Aurora Sabrià1, Rosa M Pintó1, Albert Bosch1, Rosa Bartolomé2, Thais Cornejo2, Núria Torner3, Ana Martínez4, Mercedes de Simón5, Angela Domínguez6, Susana Guix7. 1. Enteric Virus Group, Department of Microbiology, University of Barcelona, Avda Diagonal 643, 08028 Barcelona, Spain; Nutrition and Food Safety Research Institute (INSA-UB), University of Barcelona, Avda Prat de la Riba 171, 08921 Santa Coloma de Gramanet, Spain. 2. Laboratory of Microbiology, Hospital Universitari Vall d'Hebron, Pssg Vall d'Hebron 119-129, 08035 Barcelona, Spain. 3. Department of Health, Generalitat of Catalonia, Roc Boronat 81-95, 08005 Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Monforte de Lemos 5, 28029 Madrid, Spain; Department of Public Health, University of Barcelona, Casanova 143, 08036 Barcelona, Spain. 4. Department of Health, Generalitat of Catalonia, Roc Boronat 81-95, 08005 Barcelona, Spain. 5. Laboratory of the Public Health Agency, Pl. Lesseps 1, 08024 Barcelona, Spain. 6. CIBER Epidemiología y Salud Pública (CIBERESP), Instituto de Salud Carlos III, Monforte de Lemos 5, 28029 Madrid, Spain; Department of Public Health, University of Barcelona, Casanova 143, 08036 Barcelona, Spain. 7. Enteric Virus Group, Department of Microbiology, University of Barcelona, Avda Diagonal 643, 08028 Barcelona, Spain; Nutrition and Food Safety Research Institute (INSA-UB), University of Barcelona, Avda Prat de la Riba 171, 08921 Santa Coloma de Gramanet, Spain. Electronic address: susanaguix@ub.edu.
Abstract
BACKGROUND: Noroviruses (NoV) are highly contagious and the leading cause of nonbacterial outbreaks of gastroenteritis worldwide. Individuals who are infected asymptomatically may act as reservoirs and facilitate the transmission of NoV, but the likelihood of workers of becoming infected in outbreak settings has not been systematically studied. OBJECTIVES: We evaluated the occurrence of norovirus infections among workers exposed to the virus in different outbreak settings. STUDY DESIGN: We screened feces from food handlers and healthcare workers related with gastroenteritis outbreaks, and shedding concentrations over time were calculated from serial samples of infected individuals. Sequence analyses of the capsid P2 domain and region C were used to evaluate linkage between asymptomatic employees and outbreak cases. RESULTS: Of all employees, 59.1% were positive for NoV, and more than 70% of them were asymptomatic. Asymptomatic infections were significantly more frequent in foodborne compared to person-to-person transmitted outbreaks; and in restaurants and hotels, compared to nursing homes and healthcare institutions. Mean viral loads were similar between symptomatic and asymptomatic individuals, starting at 7.51±1.80 and 6.49±1.93 log10 genome copies/g, respectively, and decreasing to 5.28±0.76 and 4.52±1.45 log10 genome copies/g after 19days. CONCLUSIONS: The likelihood of becoming infected when a NoV outbreak occurs at the work place is high and similar between food handlers and healthcare workers, but asymptomatic infections are more frequently identified among food handlers. Since shed amounts of viruses in the absence of symptoms are also high, reinforcement of hygiene practices among workers is especially relevant to reduce the risk of virus secondary transmissions.
BACKGROUND: Noroviruses (NoV) are highly contagious and the leading cause of nonbacterial outbreaks of gastroenteritis worldwide. Individuals who are infected asymptomatically may act as reservoirs and facilitate the transmission of NoV, but the likelihood of workers of becoming infected in outbreak settings has not been systematically studied. OBJECTIVES: We evaluated the occurrence of norovirus infections among workers exposed to the virus in different outbreak settings. STUDY DESIGN: We screened feces from food handlers and healthcare workers related with gastroenteritis outbreaks, and shedding concentrations over time were calculated from serial samples of infected individuals. Sequence analyses of the capsid P2 domain and region C were used to evaluate linkage between asymptomatic employees and outbreak cases. RESULTS: Of all employees, 59.1% were positive for NoV, and more than 70% of them were asymptomatic. Asymptomatic infections were significantly more frequent in foodborne compared to person-to-person transmitted outbreaks; and in restaurants and hotels, compared to nursing homes and healthcare institutions. Mean viral loads were similar between symptomatic and asymptomatic individuals, starting at 7.51±1.80 and 6.49±1.93 log10 genome copies/g, respectively, and decreasing to 5.28±0.76 and 4.52±1.45 log10 genome copies/g after 19days. CONCLUSIONS: The likelihood of becoming infected when a NoV outbreak occurs at the work place is high and similar between food handlers and healthcare workers, but asymptomatic infections are more frequently identified among food handlers. Since shed amounts of viruses in the absence of symptoms are also high, reinforcement of hygiene practices among workers is especially relevant to reduce the risk of virus secondary transmissions.
Authors: Stephen P Rushton; Roy A Sanderson; William D K Reid; Mark D F Shirley; John P Harris; Paul R Hunter; Sarah J O'Brien Journal: Philos Trans R Soc Lond B Biol Sci Date: 2019-07-08 Impact factor: 6.237
Authors: Joanne L Hardstaff; Helen E Clough; Vittoria Lutje; K Marie McIntyre; John P Harris; Paul Garner; Sarah J O'Brien Journal: Foodborne Pathog Dis Date: 2018-08-15 Impact factor: 3.171