Eva Olsson Engvall

Isolation and identification of thermophilic Campylobacter species in faecal samples from Swedish dogs.

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.

Multilocus sequence typing of Campylobacter jejuni from broilers

Campylobacter jejuni isolates from a national Swedish Campylobacter monitoring in broilers were characterized by multilocus sequencing typing (MLST) in order to study the genetic diversity of this bacterial population. Isolates were initially characterized by pulsed-field gel electrophoresis (PFGE). One hundred were chosen for MLST genotyping. PFGE identified 69 distinct types compared to 44 different sequence types (STs) identified with MLST. Eighteen STs had not been described previously, while the remaining 26 STs were assigned to previously known clonal complexes. The majority of isolates were of genotypes noted in broilers and in humans in earlier studies. However, three clonal complexes, ST-206 complex, ST-677 complex and ST-1034 complex, previously associated with wild bird and environmental samples, were among the genotypes found. This study shows that most of the Swedish broiler isolates were of genotypes noted as common in broilers. However, it also highlights the potential influence of environmental sources on the broiler C. jejuni genotypes.

Serological Survey of Toxoplasma gondii Infection in Pigs Slaughtered in Sweden

The prevalence of Toxoplasma gondii infection in Swedish pigs was investigated by analysis of 807 meat juice samples collected in 1999 from 10 abattoirs in different parts of the country. When analysed using ELISA, 42 (5.2%) of the samples were found to be positive. The seroprevalence was 3.3% in fattening pigs (n = 695) and 17.3% (n = 110) in adult swine. Alternative interpretations of the results, considering estimates of the true prevalence based on the sensitivity and specificity of the test method, are discussed. It is concluded that the risk of contracting T. gondii infection as a result of eating undercooked pork from Swedish pigs, especially adult animals, is not negligible.

Cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. and demographic, clinical and tick-exposure factors in Swedish horses.

A cross-sectional study of the seroprevalence to Borrelia burgdorferi sensu lato and granulocytic Ehrlichia spp. in Swedish horses was conducted to evaluate associations with demographic, clinical and tick-exposure factors. From September 1997-1998, blood samples from 2018 horses were collected from the animals presented to veterinary clinics affiliated with the Swedish Horserace Totalizator Board (regardless of the primary cause for consultation). Standardized questionnaires with information both from owners and attending veterinarians accompanied each blood sample. The apparent seroprevalences to B. burgdorferi s. l. and granulocytic Ehrlichia spp. were 16.8 and 16.7%, respectively. The northern region had the lowest seroprevalences. Four logistic models were developed (controlling for demographic variables). In the disease model of seropositivity to B. burgdorferi s. l., age, breed, geographic region, the serologic titer to granulocytic Ehrlichia spp., season and the diagnosis coffin-joint arthritis were significant. In the tick-exposure model of B. burgdorferi s. l., pasture access the previous year and gender were significant. Age, racing activity, geographic region, season and the serologic titer to B. burgdorferi s. l. were associated with positivity to granulocytic Ehrlichia spp. In the tick-exposure model of granulocytic Ehrlichia spp., pasture access was a risk factor. An interaction between racing activity and geographic region showed that the risk of positive serologic reactions to Ehrlichia spp. was increased in the horse population in the south and middle of Sweden, but only among horses not used for racing. Except for the positive association between coffin-joint arthritis and serologic reactions to B. burgdorferi s. l., there were no significant associations in the multivariable models between non-specific or specific clinical sign or disease with seropositivity to either of these agents.

Within-flock variations of Campylobacter loads in caeca and on carcasses from broilers

The proportions of broiler caeca and carcass rinse samples positive for Campylobacter spp. within broiler flocks were determined. Twenty intact caeca per flock from 27 flocks were analyzed individually. Rinse samples were obtained from 5 to 25 carcasses from 27 other flocks. In total, 540 caecum samples and 445 carcass rinse samples were analyzed. The proportion of positive caeca within flocks ranged from 10 to 100%, and the proportion of positive carcasses ranged from 85 to 100%. The highest and lowest numbers of Campylobacter spp. found in positive caecum samples were 8.6 and 1.7log cfu/g caecal contents, respectively. The number of Campylobacter spp. in the caeca from individual broilers within a flock varied by up to 6.3log cfu/g caecal contents. The highest number found on one carcass was 4.2log cfu/ml carcass rinse sample, and the within-flock variation in Campylobacter spp. was up to 3.2log cfu/ml rinse sample. There was thus great variation in the load of Campylobacter spp. in individual caecum and carcass samples obtained from each positive broiler flock. This large variation in the numbers of Campylobacter spp. carried by individual birds should be considered when only one or a few samples are collected from a flock and the results are used for risk assessments.

Granulocytic ehrlichiosis in Swedish dogs and horses

Granulocytic ehrlichiosis is a frequently diagnosed tick-borne disease in Swedish dogs and horses. The infection is caused by a granulocytic Ehrlichia species belonging to the Ehrlichia phagocytophila genogroup. In the acute stage, the disease is mainly characterized as a febrile illness and diagnosis can be confirmed by the demonstration of ehrlichial inclusions in blood granulocytes. Seropositivity in many healthy dogs and horses indicate that the infection also can be transient without clinical signs. The infection can persist in experimentally inoculated animals for months, but to what extent this persistance also occurs in naturally infected animals and is associated with clinical signs, is not clarified yet.

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

Improved monitoring tools are important for the control of Campylobacter bacteria in poultry production. Standardized reference culture methods issued by national and international standardization organizations are time-consuming, cumbersome and not amenable to automation for screening of large numbers of samples. The ultimate goal for rapid monitoring of Campylobacter is to prevent contaminated meat from entering the food market. Currently, real-time PCR is fulfilling abovementioned criteria to a certain extent. Further development of real-time PCR, microarray PCR, miniaturized biosensors, chromatographic techniques and DNA sequencing can improve our monitoring capacity at a lower cost. Combined with innovative sampling and sample treatment, these techniques could become realistic options for on-farm and liquid-sample monitoring at slaughterhouses.

The Workshop on Animal Botulism in Europe

A workshop on animal botulism was held in Uppsala, Sweden, in June 2012. Its purpose was to explore the current status of the disease in Europe by gathering the European experts in animal botulism and to raise awareness of the disease among veterinarians and others involved in biopreparedness. Animal botulism is underreported and underdiagnosed, but an increasing number of reports, as well as the information gathered from this workshop, show that it is an emerging problem in Europe. The workshop was divided into 4 sessions: animal botulism in Europe, the bacteria behind the disease, detection and diagnostics, and European collaboration and surveillance. An electronic survey was conducted before the workshop to identify the 3 most needed discussion points, which were: prevention, preparedness and outbreak response; detection and diagnostics; and European collaboration and surveillance. The main conclusions drawn from these discussions were that there is an urgent need to replace the mouse bioassay for botulinum toxin detection with an in vitro test and that there is a need for a European network to function as a reference laboratory, which could also organize a European supply of botulinum antitoxin and vaccines. The foundation of such a network was discussed, and the proposals are presented here along with the outcome of discussions and a summary of the workshop itself.

Genetic diversity and host associations in Campylobacter jejuni from human cases and broilers in 2000 and 2008

Campylobacter jejuni is an important food-borne pathogen, with a global distribution. It can colonize numerous host species, including both domestic and wild animals, but is particularly associated with birds (poultry and wild birds). For human campylobacteriosis, poultry products are deemed the most significant risk factor for acquiring infection. We conducted a genotyping and host attribution study of a large representative collection of C. jejuni isolated from humans and broilers in Sweden in the years 2000 and 2008. In total 673 broiler and human isolates from 10 different abattoirs and 6 different hospitals were genotyped with multilocus sequence typing. Source attribution analyses confirmed the strong linkage between broiler C. jejuni and domestic human cases, but also indicated a significant association to genotypes more commonly found in wild birds. Genotype distributions did not change dramatically between the two study years, suggesting a stable population of infecting bacteria.

A Prospective Follow-Up Study on Transmission of Campylobacter from Poultry to Abattoir Workers

Contact with poultry or poultry meat is a well-known risk factor for campylobacteriosis, but prospective studies on transmission of Campylobacter from chickens to humans during slaughter are scarce. In this study, we monitored transmission of Campylobacter from slaughtered chicken to originally culture-negative abattoir workers during the peak season of colonized chicken and human Campylobacter infection. Stool samples were obtained from 28 abattoir workers together with data on health status once a month between June and September 2010, with a follow-up sample collected in February 2011. Campylobacter-positive individuals and chicken flocks were identified by culture, and isolates were further characterized using molecular techniques. Campylobacter was isolated from seven asymptomatic individuals. Four of them had been newly employed and had not reported any previous Campylobacter infection. Four human isolates had matching genetic fingerprints with isolates from recently slaughtered chickens. Our results further support the role of chicken as the source of human Campylobacter infection but suggest that asymptomatic Campylobacter infection may occur even in individuals with only limited earlier exposure to Campylobacter.