A contagious bacterial infection known as "equine strep throat" has killed more than 4,000 donkeys in northern Niger since early December, local officials said Friday.
"Of the 8,392 donkeys affected by equine distemper or equine strep throat, more than half succumbed since the infection appeared in the first 10 days of December," said the regional authorities in Agadez, Niger's renowned gateway to the Sahara.
The others survived after being treated for the infection, which hit donkeys in the Ingall area, public television reported.
The government's minister for pastoral issues, Mohamed Boucha, visited Agadez this week to assess the impact of the outbreak.
"You can see bodies littering the pastureland and the watering holes and there is a real danger of contamination" spreading through the area, he said.
The risk "is even greater" due to the fact that the infection can be transferred between equine animals and also through the pasture itself, given that the treatment of a sick animal can take several weeks, veterinary officials said.
To tackle the outbreak, Boucha invited herders to have their animals immunised "for free" by the government veterinary services.
Donkeys are used by millions of people to get around in Niger, one of the poorest countries in the world.
Official statistics show Niger has a population of more than 1.5 million donkeys.
Several years ago, there were fears the donkey could soon become an endangered species in the region due to the massive number of them slaughtered for their meat or exported to Nigeria which sells their skins to China for use in traditional medicine.
But in 2016, Niamey slapped a "strict ban" on all exports and slaughter of donkeys in order to protect them.