1. Brucellosis outbreak in a Swedish kennel in 2013: Determination of genetic markers for source tracing
Rene Kaden a,b,c,d, Joakim Ågren a, Viveca Båverud a,b, Gunilla Hallgren a, Sevinc Ferrari a,b,c, Joann Börjesson a, Martina Lindberg a,b,c,e, Stina Bäckman b,f, Tara Wahab b,g,*
a National Veterinary Institute, Ulls väg 2B, SE Uppsala, Sweden , d Uppsala University, Department of Medical Sciences, Dag Hammarskjölds väg 17, SE Uppsala, Sweden e National Food Agency, Hamnesplanaden 5, SE Uppsala, Sweden f Swedish Defence Research Agency, Cementva¨gen 20, SE Umea˚ , Sweden g Public Health Agency of Sweden, Tomtebodavägen 12B, SE Solna, Sweden
INTRODUCTION
Several abortions occurred in 2013 in a Swedish kennel that breeds Miniature Schnauzers. Brucella could be isolated from a placental sample of an abortion.
In order to map the extent of the canine brucellosis outbreak and trace the source, we decided to screen the dogs from the kennel with our recently developed qPCR.
CONCLUSIONS AND PERSPECTIVES
This is the second verified instance of B. canis in Sweden, occurring two years after the first incidence.
The source of the infection was probably an imported dog from Spain
Awareness about brucellosis among Swedish kennel owners is low, even if the number of litters from non-Swedish stud dogs is increasing.
Recommendations for testing before mating dogs from foreign countries should be followed to a higher degree to prevent future infections.
We suggest to use prophage sequence as genetic markers for the tracing of outbreaks.
Fig. 1. Schematic figure of the Brucella canis outbreak. The enclosed areas represent separate households with isolated dogs. The red dogs are the three positive cases: a 14-month old male (dog 1) imported from Spain and two aborting bitches (dogs 2 and 4). Dog 5 is a Spanish male (not tested) that mated two bitches in the kennel before returning to Spain. Thick arrows: contact through mating. Thin blue arrows: result of mating during the outbreak. Thin black arrows: other close contacts with the kennel. Black dogs tested negative for B. canis.
RESULTS
Our qPCR analysis identified Brucella canis as the causative agent.
Samples from lymph nodes, blood, spleen, liver and placenta (when applicable) were collected from 25 dogs which had been in contact with the affected dog. Brucella canis could be identified in 3 of these 25 dogs (Fig 1.).
One strain was whole genome sequenced and compared with isolates from the public database. By doing this we could identify prophages as valuable genetic markers (Fig 2.).
Fig. 2. WGS-PA of ‘‘Phage Roseobacter’’, an intact prophage from the genome of B. canis strain SVA13. R. Kaden et al. / Veterinary Microbiology 174 (2014) 523–
This project was part of ongoing work to develop and harmonise methods to increase the level of biopreparedness in Sweden performed within the Forum for Biopreparedness Diagnostics (FBD), involving four governmental institutes: the National Veterinary Institute (SVA), the Public Health Agency of Sweden (FoHM), the National Food Agency (NFA), and the Swedish Defence Research Agency (FOI). The developed methods were also tested at the Swedish Laboratory for Food Safety and Biopreparedness (RUB), a collaborative effort of the SVA and the NFA.
*Presenting Author
Reference Vet Microbiol Dec 5;174(3-4): doi: /j.vetmic Epub 2014 Oct 24.