Leprosy is discovered in wild CHIMPANZEES for the first time – Daily Mail

Leprosy has been found in groups of wild chimpanzees for the first time.

Researchers have shared shocking images of apes with the tell-tale lumps on their faces.

Cases have been confirmed among two unconnected West African populations of chimpanzees, in Guinea-Bissau and the Ivory Coast.

The leprosy strains are different and uncommon in humans, according to scientists from the Centre for Ecology and Conservation, University of Exeter.

While the origins of the infections are unclear, scientists say the disease is probably circulating in more wild animals than was previously suspected.

This could either be as a result of exposure to humans or other unknown environmental sources, they added.

Humans are considered the main host for Mycobacterium leprae bacteria, which cause leprosy, but ‘spill-over’ to other mammals is occurring. 

It has been controlled in humans with antibiotics since the 1980s, and researchers once thought it had been wiped out in the animal kingdom.

But in the last two decades scientists have found it spreading in red squirrels in the UK and armadillos in the Americas, and now, wild chimps.  

Leprosy is an infectious disease of the skin and nerves which, if left untreated, can lead to deformities and blindness.

Lead author Dr Kimberley Hockings, said: ‘This is the first confirmation of leprosy in non-human animals in Africa.

‘It’s amazing that it also happens to be in our closest living relative, the chimpanzee, especially considering how well studied chimpanzees are in the wild.

‘We first noticed possible symptoms of leprosy in a population of chimpanzees in Guinea-Bissau.

‘The symptoms appeared to be strikingly similar to those suffered by humans with advanced leprosy, including lesions and “claw” hand.

‘We contacted Professor Fabian Leendertz from the Robert Koch Institute to confirm these cases genetically.’

She said there are at least four chimpanzees in three different communities in the studied areas with severe leprosy.  

In humans, prevalence of leprosy depends on access to treatment, but no chimpanzees in the wild have ever received treatment for leprosy.  

‘Leprosy is very easy to treat in humans, but administering antibiotics to wild unhabituated chimpanzees would be a real challenge,’ Hockings told MailOnline. 

Professor Leendertz and Dr Roman Wittig from the Max Planck Institute for Evolutionary Anthropology identified further cases of leprosy at their study site, Tai National Park, Ivory Coast. 

Leprosy was also confirmed through a post-mortem examination of an older female, as well as faecal samples of an adult male which started showing symptoms.

Although the study is the first to report the disease in wild chimpanzees, there have been cases in captive chimps, researchers say.

Dr Charlotte Avanzi, from Colorado State University, said this was a step in understanding the disease.

It can help reveal details of ‘transmission in endemic countries’.

She said more investigations will eventually shed light on the dynamic of transmission between human, animal and environmental sources.

Dr Hockings added: ‘In Guinea-Bissau it is possible that chimpanzees somehow acquired leprosy from humans in this shared landscape, although people do not kill or eat chimpanzees.

‘It is clear that leprosy is now being transmitted between separate chimpanzee communities.’

In the Ivory Coast, chimpanzees are more distant from human settlements and it seems more likely that the chimpanzees acquired the infection from another animal species, Professor Leendertz explained.

This includes environmental sources such as ticks or bacteria living in water. 

While leprosy in humans is easily treated with medication, the impact on chimpanzees is hard to predict, the researchers suggest.

For the moment, the infected chimpanzees seem to be coping with their illness, although one is losing weight. 

Unfortunately, treating them is not really an option, according to Professor Leendertz, as they’re wild animals and unused to humans. 

‘Humans have to take antibiotics for months to treat leprosy. You just can’t do that with these wild animals,’ said Professor Leendertz. 

For now, the disease does not appear to put the groups as a whole at risk but it’s another risk to chimps, which also face the threats of poaching, habitat loss, and other diseases. 

‘Western chimpanzees are critically endangered, so even the loss of a few individuals could be significant,’ said Dr Hockings. 

‘Long-term health monitoring and research is needed to establish the scale and possible effects of leprosy among wild western chimpanzees,’ said Dr Wittig.

Professor Anne Stone, an evolutionary geneticist at Arizona State University who was not involved in the study, says leprosy dates back millions of years and may have inflicted beings long before humans evolved.

‘The data increasingly points to the possibility that something else than humans is actually the main host,’ she said. 

The findings are published in the journal Nature.