Human Salmonella isolates 2025

The number of Salmonella isolates confirmed this year (n=1105) showed an increase in numbers in comparison with 2024 (n= 832). Salmonella Typhimurium Sequence Type (ST) 19 was the predominant serotype, representing 18.6% of total isolates.

Salmonella serotypes showing an increase this year in comparison with 2024 included:  Salmonella Brandenburg (from 1.6% to 2.8%), Salmonella Give (from 0.2% to 1.4%), Salmonella Newport (from 1.3% to 2.9%), Salmonella Pensacola (from 0.7% to 1.3%), Salmonella Stanley (from 2.0% to 3.7%), and Salmonella Typhimurium (from 31.4% to 39.2%).

Salmonella serotypes showing a decrease this year in comparison with 2024 included: Salmonella Chester (from 3.2% to 1.4%), Salmonella Paratyphi B var. Java (from 8.2% to 6.6%), Salmonella Saintpaul (from 3.6% to 2.2%), Salmonella Typhi (from 7.2% to 4.9%), and Salmonella Virchow (from 1.4% to 0.5%).

• A cluster of monophasic Salmonella Typhimurium ST34 in the majority (80.5%) of cases is in the North Island. Between 04 November 2024 and 24 October 2025, 41 genomically clustered cases of monophasic Salmonella Typhimurium ST34 were identified. Six cases in this genomic cluster are linked to the common event outbreak in Gisborne. No common source has been identified for cases that are unlinked to the Gisborne outbreak.

The number of isolates (n=131) confirmed this month showed an increase in comparison to the number of isolates confirmed in January 2024 (n=83). Salmonella Typhimurium ST19 and Typhimurium ST568 (18.1% and 6.2% in 2024 vs 19% in 2024) were the most common serotypes confirmed this month.

The number of isolates (n=81) confirmed this month showed a decrease in comparison to the number of isolates confirmed in February 2024 (n=86). Salmonella Typhimurium ST19 (27.9% in 2024 vs 17.3% in 2025) was the most common serotype confirmed this month. Uncommon Salmonella serotype confirmed this month was S. Indiana (16 human isolates since it was first confirmed in New Zealand in 1990)

The number of isolates (n=83) confirmed this month showed a slight decrease in comparison to the number of isolates confirmed in March 2024 (n=87). Salmonella Typhimurium ST19 (13.8% in 2024 vs 25.3% in 2025) was the most common serotypes confirmed this month.

The number of isolates (n=74) confirmed this month showed an increase in comparison to the number of isolates confirmed in April 2024 (n=54). Salmonella Typhimurium ST19 (14.8% in April 2024 vs 18.9% in April 2025) was the most common type confirmed this month.

The number of isolates (n=95) confirmed this month showed an increase in comparison to the number of isolates confirmed in May 2024 (n=68). Salmonella Typhimurium ST19 (14.7% in May 2024 vs 14.7% in May 2025) was the most common type confirmed this month. Uncommon serotype confirmed this month was Salmonella Molade (2 human cases since it was first confirmed in New Zealand in 2009). Salmonella Cannstatt was confirmed for the first time in humans in New Zealand this month.

The number of isolates (n=54) confirmed this month is consistent with the number of isolates confirmed in June 2024. Salmonella Enteritidis ST11 (7.4% in June 2024 vs 14.8% in June 2025) was the most common serotype confirmed this month.

The total number of isolates (n=93) confirmed this month showed an increase in comparison to the number of isolates confirmed in July 2024 (n=40). Salmonella Typhimurium ST19 (1.5% in July 2024 vs. 14% in July 2025) was the most common serotype confirmed this month. Uncommon serotypes confirmed this month were Salmonella Ajiobo (2 human cases since it was first confirmed in New Zealand in 2009), Salmonella Carrau (2 human cases since it was first confirmed in New Zealand in 2019), and Salmonella Concord (4 human cases since it was first confirmed in New Zealand in 1999).

The number of isolates (n=75) confirmed this month showed an increase in comparison to the number of isolates confirmed in August 2024 (n=41). Salmonella Typhimurium ST568 (4.9% in August 2024 vs 20% in August 2025) was the most common strain confirmed this month. Uncommon serotypes confirmed this month were Salmonella Brunei (5 human cases since it was first confirmed in New Zealand in 1994) and Salmonella Richmond (17 human cases since it was first confirmed in New Zealand in 1989). Salmonella Vancouver was confirmed for the first time in humans in New Zealand this month.

The number of isolates (n=101) confirmed this month showed an increase in comparison to the number of isolates confirmed in September 2024 (n=49). Salmonella Typhimurium ST19 (12.2% in September 2024 vs. 24.8% in September 2025) was the most common strain confirmed this month. 

The number of isolates (n=112) confirmed this month showed an increase in comparison to the number of isolates confirmed in October 2024 (n=90). Salmonella Typhimurium ST19 (10% in October 2024 vs. 17% in October 2025) was the most common serotype confirmed this month. Uncommon Salmonella serotypes confirmed this month were S. Choleraesuis var. Kunzendorf (11 human isolates since it was first confirmed in New Zealand in 1989), S. Kedougou (17 human isolates since it was first confirmed in New Zealand in 1996), S. Larochelle (2 human isolates since it was first confirmed in New Zealand in 2011) and S. Molade (3 human isolates since it was first confirmed in New Zealand in 2009) and S. Richmond (18 human isolates since it was first confirmed in New Zealand in 1989). Salmonella Szentes was confirmed for the first time in humans in New Zealand this month.

The number of isolates (n=88) confirmed this month showed a decrease in comparison to the number of isolates confirmed in November 2024 (n=94). Salmonella Typhimurium ST19 (15.9% in October 2024 vs. 15.9% in October 2025) was the most common serotype confirmed this month. Uncommon Salmonella serotypes confirmed this month were S. Muenster (20 human isolates since it was first confirmed in New Zealand in 1994) and S. Wohlen (6 human isolates since it was first confirmed in New Zealand in 1998). Salmonella Soerenga and Salmonella Subsp. (II) ser. 58 : l,z13,z28 : z6 ST781 was confirmed for the first time in humans in New Zealand this month.

The number of isolates (n=118) confirmed this month showed an increase in comparison to the number of isolates confirmed in December 2024 (n=62). Salmonella Typhimurium ST19 (24.2% in December 2024 vs 28% in December 2025) was the most common serotypes confirmed this month. Uncommon Salmonella serotype confirmed this month was S. Richmond (19 human isolates since it was first confirmed in New Zealand in 1989). Salmonella Kisarawe and Salmonella Oritamerin were confirmed for the first time in humans in New Zealand this month.