As part of national monitoring programmes in Germany living and dead
marine mammals from the North and Baltic Seas are investigated for their health status.
Furthermore, seals rescued in the seal station Friedrichskoog are examined constantly during
their stay in the station. Investigations include blood status as well as pathological,
microbiological, parasitological, serological and chemical tests. According to reports about
Brucella infections in seas mammals, bacteriological and serological investigations in
animals found in Germany were extended also to Brucella bacteria. Between 1997 and 2000
bacteriological investigations were performed on 165 common seals (Phoca vitulina), 80
harbour porpoises (Phocoena phocoena), 11 grey seals (Halichoerus grypus) and 3
other marine mammals. The organs examined were liver, spleen, kidney, lung, intestine, stomach,
lung lymph nodes, mesenterial lymph nodes and others. For cultivation Brain-Heart-Infusion-agar
and Brucella-agar were incubated at 37° Celsius in a CO2-enriched atmosphere.
Furthermore, serum samples of 155 harbour seals were tested for Brucella-antibodies using
a tube agglutination test with a stardardised Brucella abortus antigen.
The investigations revealed that out of 259 animals 32 Brucella
strains from a total of 20 animals were isolated. The majority of the strains were found in the
lung of seals. 30 of the 155 animals (19,4%) tested serologically had antibodies ranging between
1:20 and 1:10240. So far, the Brucella isolates have been identified as Brucella
maris but specific molecular biological investigations are currently under process.
To our knowledge, this is the first report about the evidence of
Brucella bacteria in marine mammals from German waters. According to the pathological
findings, no typical lesions were associated with the evidence of Brucella sp. in this
material. Little is known about the pathogenic potential of Brucella maris, in particular
in humans, therefore special precautions should be taken when handling living or dead marine