Background
Leptospirosis is a serious, acute febrile disease caused by spirochaetes from different species of pathogenic Leptospira bacteria. The bacterium causes diseases among humans and livestock animals. It is a zoonotic disease, as pathogenic Leptospira live in the kidneys of many host animals, including livestock and rodents. In Denmark, rats and mice are considered the most common sources of human leptospirosis, but many other animals, including cows, pigs and dogs may also carry the bacteria.
The aim of this study was to investigate whether there was a correlation between Leptospira infection found in humans and livestock animals, in a one-health perspective, in order to prevent leptospirosis in humans.
Methodology and results
Data from patients tested for leptospirosis in Denmark, during the period January 2014 to December 2017 were collected retrospectively. Approximately 400 patients were tested annually (388-448), the positive rate was 4-6% during this period and was dominated by L. hurstbridge hurstbridge, L. icterohaemorrhagiae copenhageni, L. icterohaemorrhagiae icterohaemorrhagiae and L. semaranga patoc. When comparing data from published reports from DTU on leptospirosis in cattle and pigs during the same period, we found no signs of Leptospira in cattle. Pigs tested positive for antibodies against Leptospira were mainly dominated by L. Bratislava; the number of pigs tested for this serovar was between 1071-1822, and the positive rate was 37-65%.
Conclusion and perspectives
The data analyzed for this study do not indicate any correlation between humans and livestock animals infected with Leptospira. However, the high incidents of leptospirosis in pigs may suggest a future monitoring and awareness towards infection and transmission of the disease, as there may be an associated risk for humans working in close contact with pigs.