Evolution being short-circuited with deadly result

Evolution being short-circuited with deadly results, says world expert

The natural evolution of pathogens is being sped up and in some cases short-circuited by human activity with deadly results, says a world expert visiting New Zealand next week.

Avian Flu is a recent example of a pathogen that has suddenly evolved and crossed species as a result of human activity, says Dr Alonso Aguirre, who is the Director for Conservation Medicine at the Wildlife Trust in New York, and there are plenty more examples of this happening.

“The health of humans, animals and the environment are connected and changes to one can be catastrophic to all. For instance, Avian Flu was transmitted from chickens to pigs, then to humans, but now we see it being transmitted directly to humans and, at the same time, crossing to species that were never affected in the past, such as tigers and leopards.

“We are speeding up and changing the natural evolution of these pathogens and they are appearing in places and in species that they have never affected before – at least 20 diseases have appeared in recent years in Australia alone.”

Dr Aguirre is coming to New Zealand to attend the First National Symposium on Conservation Medicine on 7 – 8 July, a New Zealand-first scientific conference being held at Unitec’s Mt Albert campus.

Dr Aguirre is the keynote speaker at the conference and the foremost authority on the subject – a role that has seen him brief the US Congress, administration and federal agency leaders. Conservation medicine is a relatively new science that addresses the issues of wildlife disease from an ecological perspective and the conference brings together scientists to find ways of minimising the threat of emerging diseases.

Jointly organised by the Auckland Zoo and Unitec’s School of Natural Sciences, the conference is being opened by the Minister of Conservation, Chris Carter, on Thursday.

Dr Aguirre says that these evolutionary changes, which threaten New Zealand’s native animal species as well as New Zealanders themselves, all result from human impact on the environment.

“Biodiversity helps to dilute the potency of these diseases. Deforestation in Peru, for instance, has been shown to be behind increased cases of Dengue Fever, and the appearance of Ebola and even HIV have been linked to deforestation.

“Now we are seeing pathogens from land-based animals emerging in marine animals as a result of human activity in coastal areas.”

A human pathogen – Klebsiella – was uncovered as the probable cause of a mass die-off of Hooker sealion pups in the Southern Ocean a few years ago.

While the medical community must plan for outbreaks that affect humans, he says, it is an ambulance at the bottom of the cliff and a new approach must be used to prevent the diseases from evolving in the first place.

“Morton Bay in Queensland had an outbreak of cyanobacteria and fishermen handling the poisoned fish suffered health problems as a result. It was caused by residents dumping rubbish in the bay and after a community effort to change behaviors the bacteria disappeared, so change is possible if people are aware of the connection between human, animal and environmental health.”

What: First National Symposium on Conservation Medicine Where: Unitec New Zealand, Carrington Rd, Mt Albert, Auckland When: 7 – 8 July 2005

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