Food safety interventions before sale of poultry meat are ‘urgently’ required to reduce Campylobacter contamination frequencies, like past action on Salmonella, said researchers in Eurosurveillance.
They added that the number of infections is similar to levels of Salmonella 20 years ago.
Salmonellosis has reduced since due to control programmes targeting poultry production.
Campylobacter spp. and Salmonella spp. are the most frequently reported zoonotic infections in Switzerland. Laboratories must report isolates within one week of discovery.
Between 1988 and 2013, notified campylobacteriosis cases doubled from 3,127 to 7,499, while Salmonella cases reported decreased, from 4,291 to 1,267.
Notification rates in the work were calculated using data for the average resident population.
Genotyping and epidemiological studies in Switzerland have shown chicken meat is the most likely source of infection in the majority of human campylobacteriosis cases.
Campylobacter analysis
Case numbers increased from 1988 to 2000, until they reached 7,000. Campylobacter case notifications dropped and levelled off at 5,000 annually and then rose steadily again from 2007, exceeding the peak level reached in 2000.
The highest number was 8,480 in 2012. In each year since 1988, a peak was observed during summer months (June–August). A second, much shorter peak occurred in December and January in all years.
Among younger age groups, the increase in notification rates was less pronounced than among older age groups.
The majority of cases were tested using culture-based methods directly or confirmatively after PCR.
“Changes in patients’ health-seeking behaviour are unlikely to influence Campylobacter and Salmonella case notifications in different ways. Consequently, we assume that the decrease in Salmonella case notifications and the increase in Campylobacter case notifications represent real epidemiological trends,” said the researchers.
“The high prevalence of Campylobacter in chicken products, the low infective dose of Campylobacter and the increasing consumption of chicken meat combined with the apparent lack of knowledge about the Campylobacter-pathogen are all factors facilitating infection.”
Campylobacter notifications were stable in European Union (EU) countries between 2009 and 2013 while Salmonella ones declined.
However, reported foodborne outbreaks were more often caused by Salmonella spp. than by Campylobacter spp. (1,168 vs 414 in 2013).
Salmonella findings
Salmonellosis cases increased from 4,291 cases in 1988 to 7,806 in 1992 but have since steadily decreased until reaching 1,267 in 2013.
The highest number of notifications each year was in late summer (July–October). Time trends did not differ between sex and age.
The two most frequently reported serovars were S. Enteritidis (54%) and S. Typhimurium (13.7%).
Researchers said Campylobacter infections are a serious and increasing public health concern in Switzerland.
For Salmonella spp. infections, an epidemiological turnaround has been achieved but little has been done to prevent Campylobacter infections on a large scale, they added.
“Since the number of control options is limited, the hygienic treatment of chicken carcasses with chemicals, for example peracetic acid, should not be excluded from discussion. However, the population’s limited awareness of Campylobacter must also be addressed.
“It seems reasonable to believe that the same type of behaviour changes that reduced Salmonella infections can be applied to prevent Campylobacter infections and that caution can be extended from eggs to raw poultry meat, cutting boards and knives.”
Source: Eurosurveillance, Volume 21, Issue 6, 11 February 2016
“Inverse trends of Campylobacter and Salmonella in Swiss surveillance data 1988-2013”
Authors: C Schmutz , D Mäusezahl, M Jost, A Baumgartner, M Mäusezahl-Feuz