Epidemiology and Infection



A waterborne outbreak of small round structured virus, campylobacter and shigella co-infections in La Neuveville, Switzerland, 1998


A. M. MAURER a1c1 and D. STÜRCHLER a2
a1 Health and Social Security Direction of Bern Canton, Office of the Canton Physician, CH-3011 Bern, Switzerland
a2 Swiss Federal Office of Public Health, Division of Epidemiology and Infectious Diseases, CH-3003 Bern, Switzerland

Abstract

An outbreak of gastro-enteritis occurred in La Neuveville, township with 3358 inhabitants. A retrospective cohort study of 1915 participants showed that 1607 (84%) had been ill. Campylobacter jejuni was isolated from 28 patient faecal samples, Shigella sonnei from 21 patients and small round structured viruses (SRSV) from 6 patients. More than one pathogen was identified in eight persons. The epidemic curve was characteristic of a point-source outbreak. The risk for illness was significantly higher among persons who had drank unboiled drinking water than among those who had not (1290 [80·3%] of 1607 vs. 86 [27·9%] of 308; RR = 2·87; 95% CI 2·40–3·45). Risk increased significantly with the quantity of water consumed (P < 0·00 × 10−6). An SRSV isolate from water and one human faeces had an identical DNA sequence. The outbreak was due to a pump failure producing a spill of sewage into the groundwater. We conclude that transmission was waterborne and that measures including early warning, basic hygiene and sanitation improvements controlled this epidemic.

(Accepted June 19 2000)


Correspondence:
c1 Author for correspondence: Gesundheits- und Fürsorgedirektion des Kantons Bern, Rathausgasse 1, CH-3011 Bern, Switzerland.


Metrics