By Dr. Dawn Zimmerman

On May 9th, the Rwanda Development Board trackers reported that 3-year-old female infant Sacco, of Agashya group, was again exhibiting foot soreness and a veterinary assessment was requested. She had previously been assessed by Gorilla Doctors on February 5th after her mother Isoni left the group in January.  At that time, she was moving and sleeping with dominant silverback Agashya and appeared to be doing fine without her mother. 

The first veterinary assessment of Sacco’s feet was completed on March 13th. During this assessment, the infant was bright, alert, responsive, and feeding well with a ¾ full stomach, but moving slowly and crying.  No lameness was appreciated but both first toes appeared congested with interdigital swelling, and she did not flex her toes when picking up vegetation.  The soles appeared hyperemic.  There was no evidence of trauma (laceration, bite wound). Since the problem had first been noticed 2 days earlier after a heavy rain (high humidity), there was a possibility of softened feet allowing opportunistic microorganism overgrowth (fungal and/or bacterial), causing a local infection and leading to a localized inflammation.

Soon after this assessment, the inflammation went down and Sacco was able to travel with the group without exhibiting any pain. The only times the infant was observed crying was when dominant silverback Agashya left her behind. 

3-year-old female infant Sacco, of Agashya group.

Following RDB’s report that Sacco was again exhibiting foot soreness on May 9th, I trekked to the group to assess the infant. Sacco was found in the group but not eating or resting near dominant silverback Agashya.  She was crying often, especially when ambulating, which she did slowly.  The soles of her feet appeared slightly swollen, reddened, and pitted with ulcerations at the weight-bearing surfaces.  Trackers have speculated that the swelling, redness, and pain may correlate with rainy weather, as it has occurred previously after heavy rains.  Swelling of other peripheral regions (hands, face) were not appreciated.

Sacco’s feet were inflamed and painful, causing her to lag behind the group during travel.

On the 11th, trackers reported that Sacco was eating less, and also had a laceration to both hands.  She was not keeping up with the group as well and crying more often.  After discussing the case with the Rwanda Development Board, and considering that Agashya is no longer very protective of the infant and may not wait for the infant if she lags behind the group further, plans were made to intervene with an anti-inflammatory injection rather than a full intervention.

Multiple raised lesions were also observed around her nose.  These lesions overall had a similar pitting appearance to the feet, but may not be correlated as nasal lesions are not uncommonly seen in infants.

Multiple raised lesions were observed around Sacco’s nose.

Sacco was found within the group lying sternally next to blackback Dusangire, who protected Sacco throughout our visit.  It was rainy, windy, and very cold.  She cried when moving and moved slowly, now dragging her left foot.  The wounds on her hands that trackers observed yesterday were not seen, and trackers report they are not lacerations as previously misunderstood but have lesions similar to her feet.   

Initially she was not observed eating with a ½ + full stomach, but later climbed a tree to eat bamboo leaves and urera.  Although not appearing to lag behind the group and even being protected now by blackback Dusangire, Sacco appeared to be distressed due to her persistent crying and slow ambulation.  As the day was very cold and we wanted her to stay with the group, we proceeded with the partial intervention, to dart her with an anti-inflammatory and antibiotic to help alleviate her symptoms.  

Dr. Noel prepares a dart outside of the group, before donning a mask and approaching the infant.

Sacco was estimated at 15 kg and was darted with one 6ml dart filled with 30mg ketoprofen and 750mg ceftriaxone at 10:55am by Dr. Noel.  The dart hit her right thigh but bounced and sprayed, with an estimated 50% partial injection.  A second (3ml) dart was filled with 25mg ketoprofen and 250mg ceftriaxone, and was successfully injected into her right hip at 11:08am by Dr. Noel.  The second dart was confiscated by silverback Agashya for a bit, and finally recovered at 11:50am when we left the group.

With sole abnormalities of both feet (swelling/hyperemia/congestion/edema) with mild to moderate ulcerations at the weight-bearing surfaces causing pain and difficult/slow ambulation,  multiple etiologies should be considered (localized cellulitis and/or lymphadenitis (fungal/bacterial), bilateral foot trauma, contact allergy, immune-mediated disorder, or an underlying medical condition affecting lymph or blood circulation (venous insufficiency)). It is possible that the simplest explanation is that with the loss of her mother, who would normally carry her until 3.5+ years of age, her feet became excessively worn with infection exacerbated by the rainy season.  Since she exhibited similar clinical signs in March, we are hoping this event will also be transient, and that by injecting her with an anti-inflammatory to relieve pain and an antibiotic to fight infection, her clinical signs will abate.

Trackers will continue to report on Sacco’s condition.  If there is no improvement, a full anesthetic intervention for diagnostics and more thorough treatment may be warranted.

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