One of Africa's most endangered animals - the rhino - is facing a new threat: microscopic bacteria.
The animals living at Kenya's Ruma National Park are developing high levels of antibiotic resistance - an alarming discovery that scientists say highlights rhinos as unexpected casualties of the global overuse of antibiotics.
Resistance stems from people taking the drugs for non-bacterial diseases, those who don't finish drug doses which allows bacteria to recover and adapt, and farmers overusing the medication on their livestock.
Antibiotic use and abuse in Kenya has been rampant for decades - and this new resistance issue could be a major problem for rhinos.
They are already under huge pressure from poaching, and are susceptible to the bacterial disease bovine tuberculosis, according to researchers in South Africa's Krueger National Park.
Antibiotic resistance could make treatment for that even harder.
It's unclear how the rhinos are being exposed to the stronger bacteria.
It could be through contact with rangers protecting the animals from poachers - or from drinking at the river running through the Ruma National Park - which carries waste containing antibiotic-resistant bacteria, says researcher, Collins Kebeni.
(SOUNDBITE) (English) MASENO UNIVERSITY PHD STUDENT, COLLINS KEBENI, SAYING:
"Where we did this study, people there, the level of sanitation is still low. So we see that there's most of these resistant pathogens, people will shed them either through faecal waste disposal which will find it's way down stream and to this endangered species of animals."
Rhinos are already critically endangered. According to the International Rhino Foundation, there's only about 29,000 alive - 5% of which are in Kenya.