December 1, 2020

 

Poultry seen as main source of New Zealand's Campylobacter infections

 

 

A study has found that poultry meat is still a chief source of Campylobacter infections in New Zealand.

 

Researchers looked at transmission pathways and source attribution for campylobacteriosis in the country. Most patients were infected with strains attributed to a poultry source, and poultry meat consumption was common, while 14% were linked to cattle.

 

Since 2008, the reduction in campylobacteriosis in New Zealand has been relatively small. The decline in 2006 to 2008 was linked to interventions in broiler meat processing. In 2020, New Zealand set a public health goal for a 20% reduction in foodborne campylobacteriosis by 2025.

 

The study's purpose was to update evidence on the contributions of different sources of campylobacteriosis to inform an updated food safety risk management strategy and action plan. It was funded by New Zealand's Ministry for Primary Industries and published in the International Journal of Infectious Diseases.

 

A case-control study involved every second notified case sampled in Auckland and every patient in Manawatū and Whanganui between March 2018 and March 2019. These areas cover almost 40% of the population. More than 80% of people involved as cases or controls had consumed poultry within the previous seven days.

 

Source attribution of campylobacteriosis from these two regions was done by testing isolates from fecal samples of notified cases and from sources such as poultry, cattle and sheep and using modelling to assign a probable source for each case.

 

Members of the New Zealand Health Survey cohort were the control population. This is an annual survey of individuals from 14,000 randomly-selected households.

 

The number of cases interviewed, and for which a clinical isolate was obtained, was 666 with 445 in Auckland and 221 from Manawatū and Whanganui. Around 200 isolates each came from cattle, sheep and poultry.

 

Poultry consumption was not identified as a main risk factor as such. However, specific risk factors related to preparation and eating poultry did result in statistically significantly elevated odds ratios such as consumption of undercooked chicken or eating chicken outside the home.

 

While direct contact with poultry presents a significantly elevated risk, it affects only a small proportion of the poultry attributed cases, according to the study.

 

90% of campylobacteriosis cases in urban areas were attributed to poultry sources, compared to almost 75% of rural cases with almost all the rest linked to cattle.

 

The importance of non-poultry pathways was explored using the 93 cattle attributed cases. Results indicate that living or working on a farm is the most important risk for these cases.

 

While raw milk was a significant risk factor for cattle-attributed urban cases, it was reported by only a small proportion, mostly in the Manawatū or Whanganui region.

 

The poultry meat chain offers links where intensified or new control measures can be implemented, said researchers.

 

They added: "Generation of strong risk-based evidence on the dominant transmission pathway for campylobacteriosis in New Zealand provides a solid platform for continuing efforts by government and industry to mitigate this important public health problem."

 

- Food Safety News