Public health management of salmonella typhi/paratyphi case and contact screening: Lessons from North London

Objectives: To evaluate the public health management Salmonella enterica serovar Typhi (typhoid) and Salmonella enterica serovar Paratyphi (paratyphoid) cases and their contacts to assess the outcome of screening. Study design: Retrospective case note review. Methods: 329 cases and 1153 contacts from North London over a four year period were reviewed. Structured questionnaires were developed to capture travel history, relationship between case/contact and the number, timing and documented results of faecal specimens. Evaluation of compliance with the clearance/screening schedule was examined and the positive yield of faecal samples for cases and contacts was calculated. Results: 1% (3/329) of cases had a positive clearance sample; all were identified on their first faecal specimen. Of the 645 contacts who were screened, only 10 (1.5%), all of whom had travelled with the index case, were positive. Person-to-person transmission was only identified for two UK acquired cases, where possible carrier sources were identified outside the screening schedule. Conclusion: The lack of evidence of secondary transmission from acute cases, coupled with the low positive yield from clearance samples support the revision of the national guidance for the public health management of cases of enteric fever and their contacts.