Investigation of a Salmonella Typhi cluster among a Pacific Islander labour community in a fruit industry: perspective from a regional public health unit
DOI:
https://doi.org/10.33321/cdi.2025.49.032Keywords:
Pacific Australia Labour Mobility (PALM) scheme, Salmonella, Salmonella Typhi, regional Queensland, outbreak, diseasesAbstract
Background
Australia is largely dependent on immigrant workers to bridge the employment gap in the agricultural sector and in agriculture-related food production; this poses a potential risk of the introduction and transmission of non-endemic vaccine preventable disease. We report the response to a Salmonella Typhi (S. Typhi) outbreak amongst workers from the Pacific Australia Labour Mobility (PALM) scheme in regional Queensland.
Methods
A cluster of invasive Salmonella infections was investigated in accordance with the Communicable Diseases Network Australia guidelines. Active case finding of the at-risk group was undertaken to identify potential causal links and further transmission.
Results
Three confirmed cases of S. Typhi were reported, all male, with a median age of 31 years (range: 29–33 years). All cases were hospitalised and were managed with antibiotics and supportive care, with a median illness duration of nine days. Full recovery was reported for all cases, without complications. No recent travel history or contact with a recent typhoid case were reported. We identified 310 individuals in the exposed cohort, with a median age of 31 years (range: 22–55 years), all males. Of the exposed cohort, 305/310 individuals (98·4%) provided a faecal sample for S. Typhi testing; all returned a negative result. Genomic sequencing concluded the likely source of infection in this outbreak was chronic carriage of S. Typhi.
Conclusions
Australia has had a significant increase in the number of PALM workers in regional areas, particularly within the agricultural sector, to mitigate employment gaps. A greater emphasis on culturally appropriate and linguistically sound hand hygiene education, and consideration of pre-employment health checks and vaccinations in these workers, would be beneficial in the reduction of communicable disease outbreaks.
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