Why our birds are dropping dead ... and why it could be us next
Expert points to a toxin produced by mould or fungi - and it bodes ill for humans
If the birds are sick, the likelihood is that humans are next in line, says Cape Town avian expert Dr Deon de Beer, a vet at the Klapmuts Bird Clinic.
De Beer explained that birds show symptoms of sickness easier than humans because of their “open” air sacs, which are designed to give them lightness and the ability to fly.
The vet became concerned when he noticed birds were beginning to get very sick in 2016, with many of them dying. The cause of the illness, he discovered, was mycotoxins, a toxic chemical compound produced by mould or fungi.
Some moulds and fungi have the ability to produce these hazardous toxins, which affect the liver and influence immune function, and can trigger inflammation, allergies and asthma.
According to Grain SA they can also cause oesophageal cancer, pulmonary oedema and acute toxicity, which could result in death.
According the agricultural organisation, in nature most cereal grains, oil seeds, tree nuts, fruits and dehydrated fruits are susceptible to contamination by mycotoxin-producing fungi during the pre-harvest and post-harvest (storage) and processing stages.
For a toxic reaction the mycotoxin must get into the bloodstream. In birds, the fungal spores are inhaled and grow and have access to organs. They may then form mycotoxins which will begin poisoning the bird.
In humans, a fungal infection will develop on the skin. If there is a lesion on the skin there is potential for mycotoxins to enter the bloodstream.
De Beer became aware of mycotoxicity because he spent so much time inspecting the inside of birds.
“In my career I would say that I’ve probably done around 1.5 million endoscopic bird examinations.”
De Beer said the fungus was being inhaled through seeds the birds were eating. He contacted the Department of Agriculture, Forestry and Fisheries (DAFF) in 2016 to inform them that he believed their grain was contaminated.
He was concerned humans would also be exposed to mycotoxins. “In humans we get sick because our immune systems are compromised.”
De Beer said he was concerned because most of the population survives on grain-heavy meals, especially maize.
De Beer and a host of colleagues did further research and found the birds were dying of a fungal infection, Trichosporon asahii, because their immune systems were compromised by mycotoxins. The results were published in the Association of Avian Veterinarians Australasian Committee in 2017.
De Beer contacted the department and informed them the birds were getting sick due to the high levels of mycotoxins in animal food.
Joan Sadie from the Directorate: Plant Production said it was not up to the department to test for contamination. “We [DAFF] oversee the grain industry, not the day-to-day testing. Private companies do the testing and if disease is found then we oversee the protection of crops, and we mitigate procedures to ensure that further crops don’t get contaminated.”
Grain SA CEO Jannie de Villiers said testing of grains, both imported into and produced by SA, was supposed to be done by DAFF. “We took it upon ourselves to do the testing. We send samples to The Southern African Grain Laboratory (SAGL) and they test all grain coming in. They also test every silo in SA for contamination.”
“We look especially for mycotoxins.”
He believes the grain in SA is of a high quality and that the mycotoxin levels are below the government cut-off limit.
“We know mycotoxins are dangerous; we had a study on them causing cancer in the Eastern Cape.”
De Villiers said he did not want to downplay what De Beer had said, “but I don’t think anyone should panic. We are transparent, and our produce is healthy.”
Plant pathologist Professor Mark Laing from the University of KwaZulu-Natal said the problem is much bigger than what is reported.
“Mycotoxins are everywhere and in all food we eat; what matters is how much we are exposed to.
“Poor people are most at risk because they don’t have a diet that is varied. They eat a high-grain diet so they will be exposed to a large amount of mycotoxins.”
He said there could be no blame attached to the contamination, and believes the grain industries are doing all they can to prevent contamination.
Dr Nelesh Govender, from Healthcare-Associated Infections, Antimicrobial Resistance & Mycoses, said although the health concerns attached to mycotoxins are well known, “we study so many other potentially life-threatening diseases and the scope of mycotoxicity is so large that we really don’t have the resources to deal with it”.