Transmission of Brucella canis in a canine kennel following introduction of an infected dog.

Brucella canis is a zoonotic pathogen and the main causative agent of canine brucellosis. In the Netherlands, B. canis had previously only been detected in individual cases of imported dogs. However, an outbreak of B. canis occurred for the first time in a cohort of autochthonous dogs in a breeding kennel in 2019. The outbreak began with a positive serological test result of an imported intact male dog showing clinical symptoms of brucellosis. Consequently, urine and blood samples were collected and tested positive for B. canis by culture, matrix-assisted laser desorption/ionization - time of flight mass spectrometry (MALDI-TOF MS) and whole-genome-sequencing (WGS). Screening of the contact dogs in the kennel where the index case was kept, revealed that antibodies against B. canis could be detected in 23 out of 69 dogs (34 %) by serum agglutination test (SAT). Of the 23 seropositive dogs, B. canis could be cultured from the urine and/or heparin samples of 19 dogs (83 %). This outbreak represents the first documented case of transmission of B. canis to autochthonous contact dogs in the Netherlands. WGS revealed all B. canis isolates belonged to the same cluster, which means the transmission of B. canis in the breeding kennel was most likely caused by the introduction of one infected dog. Comparing this cluster with data from other B. canis isolates, it also appears that characteristic clusters of B. canis are present in several endemic countries. These clusters seem to remain stable over time and may help in locating the origin of new isolates found. This outbreak showed that the international movement of dogs from endemic countries poses a threat to the canine population, while serological screening and WGS proved to be valuable tools for respectively screening and the epidemiological investigation.

First Case of Human Brucella canis Infection in the Netherlands.

A patient was diagnosed with Brucella canis following exposure to infected dogs in her breeding facility. Transboundary spread of B. canis through (illegal) import of infected dogs to non-endemic countries in Europe suggest that B. canis infection should be considered in European patients with occupational exposure to dogs.

Transboundary Spread of Brucella canis through Import of Infected Dogs, the Netherlands, November 2016-December 2018.

Brucella canis had not been isolated in the Netherlands until November 2016, when it was isolated from a dog imported from Romania. Including this case, 16 suspected cases were notified to the authorities during the following 25 months. Of these 16 dogs, 10 were seropositive; tracking investigations found another 8 seropositive littermates. All seropositive animals were rescue dogs imported from Eastern Europe. B. canis was cultured from urine, blood, and other specimens collected from the dogs. Genotyping of isolates revealed clustering by litter and country. Isolating B. canis in urine indicates that shedding should be considered when assessing the risk for zoonotic transmission. This case series proves introduction of B. canis into a country to which it is not endemic through import of infected dogs from B. canis-endemic areas, posing a threat to the naive autochthonous dog population and humans.

Brucella suis Infection in Dog Fed Raw Meat, the Netherlands.

A Brucella suis biovar 1 infection was diagnosed in a dog without typical exposure risks, but the dog had been fed a raw meat-based diet (hare carcasses imported from Argentina). Track and trace investigations revealed that the most likely source of infection was the dog's raw meat diet.