Taronga Western Plains Zoo has been saddened by the recent loss of four White Rhinos that died suddenly after showing some neurologic abnormalities such as stumbling.The Zoo immediately initiated a veterinary investigation to pinpoint the cause of the deaths.  Its veterinary team is working around the clock and consulting with Rhinoceros specialists in Africa and North America, specialist government virologists, government vet services as well as pathology laboratories and specialists.So far the investigation has ruled out exposure to toxins, bacterial infection, snake venom and organ failure as causes of death. Currently tests are underway to investigate possible viral causes, although several types including Hendravirus and West Nile virus have also been ruled out.Zoo Vets are currently awaiting results from an array of further tests.As a precaution, the White Rhinos have been removed from display and placed in a quarantine area at the zoo. They are being closely monitored by keeping staff and the veterinary team.No other species have been affected by the illness and other animals at the zoo are healthy.Zoo General Manager Matt Fuller said:“Obviously the Rhino keepers and veterinary staff know and care for every individual in the herd, so this has been a huge shock and we’re all very sad and supporting each other through this difficult time.Our focus is on continuing this investigation to pinpoint the cause of the sickness and to care for the remaining animals in the herd.”