Leptospira infections reported in pets across Southern Finland

This autumn, serious cases of leptospira bacterial infections have been reported in pets, particularly dogs, in Southern Finland. The bacteria can be transmitted to pets from water puddles or contaminated sticks bitten by infected dogs. If untreated, the disease can lead to the death of the animal and may also spread from animals to humans.

According to the Finnish Food Authority, common symptoms in dogs include fever, lethargy, fatigue, loss of appetite, increased thirst and urination, vomiting, and diarrhea. In some cases, infections may be asymptomatic. Sanna Viitanen, the chief veterinarian at the Small Animal Hospital of the University of Helsinki, notes that leptospirosis was primarily an import disease from abroad a decade ago, but now it can be contracted within Finland. This seasonal phenomenon thrives in warm and humid conditions.

A few cases have been observed this autumn at the University of Helsinki’s Small Animal Hospital, with some patients last autumn as well. Although the veterinary chain Evidensia does not track the exact number of leptospirosis cases, veterinarian Minna Rinkinen estimates around 10 to 20 cases have been treated. Some infections may be “false positives,” as rapid tests can give uncertain results. Confirmatory tests may still be pending.

Leptospirosis is a notifiable animal disease, meaning case reports must be submitted to municipal veterinarians and then to the Finnish Food Authority. This year, the authority has received four reports of infections, but Rinkinen speculates that not all cases are reported in real-time.

The affected dogs typically belong to urban populations and are mostly infected locally. The Finnish Food Authority recommends vaccination for dogs traveling to areas with a high prevalence of the disease. In humans, besides fever, the disease can cause muscle pain but rarely leads to serious symptoms such as organ damage and bleeding.