Post-infectious sequelae after Campylobacter enteric infection: a pilot study in Maricopa County, Arizona, USA

Campylobacter is a leading cause of gastroenteritis across the globe caused by the ingestion of contaminated food, water, or contact with animals carrying Campylobacter bacteria. The resulting disease, campylobacteriosis, is usually self-limiting, but cases may develop post-infectious sequelae (PIS) such as gastrointestinal disorders, neurological disorders, and joint disorders. The objective of this study was to estimate a crude incidence rate for PIS among Campylobacter cases in Maricopa County, Arizona, USA and to determine the feasibility of conducting a larger scale study to understand chronic outcomes from campylobacteriosis and salmonellosis.

The pilot study spanned from August 1, 2016, to August 31, 2017. During this time, cases of campylobacteriosis were reported to the Maricopa County Department of Public Health and interviewed by public health students at the University of Arizona. Initial interviews were conducted using a routine enteric surveillance questionnaire, and eligible cases were recruited and consented into the pilot study. Follow-up with a questionnaire occurred 4 to 6 weeks from the date of each case's initial interview. Data analysis was conducted using STATA SE 14 and included chi-squared tests to determine differences in demographics, symptoms, and exposures between those enrolled in the study and those eligible but not enrolled during the study period and feasibility metrics for the study including enrollment rates, response rates, time to interview, and reasons for non-enrollment. Crude rates with 95% confidence intervals were calculated to estimate PIS.

Of the routine surveillance cases, 102 (36%) enrolled into the pilot study. Of enrolled participants, 68.6% completed the follow-up questionnaire. Most enrolled participants were non-Hispanic White, male, and aged 60 + years. Over half (52.8%, 95% CI 41.1%, 64.5%) of cases experienced PIS approximately 4 to 6 weeks after acute onset of campylobacteriosis.

Results from this pilot study indicate that a larger study is feasible. The larger study will identify the true incidence of PIS and improve the management of patient health among ethnically diverse populations.