HO Reuter, [08 May 2023 at 23:11:28]: On 12 April, a young rhino bull (1 of 2 in the camp) was seen but not showing any abnormalities. However, the next morning it was recumbent with right hind leg paralyses. I suspected trauma. On examination after darting, no external injuries were visible, no sign of injury, no fractures, joint dislocation or torn ligaments palpable. I gave the animals a good dose of fluids, Excede, Finadyne, VitE/Se, Kyroligo and Bcobolic, but had no effect. Another day later he was still trying to get up, in severe pain, but could not put any weight on the right leg. The left leg was normal. All haematology and blood chemistry results were within or close to normal range, even CK. We decided to euthanise the animal by shot in the head to prevent further suffering. On post-mortem, some bruising on the rump, and the ligament attaching femur head to acetabulum was torn. I suspected the other bull mounted him and he subluxated the hip somehow. Now not even a month later, the second bull can not get up this morning - as if his left hindleg is paralysed. He was seen in perfect condition yesterday afternoon. Could rabies symptoms cause unilateral hindleg paresis/ paralysis with no symptoms noticeable to complete down in 8 hours? Or what else could cause this? Due to the acute nature and suspected trauma, I ruled out rabies (maybe wrongly so?) on the first case. Joel Alves, [09 May 2023 at 10:05:14]: Hey HO. Seriously interesting case and I wish I had some insights to give but no experience with anything like that. Had there been a history of rabies in the area? Possible toxic plant ingestion? Just strange that it’s the exact symptoms. Or one of those funky viral diseases. No help at all but keen to hear more. Sadly, looks like he may be heading the same route as the last one! Richard Harvey, [09 May 2023 at 10:17:14]: Morning HO, I’ve seen a black rhino with similar presentation quite recently. Bilateral hind-limb paresis, rapid onset, animals in good condition. I believe there have been a number other cases recently in black rhino too, which had no definitive diagnosis and otherwise normal PMs He also had superficial bruising from dragging himself around and attempting to get up. The PM was otherwise normal. We suspected infectious, likely viral infection/inflammation of spinal cord or CNS, something such as EHV-1 neuropathic infection may cause, but had limited kit and were not able to test in that country. Chris Perkins, [09 May 2023 at 10:27:50]: Could also do cytology/ culture/ PCR for any clostridial spp. that may be in the bruised muscles Roy Bengis, [09 May 2023 at 10:30:04]: Shuni virus myelitis is certainly a DD. Dave Cooper, [09 May 2023 at 10:49:45]: An outbreak of Middleburg virus in our bomas caused similar symptoms. The paresis was however not as severe. Henry Labuschagne, [09 May 2023 at 11:56:48]: I would also rule out botulism. Check for dead animals in water source / feed. HO Reuter, 9 May 2023: Manzilli who was the first one to die received rabies vaccine on 5 Dec 2021 and a booster 4 Jan 2022. It received boosters again on 1 June 2022 and 19 Aug 2022 Thoba who died yesterday received rabies vaccine on 13 Sep 2021 and booster 11 Oct 2021 - 1June 2022 and 18 Aug 2022. Both have had a total 4 rabies vaccinations. HO Reuter, [09 May 2023 at 21:45:03]: The second rhino with acute hindlimb paralysis was euthanased and brain sent in to the Central Vet Lab. Positive for rabies on FAT Test. The previous rhino then can be assumed to have been a rabies case too. The bruising and trauma on PM is probably then from self-inflicted injury while trying to get up. Both these rhinos were vaccinated regularly with Nobivac Rabies or Rabisin vaccine, 2 cc / dose, which then obviously is not effective to prevent rabies infection in rhino. The vaccination record and very acute onset were part of my reason to have suspected trauma as cause of the paralysed hindleg in the first case. Andreas Gaugler, [10 May 2023 at 00:40:19]: Do you think 4 ml would make a difference in Rhino? Also, were they darted with Rabies shots or darted and given Rabies vaccination while down? I know it’s a stupid question, but could that perhaps make a difference - just thinking that the vaccine may get warm in the dart while either being in the helicopter or even from being on a bakkie and time taken to get the shot done?? Chris Perkins, [10 May 2023 at 01:16:58]: Interesting. It might be worth doing titre tests post vaccination to see if there is any serological response. I can’t imagine heat is a major factor since the body is often warmer than the environment and an immunological response is slower than a helicopter ride. But maybe the trauma and inflammatory response from the dart is interfering with the immunological response. Instead of clearing foreign antigen, it’s clearing damaged tissue. Henry Labuschagne, [10 May 2023 at 07:34:32]: Agree Chris. Also, Rabisin that is mostly used as vaccine is an inactivated vaccine and efficacy should not be very sensitive to environmental temperature. The scary part is even after 4 vaccinations they still got rabies. It would be interesting to do a Titre test if samples are available of the dead animals. Also do titre test on remaining rhino on the farm. HO Reuter, [10 May 2023 at 14:27:36]: They were vaccinated by dropout dart as well as immobilised and injected. Serum samples are available from these two rhino pre- and post-vaccination, as well as from numerous other rhino. Which laboratory would be the best to do ELISA serum tests, or which tests best to determine antibodies? They collected samples for a while from many rhino to actually investigate the serological response to vaccination. It is worrying that these two rhino with their vaccination history succumbed to rabies. I doubt that a higher dose of vaccine would be significantly more effective? Andreas Gaugler, [10 May 2023 at 14:36:54]: Thanks for answers HO Reuter, [10 May 2023 at 14:48:06]: More questions than answers at this stage Andreas Gaugler, [10 May 2023 at 15:00:48]: Unfortunately. And worrying Henry Labuschagne, [10 May 2023 at 17:43:27]: I would do a RNATT at Onderstepoort Veterinary Institute. You need a serum sample, and can be used even if it was kept frozen for a long time.
