The variant found in Austria, called Leptospira borgpetersenii serogroup Sejroe serovar Hardjobovis, is extremely adaptable. Credit: Thomas Suchanek/Vetmeduni
Key points:
- Researchers in Austria have genotyped the strain of Leptospirosis that is common in the country.
- The team took 410 samples from cattle before finding 5 that tested positive for the bacteria.
- Austria previously used strains from abroad to diagnose the disease in humans and animals; now the national lab can use the new strain.
Leptospirosis is a globally distributed infectious disease that affects both animals and humans. While the infection is endemic in tropical regions, its incidence appears to increase in temperate regions. The serological diagnostic test used in routine to detect antibodies against the bacteria performs better when local variants are used.
In Austria, however, no locally circulating strain has been available to date. A new study, published in Scientific Reports, has now closed this research gap.
Epidemiologist and researcher Amélie Desvars-Larrive says the search for the pathogen in Austria was anything but easy.
For 2021 and 2022, Desvars-Larrive and colleagues conducted targeted sampling to maximize their chance of isolating the bacteria in a non-endemic country. They took samples from 410 cattle—finally finding 5 whom tested positive for leptospirosis. The bacteria were successfully isolated, cultivated and precisely identified three times.
“The cultivation of Leptospira is very challenging and time-consuming. Samples had to be in the laboratory within two to six hours. The bacteria needed a complex medium in which antibiotics specifically protected them from contamination by other bacterial strains. Samples had to be cultivated for between seven and 23 weeks before the bacteria could be observed,” said first author Cynthia Sohm from Vetmeduni.
Genetic analysis revealed that the variant found in Austria, called Leptospira borgpetersenii serogroup Sejroe serovar Hardjobovis, is extremely adaptable, as it can be found in domestic and wild ruminants, as well as humans. This emphasizes the potential zoonotic risk, especially in settings where there is close interaction between humans and animals.
Compared with tropical areas where infection frequency and severity are much higher, Austria has so far considered the disease relatively harmless.
“But with global warming and associated flooding events, it is becoming increasingly common in temperate countries, including in urban areas,” said Desvars-Larrive. “This means that the risk of infection may also increase in Europe in the future.”