Friday, July 8, 2022

Public health issue ‘hasn’t been studied’

A leading Australian public health expert believes New Zealand researchers have done only half their job when assessing dung beetle release in this country.

“There is a fundamental issue here. That is, you can’t separate a public health-risk assessment from environmental impact assessment. The public health issue has not been studied. Clearly only half of the assessment has been done,” University of South Australia Dean of graduate studies Professor Philip Weinstein said.

Weinstein has a PhD in insect ecology and a faculty of public health fellowship, putting him on an equivalent footing to a medical officer of health in NZ.

He worked for two years in the NZ Ministry of Health and spent seven years as associate dean of research at the University of Otago’s Wellington School of Medicine.

Proponents of beetle release have said the Australian experience with beetle indicated no human health risk through the beetles spreading disease.

Weinstein dismisses the trans-Tasman comparison.

“Unequivocally Australia and NZ are different. NZ has a higher rural population density and increased surface water runoff,” he said.

Water contaminated with bacteria from dung beetles was a potential problem for infecting rural populations, he said.

“In Australia we do not have that sort of exposure to it. There is less run-off and no large rural population exposed to it.”

In light of these differences, defaulting to the Australian experience deepened his concern about whether a NZ human health impact had even been done.

“It (beetle) may not present a risk at all. If so, tick the box, but that first needs to be determined.”

Nor does he believe the claim that other soil-bound invertebrates, including earthworms, are equally likely to spread disease.

“The ecology of every insect is completely different. Earthworms for a start, they cannot fly around like dung beetles can. Cockroaches, they tend to be attracted to human environments, not outside where dung is. It is inappropriate to extrapolate from one insect to another.”

Weinstein believes there is a wider issue at stake around NZ’s ability to field experts in areas like insect science, an area with major relevance to biosecurity, crop production and public health.

“There is an issue in retaining critical mass in entomology to address these questions.”

He applauded Auckland’s chief medical officer Dr Denise Barnfather (see accompanying article) for stepping up and voicing her concerns over the public health risk the beetle’s release might create. 

Related stories: Beetles effective in AustraliaEPA backs dung beetle decisionExperts dump on dung beetle

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