Australian National University research tracked changes between 2000 and 2010.
Findings should assist policy makers to improve regulation and control of foodborne disease for specific pathogens, said the researchers.
Foodborne illness caused an estimated 4.1 million illnesses, 30,600 hospitalizations, and 60 deaths in 2010. The figure for illnesses circa 2000 was 4.3 million.
Millions of cases unidentified causes
Of the total illnesses 0.8 million were caused by 18 pathogens but the remaining 3.3 million had unknown or unidentified causes.
The rate of foodborne campylobacteriosis was 13% higher in 2010 than 2000 and salmonellosis was 24% higher in the same period.
Pathogenic E.coli, Norovirus, Campylobacter and nontyphoidal Salmonella were responsible for 93% of the foodborne illnesses caused by known pathogens.
Contaminated food also caused 5,140 cases of nongastrointestinal illness circa 2010.
Toxoplasmosis was the most common foodborne nongastrointestinal illness with 3,750 cases each year.
Listeria monocytogenes and nontyphoidal Salmonella infections were the leading causes of death.
“In Australia from 2006 onward, the number of raw egg–associated salmonellosis outbreaks has markedly increased and since 2000, the numbers of notified laboratory-confirmed cases of campylobacteriosis and salmonellosis have increased,” said the researchers.
“Estimates of rotavirus cases for circa 2010 were lower than those for circa 2000, reflecting the success of the vaccination program.
“Also, the estimated number of foodborne illness cases caused by hepatitis A virus declined from 150 cases/year circa 2000 to 40 cases/year circa 2010, reflecting improved disease control through vaccination.”
The researchers said methods to calculate estimates were refined from the circa 2000 study, and in the intervening years, surveillance has improved and data availability has increased.
Underreporting multipliers were used to estimate the community incidence of foodborne illness for infected people who did not seek treatment or submit specimens for testing.
The researchers also acknowledged gaps and limitations in the data.
“While National Notifiable Diseases Surveillance System (NNDSS) and the OzFood-Net Outbreak Register are nationally representative, jurisdictions may have reported or coded their data differently.
“We used data from the Water Quality Study (WQS) for pathogens that were not nationally notifiable or had limited outbreak data. The WQS study was the best of its kind in Australia; however, the data are now >15 years old…
“We adjusted WQS data for changes over time and weighted the data for the age structure of the general population.”
Source: Emerging Infectious Diseases, volume 20, Number 11 – November 2014
Authors: Martyn Kirk, Laura Ford, Kathryn Glass, and Gillian Hall