An outbreak of viral gastroenteritis associated with consumption of sandwiches: implications for the control of transmission by food handlers.
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Although food handlers are often implicated as the source of infection in outbreaks of food-borne viral gastroenteritis, little is known about the timing of infectivity in relation to illness. We investigated a gastroenteritis outbreak among employees of a manufacturing company and found an association (RR = 14.1, 95% CI = 2.0-97.3) between disease and eating sandwiches prepared by 6 food handlers, 1 of whom reported gastroenteritis which had subsided 4 days earlier. Norwalk-like viruses were detected by electron microscopy or reverse transcriptase-polymerase chain reaction (RT-PCR) in stool specimens from several company employees, the sick food handler whose specimen was obtained 10 days after resolution of illness, and an asymptomatic food handler. All RT-PCR product sequences were identical, suggesting a common source of infection. These data support observations from recent volunteer studies that current recommendations to exclude food handlers from work for 48-72 h after recovery from illness may not always prevent transmission of Norwalk-like viruses because virus can be shed up to 10 days after illness or while exhibiting no symptoms. (+info)
A community outbreak of food-borne small round-structured virus gastroenteritis caused by a contaminated water supply.
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In August 1994, 30 of 135 (23%) bakery plant employees and over 100 people from South Wales and Bristol in the United Kingdom, were affected by an outbreak of gastroenteritis. Epidemiological studies of employees and three community clusters found illness in employees to be associated with drinking cold water at the bakery (relative risk 3.3, 95%, CI 1.6-7.0), and in community cases with eating custard slices (relative risk 19.8, 95%, CI 2.9-135.1) from a variety of stores supplied by one particular bakery. Small round-structured viruses (SRSV) were identified in stool specimens from 4 employees and 7 community cases. Analysis of the polymerase and capsid regions of the SRSV genome by reverse transcription-polymerase chain reaction (RT-PCR) demonstrated viruses of both genogroups (1 and 2) each with several different nucleotide sequences. The heterogeneity of the viruses identified in the outbreak suggests that dried custard mix may have been inadvertently reconstituted with contaminated water. The incident shows how secondary food contamination can cause wide-scale community gastroenteritis outbreaks, and demonstrates the ability of molecular techniques to support classical epidemiological methods in outbreak investigations. (+info)
Immunization with potato plants expressing VP60 protein protects against rabbit hemorrhagic disease virus.
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The major structural protein VP60 of rabbit hemorrhagic disease virus (RHDV) has been produced in transgenic potato plants under the control of a cauliflower mosaic virus 35S promoter or a modified 35S promoter that included two copies of a strong transcriptional enhancer. Both types of promoters allowed the production of specific mRNAs and detectable levels of recombinant VP60, which were higher for the constructs carrying the modified 35S promoter. Rabbits immunized with leaf extracts from plants carrying this modified 35S promoter showed high anti-VP60 antibody titers and were fully protected against the hemorrhagic disease. (+info)
Norwalk-like viral gastroenteritis in U.S. Army trainees--Texas, 1998.
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During August 27-September 1, 1998, 99 (12%) of 835 soldiers in one unit at a U.S. Army training center in El Paso, Texas, were hospitalized for acute gastroenteritis (AGE). Their symptoms included acute onset of vomiting, abdominal pain, diarrhea, and fever. Review of medical center admission records for AGE during the previous year indicated that fewer than five cases occurred each month. This report describes the outbreak investigation initiated on August 30 by a U.S. Army Epidemiologic Consultation Service (EPICON) team; the findings indicated the outbreak was caused by a Norwalk-like virus (NLV). (+info)
Identification of a distinct common strain of "Norwalk-like viruses" having a global distribution.
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"Norwalk-like viruses" (NLVs) are the most common cause of outbreaks of nonbacterial gastroenteritis. During molecular surveillance of NLV strains from 152 outbreaks of gastroenteritis that occurred in the US between August 1993 and July 1997, we identified an NLV strain that predominated during the 1995-1996 season. The "95/96-US" strain caused 60 outbreaks in geographically distant locations within the US and was identified, by sequence comparisons, in an additional 7 countries on 5 continents during the same period. This is the first demonstration linking a single NLV strain globally and suggests that the circulation of these strains might involve patterns of transmission not previously considered. The diagnostic techniques are now available to establish a global network for surveillance of NLV strains that would highlight the importance of NLVs worldwide and allow molecular identification of common strains having a global distribution so as to consider interventions for their control. (+info)
Neutralizing feature of commercially available feline calicivirus (FCV) vaccine immune sera against FCV field isolates.
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Four types of commercially available feline calicivirus (FCV) vaccine were compared in terms of their efficacy on the basis of the ability of the sera of specific-pathogen-free cats immunized by two injections of each type of vaccine to neutralize FCV field isolates. Each vaccine immune serum neutralized relatively well strains F4, F9, and 255, which were FCV laboratory strains. As to 36 strains of field isolates, however, vaccines A, B, C, and D immune sera did not neutralize 18-20 of the strains (50.0%-55.6%), 19-22 of the strains (52.8%-61.1%), 22-25 of the strains (61.1%-69.4%), and 8-16 of the strains (22.2%-44.4%), respectively. These results indicate that there is much difference in neutralizing antigenicity between the existing vaccine strains and the FCV strains that are prevalent in Japan, suggesting the need for improvement of FCV vaccines. (+info)
Immunoglobulin M antibody test to detect genogroup II Norwalk-like virus infection.
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Sera obtained from adult volunteers inoculated with genogroup II Norwalk-like viruses (NLVs), Hawaii virus, and Snow Mountain virus and from patients involved in outbreaks of gastroenteritis were tested for genogroup II NLV Mexico virus-specific immunoglobulin M (IgM) by use of a monoclonal antibody, recombinant Mexico virus antigen (rMXV)-based IgM capture enzyme-linked immunosorbent assay (ELISA). Sera from genogroup I Norwalk virus (NV)-inoculated volunteers and from patients involved in a genogroup I NLV outbreak were also tested. In sera from those infected with genogroup I NV or NLVs in volunteer and outbreak studies, only 3 of 25 were rMXV IgM positive; in contrast, 24 of 25 were IgM positive for recombinant NV (rNV). In sera from those infected with genogroup II NLVs in volunteer and outbreak studies, 28 of 47 were rMXV IgM positive and none were IgM positive for rNV, showing the specificity of each IgM test for its respective genogroup. In an outbreak of gastroenteritis not characterized as being of viral etiology but suspected to be due to NV, 7 of 13 persons had IgM responses to rMXV, whereas none had IgM responses to rNV, thus establishing the diagnosis as genogroup II NLV infection. The rMXV-based IgM capture ELISA developed is specific for the diagnosis of genogroup II NLV infections. (+info)
Prevalence of group A rotavirus, human calicivirus, astrovirus, and adenovirus type 40 and 41 infections among children with acute gastroenteritis in Dijon, France.
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Group A rotaviruses, human caliciviruses, astroviruses, and adenovirus types 40 and 41 were detected by enzyme immunoassay or reverse transcription-PCR in 61, 14, 6, and 3% of stool specimens from 414 children consulting for gastroenteritis between 1995 and 1998. These data highlight the importance of caliciviruses in infantile gastroenteritis. Among these, Norwalk-like viruses belonging to genogroup II were predominant. (+info)