Pestilence, pandemics, and climate change: public lecture

Health officials in Queensland at property that had been visited by a vet who died from the bat-borne-Hendra virus. AAP/Dave Hunt.

Recent outbreaks of deadly bat-borne diseases could be a sign of things to come as rising heat and changing rains help the spread of infectious disease in Australia.

Such is the warning that Professor Tony McMichael of the Australian National University’s National Centre for Epidemiology and Population Health will deliver in a public lecture tomorrow night.

In his advance notes for the talk, Professor McMichael writes that “recent outbreaks of bat-borne viral diseases in horses and humans in Australia are a pointer to likely future risks to human health - as climate change causes the displacement of species such as bats from their natural habitat (and, perhaps, into the urban and suburban environments).”

Health fears: a man in the Northern territory expels flying foxes with a repellent device to expel flying foxes. AAP/Bird Gard

Professor McMichael will also talk about the growing chance that mosquitoes carrying dengue fever will make their way to Australia, given their expanding territorial reach in countries including Japan and the Philippines.

In notes for the lecture, Professor McMichael mentions that climate change partly triggered the 14th Century Black Death that killed up to half of the population of many European cities. He also writes that the last decade’s leap in the reach of the dengue mosquito (Aedes albopictus) into Manila jumped the most when the greatest year-on-year warming occurred (2005-2006).

In Japan the dengue mosquito has “extended its zone northwards by 500 kilometres over the past half century in association with warming”.

Mosquito fears: a man sprays a residential district in Malaysia with pesticide aimed at killing dengue-bearing mosquitoes. AAP/AFP/Tengku Bahar

Higher temperatures in China have lead to the spread of the snail that hosts schistosomiasis, or snail fever, that retards physical and cognitive development in children.

Climate change could also hit Australia with the spread of Ross River Virus, as well as gastroenteritis from contamination spreadings into food and water sources, Professor McMichael writes.

Professor McMichael also points to Asia’s experience of an acceleration of new infectious diseases that are associated with intensive land-clearing, human migration, trading patterns, and climate-related shifts in animal migration.

“Such disruptions to natural ecological patterns and relationships provide great opportunities for infectious patterns and relationships to ‘jump’ into the human species as a newly available host. More such jumps will occur,” Professor McMichael writes.

Details of the Tuesday November 1 lecture in Canberra can be found here.

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