France is facing its worst outbreak of anthrax in almost 20 years, following the deaths of more than 50 animals across 28 different farms, according to local media outlets.

The outbreak of the disease is being reported in the French department of Haute-Alpes, in the south-east of the country, and has been ongoing since June, according to French publication AFP.

The disease has killed cattle, sheep and horses so far.

The first cases in animals were discovered in Montgardin, about 15km east of Gap, where six cows were found dead on June 28.

Caused by the bacterium Bacillus anthracis, and transmitted by spores, the disease can cause sudden death in animals; anthrax is transmissible to humans and potentially fatal in its rarest forms.

Animals on the affected farms are being vaccinated for anthrax, authorities confirmed to AFP, and production is being locked up for at least 21 days, with milk from the farms being dumped for safety while cleaning and disinfection procedures get underway.

Described by AFP as “rare but not exceptional”, more than one hundred outbreaks have been recorded in France since 1999, with up to 10 cases reported per year on average.

It apparently occurs more frequently during hot summers that follow periods of heavy rains.

In 2008, 23 outbreaks were recorded, with 21 the following year. The last known case in the Hautes-Alpes dates back to 1992.