Human Salmonella Isolates, 2015 No. 3, March

The number of isolates (n=95) confirmed this month showed an increase in comparison to the number of isolates confirmed in March 2014 (n=78). Salmonella Typhimurium phage type 101 (5.1% in March 2014 vs. 11.6% in March 2015) was the most common serotype confirmed this month. Uncommon Salmonella serotypes confirmed this month included S. Bardo (6 human cases since it was first confirmed in 1989), S. Chailey (4 human cases since it was first confirmed in 1992) and S. Typhimurium phage type 197 variant (this is a variant of S. Typhimurium phage type 197 of which 13 human cases have been confirmed since 1994 when first isolated in New Zealand).

Increase in Salmonella Typhimurium phage type 101 (Source: EpiSurv, ERL)

·         From 01 Feb to 01 April 2015 there have been 22 cases of S. Typhimurium phage type 101 reported to EpiSurv. This is an increase compared to the same period in previous years (9 in 2014, 7 in 2013 and 8 in 2012).

·         Cases were reported from the following DHBs: Canterbury (15 cases compared to 3 in 2014, 3 in 2013 and 4 in 2012), Waitemata (5 cases compared to 3 in 2014, 2 in 2013 and 0 in 2012), Southern and Whanganui (1 case each).

·         No common exposures have been identified from EpiSurv data. No cases are known to have travelled overseas during the incubation period (travel history is known for 11 cases).