Salmonella Bovismorbificans was the most common serotype confirmed in October in New Zealand, according to monthly surveillance data.

The total number of human Salmonella isolates (95) confirmed last month decreased compared to the figure in October 2017 (112). Salmonella Bovismorbificans represented 11.6 percent in October this year versus 8.9 percent in October 2017. This strain has been the most reported one every month since July this year when it was Salmonella Typhimurium phage type 56.

Uncommon Salmonella serotypes were Salmonella Enteritidis phage type 34b with two human isolates since it was first confirmed in New Zealand in 2003 and Salmonella Muenster with 11 human isolates since first confirmation in the country in 1994.

Salmonella Enteritidis phage type 50 was confirmed for the first time in New Zealand last month; the case had recently travelled to China.

New Zealand surveillance data is provided by the Institute of Environmental Science and Research (ESR), funded by the Ministry of Health with cooperation of diagnostic laboratories.

In September, the number of isolates (85) declined in comparison to the number in September 2017 (120).

Uncommon Salmonella serotypes confirmed in September were Salmonella Brunei with four human isolates since it was first confirmed in New Zealand in 1994 and Salmonella Enteritidis phage type 34 had six human isolates since first confirmation in the country in 2004.

Salmonella Enteritidis phage type 1c with recent travel to Vietnam was confirmed for the first time in New Zealand.

Every day, more than 500 New Zealanders get food poisoning, according to official statistics, with Campylobacter being the most common cause of foodborne illness. In 2016, 7,456 Campylobacteriosis cases were reported and 1,091 infections due to Salmonellosis.

Based on 2017 data, Shiga toxin-producing E. coli (STEC), also known as verocytotoxin-producing E. coli (VTEC), confirmations continued to increase from 488 in 2016 to 528 in 2017 as another laboratory started culture independent detection testing (CIDT) at the beginning of 2017.

Whole genome sequencing (WGS) was used over some of last year allowing typing of isolates not fully identifiable by phenotypic methods.

The 10 most common O types are: O157, O26, O128, O146, O38, O123/186, O176, O84, O91 and O107/117.

The latest data for Shigella shows numbers again increased in 2017 with isolates confirmed from 239 cases compared with 156 in 2016, and 112 in 2015.

Shigella sonnei biotype g remained the most common New Zealand type, with the emergence of Shigella flexneri 6 Boyd 88 and Shigella flexneri 1b pushing the historically most common type – Shigella sonnei biotype a – to fourth most common for the year. A travel history which includes Tonga appears to be associated with Shigella flexneri 1b.

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