"Our veterinary services are now working at the area to determine the cause of death ... but the signs so far show that it could be anthrax", Namibia's environment minister says, per the Guardian.
More than 100 hippopotamuses have died over the past week in Bwabwata National Park, in northeast Namibia, leaving authorities scrambling to explain the cause.
Images of the dead hippos show dozens of them laying on their back in rivers with low water levels.
Anthrax is a fatal bacterial disease that is capable of killing animals, cattle and even humans.
He said crocodiles and vultures are feeding were feeding on the corpses of the hippos, and that local people needed to be aware they should not eat the meat as it may be contaminated with anthrax.
It's now unclear if there have been more deaths than the reported 109, as local wildlife such as crocodiles and vultures have been consuming the bodies. Animals can contract anthrax spores in soil from grazing in warm arid climates - such as the African savannah.
If confirmed, this is likely to be the first anthrax outbreak affecting Namibia that had an estimated population of about 1,300 hippos before the recent deaths.
Such outbreaks are common in the region, added the official but insisted the disease is unlikely to spread further since the hippos lived in a remote part of the park. One service official said Namibia had never observed anything like this. A similar outbreak in 2004 killed up to 200 hippos in Uganda.