98 % Human: two interesting patients in Sierra Leone

By KSLP Technical Advisor, Professor John Rees

In the middle of January I flew out for my fourth trip to Sierra Leone to spend a week with the KSLP team to support a two-day faculty workshop to kick off a process of overhauling and modernising the medical curriculum at COMAHS.

On my last day, in what I thought would be a break from work, I decided to venture out to the Tacugama Chimpanzee Sanctuary on the outskirts of Freetown. Each month the sanctuary has a birds and breakfast walk on a Saturday morning consisting of a three hour stroll through the bush with two guides and then a cooked breakfast. My KSLP colleague Suzanne Thomas decided to take part. The sanctuary is a 30-40 minute drive out of Freetown for a 7.15am start.

We heard lots of birds identified by the guide, we saw rather fewer but still had some good sightings of bee eaters, paradise flycatchers and sunbirds and a really pleasant stroll around the forest and the dam, where we saw the resident crocodile. During breakfast we were politely ambushed by the veterinarian for the sanctuary with a request for our opinion on two problems. I later discovered that they’d spotted that I was a Professor at the KCL School of Medicine from the footer of my reservation email, and were lying in wait for us. It’s not uncommon to be asked for advice when people know you are medical but advice on sick chimpanzees was a first for us. Patient confidentiality prevents me from naming the chimps involved, but one has chronic osteomyelitis of the radius (ie a longstanding infection of a bone in the arm) after a bite from a friend. He has had lots of antibiotics but we were able to suggest some ideas for choice of antibiotic and length of course.

The second problem was more challenging and we were not the first to be consulted. They have noticed that some chimps come in from the forest with ataxia, lethargy and vomiting. Some go on to have seizures and some have died suddenly, sometimes in a stress situation after they seem to have recovered. None of the chimps in the small enclosures where they are being monitored after initial rescue from captivity have been affected. In contrast to human patients in Freetown the chimps have been investigated by autopsy, virology including PCR (molecular testing) of various samples, deep frozen tissue sent to laboratories around the world, opinions of plant experts, vets and other experts. The current theory is that this is related to a toxin from a local plant in the forest, which has properties used as a rodenticide.

We had a chance to look around the enclosures at Tacugama, avoiding a chimp throwing stones at us with accuracy showing he was not ataxic. We were still no clearer on the likely diagnosis but if anyone could tell us we are happy to pass on any ideas that anyone might have to the vet at the sanctuary.