Health authorities need to take urgent action to plan for the likelihood of future pandemics following an alarming increase in new flu viruses over the past decade, a new study says.
Researchers at the University of New South Wales (UNSW) identified seven new influenza strains that emerged in humans between 2011 and 2015.
In contrast, it was almost 40 years after the 1918 Spanish flu pandemic, which killed over 50 million people, before the next novel virus appeared.
The rapid escalation in new strains has increased the risk that new influenza viruses could mutate and start transmitting from person to person, researchers said.
"This urgency needs to be acknowledged by national and international pandemic planning organisations," said Dr Chau Bui, one of the study's authors.
The study, published in the Archives of Public Health, identified 19 influenza outbreaks since 1918, with 10 identified as animal to human infections and three predominantly swine variants.
Several explanations were given for the trend, including an improvement in detection capabilities.
Dr Bui said increased global poultry production, particularly in low-to-middle income countries that do not have adequate biosecurity measures, may be a contributing factor.
"For example in China in the past 20-30 years there has been a huge increase in the poultry market and the same thing is happening in a lot of low-to-middle income countries," she said.
With more birds there was a greater number of hosts, Dr Bui said.
Urbanisation and climate change may also be playing a role, according to the study.
As areas like wetlands and lakes disappeared, the potential for contact with wild migratory birds - the traditional hosts in influenza viruses - increased among humans and domestic animals.
Dr Bui said international pandemic preparedness needed to focus on controlling avian influenza in the poultry.
"There has been some criticism that the control measures rely on detecting the virus and responding to outbreaks, whereas what should be done is implementing fundamental changes to poultry production systems."
