The mystery surrounding the cause of the deaths of birds at the Florida Lake is no closer to being solved, although the team at the Johannesburg Zoo has their suspicions.
A clean-up of the bird island at Florida Lake last weekend revealed over 70 bird carcasses in various stages of decomposition. The clean-up was organised by concerned local angler Quintin Scott.
According to answers received from a veterinary nurse at the zoo, the zoo’s veterinarian has performed autopsies on two bird carcasses that were deemed fresh enough to potentially yield results and found nothing significant.
She adds that samples were collected from the carcasses to test for Avian flu, just in case, and noted that there have not been any other cases of the disease recently and tests done on birds that died at the zoo some months ago were negative for Avian Flu.
She says that other suspects could be chemical or pollutant poisoning as seen a few years ago when birds died in large numbers at Wemmerpan.
“This turned out to be the result of E.coli from a sewage leak into the dam, but indications, like diarrhoea, would be seen on postmortems.
“The other causes from a veterinary point of view could be botulism, which is highly likely considering the water level dropping, and the hot/ cold weather we have had recently.
“Having a fairly normal postmortem after a sudden death is the course that botulism takes as the toxin causes general paralysis, so the birds are not able to eat or move around.
“It is very difficult to treat because birds are usually too far gone when they get found. Testing for botulism has been declared unethical, so diagnosis is usually based on symptoms.
“The veterinarian has enquired with the National Institute for Communicable Diseases in case there is another alternative to test for botulism.”
She concludes by saying that the testing will take a few days, and in the meantime, people must be very careful to wash and sanitise properly when handling the carcasses.
“If any living but sick birds are found, please bring them to the zoo’s veterinary hospital to allow us to sample blood and droppings as well.”
