Salmonella Paratyphi A infection: implications for public health management of extra-intestinal presentations - case study of a neck abscess

Abstract

This study explores the implications of unusual presentations of Salmonella enterica subsp. enterica ser. Paratyphi (S. Paratyphi) infection for public health management, through a literature review and case study. In 2016, a 36-year-old male presented with a five-day history of right sided painful neck swelling, coryza and a two-day history of fevers after arriving in Australia from India nine weeks earlier. S. Paratyphi A was isolated from a fine needle aspirate sample. A descriptive epidemiological review was performed of confirmed cases of S. Paratyphi notified in New South Wales between 2008 and 2017. S. Paratyphi was isolated in blood and/or faecal samples in 247 cases (98.4%). Only four specimens (1.6%) were from a focal site. A literature review of extraintestinal infections of S. Paratyphi A or B was performed. Of the 41 such cases reported, 16 (39%) had a clear history of a prior gastroenteritis and/or febrile illness, or information suggested this was highly likely. No preceding gastroenteritis or febrile illness occurred in 15 (37%) of the cases. Information was reviewed and presented with a public health lens, valuable for 'evidence-informed' public health risk assessment of contacts and exposures related to these types of S. Paratyphi infection. S. Paratyphi infection usually presents as an enteric fever illness. Our case illustrates the variable nature of infectious diseases and the importance of laboratory testing in obtaining a diagnosis. S. Paratyphi can have unusual presentations, which may require adjustment in the public health management of the case. Public health staff should keep an open mind when investigating possible sources and assessing risk. In Western Sydney, this disease is largely associated with residents travelling to high-incidence countries to visit family and friends, and receiving family visits from these countries. The increasing number of cases of S. Paratyphi (prior to COVID-19) in Western Sydney and the importance of awareness of the risk of enteric fever to travellers to endemic regions is highlighted.

Keywords: Focal infection; Salmonella Paratyphi A; public health.