A prolonged outbreak of Norwalk-like calicivirus (NLV) gastroenteritis in a rehabilitation centre due to environmental contamination

Abstract

An outbreak of Norwalk-like calicivirus (NLV) gastroenteritis occurred in a rehabilitation centre in southern Finland between December 1999 and February 2000. An epidemiological investigation was conducted to determine the source and extent of the outbreak. More than 300 guests and staff members became ill during the outbreak. No food or activity in the centre could be linked epidemiologically to illness. NLV genogroup II was detected by RT-PCR in stool samples of symptomatic guests and employees. All strains reacted similarly with the microplate hybridization probe panel and showed the same nucleotide sequence, indicating that they represented the same NLV strain. Food and water samples were negative for NLV, whereas NLV was detected in three environmental specimens. The strains from patients and environment were identical based on microplate hybridization probes, suggesting that environmental contamination may have been important for the spread of calicivirus and the protracted course of the outbreak.

Inactivation and UV Disinfection of Murine Norovirus with TiO 2 under Various Environmental Conditions

“…Overall, our results are consistent with those of these studies. The results demonstrate that NoVs can survive for a long time, particularly at lower temperatures, and can be transmitted to susceptible populations through environmental media (16,25). Our data indicate that MNVs can survive better in a stool suspension than on the surface of gauze or a diaper.…”

“…These viruses, released from symptomatic or asymptomatic infected people, can be transmitted through contaminated water, food, fomites, or direct contact. NoVs are highly infectious because of their low infectious dose (ϳ10 viral particles), the lack of long-term immunity in humans, and their high levels of resistance to various environmental stresses (6,11,17,19,25,27,29,37). Outbreaks caused by NoVs have been reported in a variety of settings, including cruise ships, hotels, hospitals, restaurants, and schools (2,28,35).…”

Inactivation of Caliciviruses

“…Even though notable differences in time to 1 D inactivation at room temperature have been reported, overall, both viruses showed long-term survival in suspension at environmental temperatures, indicating that transmission by a route involving, for example, drinking or surface water, moisture fomites, or workplace surfaces is possible. Indeed, norovirus-related outbreaks have been shown to be caused by contaminated drinking water in countries such as Finland, Sweden, and the United States (5,24,35) and environmental contamination in settings such as hotels (4, 7), a rehabilitation center (25), and a concert hall (15). Heat inactivation was highly comparable for both viruses at temperatures ranging from 37 to 100°C.…”

Mutation in a Lordsdale Norovirus Epidemic Strain as a Potential Indicator of Transmission Routes

“…For comparison, strains from outbreaks during the same season at six additional hospitals were included (Table 1). These were from two outbreaks in the nearby hospital B and one each in hospitals C, D, E, F, and G, located 12,14,14,20, and 28 miles from hospital A. The stool samples were stored at 4°C.…”

“…Transmission occurs fecal-orally via aerosols, fomites, food, or water, and the attack rate is high, with the virus affecting all age groups (5). Outbreak control is hampered by the low infectious dose and environmental persistence of the virus (14). It is estimated that in the United States 23,000,000 infections, 50,000 hospitalizations, and 300 deaths are caused by noroviruses each year (23).…”