TABLE 1.
Time line of relevant events related to the waterborne outbreak of giardiasis in Bergena
| Date | Event |
|---|---|
| 20-21 August 2004 | 25-30 mm rainfall recorded each day at Florida Measuring Station in Bergen |
| 28 August 2004 | 45 mm rainfall recorded at Florida Measuring Station in Bergen |
| 30 August-5 September 2004 | Significant increase in Escherichia coli numbers in raw water (to around 65 cells/100 ml, compared to around 5 cells/100 ml at the previous measurement on 16-22 August) |
| 11 September-20 September 2004. | One case of giardiasis recorded at HUS, Bergen; case associated with travel abroad |
| 21 September-30 September 2004. | Three cases of giardiasis recorded at HUS, Bergen; two cases not associated with travel abroad |
| 30 September 2004. | Routine analysis of water from implicated water source due to detection of low concentrations of Clostridium perfringens in treated water; Giardia analysis conducted by commercial laboratory in Stavanger, Norway, and one Giardia cyst per 10 liters raw water documented; at this point no giardiasis outbreak had been recognized |
| 1 October-10 October 2004. | Four cases of giardiasis recorded at HUS, Bergen; three cases not associated with travel abroad |
| 11 October-20 October 2004. | 13 cases of giardiasis recorded at HUS, Bergen; 11 cases not associated with travel abroad |
| 21 October-30 October 2004. | 16 cases of giardiasis recorded at HUS, Bergen; 15 cases not associated with travel abroad |
| 29 October 2004 | Infectious diseases office in Bergen advised of the increase in diagnosis of giardiasis |
| 1 November 2004 | Crisis management team established in Bergen |
| 3 November 2004 | Water samples taken and sent to NVH in Oslo |
| 4 November 2004 | Water samples received at NVH in Oslo and prepared for microscopy by U.S. Environmental Protection Agency Method 1623 |
| 5 November 2004 | Microscopy of water sample concentrates performed at NVH in Oslo, and results (two Giardia cysts in raw water and five Giardia cysts in treated water from implicated water source) reported to Bergen |
| 5-6 November 2004 | Boil water notices announced for the premises served by the implicated water source |
| 24 November 2004 | By this date 900 cases of giardiasis had been registered |
| 9 December 2004 | Septic tank sewage samples collected and sent to NVH, Oslo, for analysis |
| 9 and 13 December 2004 | Soil samples associated with the septic tank collected and sent to NVH, Oslo, for analysis |
| 21 December 2004 | Boil water notice withdrawn |
a
Much of the information in this time line was obtained from reference 10.