restriction enzyme analysis techniques. Campylobacter upsaliensis predominated and was isolated from 39 dogs, C. jejuni from 10, C. coli from 2, C. helveticus from 2 and C. lari from 1 dog. Four dogs had mixed flora with 2 different Campylobacter species. These data clearly show that younger dogs in particular frequently shed thermophilic Campylobacter spp, which could be of impact for public health. To establish the zoonotic potential of canine Campylobacter isolates, both human and canine isolates have to be further characterized and compared.


  • Open Access

    Validation of a polymerase chain reaction/restriction enzyme analysis method for species identification of thermophilic campylobacters isolated from domestic and wild animals

    by E. O. Engvall, B. Brandstrom, A. Gunnarsson, T. Morner, H. Wahlstrom, C. Fermer

    Aims: To compare and evaluate a polymerase chain reaction/restriction enzyme analysis (PCR/REA) method with standard phenotypic tests for the identification and differentiation of the thermophilic c...


  • A 16S rRNA-based PCR assay for detection and identification of granulocytic Ehrlichia species in dogs, horses, and cattle

    by E O Engvall, B Pettersson, M Persson, K Artursson, K E Johansson

    A PCR-based assay was developed for detecting DNA of granulocytic ehrlichiae in blood samples from dogs, horses, and cattle, Primers were designed from 16S rRNA sequence information to specifically amplify DNA from a newly identified Swedish Ehrlichia species. The 16S rRNA nucleotide sequence of this Swedish species differs in only two and three positions from the sequences of Ehrlichia phagocytophila and Ehrlichia equi, respectively, which were also amplified by this PCR system. For evaluation, PCR results were compared with microscopic examination of stained blood smears for the detection of granulocytes containing ehrlichiae (morulae). Thirty-four of 36 microscopically positive samples were also positive by PCR, and 6 microscopically negative samples were negative by PCR as well. Six samples, in which morulae-like structures had been seen, were negative by PCR, also at a lower annealing temperature and when a reamplification of the first PCR products was performed. The identities of the PCR products from some canine and equine isolates were verified by direct DNA sequencing and were found to be identical with the Ehrlichia sequence found in these animal species that had been obtained earlier. The sequences of a segment of approximately 600 nucleotides from two bovine isolates were identical to that of E. phagocytophila, whereas the sequence of another bovine isolate differed in two positions from that of E. phagocytophila and in three positions from the sequences of the canine and equine isolates. Serum samples were analyzed by indirect fluorescent-antibody testing. Seventy-three percent of the animals which were positive by microscopy and PCR also had positive antibody titers. However, it was not possible to rely on a single serological result for diagnosis of present infection. It was, therefore, concluded that PCR was the most reliable method, useful in the clinical laboratory for specific and early diagnosis of granulocytic ehrlichiosis in animals.