Non-Human Salmonella Isolates, 2014

The Enteric Reference Laboratory confirmed 729 non-human Salmonella isolates in 2014 compared with 967 in 2013.

There was a decrease in the number of animal (585 in 2013 vs. 457 in 2014), poultry (107 in 2013 vs. 86 in 2014) and environmental isolates (118 in 2013 vs. 38 in 2014).

Several Salmonella serotypes showed a decreased in comparison with 2013, including:

• S. Agona: From 4.3% down to 2.3%, linked to a decrease in poultry isolates.
• S. Brandenburg: From 20.4% down to 17.8%, linked to a decrease in environmental isolates. Bovine isolates, however, showed a 2.5% increase in comparison to 2013.
• S. Infantis: From 6.9% down to 3.7%, linked to a decrease in meat and bonemeal isolates.
• S. Montevideo: From 3.0% down to 0.6%, linked to a decrease in meat and bonemeal isolates.
• S. Typhimurium phage type 9: From 4.0% down to 1.2%, linked to a decrease in bovine isolates.
• S. Typhimurium phage type 56 variant: From 8.2% down to 5.2%, linked to a decrease in feline isolates.

One serotype, S. Hindmarsh, showed an increase this year in comparison to 2013, rising from 5.8% to 10.6% mainly due to an increase in ovine isolates. A seasonal increase in S. Hindmarsh in sheep has previously been reported https://surv.esr.cri.nz/enteric_reference/nonhuman_salmonella.php?we_objectID=3647. No increase in human cases was observed.

Increase in S. Brandenburg during the month of September:

Occurrence of Salmonella Brandenburg infection in humans is a seasonal phenomenon in the southern half of the South Island (Baker et al. 2007 in Epidemiol. Infect. 135(1):76–83) and is often linked with occurrence of the serotype in livestock.
Salmonella Brandenburg has caused periodic epidemics of disease in sheep flocks in Otago and Southland since 1997 see: http://www.stuff.co.nz/business/farming/sheep/9090477/Bacterial-outbreak-killing-South-Island-sheep