ABSTRACT
Following an unusually heavy rainfall in June 2009, a community-wide outbreak of Campylobacter gastroenteritis occurred in a small Danish town. The outbreak investigation consisted of (1) a cohort study using an e-questionnaire of disease determinants, (2) microbiological study of stool samples, (3) serological study of blood samples from cases and asymptomatic members of case households, and (4) environmental analyses of the water distribution system. The questionnaire study identified 163 cases (respondent attack rate 16%). Results showed a significant dose-response relationship between consumption of tap water and risk of gastroenteritis. Campylobacter jejuni belonging to two related flaA types were isolated from stool samples. Serum antibody levels against Campylobacter were significantly higher in cases than in asymptomatic persons. Water samples were positive for coliform bacteria, and the likely mode of contamination was found to be surface water leaking into the drinking-water system. This geographically constrained outbreak presented an ideal opportunity to study the serological response in persons involved in a Campylobacter outbreak. The serology indicated that asymptomatic persons from the same household may have been exposed, during the outbreak period, to Campylobacter at doses that did not elicit symptoms or alternatively had been exposed to Campylobacter at a time prior to the outbreak, resulting in residual immunity and thus absence of clinical signs.
Subject(s)
Campylobacter Infections/epidemiology , Campylobacter jejuni/isolation & purification , Disease Outbreaks , Gastroenteritis/epidemiology , Water Microbiology , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Bacterial/blood , Campylobacter jejuni/classification , Campylobacter jejuni/genetics , Child , Child, Preschool , Cohort Studies , Denmark/epidemiology , Feces/microbiology , Female , Flagellin/genetics , Genotype , Humans , Infant , Male , Middle Aged , Surveys and Questionnaires , Young AdultSubject(s)
Disease Notification/statistics & numerical data , Leptospira/classification , Leptospirosis/epidemiology , Adolescent , Adult , Age Distribution , Aged , Aged, 80 and over , Child , Child, Preschool , Denmark/epidemiology , Female , Hospitalization/statistics & numerical data , Hospitalization/trends , Humans , Incidence , Infant , Infant, Newborn , Leptospira/isolation & purification , Leptospirosis/diagnosis , Leptospirosis/transmission , Male , Mandatory Reporting , Middle Aged , Mortality/trends , Polymerase Chain Reaction , Population Surveillance , Serotyping , Sex Distribution , Socioeconomic Factors , Young AdultABSTRACT
Non-typhoid salmonellosis is one of the most common causes of foodborne illness throughout the world. Serological methods for the diagnosis of Salmonella infections vary widely and the most commonly used test is limited by high running costs as well as low sensitivity and specificity. Fast and reliable immunoassays which detect subunit antigens for Salmonella enterica subsp. enterica serovar Typhi are commercially available but at present there is no international consensus on similar tests for non-typhoid salmonellosis. In contrast to the veterinary and food sectors, most immunoassays for non-typhoid human Salmonella diagnosis are developed in-house and used in-house for research or surveillance purposes, rather than for routine diagnostics. Considering the current burden of disease, the development of a validated and standardized, commercially available antibody assay for diagnosing non-typhoid human salmonellosis could be of great benefit for diagnostic and surveillance purposes throughout the world.
